Sync with 2.17.3

* maint-2.17: (32 commits)
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  is_ntfs_dotgit(): speed it up
  mingw: disallow backslash characters in tree objects' file names
  ...
diff --git a/.gitattributes b/.gitattributes
index 8ce9c6b..1bdc91e 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,8 +1,10 @@
 * whitespace=!indent,trail,space
 *.[ch] whitespace=indent,trail,space diff=cpp
 *.sh whitespace=indent,trail,space eol=lf
-*.perl eol=lf
-*.pm eol=lf
+*.perl eol=lf diff=perl
+*.pl eof=lf diff=perl
+*.pm eol=lf diff=perl
+*.py eol=lf diff=python
 /Documentation/git-*.txt eol=lf
 /command-list.txt eol=lf
 /GIT-VERSION-GEN eol=lf
diff --git a/.gitignore b/.gitignore
index 833ef3b..388cc4b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 /GIT-LDFLAGS
 /GIT-PREFIX
 /GIT-PERL-DEFINES
+/GIT-PERL-HEADER
 /GIT-PYTHON-VARS
 /GIT-SCRIPT-DEFINES
 /GIT-USER-AGENT
@@ -34,6 +35,7 @@
 /git-clone
 /git-column
 /git-commit
+/git-commit-graph
 /git-commit-tree
 /git-config
 /git-count-objects
@@ -140,6 +142,7 @@
 /git-rm
 /git-send-email
 /git-send-pack
+/git-serve
 /git-sh-i18n
 /git-sh-i18n--envsubst
 /git-sh-setup
@@ -179,7 +182,7 @@
 /gitweb/gitweb.cgi
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
-/common-cmds.h
+/command-list.h
 *.tar.gz
 *.dsc
 *.deb
diff --git a/.mailmap b/.mailmap
index 7c71e88..df7cf63 100644
--- a/.mailmap
+++ b/.mailmap
@@ -25,8 +25,8 @@
 Benoit Sigoure <tsunanet@gmail.com> <tsuna@lrde.epita.fr>
 Bernt Hansen <bernt@norang.ca> <bernt@alumni.uwaterloo.ca>
 Brandon Casey <drafnel@gmail.com> <casey@nrlssc.navy.mil>
-brian m. carlson <sandals@crustytoothpaste.ath.cx> Brian M. Carlson <sandals@crustytoothpaste.ath.cx>
-brian m. carlson <sandals@crustytoothpaste.ath.cx> <sandals@crustytoothpaste.net>
+brian m. carlson <sandals@crustytoothpaste.net> Brian M. Carlson <sandals@crustytoothpaste.ath.cx>
+brian m. carlson <sandals@crustytoothpaste.net> <sandals@crustytoothpaste.ath.cx>
 Bryan Larsen <bryan@larsen.st> <bryan.larsen@gmail.com>
 Bryan Larsen <bryan@larsen.st> <bryanlarsen@yahoo.com>
 Cheng Renquan <crquan@gmail.com>
diff --git a/.travis.yml b/.travis.yml
index 5f5ee4f..4d4e26c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,10 +16,13 @@
 
 addons:
   apt:
+    sources:
+    - ubuntu-toolchain-r-test
     packages:
     - language-pack-is
     - git-svn
     - apache2
+    - gcc-8
 
 matrix:
   include:
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 6232143..d079d7c 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -78,6 +78,7 @@
 TECH_DOCS += technical/pack-protocol
 TECH_DOCS += technical/protocol-capabilities
 TECH_DOCS += technical/protocol-common
+TECH_DOCS += technical/protocol-v2
 TECH_DOCS += technical/racy-git
 TECH_DOCS += technical/send-pack-pipeline
 TECH_DOCS += technical/shallow
@@ -184,7 +185,7 @@
 ASCIIDOC_CONF =
 ASCIIDOC_HTML = xhtml5
 ASCIIDOC_DOCBOOK = docbook45
-ASCIIDOC_EXTRA += -acompat-mode
+ASCIIDOC_EXTRA += -acompat-mode -atabsize=8
 ASCIIDOC_EXTRA += -I. -rasciidoctor-extensions
 ASCIIDOC_EXTRA += -alitdd='&\#x2d;&\#x2d;'
 DBLATEX_COMMON =
diff --git a/Documentation/RelNotes/1.7.11.7.txt b/Documentation/RelNotes/1.7.11.7.txt
index e7e79d9..e743a2a 100644
--- a/Documentation/RelNotes/1.7.11.7.txt
+++ b/Documentation/RelNotes/1.7.11.7.txt
@@ -25,7 +25,7 @@
    references" nor "Reload" did not update what is shown as the
    contents of it, when the user overwrote the tag with "git tag -f".
 
- * "git for-each-ref" did not currectly support more than one --sort
+ * "git for-each-ref" did not correctly support more than one --sort
    option.
 
  * "git log .." errored out saying it is both rev range and a path
diff --git a/Documentation/RelNotes/2.17.0.txt b/Documentation/RelNotes/2.17.0.txt
index d6db0e1..c2cf891 100644
--- a/Documentation/RelNotes/2.17.0.txt
+++ b/Documentation/RelNotes/2.17.0.txt
@@ -342,7 +342,7 @@
    validate the data and connected-ness of objects in the received
    pack; the code to perform this check has been taught about the
    narrow clone's convention that missing objects that are reachable
-   from objects in a pack that came from a promissor remote is OK.
+   from objects in a pack that came from a promisor remote is OK.
 
  * There was an unused file-scope static variable left in http.c when
    building for versions of libCURL that is older than 7.19.4, which
diff --git a/Documentation/RelNotes/2.18.0.txt b/Documentation/RelNotes/2.18.0.txt
new file mode 100644
index 0000000..3ea280c
--- /dev/null
+++ b/Documentation/RelNotes/2.18.0.txt
@@ -0,0 +1,583 @@
+Git 2.18 Release Notes
+======================
+
+Updates since v2.17
+-------------------
+
+UI, Workflows & Features
+
+ * Rename detection logic that is used in "merge" and "cherry-pick" has
+   learned to guess when all of x/a, x/b and x/c have moved to z/a,
+   z/b and z/c, it is likely that x/d added in the meantime would also
+   want to move to z/d by taking the hint that the entire directory
+   'x' moved to 'z'.  A bug causing dirty files involved in a rename
+   to be overwritten during merge has also been fixed as part of this
+   work.  Incidentally, this also avoids updating a file in the
+   working tree after a (non-trivial) merge whose result matches what
+   our side originally had.
+
+ * "git filter-branch" learned to use a different exit code to allow
+   the callers to tell the case where there was no new commits to
+   rewrite from other error cases.
+
+ * When built with more recent cURL, GIT_SSL_VERSION can now specify
+   "tlsv1.3" as its value.
+
+ * "git gui" learned that "~/.ssh/id_ecdsa.pub" and
+   "~/.ssh/id_ed25519.pub" are also possible SSH key files.
+   (merge 2e2f0288ef bb/git-gui-ssh-key-files later to maint).
+
+ * "git gui" performs commit upon CTRL/CMD+ENTER but the
+   CTRL/CMD+KP_ENTER (i.e. enter key on the numpad) did not have the
+   same key binding.  It now does.
+   (merge 28a1d94a06 bp/git-gui-bind-kp-enter later to maint).
+
+ * "git gui" has been taught to work with old versions of tk (like
+   8.5.7) that do not support "ttk::style theme use" as a way to query
+   the current theme.
+   (merge 4891961105 cb/git-gui-ttk-style later to maint).
+
+ * "git rebase" has learned to honor "--signoff" option when using
+   backends other than "am" (but not "--preserve-merges").
+
+ * "git branch --list" during an interrupted "rebase -i" now lets
+   users distinguish the case where a detached HEAD is being rebased
+   and a normal branch is being rebased.
+
+ * "git mergetools" learned talking to guiffy.
+
+ * The scripts in contrib/emacs/ have outlived their usefulness and
+   have been replaced with a stub that errors out and tells the user
+   there are replacements.
+
+ * The new "working-tree-encoding" attribute can ask Git to convert the
+   contents to the specified encoding when checking out to the working
+   tree (and the other way around when checking in).
+
+ * The "git config" command uses separate options e.g. "--int",
+   "--bool", etc. to specify what type the caller wants the value to
+   be interpreted as.  A new "--type=<typename>" option has been
+   introduced, which would make it cleaner to define new types.
+
+ * "git config --get" learned the "--default" option, to help the
+   calling script.  Building on top of the above changes, the
+   "git config" learns "--type=color" type.  Taken together, you can
+   do things like "git config --get foo.color --default blue" and get
+   the ANSI color sequence for the color given to foo.color variable,
+   or "blue" if the variable does not exist.
+
+ * "git ls-remote" learned an option to allow sorting its output based
+   on the refnames being shown.
+
+ * The command line completion (in contrib/) has been taught that "git
+   stash save" has been deprecated ("git stash push" is the preferred
+   spelling in the new world) and does not offer it as a possible
+   completion candidate when "git stash push" can be.
+
+ * "git gc --prune=nonsense" spent long time repacking and then
+   silently failed when underlying "git prune --expire=nonsense"
+   failed to parse its command line.  This has been corrected.
+
+ * Error messages from "git push" can be painted for more visibility.
+
+ * "git http-fetch" (deprecated) had an optional and experimental
+   "feature" to fetch only commits and/or trees, which nobody used.
+   This has been removed.
+
+ * The functionality of "$GIT_DIR/info/grafts" has been superseded by
+   the "refs/replace/" mechanism for some time now, but the internal
+   code had support for it in many places, which has been cleaned up
+   in order to drop support of the "grafts" mechanism.
+
+ * "git worktree add" learned to check out an existing branch.
+
+ * "git --no-pager cmd" did not have short-and-sweet single letter
+   option. Now it does as "-P".
+   (merge 7213c28818 js/no-pager-shorthand later to maint).
+
+ * "git rebase" learned "--rebase-merges" to transplant the whole
+   topology of commit graph elsewhere.
+
+ * "git status" learned to pay attention to UI related diff
+   configuration variables such as diff.renames.
+
+ * The command line completion mechanism (in contrib/) learned to load
+   custom completion file for "git $command" where $command is a
+   custom "git-$command" that the end user has on the $PATH when using
+   newer version of bash-completion.
+
+ * "git send-email" can sometimes offer confirmation dialog "Send this
+   email?" with choices 'Yes', 'No', 'Quit', and 'All'.  A new action
+   'Edit' has been added to this dialog's choice.
+
+ * With merge.renames configuration set to false, the recursive merge
+   strategy can be told not to spend cycles trying to find renamed
+   paths and merge them accordingly.
+
+ * "git status" learned to honor a new status.renames configuration to
+   skip rename detection, which could be useful for those who want to
+   do so without disabling the default rename detection done by the
+   "git diff" command.
+
+ * Command line completion (in contrib/) learned to complete pathnames
+   for various commands better.
+
+ * "git blame" learns to unhighlight uninteresting metadata from the
+   originating commit on lines that are the same as the previous one,
+   and also paint lines in different colors depending on the age of
+   the commit.
+
+ * Transfer protocol v2 learned to support the partial clone.
+
+ * When a short hexadecimal string is used to name an object but there
+   are multiple objects that share the string as the prefix of their
+   names, the code lists these ambiguous candidates in a help message.
+   These object names are now sorted according to their types for
+   easier eyeballing.
+
+ * "git fetch $there $refspec" that talks over protocol v2 can take
+   advantage of server-side ref filtering; the code has been extended
+   so that this mechanism triggers also when fetching with configured
+   refspec.
+
+ * Our HTTP client code used to advertise that we accept gzip encoding
+   from the other side; instead, just let cURL library to advertise
+   and negotiate the best one.
+
+ * "git p4" learned to "unshelve" shelved commit from P4.
+   (merge 123f631761 ld/p4-unshelve later to maint).
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * A "git fetch" from a repository with insane number of refs into a
+   repository that is already up-to-date still wasted too many cycles
+   making many lstat(2) calls to see if these objects at the tips
+   exist as loose objects locally.  These lstat(2) calls are optimized
+   away by enumerating all loose objects beforehand.
+   It is unknown if the new strategy negatively affects existing use
+   cases, fetching into a repository with many loose objects from a
+   repository with small number of refs.
+
+ * Git can be built to use either v1 or v2 of the PCRE library, and so
+   far, the build-time configuration USE_LIBPCRE=YesPlease instructed
+   the build procedure to use v1, but now it means v2.  USE_LIBPCRE1
+   and USE_LIBPCRE2 can be used to explicitly choose which version to
+   use, as before.
+
+ * The build procedure learned to optionally use symbolic links
+   (instead of hardlinks and copies) to install "git-foo" for built-in
+   commands, whose binaries are all identical.
+
+ * Conversion from uchar[20] to struct object_id continues.
+
+ * The way "git worktree prune" worked internally has been simplified,
+   by assuming how "git worktree move" moves an existing worktree to a
+   different place.
+
+ * Code clean-up for the "repository" abstraction.
+   (merge 00a3da2a13 nd/remove-ignore-env-field later to maint).
+
+ * Code to find the length to uniquely abbreviate object names based
+   on packfile content, which is a relatively recent addtion, has been
+   optimized to use the same fan-out table.
+
+ * The mechanism to use parse-options API to automate the command line
+   completion continues to get extended and polished.
+
+ * Copies of old scripted Porcelain commands in contrib/examples/ have
+   been removed.
+
+ * Some tests that rely on the exact hardcoded values of object names
+   have been updated in preparation for hash function migration.
+
+ * Perf-test update.
+
+ * Test helper update.
+
+ * The effort continues to refactor the internal global data structure
+   to make it possible to open multiple repositories, work with and
+   then close them,
+
+ * Small test-helper programs have been consolidated into a single
+   binary.
+
+ * API clean-up around ref-filter code.
+
+ * Shell completion (in contrib) that gives list of paths have been
+   optimized somewhat.
+
+ * The index file is updated to record the fsmonitor section after a
+   full scan was made, to avoid wasting the effort that has already
+   spent.
+
+ * Performance measuring framework in t/perf learned to help bisecting
+   performance regressions.
+
+ * Some multi-word source filenames are being renamed to separate
+   words with dashes instead of underscores.
+
+ * An reusable "memory pool" implementation has been extracted from
+   fast-import.c, which in turn has become the first user of the
+   mem-pool API.
+
+ * A build-time option has been added to allow Git to be told to refer
+   to its associated files relative to the main binary, in the same
+   way that has been possible on Windows for quite some time, for
+   Linux, BSDs and Darwin.
+
+ * Precompute and store information necessary for ancestry traversal
+   in a separate file to optimize graph walking.
+
+ * The effort to pass the repository in-core structure throughout the
+   API continues.  This round deals with the code that implements the
+   refs/replace/ mechanism.
+
+ * The build procedure "make DEVELOPER=YesPlease" learned to enable a
+   bit more warning options depending on the compiler used to help
+   developers more.  There also is "make DEVOPTS=tokens" knob
+   available now, for those who want to help fixing warnings we
+   usually ignore, for example.
+
+ * A new version of the transport protocol is being worked on.
+
+ * The code to interface to GPG has been restructured somewhat to make
+   it cleaner to integrate with other types of signature systems later.
+
+ * The code has been taught to use the duplicated information stored
+   in the commit-graph file to learn the tree object name for a commit
+   to avoid opening and parsing the commit object when it makes sense
+   to do so.
+
+ * "git gc" in a large repository takes a lot of time as it considers
+   to repack all objects into one pack by default.  The command has
+   been taught to pretend as if the largest existing packfile is
+   marked with ".keep" so that it is left untouched while objects in
+   other packs and loose ones are repacked.
+
+ * The transport protocol v2 is getting updated further.
+
+ * The codepath around object-info API has been taught to take the
+   repository object (which in turn tells the API which object store
+   the objects are to be located).
+
+ * "git pack-objects" needs to allocate tons of "struct object_entry"
+   while doing its work, and shrinking its size helps the performance
+   quite a bit.
+
+ * The implementation of "git rebase -i --root" has been updated to use
+   the sequencer machinery more.
+
+ * Developer support update, by using BUG() macro instead of die() to
+   mark codepaths that should not happen more clearly.
+
+ * Developer support.  Use newer GCC on one of the builds done at
+   TravisCI.org to get more warnings and errors diagnosed.
+
+ * Conversion from uchar[20] to struct object_id continues.
+
+ * By code restructuring of submodule merge in merge-recursive,
+   informational messages from the codepath are now given using the
+   same mechanism as other output, and honor the merge.verbosity
+   configuration.  The code also learned to give a few new messages
+   when a submodule three-way merge resolves cleanly when one side
+   records a descendant of the commit chosen by the other side.
+
+ * Avoid unchecked snprintf() to make future code auditing easier.
+   (merge ac4896f007 jk/snprintf-truncation later to maint).
+
+ * Many tests hardcode the raw object names, which would change once
+   we migrate away from SHA-1.  While some of them must test against
+   exact object names, most of them do not have to use hardcoded
+   constants in the test.  The latter kind of tests have been updated
+   to test the moral equivalent of the original without hardcoding the
+   actual object names.
+
+ * The list of commands with their various attributes were spread
+   across a few places in the build procedure, but it now is getting a
+   bit more consolidated to allow more automation.
+
+ * Quite a many tests assumed that newly created refs are made as
+   loose refs using the files backend, which have been updated to use
+   proper plumbing like rev-parse and update-ref, to avoid breakage
+   once we start using different ref backends.
+
+
+Also contains various documentation updates and code clean-ups.
+
+
+Fixes since v2.17
+-----------------
+
+ * "git shortlog cruft" aborted with a BUG message when run outside a
+   Git repository.  The command has been taught to complain about
+   extra and unwanted arguments on its command line instead in such a
+   case.
+   (merge 4aa0161e83 ma/shortlog-revparse later to maint).
+
+ * "git stash push -u -- <pathspec>" gave an unnecessary and confusing
+   error message when there was no tracked files that match the
+   <pathspec>, which has been fixed.
+   (merge 353278687e tg/stash-untracked-with-pathspec-fix later to maint).
+
+ * "git tag --contains no-such-commit" gave a full list of options
+   after giving an error message.
+   (merge 3bb0923f06 ps/contains-id-error-message later to maint).
+
+ * "diff-highlight" filter (in contrib/) learned to understand "git log
+   --graph" output better.
+   (merge 4551fbba14 jk/diff-highlight-graph-fix later to maint).
+
+ * when refs that do not point at committish are given, "git
+   filter-branch" gave a misleading error messages.  This has been
+   corrected.
+   (merge f78ab355e7 yk/filter-branch-non-committish-refs later to maint).
+
+ * "git submodule status" misbehaved on a submodule that has been
+   removed from the working tree.
+   (merge 74b6bda32f rs/status-with-removed-submodule later to maint).
+
+ * When credential helper exits very quickly without reading its
+   input, it used to cause Git to die with SIGPIPE, which has been
+   fixed.
+   (merge a0d51e8d0e eb/cred-helper-ignore-sigpipe later to maint).
+
+ * "git rebase --keep-empty" still removed an empty commit if the
+   other side contained an empty commit (due to the "does an
+   equivalent patch exist already?" check), which has been corrected.
+   (merge 3d946165e1 pw/rebase-keep-empty-fixes later to maint).
+
+ * Some codepaths, including the refs API, get and keep relative
+   paths, that go out of sync when the process does chdir(2).  The
+   chdir-notify API is introduced to let these codepaths adjust these
+   cached paths to the new current directory.
+   (merge fb9c2d2703 jk/relative-directory-fix later to maint).
+
+ * "cd sub/dir && git commit ../path" ought to record the changes to
+   the file "sub/path", but this regressed long time ago.
+   (merge 86238e07ef bw/commit-partial-from-subdirectory-fix later to maint).
+
+ * Recent introduction of "--log-destination" option to "git daemon"
+   did not work well when the daemon was run under "--inetd" mode.
+   (merge e67d906d73 lw/daemon-log-destination later to maint).
+
+ * Small fix to the autoconf build procedure.
+   (merge 249482daf0 es/fread-reads-dir-autoconf-fix later to maint).
+
+ * Fix an unexploitable (because the oversized contents are not under
+   attacker's control) buffer overflow.
+   (merge d8579accfa bp/fsmonitor-bufsize-fix later to maint).
+
+ * Recent simplification of build procedure forgot a bit of tweak to
+   the build procedure of contrib/mw-to-git/
+   (merge d8698987f3 ab/simplify-perl-makefile later to maint).
+
+ * Moving a submodule that itself has submodule in it with "git mv"
+   forgot to make necessary adjustment to the nested sub-submodules;
+   now the codepath learned to recurse into the submodules.
+
+ * "git config --unset a.b", when "a.b" is the last variable in an
+   otherwise empty section "a", left an empty section "a" behind, and
+   worse yet, a subsequent "git config a.c value" did not reuse that
+   empty shell and instead created a new one.  These have been
+   (partially) corrected.
+   (merge c71d8bb38a js/empty-config-section-fix later to maint).
+
+ * "git worktree remove" learned that "-f" is a shorthand for
+   "--force" option, just like for "git worktree add".
+   (merge d228eea514 sb/worktree-remove-opt-force later to maint).
+
+ * The completion script (in contrib/) learned to clear cached list of
+   command line options upon dot-sourcing it again in a more efficient
+   way.
+   (merge 94408dc71c sg/completion-clear-cached later to maint).
+
+ * "git svn" had a minor thinko/typo which has been fixed.
+   (merge 51db271587 ab/git-svn-get-record-typofix later to maint).
+
+ * During a "rebase -i" session, the code could give older timestamp
+   to commits created by later "pick" than an earlier "reword", which
+   has been corrected.
+   (merge 12f7babd6b js/ident-date-fix later to maint).
+
+ * "git submodule status" did not check the symbolic revision name it
+   computed for the submodule HEAD is not the NULL, and threw it at
+   printf routines, which has been corrected.
+   (merge 0b5e2ea7cf nd/submodule-status-fix later to maint).
+
+ * When fed input that already has In-Reply-To: and/or References:
+   headers and told to add the same information, "git send-email"
+   added these headers separately, instead of appending to an existing
+   one, which is a violation of the RFC.  This has been corrected.
+   (merge 256be1d3f0 sa/send-email-dedup-some-headers later to maint).
+
+ * "git fast-export" had a regression in v2.15.0 era where it skipped
+   some merge commits in certain cases, which has been corrected.
+   (merge be011bbe00 ma/fast-export-skip-merge-fix later to maint).
+
+ * The code did not propagate the terminal width to subprocesses via
+   COLUMNS environment variable, which it now does.  This caused
+   trouble to "git column" helper subprocess when "git tag --column=row"
+   tried to list the existing tags on a display with non-default width.
+   (merge b5d5a567fb nd/term-columns later to maint).
+
+ * We learned that our source files with ".pl" and ".py" extensions
+   are Perl and Python files respectively and changes to them are
+   better viewed as such with appropriate diff drivers.
+   (merge 7818b619e2 ab/perl-python-attrs later to maint).
+
+ * "git rebase -i" sometimes left intermediate "# This is a
+   combination of N commits" message meant for the human consumption
+   inside an editor in the final result in certain corner cases, which
+   has been fixed.
+   (merge 15ef69314d js/rebase-i-clean-msg-after-fixup-continue later to maint).
+
+ * A test to see if the filesystem normalizes UTF-8 filename has been
+   updated to check what we need to know in a more direct way, i.e. a
+   path created in NFC form can be accessed with NFD form (or vice
+   versa) to cope with APFS as well as HFS.
+   (merge 742ae10e35 tb/test-apfs-utf8-normalization later to maint).
+
+ * "git format-patch --cover --attach" created a broken MIME multipart
+   message for the cover letter, which has been fixed by keeping the
+   cover letter as plain text file.
+   (merge 50cd54ef4e bc/format-patch-cover-no-attach later to maint).
+
+ * The split-index feature had a long-standing and dormant bug in
+   certain use of the in-core merge machinery, which has been fixed.
+   (merge 7db118303a en/unpack-trees-split-index-fix later to maint).
+
+ * Asciidoctor gives a reasonable imitation for AsciiDoc, but does not
+   render illustration in a literal block correctly when indented with
+   HT by default. The problem is fixed by forcing 8-space tabs.
+   (merge 379805051d bc/asciidoctor-tab-width later to maint).
+
+ * Code clean-up to adjust to a more recent lockfile API convention that
+   allows lockfile instances kept on the stack.
+   (merge 0fa5a2ed8d ma/lockfile-cleanup later to maint).
+
+ * the_repository->index is not a allocated piece of memory but
+   repo_clear() indiscriminately attempted to free(3) it, which has
+   been corrected.
+   (merge 74373b5f10 nd/repo-clear-keep-the-index later to maint).
+
+ * Code clean-up to avoid non-standard-conformant pointer arithmetic.
+   (merge c112084af9 rs/no-null-ptr-arith-in-fast-export later to maint).
+
+ * Code clean-up to turn history traversal more robust in a
+   semi-corrupt repository.
+   (merge 8702b30fd7 jk/unavailable-can-be-missing later to maint).
+
+ * "git update-ref A B" is supposed to ensure that ref A does not yet
+   exist when B is a NULL OID, but this check was not done correctly
+   for pseudo-refs outside refs/ hierarchy, e.g. MERGE_HEAD.
+
+ * "git submodule update" and "git submodule add" supported the
+   "--reference" option to borrow objects from a neighbouring local
+   repository like "git clone" does, but lacked the more recent
+   invention "--dissociate".  Also "git submodule add" has been taught
+   to take the "--progress" option.
+   (merge a0ef29341a cf/submodule-progress-dissociate later to maint).
+
+ * Update credential-netrc helper (in contrib/) to allow customizing
+   the GPG used to decrypt the encrypted .netrc file.
+   (merge 786ef50a23 lm/credential-netrc later to maint).
+
+ * "git submodule update" attempts two different kinds of "git fetch"
+   against the upstream repository to grab a commit bound at the
+   submodule's path, but it incorrectly gave up if the first kind
+   (i.e. a normal fetch) failed, making the second "last resort" one
+   (i.e. fetching an exact commit object by object name) ineffective.
+   This has been corrected.
+   (merge e30d833671 sb/submodule-update-try-harder later to maint).
+
+ * Error behaviour of "git grep" when it cannot read the index was
+   inconsistent with other commands that uses the index, which has
+   been corrected to error out early.
+   (merge b2aa84c789 sb/grep-die-on-unreadable-index later to maint).
+
+ * We used to call regfree() after regcomp() failed in some codepaths,
+   which have been corrected.
+   (merge 17154b1576 ma/regex-no-regfree-after-comp-fail later to maint).
+
+ * The import-tars script (in contrib/) has been taught to handle
+   tarballs with overly long paths that use PAX extended headers.
+   (merge 12ecea46e3 pa/import-tars-long-names later to maint).
+
+ * "git rev-parse Y..." etc. misbehaved when given endpoints were
+   not committishes.
+   (merge 0ed556d38f en/rev-parse-invalid-range later to maint).
+
+ * "git pull --recurse-submodules --rebase", when the submodule
+   repository's history did not have anything common between ours and
+   the upstream's, failed to execute.  We need to fetch from them to
+   continue even in such a case.
+   (merge 4d36f88be7 jt/submodule-pull-recurse-rebase later to maint).
+
+ * "git remote update" can take both a single remote nickname and a
+   nickname for remote groups, but only one of them was documented.
+   (merge a97447a42a nd/remote-update-doc later to maint).
+
+ * "index-pack --strict" has been taught to make sure that it runs the
+   final object integrity checks after making the freshly indexed
+   packfile available to itself.
+   (merge 3737746120 jk/index-pack-maint later to maint).
+
+ * Make zlib inflate codepath more robust against versions of zlib
+   that clobber unused portion of outbuf.
+   (merge b611396e97 jl/zlib-restore-nul-termination later to maint).
+
+ * Fix old merge glitch in Documentation during v2.13-rc0 era.
+   (merge 28cb06020b mw/doc-merge-enumfix later to maint).
+
+ * The code to read compressed bitmap was not careful to avoid reading
+   past the end of the file, which has been corrected.
+   (merge 1140bf01ec jk/ewah-bounds-check later to maint).
+
+ * "make NO_ICONV=NoThanks" did not override NEEDS_LIBICONV
+   (i.e. linkage of -lintl, -liconv, etc. that are platform-specific
+   tweaks), which has been corrected.
+   (merge fdb1fbbc7d es/make-no-iconv later to maint).
+
+ * Other minor doc, test and build updates and code cleanups.
+   (merge 248f66ed8e nd/trace-with-env later to maint).
+   (merge 14ced5562c ys/bisect-object-id-missing-conversion-fix later to maint).
+   (merge 5988eb631a ab/doc-hash-brokenness later to maint).
+   (merge a4d4e32a70 pk/test-avoid-pipe-hiding-exit-status later to maint).
+   (merge 05e293c1ac jk/flockfile-stdio later to maint).
+   (merge e9184b0789 jk/t5561-missing-curl later to maint).
+   (merge b1801b85a3 nd/worktree-move later to maint).
+   (merge bbd374dd20 ak/bisect-doc-typofix later to maint).
+   (merge 4855f06fb3 mn/send-email-credential-doc later to maint).
+   (merge 8523b1e355 en/doc-typoes later to maint).
+   (merge 43b44ccfe7 js/t5404-path-fix later to maint).
+   (merge decf711fc1 ps/test-chmtime-get later to maint).
+   (merge 22d11a6e8e es/worktree-docs later to maint).
+   (merge 92a5dbbc22 tg/use-git-contacts later to maint).
+   (merge adc887221f tq/t1510 later to maint).
+   (merge bed21a8ad6 sg/doc-gc-quote-mismatch-fix later to maint).
+   (merge 73364e4f10 tz/doc-git-urls-reference later to maint).
+   (merge cd1e606bad bc/mailmap-self later to maint).
+   (merge f7997e3682 ao/config-api-doc later to maint).
+   (merge ee930754d8 jk/apply-p-doc later to maint).
+   (merge 011b648646 nd/pack-format-doc later to maint).
+   (merge 87a6bb701a sg/t5310-jgit-bitmap-test later to maint).
+   (merge f6b82970aa sg/t5516-fixes later to maint).
+   (merge 4362da078e sg/t7005-spaces-in-filenames-cleanup later to maint).
+   (merge 7d0ee47c11 js/test-unset-prereq later to maint).
+   (merge 5356a3c354 ah/misc-doc-updates later to maint).
+   (merge 92c4a7a129 nd/completion-aliasfiletype-typofix later to maint).
+   (merge 58bd77b66a nd/pack-unreachable-objects-doc later to maint).
+   (merge 4ed79d5203 sg/t6500-no-redirect-of-stdin later to maint).
+   (merge 17b8a2d6cd jk/config-blob-sans-repo later to maint).
+   (merge 590551ca2c rd/tag-doc-lightweight later to maint).
+   (merge 44f560fc16 rd/init-typo later to maint).
+   (merge f156a0934a rd/p4-doc-markup-env later to maint).
+   (merge 2a00502b14 tg/doc-sec-list later to maint).
+   (merge 47cc91310a jk/submodule-fsck-loose-fixup later to maint).
+   (merge efde7b725c rd/comment-typofix-in-sha1-file later to maint).
+   (merge 7eedad15df rd/diff-options-typofix later to maint).
+   (merge 58ebd936cc km/doc-workflows-typofix later to maint).
+   (merge 30aa96cdf8 rd/doc-remote-tracking-with-hyphen later to maint).
+   (merge cf317877e3 ks/branch-set-upstream later to maint).
+   (merge 8de19d6be8 sg/t7406-chain-fix later to maint).
diff --git a/Documentation/RelNotes/2.18.1.txt b/Documentation/RelNotes/2.18.1.txt
new file mode 100644
index 0000000..2098cdd
--- /dev/null
+++ b/Documentation/RelNotes/2.18.1.txt
@@ -0,0 +1,6 @@
+Git v2.18.1 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.14.5 and in
+v2.17.2 to address the recently reported CVE-2018-17456; see the
+release notes for those versions for details.
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
index a1d0fec..2488544 100644
--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -176,6 +176,12 @@
 [[send-patches]]
 === Sending your patches.
 
+:security-ml: footnoteref:[security-ml,The Git Security mailing list: git-security@googlegroups.com]
+
+Before sending any patches, please note that patches that may be
+security relevant should be submitted privately to the Git Security
+mailing list{security-ml}, instead of the public mailing list.
+
 Learn to use format-patch and send-email if possible.  These commands
 are optimized for the workflow of sending patches, avoiding many ways
 your existing e-mail client that is optimized for "multipart/*" mime
@@ -259,17 +265,24 @@
 that starts with `-----BEGIN PGP SIGNED MESSAGE-----`.  That is
 not a text/plain, it's something else.
 
+:security-ml-ref: footnoteref:[security-ml]
+
+As mentioned at the beginning of the section, patches that may be
+security relevant should not be submitted to the public mailing list
+mentioned below, but should instead be sent privately to the Git
+Security mailing list{security-ml-ref}.
+
 Send your patch with "To:" set to the mailing list, with "cc:" listing
-people who are involved in the area you are touching (the output from
-`git blame $path` and `git shortlog --no-merges $path` would help to
+people who are involved in the area you are touching (the `git
+contacts` command in `contrib/contacts/` can help to
 identify them), to solicit comments and reviews.
 
-:1: footnote:[The current maintainer: gitster@pobox.com]
-:2: footnote:[The mailing list: git@vger.kernel.org]
+:current-maintainer: footnote:[The current maintainer: gitster@pobox.com]
+:git-ml: footnote:[The mailing list: git@vger.kernel.org]
 
 After the list reached a consensus that it is a good idea to apply the
-patch, re-send it with "To:" set to the maintainer{1} and "cc:" the
-list{2} for inclusion.
+patch, re-send it with "To:" set to the maintainer{current-maintainer} and "cc:" the
+list{git-ml} for inclusion.
 
 Do not forget to add trailers such as `Acked-by:`, `Reviewed-by:` and
 `Tested-by:` lines as necessary to credit people who helped your
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 4e0cff8..ab641bf 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -530,6 +530,12 @@
 	This variable can be set to 'input',
 	in which case no output conversion is performed.
 
+core.checkRoundtripEncoding::
+	A comma and/or whitespace separated list of encodings that Git
+	performs UTF-8 round trip checks on if they are used in an
+	`working-tree-encoding` attribute (see linkgit:gitattributes[5]).
+	The default value is `SHIFT-JIS`.
+
 core.symlinks::
 	If false, symbolic links are checked out as small plain files that
 	contain the link text. linkgit:git-update-index[1] and
@@ -898,6 +904,10 @@
 This setting defaults to "refs/notes/commits", and it can be overridden by
 the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].
 
+core.commitGraph::
+	Enable git commit graph feature. Allows reading from the
+	commit-graph file.
+
 core.sparseCheckout::
 	Enable "sparse checkout" feature. See section "Sparse checkout" in
 	linkgit:git-read-tree[1] for more information.
@@ -1058,6 +1068,10 @@
 	"git pull" is run. See "pull.rebase" for doing this in a non
 	branch-specific manner.
 +
+When `merges`, pass the `--rebase-merges` option to 'git rebase'
+so that the local merge commits are included in the rebase (see
+linkgit:git-rebase[1] for details).
++
 When preserve, also pass `--preserve-merges` along to 'git rebase'
 so that locally committed merge commits will not be flattened
 by running 'git pull'.
@@ -1088,6 +1102,16 @@
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
 
+color.advice::
+	A boolean to enable/disable color in hints (e.g. when a push
+	failed, see `advice.*` for a list).  May be set to `always`,
+	`false` (or `never`) or `auto` (or `true`), in which case colors
+	are used only when the error output goes to a terminal. If
+	unset, then the value of `color.ui` is used (`auto` by default).
+
+color.advice.hint::
+	Use customized color for hints.
+
 color.branch::
 	A boolean to enable/disable color in the output of
 	linkgit:git-branch[1]. May be set to `always`,
@@ -1190,6 +1214,15 @@
 	A boolean to enable/disable colored output when the pager is in
 	use (default is true).
 
+color.push::
+	A boolean to enable/disable color in push errors. May be set to
+	`always`, `false` (or `never`) or `auto` (or `true`), in which
+	case colors are used only when the error output goes to a terminal.
+	If unset, then the value of `color.ui` is used (`auto` by default).
+
+color.push.error::
+	Use customized color for push errors.
+
 color.showBranch::
 	A boolean to enable/disable color in the output of
 	linkgit:git-show-branch[1]. May be set to `always`,
@@ -1218,6 +1251,42 @@
 	status short-format), or
 	`unmerged` (files which have unmerged changes).
 
+color.blame.repeatedLines::
+	Use the customized color for the part of git-blame output that
+	is repeated meta information per line (such as commit id,
+	author name, date and timezone). Defaults to cyan.
+
+color.blame.highlightRecent::
+	This can be used to color the metadata of a blame line depending
+	on age of the line.
++
+This setting should be set to a comma-separated list of color and date settings,
+starting and ending with a color, the dates should be set from oldest to newest.
+The metadata will be colored given the colors if the the line was introduced
+before the given timestamp, overwriting older timestamped colors.
++
+Instead of an absolute timestamp relative timestamps work as well, e.g.
+2.weeks.ago is valid to address anything older than 2 weeks.
++
+It defaults to 'blue,12 month ago,white,1 month ago,red', which colors
+everything older than one year blue, recent changes between one month and
+one year old are kept white, and lines introduced within the last month are
+colored red.
+
+blame.coloring::
+	This determines the coloring scheme to be applied to blame
+	output. It can be 'repeatedLines', 'highlightRecent',
+	or 'none' which is the default.
+
+color.transport::
+	A boolean to enable/disable color when pushes are rejected. May be
+	set to `always`, `false` (or `never`) or `auto` (or `true`), in which
+	case colors are used only when the error output goes to a terminal.
+	If unset, then the value of `color.ui` is used (`auto` by default).
+
+color.transport.rejected::
+	Use customized color when a push was rejected.
+
 color.ui::
 	This variable determines the default value for variables such
 	as `color.diff` and `color.grep` that control the use of color
@@ -1343,6 +1412,14 @@
 credentialCache.ignoreSIGHUP::
 	Tell git-credential-cache--daemon to ignore SIGHUP, instead of quitting.
 
+completion.commands::
+	This is only used by git-completion.bash to add or remove
+	commands from the list of completed commands. Normally only
+	porcelain commands and a few select others are completed. You
+	can add more commands, separated by space, in this
+	variable. Prefixing the command with '-' will remove it from
+	the existing list.
+
 include::diff-config.txt[]
 
 difftool.<tool>.path::
@@ -1558,6 +1635,18 @@
 	Make `git gc --auto` return immediately and run in background
 	if the system supports it. Default is true.
 
+gc.bigPackThreshold::
+	If non-zero, all packs larger than this limit are kept when
+	`git gc` is run. This is very similar to `--keep-base-pack`
+	except that all packs that meet the threshold are kept, not
+	just the base pack. Defaults to zero. Common unit suffixes of
+	'k', 'm', or 'g' are supported.
++
+Note that if the number of kept packs is more than gc.autoPackLimit,
+this configuration variable is ignored, all packs except the base pack
+will be repacked. After this the number of packs should go below
+gc.autoPackLimit and gc.bigPackThreshold should be respected again.
+
 gc.logExpiry::
 	If the file gc.log exists, then `git gc --auto` won't run
 	unless that file is more than 'gc.logExpiry' old.  Default is
@@ -1957,6 +2046,7 @@
 	- tlsv1.0
 	- tlsv1.1
 	- tlsv1.2
+	- tlsv1.3
 
 +
 Can be overridden by the `GIT_SSL_VERSION` environment variable.
@@ -2421,6 +2511,7 @@
 pack.depth::
 	The maximum delta depth used by linkgit:git-pack-objects[1] when no
 	maximum depth is given on the command line. Defaults to 50.
+	Maximum value is 4095.
 
 pack.windowMemory::
 	The maximum size of memory that is consumed by each thread
@@ -2457,7 +2548,8 @@
 	The maximum size of a delta, that is cached in
 	linkgit:git-pack-objects[1]. This cache is used to speed up the
 	writing object phase by not having to recompute the final delta
-	result once the best match for all objects is found. Defaults to 1000.
+	result once the best match for all objects is found.
+	Defaults to 1000. Maximum value is 65535.
 
 pack.threads::
 	Specifies the number of threads to spawn when searching for best
@@ -2616,6 +2708,10 @@
 	pull" is run. See "branch.<name>.rebase" for setting this on a
 	per-branch basis.
 +
+When `merges`, pass the `--rebase-merges` option to 'git rebase'
+so that the local merge commits are included in the rebase (see
+linkgit:git-rebase[1] for details).
++
 When preserve, also pass `--preserve-merges` along to 'git rebase'
 so that locally committed merge commits will not be flattened
 by running 'git pull'.
@@ -3118,6 +3214,18 @@
 	behavior of linkgit:git-status[1] in Git 1.8.4 and previous.
 	Defaults to false.
 
+status.renameLimit::
+	The number of files to consider when performing rename detection
+	in linkgit:git-status[1] and linkgit:git-commit[1]. Defaults to
+	the value of diff.renameLimit.
+
+status.renames::
+	Whether and how Git detects renames in linkgit:git-status[1] and
+	linkgit:git-commit[1] .  If set to "false", rename detection is
+	disabled. If set to "true", basic rename detection is enabled.
+	If set to "copies" or "copy", Git will detect copies, as well.
+	Defaults to the value of diff.renames.
+
 status.showStash::
 	If set to true, linkgit:git-status[1] will display the number of
 	entries currently stashed away.
diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index 5ca942a..77caa66 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -112,7 +112,8 @@
 
 diff.renameLimit::
 	The number of files to consider when performing the copy/rename
-	detection; equivalent to the 'git diff' option `-l`.
+	detection; equivalent to the 'git diff' option `-l`. This setting
+	has no effect if rename detection is turned off.
 
 diff.renames::
 	Whether and how Git detects renames.  If set to "false",
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index e3a44f0..4106490 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -64,7 +64,7 @@
 endif::git-format-patch[]
 
 --indent-heuristic::
-	Enable the heuristic that shift diff hunk boundaries to make patches
+	Enable the heuristic that shifts diff hunk boundaries to make patches
 	easier to read. This is the default.
 
 --no-indent-heuristic::
@@ -106,7 +106,7 @@
 	low-occurrence common elements".
 --
 +
-For instance, if you configured diff.algorithm variable to a
+For instance, if you configured the `diff.algorithm` variable to a
 non-default value and want to use the default one, then you
 have to use `--diff-algorithm=default` option.
 
@@ -133,7 +133,7 @@
 	as file creations or deletions ("new" or "gone", optionally "+l"
 	if it's a symlink) and mode changes ("+x" or "-x" for adding
 	or removing executable bit respectively) in diffstat. The
-	information is put betwen the filename part and the graph
+	information is put between the filename part and the graph
 	part. Implies `--stat`.
 
 --numstat::
@@ -350,7 +350,7 @@
 	Warn if changes introduce conflict markers or whitespace errors.
 	What are considered whitespace errors is controlled by `core.whitespace`
 	configuration.  By default, trailing whitespaces (including
-	lines that solely consist of whitespaces) and a space character
+	lines that consist solely of whitespaces) and a space character
 	that is immediately followed by a tab character inside the
 	initial indent of the line are considered whitespace errors.
 	Exits with non-zero status if problems are found. Not compatible
@@ -364,7 +364,7 @@
 	this option is not given, and the configuration variable
 	`diff.wsErrorHighlight` is not set, only whitespace errors in
 	`new` lines are highlighted. The whitespace errors are colored
-	whith `color.diff.whitespace`.
+	with `color.diff.whitespace`.
 
 endif::git-format-patch[]
 
@@ -568,7 +568,7 @@
 --
 +
 Patterns have the same syntax and semantics as patterns used for
-fnmantch(3) without the FNM_PATHNAME flag, except a pathname also
+fnmatch(3) without the FNM_PATHNAME flag, except a pathname also
 matches a pattern if removing any number of the final pathname
 components matches the pattern.  For example, the pattern "`foo*bar`"
 matches "`fooasdfbar`" and "`foo/bar/baz/asdf`" but not "`foobarx`".
@@ -592,7 +592,7 @@
 	Treat all files as text.
 
 --ignore-cr-at-eol::
-	Ignore carrige-return at the end of line when doing a comparison.
+	Ignore carriage-return at the end of line when doing a comparison.
 
 --ignore-space-at-eol::
 	Ignore changes in whitespace at EOL.
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 8631e36..97d3217 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -188,6 +188,14 @@
 	is specified. This flag forces progress status even if the
 	standard error stream is not directed to a terminal.
 
+-o <option>::
+--server-option=<option>::
+	Transmit the given string to the server when communicating using
+	protocol version 2.  The given string must not contain a NUL or LF
+	character.
+	When multiple `--server-option=<option>` are given, they are all
+	sent to the other side in the order listed on the command line.
+
 -4::
 --ipv4::
 	Use IPv4 addresses only, ignoring IPv6 addresses.
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index d50fa33..45652fe 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -193,7 +193,7 @@
 	for command-line options).
 
 
-Configuration
+CONFIGURATION
 -------------
 
 The optional configuration variable `core.excludesFile` indicates a path to a
@@ -226,7 +226,7 @@
 listing the files explicitly), it does not consider
 `subdir/git-foo.sh`.
 
-Interactive mode
+INTERACTIVE MODE
 ----------------
 When the command enters the interactive mode, it shows the
 output of the 'status' subcommand, and then goes into its
diff --git a/Documentation/git-annotate.txt b/Documentation/git-annotate.txt
index 05fd482..e44a831 100644
--- a/Documentation/git-annotate.txt
+++ b/Documentation/git-annotate.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git annotate' [options] file [revision]
+'git annotate' [<options>] <file> [<revision>]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index 4ebc3d3..6722849 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -113,8 +113,10 @@
 linkgit:git-config[1]).
 
 -p<n>::
-	Remove <n> leading slashes from traditional diff paths. The
-	default is 1.
+	Remove <n> leading path components (separated by slashes) from
+	traditional diff paths. E.g., with `-p2`, a patch against
+	`a/dir/file` will be applied directly to `file`. The default is
+	1.
 
 -C<n>::
 	Ensure at least <n> lines of surrounding context match before
@@ -240,7 +242,7 @@
 the `--unsafe-paths` option to override this safety check.  This option
 has no effect when `--index` or `--cached` is in use.
 
-Configuration
+CONFIGURATION
 -------------
 
 apply.ignoreWhitespace::
@@ -251,7 +253,7 @@
 	When no `--whitespace` flag is given from the command
 	line, this configuration item is used as the default.
 
-Submodules
+SUBMODULES
 ----------
 If the patch contains any changes to submodules then 'git apply'
 treats these changes as follows.
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 4a1417b..4b45d83 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -165,8 +165,8 @@
 git bisect terms
 ------------------------------------------------
 
-You can get just the old (respectively new) term with `git bisect term
---term-old` or `git bisect term --term-good`.
+You can get just the old (respectively new) term with `git bisect terms
+--term-old` or `git bisect terms --term-good`.
 
 If you would like to use your own terms instead of "bad"/"good" or
 "new"/"old", you can choose any names you like (except existing bisect
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index b3084c9..02eccbb 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -287,7 +287,7 @@
 `--list` is used or implied. The default is to use a pager.
 See linkgit:git-config[1].
 
-Examples
+EXAMPLES
 --------
 
 Start development from a known tag::
@@ -318,7 +318,7 @@
 is currently checked out) does not have all commits from the test branch.
 
 
-Notes
+NOTES
 -----
 
 If you are creating a branch that you want to checkout immediately, it is
diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
index 3a8120c..7d6c9dc 100644
--- a/Documentation/git-bundle.txt
+++ b/Documentation/git-bundle.txt
@@ -92,8 +92,8 @@
 to contain objects already in the destination, as these are ignored
 when unpacking at the destination.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Assume you want to transfer the history from a repository R1 on machine A
 to another repository R2 on machine B.
diff --git a/Documentation/git-check-attr.txt b/Documentation/git-check-attr.txt
index aa3b2bf..3c05782 100644
--- a/Documentation/git-check-attr.txt
+++ b/Documentation/git-check-attr.txt
@@ -9,8 +9,8 @@
 SYNOPSIS
 --------
 [verse]
-'git check-attr' [-a | --all | attr...] [--] pathname...
-'git check-attr' --stdin [-z] [-a | --all | attr...]
+'git check-attr' [-a | --all | <attr>...] [--] <pathname>...
+'git check-attr' --stdin [-z] [-a | --all | <attr>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-check-ignore.txt b/Documentation/git-check-ignore.txt
index 611754f..8b42cb3 100644
--- a/Documentation/git-check-ignore.txt
+++ b/Documentation/git-check-ignore.txt
@@ -9,8 +9,8 @@
 SYNOPSIS
 --------
 [verse]
-'git check-ignore' [options] pathname...
-'git check-ignore' [options] --stdin
+'git check-ignore' [<options>] <pathname>...
+'git check-ignore' [<options>] --stdin
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-check-mailmap.txt b/Documentation/git-check-mailmap.txt
index 39028ee..aa2055d 100644
--- a/Documentation/git-check-mailmap.txt
+++ b/Documentation/git-check-mailmap.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git check-mailmap' [options] <contact>...
+'git check-mailmap' [<options>] <contact>...
 
 
 DESCRIPTION
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 42ca7b5..a55536f 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -260,7 +260,7 @@
 
 <repository>::
 	The (possibly remote) repository to clone from.  See the
-	<<URLS,URLS>> section below for more information on specifying
+	<<URLS,GIT URLS>> section below for more information on specifying
 	repositories.
 
 <directory>::
@@ -273,7 +273,7 @@
 :git-clone: 1
 include::urls.txt[]
 
-Examples
+EXAMPLES
 --------
 
 * Clone from upstream:
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
new file mode 100644
index 0000000..4c97b55
--- /dev/null
+++ b/Documentation/git-commit-graph.txt
@@ -0,0 +1,94 @@
+git-commit-graph(1)
+===================
+
+NAME
+----
+git-commit-graph - Write and verify Git commit graph files
+
+
+SYNOPSIS
+--------
+[verse]
+'git commit-graph read' [--object-dir <dir>]
+'git commit-graph write' <options> [--object-dir <dir>]
+
+
+DESCRIPTION
+-----------
+
+Manage the serialized commit graph file.
+
+
+OPTIONS
+-------
+--object-dir::
+	Use given directory for the location of packfiles and commit graph
+	file. This parameter exists to specify the location of an alternate
+	that only has the objects directory, not a full .git directory. The
+	commit graph file is expected to be at <dir>/info/commit-graph and
+	the packfiles are expected to be in <dir>/pack.
+
+
+COMMANDS
+--------
+'write'::
+
+Write a commit graph file based on the commits found in packfiles.
++
+With the `--stdin-packs` option, generate the new commit graph by
+walking objects only in the specified pack-indexes. (Cannot be combined
+with --stdin-commits.)
++
+With the `--stdin-commits` option, generate the new commit graph by
+walking commits starting at the commits specified in stdin as a list
+of OIDs in hex, one OID per line. (Cannot be combined with
+--stdin-packs.)
++
+With the `--append` option, include all commits that are present in the
+existing commit-graph file.
+
+'read'::
+
+Read a graph file given by the commit-graph file and output basic
+details about the graph file. Used for debugging purposes.
+
+
+EXAMPLES
+--------
+
+* Write a commit graph file for the packed commits in your local .git folder.
++
+------------------------------------------------
+$ git commit-graph write
+------------------------------------------------
+
+* Write a graph file, extending the current graph file using commits
+* in <pack-index>.
++
+------------------------------------------------
+$ echo <pack-index> | git commit-graph write --stdin-packs
+------------------------------------------------
+
+* Write a graph file containing all reachable commits.
++
+------------------------------------------------
+$ git show-ref -s | git commit-graph write --stdin-commits
+------------------------------------------------
+
+* Write a graph file containing all commits in the current
+* commit-graph file along with those reachable from HEAD.
++
+------------------------------------------------
+$ git rev-parse HEAD | git commit-graph write --stdin-commits --append
+------------------------------------------------
+
+* Read basic information from the commit-graph file.
++
+------------------------------------------------
+$ git commit-graph read
+------------------------------------------------
+
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index e09ed5d..18ddc78 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -9,13 +9,13 @@
 SYNOPSIS
 --------
 [verse]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] name [value [value_regex]]
-'git config' [<file-option>] [type] --add name value
-'git config' [<file-option>] [type] --replace-all name value [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get name [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get-all name [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex]
-'git config' [<file-option>] [type] [-z|--null] --get-urlmatch name URL
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] name [value [value_regex]]
+'git config' [<file-option>] [--type=<type>] --add name value
+'git config' [<file-option>] [--type=<type>] --replace-all name value [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get-all name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex]
+'git config' [<file-option>] [--type=<type>] [-z|--null] --get-urlmatch name URL
 'git config' [<file-option>] --unset name [value_regex]
 'git config' [<file-option>] --unset-all name [value_regex]
 'git config' [<file-option>] --rename-section old_name new_name
@@ -38,12 +38,10 @@
 you want to handle the lines that do *not* match the regex, just
 prepend a single exclamation mark in front (see also <<EXAMPLES>>).
 
-The type specifier can be either `--int` or `--bool`, to make
-'git config' ensure that the variable(s) are of the given type and
-convert the value to the canonical form (simple decimal number for int,
-a "true" or "false" string for bool), or `--path`, which does some
-path expansion (see `--path` below).  If no type specifier is passed, no
-checks or transformations are performed on the value.
+The `--type=<type>` option instructs 'git config' to ensure that incoming and
+outgoing values are canonicalize-able under the given <type>.  If no
+`--type=<type>` is given, no canonicalization will be performed. Callers may
+unset an existing `--type` specifier with `--no-type`.
 
 When reading, the values are read from the system, global and
 repository local configuration files by default, and options
@@ -160,30 +158,43 @@
 --list::
 	List all variables set in config file, along with their values.
 
+--type <type>::
+  'git config' will ensure that any input or output is valid under the given
+  type constraint(s), and will canonicalize outgoing values in `<type>`'s
+  canonical form.
++
+Valid `<type>`'s include:
++
+- 'bool': canonicalize values as either "true" or "false".
+- 'int': canonicalize values as simple decimal numbers. An optional suffix of
+  'k', 'm', or 'g' will cause the value to be multiplied by 1024, 1048576, or
+  1073741824 upon input.
+- 'bool-or-int': canonicalize according to either 'bool' or 'int', as described
+  above.
+- 'path': canonicalize by adding a leading `~` to the value of `$HOME` and
+  `~user` to the home directory for the specified user. This specifier has no
+  effect when setting the value (but you can use `git config section.variable
+  ~/` from the command line to let your shell do the expansion.)
+- 'expiry-date': canonicalize by converting from a fixed or relative date-string
+  to a timestamp. This specifier has no effect when setting the value.
+- 'color': When getting a value, canonicalize by converting to an ANSI color
+  escape sequence. When setting a value, a sanity-check is performed to ensure
+  that the given value is canonicalize-able as an ANSI color, but it is written
+  as-is.
++
+
 --bool::
-	'git config' will ensure that the output is "true" or "false"
-
 --int::
-	'git config' will ensure that the output is a simple
-	decimal number.  An optional value suffix of 'k', 'm', or 'g'
-	in the config file will cause the value to be multiplied
-	by 1024, 1048576, or 1073741824 prior to output.
-
 --bool-or-int::
-	'git config' will ensure that the output matches the format of
-	either --bool or --int, as described above.
-
 --path::
-	`git config` will expand a leading `~` to the value of
-	`$HOME`, and `~user` to the home directory for the
-	specified user.  This option has no effect when setting the
-	value (but you can use `git config section.variable ~/`
-	from the command line to let your shell do the expansion).
-
 --expiry-date::
-	`git config` will ensure that the output is converted from
-	a fixed or relative date-string to a timestamp. This option
-	has no effect when setting the value.
+  Historical options for selecting a type specifier. Prefer instead `--type`,
+  (see: above).
+
+--no-type::
+  Un-sets the previously set type specifier (if one was previously set). This
+  option requests that 'git config' not canonicalize the retrieved variable.
+  `--no-type` has no effect without `--type=<type>` or `--<type>`.
 
 -z::
 --null::
@@ -221,6 +232,8 @@
 	output it as the ANSI color escape sequence to the standard
 	output.  The optional `default` parameter is used instead, if
 	there is no color configured for `name`.
++
+`--type=color [--default=<default>]` is preferred over `--get-color`.
 
 -e::
 --edit::
@@ -233,6 +246,10 @@
 	using `--file`, `--global`, etc) and `on` when searching all
 	config files.
 
+--default <value>::
+  When using `--get`, and the requested variable is not found, behave as if
+  <value> were the value assigned to the that variable.
+
 CONFIGURATION
 -------------
 `pager.config` is only respected when listing configuration, i.e., when
diff --git a/Documentation/git-credential-cache.txt b/Documentation/git-credential-cache.txt
index 2b85826..0216c18 100644
--- a/Documentation/git-credential-cache.txt
+++ b/Documentation/git-credential-cache.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 -----------------------------
-git config credential.helper 'cache [options]'
+git config credential.helper 'cache [<options>]'
 -----------------------------
 
 DESCRIPTION
diff --git a/Documentation/git-credential-store.txt b/Documentation/git-credential-store.txt
index 25fb963..693dd9d 100644
--- a/Documentation/git-credential-store.txt
+++ b/Documentation/git-credential-store.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 -------------------
-git config credential.helper 'store [options]'
+git config credential.helper 'store [<options>]'
 -------------------
 
 DESCRIPTION
diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt
index ba90066..f98b7c6 100644
--- a/Documentation/git-cvsserver.txt
+++ b/Documentation/git-cvsserver.txt
@@ -22,7 +22,7 @@
 Usage:
 
 [verse]
-'git-cvsserver' [options] [pserver|server] [<directory> ...]
+'git-cvsserver' [<options>] [pserver|server] [<directory> ...]
 
 OPTIONS
 -------
@@ -207,7 +207,7 @@
 ------
 
 [[dbbackend]]
-Database Backend
+DATABASE BACKEND
 ----------------
 
 'git-cvsserver' uses one database per Git head (i.e. CVS module) to
@@ -321,7 +321,7 @@
 When these environment variables are set, the corresponding
 command-line arguments may not be used.
 
-Eclipse CVS Client Notes
+ECLIPSE CVS CLIENT NOTES
 ------------------------
 
 To get a checkout with the Eclipse CVS client:
@@ -346,7 +346,7 @@
 the cvs utility on the server with 'git-cvsserver' or manipulate your `.bashrc`
 so that calling 'cvs' effectively calls 'git-cvsserver'.
 
-Clients known to work
+CLIENTS KNOWN TO WORK
 ---------------------
 
 - CVS 1.12.9 on Debian
@@ -354,7 +354,7 @@
 - Eclipse 3.0, 3.1.2 on MacOSX (see Eclipse CVS Client Notes)
 - TortoiseCVS
 
-Operations supported
+OPERATIONS SUPPORTED
 --------------------
 
 All the operations required for normal use are supported, including
@@ -424,7 +424,7 @@
 defaults by setting `gitcvs.usecrlfattr` to true,
 and `gitcvs.allBinary` to "guess".
 
-Dependencies
+DEPENDENCIES
 ------------
 'git-cvsserver' depends on DBD::SQLite.
 
diff --git a/Documentation/git-diff-index.txt b/Documentation/git-diff-index.txt
index b380677..f4bd815 100644
--- a/Documentation/git-diff-index.txt
+++ b/Documentation/git-diff-index.txt
@@ -37,14 +37,14 @@
 
 include::diff-format.txt[]
 
-Operating Modes
+OPERATING MODES
 ---------------
 You can choose whether you want to trust the index file entirely
 (using the `--cached` flag) or ask the diff logic to show any files
 that don't match the stat state as being "tentatively changed".  Both
 of these operations are very useful indeed.
 
-Cached Mode
+CACHED MODE
 -----------
 If `--cached` is specified, it allows you to ask:
 
@@ -77,7 +77,7 @@
 asking yourself "what have I already marked for being committed, and
 what's the difference to a previous tree".
 
-Non-cached Mode
+NON-CACHED MODE
 ---------------
 The "non-cached" mode takes a different approach, and is potentially
 the more useful of the two in that what it does can't be emulated with
diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt
index 7870e17..2319b2b 100644
--- a/Documentation/git-diff-tree.txt
+++ b/Documentation/git-diff-tree.txt
@@ -116,7 +116,7 @@
 include::pretty-formats.txt[]
 
 
-Limiting Output
+LIMITING OUTPUT
 ---------------
 If you're only interested in differences in a subset of files, for
 example some architecture-specific files, you might do:
diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index b0c1bb9..b180f1f 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -9,11 +9,11 @@
 SYNOPSIS
 --------
 [verse]
-'git diff' [options] [<commit>] [--] [<path>...]
-'git diff' [options] --cached [<commit>] [--] [<path>...]
-'git diff' [options] <commit> <commit> [--] [<path>...]
-'git diff' [options] <blob> <blob>
-'git diff' [options] [--no-index] [--] <path> <path>
+'git diff' [<options>] [<commit>] [--] [<path>...]
+'git diff' [<options>] --cached [<commit>] [--] [<path>...]
+'git diff' [<options>] <commit> <commit> [--] [<path>...]
+'git diff' [<options>] <blob> <blob>
+'git diff' [<options>] --no-index [--] <path> <path>
 
 DESCRIPTION
 -----------
@@ -21,7 +21,7 @@
 between the index and a tree, changes between two trees, changes between
 two blob objects, or changes between two files on disk.
 
-'git diff' [--options] [--] [<path>...]::
+'git diff' [<options>] [--] [<path>...]::
 
 	This form is to view the changes you made relative to
 	the index (staging area for the next commit).  In other
@@ -29,7 +29,7 @@
 	further add to the index but you still haven't.  You can
 	stage these changes by using linkgit:git-add[1].
 
-'git diff' --no-index [--options] [--] [<path>...]::
+'git diff' [<options>] --no-index [--] <path> <path>::
 
 	This form is to compare the given two paths on the
 	filesystem.  You can omit the `--no-index` option when
@@ -38,7 +38,7 @@
 	or when running the command outside a working tree
 	controlled by Git.
 
-'git diff' [--options] --cached [<commit>] [--] [<path>...]::
+'git diff' [<options>] --cached [<commit>] [--] [<path>...]::
 
 	This form is to view the changes you staged for the next
 	commit relative to the named <commit>.  Typically you
@@ -48,7 +48,7 @@
 	<commit> is not given, it shows all staged changes.
 	--staged is a synonym of --cached.
 
-'git diff' [--options] <commit> [--] [<path>...]::
+'git diff' [<options>] <commit> [--] [<path>...]::
 
 	This form is to view the changes you have in your
 	working tree relative to the named <commit>.  You can
@@ -56,18 +56,18 @@
 	branch name to compare with the tip of a different
 	branch.
 
-'git diff' [--options] <commit> <commit> [--] [<path>...]::
+'git diff' [<options>] <commit> <commit> [--] [<path>...]::
 
 	This is to view the changes between two arbitrary
 	<commit>.
 
-'git diff' [--options] <commit>..<commit> [--] [<path>...]::
+'git diff' [<options>] <commit>..<commit> [--] [<path>...]::
 
 	This is synonymous to the previous form.  If <commit> on
 	one side is omitted, it will have the same effect as
 	using HEAD instead.
 
-'git diff' [--options] <commit>\...<commit> [--] [<path>...]::
+'git diff' [<options>] <commit>\...<commit> [--] [<path>...]::
 
 	This form is to view the changes on the branch containing
 	and up to the second <commit>, starting at a common ancestor
@@ -87,7 +87,7 @@
 "<commit>\...<commit>") do not mean a range as defined in the
 "SPECIFYING RANGES" section in linkgit:gitrevisions[7].
 
-'git diff' [options] <blob> <blob>::
+'git diff' [<options>] <blob> <blob>::
 
 	This form is to view the differences between the raw
 	contents of two blob objects.
diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index ed57c68..ce954be 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git fast-export [options]' | 'git fast-import'
+'git fast-export [<options>]' | 'git fast-import'
 
 DESCRIPTION
 -----------
@@ -202,7 +202,7 @@
 no private data in the stream.
 
 
-Limitations
+LIMITATIONS
 -----------
 
 Since 'git fast-import' cannot tag trees, you will not be
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index ff71fc2..9e3b958 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-frontend | 'git fast-import' [options]
+frontend | 'git fast-import' [<options>]
 
 DESCRIPTION
 -----------
@@ -154,7 +154,7 @@
 fastimport.unpackLimit::
 	See linkgit:git-config[1]
 
-Performance
+PERFORMANCE
 -----------
 The design of fast-import allows it to import large projects in a minimum
 amount of memory usage and processing time.  Assuming the frontend
@@ -170,7 +170,7 @@
 destination Git repository (due to less IO contention).
 
 
-Development Cost
+DEVELOPMENT COST
 ----------------
 A typical frontend for fast-import tends to weigh in at approximately 200
 lines of Perl/Python/Ruby code.  Most developers have been able to
@@ -180,7 +180,7 @@
 (use once, and never look back).
 
 
-Parallel Operation
+PARALLEL OPERATION
 ------------------
 Like 'git push' or 'git fetch', imports handled by fast-import are safe to
 run alongside parallel `git repack -a -d` or `git gc` invocations,
@@ -201,7 +201,7 @@
 is not necessary for an initial import into an empty repository.
 
 
-Technical Discussion
+TECHNICAL DISCUSSION
 --------------------
 fast-import tracks a set of branches in memory.  Any branch can be created
 or modified at any point during the import process by sending a
@@ -219,7 +219,7 @@
 need to perform any costly file update operations when switching
 between branches.
 
-Input Format
+INPUT FORMAT
 ------------
 With the exception of raw file data (which Git does not interpret)
 the fast-import input format is text (ASCII) based.  This text based
@@ -1146,7 +1146,7 @@
 in use, the `done` command is mandatory and marks the end of the
 stream.
 
-Responses To Commands
+RESPONSES TO COMMANDS
 ---------------------
 New objects written by fast-import are not available immediately.
 Most fast-import commands have no visible effect until the next
@@ -1175,7 +1175,7 @@
 pending output from `progress`, `ls`, `get-mark`, and `cat-blob` before
 performing writes to fast-import that might block.
 
-Crash Reports
+CRASH REPORTS
 -------------
 If fast-import is supplied invalid input it will terminate with a
 non-zero exit status and create a crash report in the top level of
@@ -1262,7 +1262,7 @@
 	END OF CRASH REPORT
 ====
 
-Tips and Tricks
+TIPS AND TRICKS
 ---------------
 The following tips and tricks have been collected from various
 users of fast-import, and are offered here as suggestions.
@@ -1364,7 +1364,7 @@
 has been processed.
 
 
-Packfile Optimization
+PACKFILE OPTIMIZATION
 ---------------------
 When packing a blob fast-import always attempts to deltify against the last
 blob written.  Unless specifically arranged for by the frontend,
@@ -1395,7 +1395,7 @@
 final packfile size (30-50% smaller can be quite typical).
 
 
-Memory Utilization
+MEMORY UTILIZATION
 ------------------
 There are a number of factors which affect how much memory fast-import
 requires to perform an import.  Like critical sections of core
@@ -1473,7 +1473,7 @@
 projects with 2,000+ branches and 45,114+ files in a very limited
 memory footprint (less than 2.7 MiB per active branch).
 
-Signals
+SIGNALS
 -------
 Sending *SIGUSR1* to the 'git fast-import' process ends the current
 packfile early, simulating a `checkpoint` command.  The impatient
diff --git a/Documentation/git-fetch-pack.txt b/Documentation/git-fetch-pack.txt
index f7ebe36..c975884 100644
--- a/Documentation/git-fetch-pack.txt
+++ b/Documentation/git-fetch-pack.txt
@@ -88,7 +88,7 @@
 	infinite even if there is an ancestor-chain that long.
 
 --shallow-since=<date>::
-	Deepen or shorten the history of a shallow'repository to
+	Deepen or shorten the history of a shallow repository to
 	include all reachable commits after <date>.
 
 --shallow-exclude=<revision>::
diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index 3a52e4d..e6f08ab 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -222,7 +222,15 @@
 was not excluded.
 
 
-Examples
+EXIT STATUS
+-----------
+
+On success, the exit status is `0`.  If the filter can't find any commits to
+rewrite, the exit status is `2`.  On any other error, the exit status may be
+any other non-zero value.
+
+
+EXAMPLES
 --------
 
 Suppose you want to remove a file (containing confidential information
@@ -280,7 +288,7 @@
 or even simpler:
 
 -----------------------------------------------
-echo "$commit-id $graft-id" >> .git/info/grafts
+git replace --graft $commit-id $graft-id
 git filter-branch $graft-id..HEAD
 -----------------------------------------------
 
@@ -398,7 +406,7 @@
 
 
 
-Checklist for Shrinking a Repository
+CHECKLIST FOR SHRINKING A REPOSITORY
 ------------------------------------
 
 git-filter-branch can be used to get rid of a subset of files,
@@ -437,7 +445,7 @@
   (or if your git-gc is not new enough to support arguments to
   `--prune`, use `git repack -ad; git prune` instead).
 
-Notes
+NOTES
 -----
 
 git-filter-branch allows you to make complex shell-scripted rewrites
diff --git a/Documentation/git-fmt-merge-msg.txt b/Documentation/git-fmt-merge-msg.txt
index 44892c4..423b6e0 100644
--- a/Documentation/git-fmt-merge-msg.txt
+++ b/Documentation/git-fmt-merge-msg.txt
@@ -57,8 +57,8 @@
 	Synonym to `merge.log`; this is deprecated and will be removed in
 	the future.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 ---------
 $ git fetch origin master
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index dffa14a..085d177 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -121,7 +121,7 @@
 	stripping with positive <N>, or it becomes the full refname if
 	stripping with negative <N>.  Neither is an error.
 +
-`strip` can be used as a synomym to `lstrip`.
+`strip` can be used as a synonym to `lstrip`.
 
 objecttype::
 	The type of the object (`blob`, `tree`, `commit`, `tag`).
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 6cbe462..b41e132 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -47,7 +47,7 @@
 
 The first rule takes precedence in the case of a single <commit>.  To
 apply the second rule, i.e., format everything since the beginning of
-history up until <commit>, use the '\--root' option: `git format-patch
+history up until <commit>, use the `--root` option: `git format-patch
 --root <commit>`.  If you want to format only <commit> itself, you
 can do this with `git format-patch -1 <commit>`.
 
diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index 571b5a7..24b2dd4 100644
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -9,14 +9,15 @@
 SYNOPSIS
 --------
 [verse]
-'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force]
+'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]
 
 DESCRIPTION
 -----------
 Runs a number of housekeeping tasks within the current repository,
 such as compressing file revisions (to reduce disk space and increase
-performance) and removing unreachable objects which may have been
-created from prior invocations of 'git add'.
+performance), removing unreachable objects which may have been
+created from prior invocations of 'git add', packing refs, pruning
+reflog, rerere metadata or stale working trees.
 
 Users are encouraged to run this task on a regular basis within
 each repository to maintain good disk space utilization and good
@@ -45,20 +46,31 @@
 	With this option, 'git gc' checks whether any housekeeping is
 	required; if not, it exits without performing any work.
 	Some git commands run `git gc --auto` after performing
-	operations that could create many loose objects.
+	operations that could create many loose objects. Housekeeping
+	is required if there are too many loose objects or too many
+	packs in the repository.
 +
-Housekeeping is required if there are too many loose objects or
-too many packs in the repository. If the number of loose objects
-exceeds the value of the `gc.auto` configuration variable, then
-all loose objects are combined into a single pack using
-`git repack -d -l`.  Setting the value of `gc.auto` to 0
-disables automatic packing of loose objects.
+If the number of loose objects exceeds the value of the `gc.auto`
+configuration variable, then all loose objects are combined into a
+single pack using `git repack -d -l`.  Setting the value of `gc.auto`
+to 0 disables automatic packing of loose objects.
 +
 If the number of packs exceeds the value of `gc.autoPackLimit`,
-then existing packs (except those marked with a `.keep` file)
+then existing packs (except those marked with a `.keep` file
+or over `gc.bigPackThreshold` limit)
 are consolidated into a single pack by using the `-A` option of
-'git repack'. Setting `gc.autoPackLimit` to 0 disables
-automatic consolidation of packs.
+'git repack'.
+If the amount of memory is estimated not enough for `git repack` to
+run smoothly and `gc.bigPackThreshold` is not set, the largest
+pack will also be excluded (this is the equivalent of running `git gc`
+with `--keep-base-pack`).
+Setting `gc.autoPackLimit` to 0 disables automatic consolidation of
+packs.
++
+If houskeeping is required due to many loose objects or packs, all
+other housekeeping tasks (e.g. rerere, working trees, reflog...) will
+be performed as well.
+
 
 --prune=<date>::
 	Prune loose objects older than date (default is 2 weeks ago,
@@ -78,7 +90,12 @@
 	Force `git gc` to run even if there may be another `git gc`
 	instance running on this repository.
 
-Configuration
+--keep-largest-pack::
+	All packs except the largest pack and those marked with a
+	`.keep` files are consolidated into a single pack. When this
+	option is used, `gc.bigPackThreshold` is ignored.
+
+CONFIGURATION
 -------------
 
 The optional configuration variable `gc.reflogExpire` can be
@@ -123,7 +140,7 @@
 much time is spent optimizing the delta compression of the objects in
 the repository when the --aggressive option is specified.  The larger
 the value, the more time is spent optimizing the delta compression.  See
-the documentation for the --window' option in linkgit:git-repack[1] for
+the documentation for the --window option in linkgit:git-repack[1] for
 more details.  This defaults to 250.
 
 Similarly, the optional configuration variable `gc.aggressiveDepth`
@@ -133,8 +150,12 @@
 the unreferenced loose objects have to be before they are pruned.  The
 default is "2 weeks ago".
 
+Optional configuration variable `gc.worktreePruneExpire` controls how
+old a stale working tree should be before `git worktree prune` deletes
+it. Default is "3 months ago".
 
-Notes
+
+NOTES
 -----
 
 'git gc' tries very hard not to delete objects that are referenced
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 18b4947..312409a 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -293,7 +293,7 @@
 For more details about the <pathspec> syntax, see the 'pathspec' entry
 in linkgit:gitglossary[7].
 
-Examples
+EXAMPLES
 --------
 
 `git grep 'time_t' -- '*.[ch]'`::
diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt
index 40d328a..a40fc38 100644
--- a/Documentation/git-help.txt
+++ b/Documentation/git-help.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git help' [-a|--all] [-g|--guide]
+'git help' [-a|--all [--verbose]] [-g|--guide]
 	   [-i|--info|-m|--man|-w|--web] [COMMAND|GUIDE]
 
 DESCRIPTION
@@ -42,6 +42,8 @@
 --all::
 	Prints all the available commands on the standard output. This
 	option overrides any given command or guide name.
+	When used with `--verbose` print description for all recognized
+	commands.
 
 -g::
 --guides::
diff --git a/Documentation/git-http-fetch.txt b/Documentation/git-http-fetch.txt
index 21a33d2..666b042 100644
--- a/Documentation/git-http-fetch.txt
+++ b/Documentation/git-http-fetch.txt
@@ -15,8 +15,9 @@
 -----------
 Downloads a remote Git repository via HTTP.
 
-*NOTE*: use of this command without -a is deprecated.  The -a
-behaviour will become the default in a future release.
+This command always gets all objects. Historically, there were three options
+`-a`, `-c` and `-t` for choosing which objects to download. They are now
+silently ignored.
 
 OPTIONS
 -------
@@ -24,12 +25,8 @@
         Either the hash or the filename under [URL]/refs/ to
         pull.
 
--c::
-	Get the commit objects.
--t::
-	Get trees associated with the commit objects.
--a::
-	Get all the objects.
+-a, -c, -t::
+	These options are ignored for historical reasons.
 -v::
 	Report what is downloaded.
 
diff --git a/Documentation/git-http-push.txt b/Documentation/git-http-push.txt
index 2aceb6f..ea03a4e 100644
--- a/Documentation/git-http-push.txt
+++ b/Documentation/git-http-push.txt
@@ -55,7 +55,7 @@
 	The remote refs to update.
 
 
-Specifying the Refs
+SPECIFYING THE REFS
 -------------------
 
 A '<ref>' specification can be either a single pattern, or a pair
diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
index 5d1e4c8..032613c 100644
--- a/Documentation/git-imap-send.txt
+++ b/Documentation/git-imap-send.txt
@@ -136,8 +136,8 @@
 .........................
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 To submit patches using GMail's IMAP interface, first, edit your ~/.gitconfig
 to specify your account settings:
 
diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt
index 138edb4..d5b7560 100644
--- a/Documentation/git-index-pack.txt
+++ b/Documentation/git-index-pack.txt
@@ -93,8 +93,8 @@
 --max-input-size=<size>::
 	Die, if the pack is larger than <size>.
 
-Note
-----
+NOTES
+-----
 
 Once the index has been created, the list of object names is sorted
 and the SHA-1 hash of that list is printed to stdout. If --stdin was
diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt
index ff446f1..9111c47 100644
--- a/Documentation/git-interpret-trailers.txt
+++ b/Documentation/git-interpret-trailers.txt
@@ -8,8 +8,8 @@
 SYNOPSIS
 --------
 [verse]
-'git interpret-trailers' [options] [(--trailer <token>[(=|:)<value>])...] [<file>...]
-'git interpret-trailers' [options] [--parse] [<file>...]
+'git interpret-trailers' [<options>] [(--trailer <token>[(=|:)<value>])...] [<file>...]
+'git interpret-trailers' [<options>] [--parse] [<file>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 5437f8b..90761f1 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git log' [<options>] [<revision range>] [[\--] <path>...]
+'git log' [<options>] [<revision range>] [[--] <path>...]
 
 DESCRIPTION
 -----------
@@ -90,13 +90,13 @@
 	ways to spell <revision range>, see the 'Specifying Ranges'
 	section of linkgit:gitrevisions[7].
 
-[\--] <path>...::
+[--] <path>...::
 	Show only commits that are enough to explain how the files
 	that match the specified paths came to be.  See 'History
 	Simplification' below for details and other simplification
 	modes.
 +
-Paths may need to be prefixed with ``\-- '' to separate them from
+Paths may need to be prefixed with `--` to separate them from
 options or the revision range, when confusion arises.
 
 include::rev-list-options.txt[]
@@ -125,7 +125,7 @@
 `git log --since="2 weeks ago" -- gitk`::
 
 	Show the changes during the last two weeks to the file 'gitk'.
-	The ``--'' is necessary to avoid confusion with the *branch* named
+	The `--` is necessary to avoid confusion with the *branch* named
 	'gitk'
 
 `git log --name-status release..test`::
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 3ac3e3a..5298f1b 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -53,7 +53,8 @@
 	Show only ignored files in the output. When showing files in the
 	index, print only those matched by an exclude pattern. When
 	showing "other" files, show only those matched by an exclude
-	pattern.
+	pattern. Standard ignore rules are not automatically activated,
+	therefore at least one of the `--exclude*` options is required.
 
 -s::
 --stage::
@@ -183,7 +184,7 @@
 	Files to show. If no files are given all files which match the other
 	specified criteria are shown.
 
-Output
+OUTPUT
 ------
 'git ls-files' just outputs the filenames unless `--stage` is specified in
 which case it outputs:
@@ -208,7 +209,7 @@
 verbatim and the line is terminated by a NUL byte.
 
 
-Exclude Patterns
+EXCLUDE PATTERNS
 ----------------
 
 'git ls-files' can use a list of "exclude patterns" when
diff --git a/Documentation/git-ls-remote.txt b/Documentation/git-ls-remote.txt
index 5f2628c..b9fd377 100644
--- a/Documentation/git-ls-remote.txt
+++ b/Documentation/git-ls-remote.txt
@@ -10,7 +10,7 @@
 --------
 [verse]
 'git ls-remote' [--heads] [--tags] [--refs] [--upload-pack=<exec>]
-	      [-q | --quiet] [--exit-code] [--get-url]
+	      [-q | --quiet] [--exit-code] [--get-url] [--sort=<key>]
 	      [--symref] [<repository> [<refs>...]]
 
 DESCRIPTION
@@ -60,6 +60,24 @@
 	upload-pack only shows the symref HEAD, so it will be the only
 	one shown by ls-remote.
 
+--sort=<key>::
+	Sort based on the key given. Prefix `-` to sort in descending order
+	of the value. Supports "version:refname" or "v:refname" (tag names
+	are treated as versions). The "version:refname" sort order can also
+	be affected by the "versionsort.suffix" configuration variable.
+	See linkgit:git-for-each-ref[1] for more sort options, but be aware
+	keys like `committerdate` that require access to the objects
+	themselves will not work for refs whose objects have not yet been
+	fetched from the remote, and will give a `missing object` error.
+
+-o <option>::
+--server-option=<option>::
+	Transmit the given string to the server when communicating using
+	protocol version 2.  The given string must not contain a NUL or LF
+	character.
+	When multiple `--server-option=<option>` are given, they are all
+	sent to the other side in the order listed on the command line.
+
 <repository>::
 	The "remote" repository to query.  This parameter can be
 	either a URL or the name of a remote (see the GIT URLS and
@@ -90,6 +108,10 @@
 	c5db5456ae3b0873fc659c19fafdde22313cc441	refs/tags/v0.99.2
 	7ceca275d047c90c0c7d5afb13ab97efdf51bd6e	refs/tags/v0.99.3
 
+SEE ALSO
+--------
+linkgit:git-check-ref-format[1].
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt
index d5dfd84..6a5c00e 100644
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@ -57,7 +57,7 @@
 discouraged: while possible, it may leave you in a state that is hard to
 back out of in the case of a conflict.
 
-The fourth syntax ("`git merge --continue`") can only be run after the
+The third syntax ("`git merge --continue`") can only be run after the
 merge has resulted in conflicts.
 
 OPTIONS
diff --git a/Documentation/git-mktree.txt b/Documentation/git-mktree.txt
index c3616e7..27fe2b3 100644
--- a/Documentation/git-mktree.txt
+++ b/Documentation/git-mktree.txt
@@ -14,7 +14,7 @@
 DESCRIPTION
 -----------
 Reads standard input in non-recursive `ls-tree` output format, and creates
-a tree object.  The order of the tree entries is normalised by mktree so
+a tree object.  The order of the tree entries is normalized by mktree so
 pre-sorting the input is not required.  The object name of the tree object
 built is written to the standard output.
 
diff --git a/Documentation/git-name-rev.txt b/Documentation/git-name-rev.txt
index e8e68f5..5cb0eb0 100644
--- a/Documentation/git-name-rev.txt
+++ b/Documentation/git-name-rev.txt
@@ -61,8 +61,8 @@
 --always::
 	Show uniquely abbreviated commit object as fallback.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Given a commit, find out where it is relative to the local refs. Say somebody
 wrote you about that fantastic commit 33db5f4d9027a10e477ccf054b2c1ab94f74c85a.
diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
index d8c8f11..f0de3b8 100644
--- a/Documentation/git-p4.txt
+++ b/Documentation/git-p4.txt
@@ -29,8 +29,8 @@
 the updated p4 remote branch.
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 * Clone a repository:
 +
 ------------
@@ -149,6 +149,12 @@
 $ git p4 submit topicbranch
 ------------
 
+To specify a single commit or a range of commits, use:
+------------
+$ git p4 submit --commit <sha1>
+$ git p4 submit --commit <sha1..sha1>
+------------
+
 The upstream reference is generally 'refs/remotes/p4/master', but can
 be overridden using the `--origin=` command-line option.
 
@@ -164,6 +170,31 @@
 $ git p4 submit --update-shelve 1234 --update-shelve 2345
 ----
 
+
+Unshelve
+~~~~~~~~
+Unshelving will take a shelved P4 changelist, and produce the equivalent git commit
+in the branch refs/remotes/p4/unshelved/<changelist>.
+
+The git commit is created relative to the current origin revision (HEAD by default).
+If the shelved changelist's parent revisions differ, git-p4 will refuse to unshelve;
+you need to be unshelving onto an equivalent tree.
+
+The origin revision can be changed with the "--origin" option.
+
+If the target branch in refs/remotes/p4/unshelved already exists, the old one will
+be renamed.
+
+----
+$ git p4 sync
+$ git p4 unshelve 12345
+$ git show refs/remotes/p4/unshelved/12345
+<submit more changes via p4 to the same files>
+$ git p4 unshelve 12345
+<refuses to unshelve until git is in sync with p4 again>
+
+----
+
 OPTIONS
 -------
 
@@ -330,6 +361,19 @@
 	p4/master.  See the "Sync options" section above for more
 	information.
 
+--commit <sha1>|<sha1..sha1>::
+    Submit only the specified commit or range of commits, instead of the full
+    list of changes that are in the current Git branch.
+
+--disable-rebase::
+    Disable the automatic rebase after all commits have been successfully
+    submitted. Can also be set with git-p4.disableRebase.
+
+--disable-p4sync::
+    Disable the automatic sync of p4/master from Perforce after commits have
+    been submitted. Implies --disable-rebase. Can also be set with
+    git-p4.disableP4Sync. Sync with origin/master still goes ahead if possible.
+
 Rebase options
 ~~~~~~~~~~~~~~
 These options can be used to modify 'git p4 rebase' behavior.
@@ -337,6 +381,13 @@
 --import-labels::
 	Import p4 labels.
 
+Unshelve options
+~~~~~~~~~~~~~~~~
+
+--origin::
+    Sets the git refspec against which the shelved P4 changelist is compared.
+    Defaults to p4/master.
+
 DEPOT PATH SYNTAX
 -----------------
 The p4 depot path argument to 'git p4 sync' and 'git p4 clone' can
@@ -392,7 +443,7 @@
 The name of the client can be given to 'git p4' in multiple ways.  The
 variable 'git-p4.client' takes precedence if it exists.  Otherwise,
 normal p4 mechanisms of determining the client are used:  environment
-variable P4CLIENT, a file referenced by P4CONFIG, or the local host name.
+variable `P4CLIENT`, a file referenced by `P4CONFIG`, or the local host name.
 
 
 BRANCH DETECTION
@@ -461,22 +512,22 @@
 ~~~~~~~~~~~~~~~~~
 git-p4.user::
 	User specified as an option to all p4 commands, with '-u <user>'.
-	The environment variable 'P4USER' can be used instead.
+	The environment variable `P4USER` can be used instead.
 
 git-p4.password::
 	Password specified as an option to all p4 commands, with
 	'-P <password>'.
-	The environment variable 'P4PASS' can be used instead.
+	The environment variable `P4PASS` can be used instead.
 
 git-p4.port::
 	Port specified as an option to all p4 commands, with
 	'-p <port>'.
-	The environment variable 'P4PORT' can be used instead.
+	The environment variable `P4PORT` can be used instead.
 
 git-p4.host::
 	Host specified as an option to all p4 commands, with
 	'-h <host>'.
-	The environment variable 'P4HOST' can be used instead.
+	The environment variable `P4HOST` can be used instead.
 
 git-p4.client::
 	Client specified as an option to all p4 commands, with
@@ -644,6 +695,12 @@
 	Specify submit behavior when a conflict with p4 is found, as per
 	--conflict.  The default behavior is 'ask'.
 
+git-p4.disableRebase::
+    Do not rebase the tree against p4/master following a submit.
+
+git-p4.disableP4Sync::
+    Do not sync p4/master with Perforce following a submit. Implies git-p4.disableRebase.
+
 IMPLEMENTATION DETAILS
 ----------------------
 * Changesets from p4 are imported using Git fast-import.
diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt
index 81bc490..d95b472 100644
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -12,7 +12,7 @@
 'git pack-objects' [-q | --progress | --all-progress] [--all-progress-implied]
 	[--no-reuse-delta] [--delta-base-offset] [--non-empty]
 	[--local] [--incremental] [--window=<n>] [--depth=<n>]
-	[--revs [--unpacked | --all]]
+	[--revs [--unpacked | --all]] [--keep-pack=<pack-name>]
 	[--stdout [--filter=<filter-spec>] | base-name]
 	[--shallow] [--keep-true-parents] < object-list
 
@@ -96,7 +96,9 @@
 	it too deep affects the performance on the unpacker
 	side, because delta data needs to be applied that many
 	times to get to the necessary object.
-	The default value for --window is 10 and --depth is 50.
++
+The default value for --window is 10 and --depth is 50. The maximum
+depth is 4095.
 
 --window-memory=<n>::
 	This option provides an additional limit on top of `--window`;
@@ -126,6 +128,13 @@
 	has a .keep file to be ignored, even if it would have
 	otherwise been packed.
 
+--keep-pack=<pack-name>::
+	This flag causes an object already in the given pack to be
+	ignored, even if it would have otherwise been
+	packed. `<pack-name>` is the the pack file name without
+	leading directory (e.g. `pack-123.pack`). The option could be
+	specified multiple times to keep multiple packs.
+
 --incremental::
 	This flag causes an object already in a pack to be ignored
 	even if it would have otherwise been packed.
@@ -267,6 +276,19 @@
 	locally created objects [without .promisor] and objects from the
 	promisor remote [with .promisor].)  This is used with partial clone.
 
+--keep-unreachable::
+	Objects unreachable from the refs in packs named with
+	--unpacked= option are added to the resulting pack, in
+	addition to the reachable objects that are not in packs marked
+	with *.keep files. This implies `--revs`.
+
+--pack-loose-unreachable::
+	Pack unreachable loose objects (and their loose counterparts
+	removed). This implies `--revs`.
+
+--unpack-unreachable::
+	Keep unreachable objects in loose form. This implies `--revs`.
+
 SEE ALSO
 --------
 linkgit:git-rev-list[1]
diff --git a/Documentation/git-prune.txt b/Documentation/git-prune.txt
index a37c0af..03552dd 100644
--- a/Documentation/git-prune.txt
+++ b/Documentation/git-prune.txt
@@ -56,8 +56,8 @@
 	reachable from any of our references, keep objects
 	reachable from listed <head>s.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To prune objects not used by your repository or another that
 borrows from your repository via its
@@ -67,7 +67,7 @@
 $ git prune $(cd ../another && git rev-parse --all)
 ------------
 
-Notes
+NOTES
 -----
 
 In most cases, users will not need to call 'git prune' directly, but
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index ce05b7a..118d9d8 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git pull' [options] [<repository> [<refspec>...]]
+'git pull' [<options>] [<repository> [<refspec>...]]
 
 
 DESCRIPTION
@@ -101,13 +101,17 @@
 include::merge-options.txt[]
 
 -r::
---rebase[=false|true|preserve|interactive]::
+--rebase[=false|true|merges|preserve|interactive]::
 	When true, rebase the current branch on top of the upstream
 	branch after fetching. If there is a remote-tracking branch
 	corresponding to the upstream branch and the upstream branch
 	was rebased since last fetched, the rebase uses that information
 	to avoid rebasing non-local changes.
 +
+When set to `merges`, rebase using `git rebase --rebase-merges` so that
+the local merge commits are included in the rebase (see
+linkgit:git-rebase[1] for details).
++
 When set to preserve, rebase with the `--preserve-merges` option passed
 to `git rebase` so that locally created merge commits will not be flattened.
 +
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 5b08302..55277a9 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -11,7 +11,7 @@
 [verse]
 'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
 	   [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
-	   [-u | --set-upstream] [--push-option=<string>]
+	   [-u | --set-upstream] [-o <string> | --push-option=<string>]
 	   [--[no-]signed|--signed=(true|false|if-asked)]
 	   [--force-with-lease[=<refname>[:<expect>]]]
 	   [--no-verify] [<repository> [<refspec>...]]
@@ -123,6 +123,7 @@
 	will be tab-separated and sent to stdout instead of stderr.  The full
 	symbolic names of the refs will be given.
 
+-d::
 --delete::
 	All listed refs are deleted from the remote repository. This is
 	the same as prefixing all refs with a colon.
@@ -300,7 +301,7 @@
 	These options are passed to linkgit:git-send-pack[1]. A thin transfer
 	significantly reduces the amount of sent data when the sender and
 	receiver share many of the same objects in common. The default is
-	\--thin.
+	`--thin`.
 
 -q::
 --quiet::
@@ -423,7 +424,7 @@
 	refs, no explanation is needed. For a failed ref, the reason for
 	failure is described.
 
-Note about fast-forwards
+NOTE ABOUT FAST-FORWARDS
 ------------------------
 
 When an update changes a branch (or more in general, a ref) that used to
@@ -510,7 +511,7 @@
 a case where you do mean to lose history.
 
 
-Examples
+EXAMPLES
 --------
 
 `git push`::
diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index f2a07d5..5c70bc2 100644
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -132,7 +132,7 @@
 	The id of the tree object(s) to be read/merged.
 
 
-Merging
+MERGING
 -------
 If `-m` is specified, 'git read-tree' can perform 3 kinds of
 merge, a single tree merge if only 1 tree is given, a
@@ -382,7 +382,7 @@
 have finished your work-in-progress), attempt the merge again.
 
 
-Sparse checkout
+SPARSE CHECKOUT
 ---------------
 
 "Sparse checkout" allows populating the working directory sparsely.
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 3277ca1..0e20a66 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -8,9 +8,9 @@
 SYNOPSIS
 --------
 [verse]
-'git rebase' [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
+'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
 	[<upstream> [<branch>]]
-'git rebase' [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
+'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
 	--root [<branch>]
 'git rebase' --continue | --skip | --abort | --quit | --edit-todo | --show-current-patch
 
@@ -364,9 +364,10 @@
 	Incompatible with the --interactive option.
 
 --signoff::
-	This flag is passed to 'git am' to sign off all the rebased
-	commits (see linkgit:git-am[1]). Incompatible with the
-	--interactive option.
+	Add a Signed-off-by: trailer to all the rebased commits. Note
+	that if `--interactive` is given then only commits marked to be
+	picked, edited or reworded will have the trailer added. Incompatible
+	with the `--preserve-merges` option.
 
 -i::
 --interactive::
@@ -378,6 +379,33 @@
 rebase.instructionFormat.  A customized instruction format will automatically
 have the long commit hash prepended to the format.
 
+-r::
+--rebase-merges[=(rebase-cousins|no-rebase-cousins)]::
+	By default, a rebase will simply drop merge commits from the todo
+	list, and put the rebased commits into a single, linear branch.
+	With `--rebase-merges`, the rebase will instead try to preserve
+	the branching structure within the commits that are to be rebased,
+	by recreating the merge commits. Any resolved merge conflicts or
+	manual amendments in these merge commits will have to be
+	resolved/re-applied manually.
++
+By default, or when `no-rebase-cousins` was specified, commits which do not
+have `<upstream>` as direct ancestor will keep their original branch point,
+i.e. commits that would be excluded by gitlink:git-log[1]'s
+`--ancestry-path` option will keep their original ancestry by default. If
+the `rebase-cousins` mode is turned on, such commits are instead rebased
+onto `<upstream>` (or `<onto>`, if specified).
++
+The `--rebase-merges` mode is similar in spirit to `--preserve-merges`, but
+in contrast to that option works well in interactive rebases: commits can be
+reordered, inserted and dropped at will.
++
+It is currently only possible to recreate the merge commits using the
+`recursive` merge strategy; Different merge strategies can be used only via
+explicit `exec git merge -s <strategy> [...]` commands.
++
+See also REBASING MERGES below.
+
 -p::
 --preserve-merges::
 	Recreate merge commits instead of flattening the history by replaying
@@ -775,12 +803,146 @@
 'everyone' downstream from 'topic' will now have to perform a "hard
 case" recovery too!
 
+REBASING MERGES
+-----------------
+
+The interactive rebase command was originally designed to handle
+individual patch series. As such, it makes sense to exclude merge
+commits from the todo list, as the developer may have merged the
+then-current `master` while working on the branch, only to rebase
+all the commits onto `master` eventually (skipping the merge
+commits).
+
+However, there are legitimate reasons why a developer may want to
+recreate merge commits: to keep the branch structure (or "commit
+topology") when working on multiple, inter-related branches.
+
+In the following example, the developer works on a topic branch that
+refactors the way buttons are defined, and on another topic branch
+that uses that refactoring to implement a "Report a bug" button. The
+output of `git log --graph --format=%s -5` may look like this:
+
+------------
+*   Merge branch 'report-a-bug'
+|\
+| * Add the feedback button
+* | Merge branch 'refactor-button'
+|\ \
+| |/
+| * Use the Button class for all buttons
+| * Extract a generic Button class from the DownloadButton one
+------------
+
+The developer might want to rebase those commits to a newer `master`
+while keeping the branch topology, for example when the first topic
+branch is expected to be integrated into `master` much earlier than the
+second one, say, to resolve merge conflicts with changes to the
+DownloadButton class that made it into `master`.
+
+This rebase can be performed using the `--rebase-merges` option.
+It will generate a todo list looking like this:
+
+------------
+label onto
+
+# Branch: refactor-button
+reset onto
+pick 123456 Extract a generic Button class from the DownloadButton one
+pick 654321 Use the Button class for all buttons
+label refactor-button
+
+# Branch: report-a-bug
+reset refactor-button # Use the Button class for all buttons
+pick abcdef Add the feedback button
+label report-a-bug
+
+reset onto
+merge -C a1b2c3 refactor-button # Merge 'refactor-button'
+merge -C 6f5e4d report-a-bug # Merge 'report-a-bug'
+------------
+
+In contrast to a regular interactive rebase, there are `label`, `reset`
+and `merge` commands in addition to `pick` ones.
+
+The `label` command associates a label with the current HEAD when that
+command is executed. These labels are created as worktree-local refs
+(`refs/rewritten/<label>`) that will be deleted when the rebase
+finishes. That way, rebase operations in multiple worktrees linked to
+the same repository do not interfere with one another. If the `label`
+command fails, it is rescheduled immediately, with a helpful message how
+to proceed.
+
+The `reset` command resets the HEAD, index and worktree to the specified
+revision. It is isimilar to an `exec git reset --hard <label>`, but
+refuses to overwrite untracked files. If the `reset` command fails, it is
+rescheduled immediately, with a helpful message how to edit the todo list
+(this typically happens when a `reset` command was inserted into the todo
+list manually and contains a typo).
+
+The `merge` command will merge the specified revision into whatever is
+HEAD at that time. With `-C <original-commit>`, the commit message of
+the specified merge commit will be used. When the `-C` is changed to
+a lower-case `-c`, the message will be opened in an editor after a
+successful merge so that the user can edit the message.
+
+If a `merge` command fails for any reason other than merge conflicts (i.e.
+when the merge operation did not even start), it is rescheduled immediately.
+
+At this time, the `merge` command will *always* use the `recursive`
+merge strategy, with no way to choose a different one. To work around
+this, an `exec` command can be used to call `git merge` explicitly,
+using the fact that the labels are worktree-local refs (the ref
+`refs/rewritten/onto` would correspond to the label `onto`, for example).
+
+Note: the first command (`label onto`) labels the revision onto which
+the commits are rebased; The name `onto` is just a convention, as a nod
+to the `--onto` option.
+
+It is also possible to introduce completely new merge commits from scratch
+by adding a command of the form `merge <merge-head>`. This form will
+generate a tentative commit message and always open an editor to let the
+user edit it. This can be useful e.g. when a topic branch turns out to
+address more than a single concern and wants to be split into two or
+even more topic branches. Consider this todo list:
+
+------------
+pick 192837 Switch from GNU Makefiles to CMake
+pick 5a6c7e Document the switch to CMake
+pick 918273 Fix detection of OpenSSL in CMake
+pick afbecd http: add support for TLS v1.3
+pick fdbaec Fix detection of cURL in CMake on Windows
+------------
+
+The one commit in this list that is not related to CMake may very well
+have been motivated by working on fixing all those bugs introduced by
+switching to CMake, but it addresses a different concern. To split this
+branch into two topic branches, the todo list could be edited like this:
+
+------------
+label onto
+
+pick afbecd http: add support for TLS v1.3
+label tlsv1.3
+
+reset onto
+pick 192837 Switch from GNU Makefiles to CMake
+pick 918273 Fix detection of OpenSSL in CMake
+pick fdbaec Fix detection of cURL in CMake on Windows
+pick 5a6c7e Document the switch to CMake
+label cmake
+
+reset onto
+merge tlsv1.3
+merge cmake
+------------
+
 BUGS
 ----
 The todo list presented by `--preserve-merges --interactive` does not
 represent the topology of the revision graph.  Editing commits and
 rewording their commit messages should work fine, but attempts to
-reorder commits tend to produce counterintuitive results.
+reorder commits tend to produce counterintuitive results. Use
+`--rebase-merges` in such scenarios instead.
 
 For example, an attempt to rearrange
 ------------
diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt
index 86a4b32..dedf97e 100644
--- a/Documentation/git-receive-pack.txt
+++ b/Documentation/git-receive-pack.txt
@@ -41,7 +41,7 @@
 <directory>::
 	The repository to sync into.
 
-pre-receive Hook
+PRE-RECEIVE HOOK
 ----------------
 Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
 and is executable, it will be invoked once with no parameters.  The
@@ -116,7 +116,7 @@
 
 See the notes on the quarantine environment below.
 
-update Hook
+UPDATE HOOK
 -----------
 Before each ref is updated, if $GIT_DIR/hooks/update file exists
 and is executable, it is invoked once per ref, with three parameters:
@@ -138,7 +138,7 @@
 As such it is not a good idea to send notices (e.g. email) from
 this hook.  Consider using the post-receive hook instead.
 
-post-receive Hook
+POST-RECEIVE HOOK
 -----------------
 After all refs were updated (or attempted to be updated), if any
 ref update was successful, and if $GIT_DIR/hooks/post-receive
@@ -198,7 +198,7 @@
 to evaluate it.  It is recommended that hooks rely on sha1-new
 rather than the current value of refname.
 
-post-update Hook
+POST-UPDATE HOOK
 ----------------
 After all other processing, if at least one ref was updated, and
 if $GIT_DIR/hooks/post-update file exists and is executable, then
@@ -216,7 +216,7 @@
 	exec git update-server-info
 
 
-Quarantine Environment
+QUARANTINE ENVIRONMENT
 ----------------------
 
 When `receive-pack` takes in objects, they are placed into a temporary
diff --git a/Documentation/git-remote-ext.txt b/Documentation/git-remote-ext.txt
index b25d0b5..3fc5d94 100644
--- a/Documentation/git-remote-ext.txt
+++ b/Documentation/git-remote-ext.txt
@@ -55,14 +55,14 @@
 	the vhost field in the git:// service request (to rest of the argument).
 	Default is not to send vhost in such request (if sent).
 
-ENVIRONMENT VARIABLES:
-----------------------
+ENVIRONMENT VARIABLES
+---------------------
 
 GIT_TRANSLOOP_DEBUG::
 	If set, prints debugging information about various reads/writes.
 
-ENVIRONMENT VARIABLES PASSED TO COMMAND:
-----------------------------------------
+ENVIRONMENT VARIABLES PASSED TO COMMAND
+---------------------------------------
 
 GIT_EXT_SERVICE::
 	Set to long name (git-upload-pack, etc...) of service helper needs
@@ -73,8 +73,8 @@
 	to invoke.
 
 
-EXAMPLES:
----------
+EXAMPLES
+--------
 This remote helper is transparently used by Git when
 you use commands such as "git fetch <URL>", "git clone <URL>",
 , "git push <URL>" or "git remote add <nick> <URL>", where <URL>
diff --git a/Documentation/git-remote.txt b/Documentation/git-remote.txt
index 4feddc0..0cad37f 100644
--- a/Documentation/git-remote.txt
+++ b/Documentation/git-remote.txt
@@ -186,8 +186,8 @@
 
 'update'::
 
-Fetch updates for a named set of remotes in the repository as defined by
-remotes.<group>.  If a named group is not specified on the command line,
+Fetch updates for remotes or remote groups in the repository as defined by
+remotes.<group>.  If neither group nor remote is specified on the command line,
 the configuration parameter remotes.default will be used; if
 remotes.default is not defined, all remotes which do not have the
 configuration parameter remote.<name>.skipDefaultUpdate set to true will
@@ -203,7 +203,7 @@
 `remote.origin.fetch` configuration variables.  (See
 linkgit:git-config[1]).
 
-Examples
+EXAMPLES
 --------
 
 * Add a new remote, fetch, and check out a branch from it
diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
index ae750e9..d90e790 100644
--- a/Documentation/git-repack.txt
+++ b/Documentation/git-repack.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [--window=<n>] [--depth=<n>] [--threads=<n>]
+'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
 
 DESCRIPTION
 -----------
@@ -90,7 +90,9 @@
 	space. `--depth` limits the maximum delta depth; making it too deep
 	affects the performance on the unpacker side, because delta data needs
 	to be applied that many times to get to the necessary object.
-	The default value for --window is 10 and --depth is 50.
++
+The default value for --window is 10 and --depth is 50. The maximum
+depth is 4095.
 
 --threads=<n>::
 	This option is passed through to `git pack-objects`.
@@ -133,6 +135,13 @@
 	with `-b` or `repack.writeBitmaps`, as it ensures that the
 	bitmapped packfile has the necessary objects.
 
+--keep-pack=<pack-name>::
+	Exclude the given pack from repacking. This is the equivalent
+	of having `.keep` file on the pack. `<pack-name>` is the the
+	pack file name without leading directory (e.g. `pack-123.pack`).
+	The option could be specified multiple times to keep multiple
+	packs.
+
 --unpack-unreachable=<when>::
 	When loosening unreachable objects, do not bother loosening any
 	objects older than `<when>`. This can be used to optimize out
diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt
index e5c57ae..246dc99 100644
--- a/Documentation/git-replace.txt
+++ b/Documentation/git-replace.txt
@@ -11,6 +11,7 @@
 'git replace' [-f] <object> <replacement>
 'git replace' [-f] --edit <object>
 'git replace' [-f] --graft <commit> [<parent>...]
+'git replace' [-f] --convert-graft-file
 'git replace' -d <object>...
 'git replace' [--format=<format>] [-l [<pattern>]]
 
@@ -87,9 +88,13 @@
 	content as <commit> except that its parents will be
 	[<parent>...] instead of <commit>'s parents. A replacement ref
 	is then created to replace <commit> with the newly created
-	commit. See contrib/convert-grafts-to-replace-refs.sh for an
-	example script based on this option that can convert grafts to
-	replace refs.
+	commit. Use `--convert-graft-file` to convert a
+	`$GIT_DIR/info/grafts` file and use replace refs instead.
+
+--convert-graft-file::
+	Creates graft commits for all entries in `$GIT_DIR/info/grafts`
+	and deletes that file upon success. The purpose is to help users
+	with transitioning off of the now-deprecated graft file.
 
 -l <pattern>::
 --list <pattern>::
diff --git a/Documentation/git-request-pull.txt b/Documentation/git-request-pull.txt
index c32cb0b..4d4392d 100644
--- a/Documentation/git-request-pull.txt
+++ b/Documentation/git-request-pull.txt
@@ -46,8 +46,8 @@
 its remote name.
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Imagine that you built your work on your `master` branch on top of
 the `v1.0` release, and want it to be integrated to the project.
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 95326b8..e72d332 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git rev-parse' [ --option ] <args>...
+'git rev-parse' [<options>] <args>...
 
 DESCRIPTION
 -----------
@@ -360,7 +360,7 @@
 
 ------------
 OPTS_SPEC="\
-some-command [options] <args>...
+some-command [<options>] <args>...
 
 some-command does foo and bar!
 --
@@ -385,7 +385,7 @@
 usage text would be shown:
 
 ------------
-usage: some-command [options] <args>...
+usage: some-command [<options>] <args>...
 
     some-command does foo and bar!
 
diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 71ef97b..4f3efde 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git send-email' [options] <file|directory|rev-list options>...
+'git send-email' [<options>] <file|directory|rev-list options>...
 'git send-email' --dump-aliases
 
 
@@ -255,7 +255,7 @@
 
 --batch-size=<num>::
 	Some email servers (e.g. smtp.163.com) limit the number emails to be
-	sent per session (connection) and this will lead to a faliure when
+	sent per session (connection) and this will lead to a failure when
 	sending many messages.  With this option, send-email will disconnect after
 	sending $<num> messages and wait for a few seconds (see --relogin-delay)
 	and reconnect, to work around such a limit.  You may want to
@@ -458,8 +458,8 @@
 	one of 'always', 'never', 'cc', 'compose', or 'auto'. See `--confirm`
 	in the previous section for the meaning of these values.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 Use gmail as the smtp server
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 To use 'git send-email' to send your patches through the GMail SMTP server,
@@ -473,16 +473,7 @@
 
 If you have multifactor authentication setup on your gmail account, you will
 need to generate an app-specific password for use with 'git send-email'. Visit
-https://security.google.com/settings/security/apppasswords to setup an
-app-specific password.  Once setup, you can store it with the credentials
-helper:
-
-	$ git credential fill
-	protocol=smtp
-	host=smtp.gmail.com
-	username=youname@gmail.com
-	password=app-password
-
+https://security.google.com/settings/security/apppasswords to create it.
 
 Once your commits are ready to be sent to the mailing list, run the
 following commands:
@@ -491,6 +482,11 @@
 	$ edit outgoing/0000-*
 	$ git send-email outgoing/*
 
+The first time you run it, you will be prompted for your credentials.  Enter the
+app-specific or your regular password as appropriate.  If you have credential
+helper configured (see linkgit:git-credential[1]), the password will be saved in
+the credential store so you won't have to type it the next time.
+
 Note: the following perl modules are required
       Net::SMTP::SSL, MIME::Base64 and Authen::SASL
 
diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt
index f51c649..44fd146 100644
--- a/Documentation/git-send-pack.txt
+++ b/Documentation/git-send-pack.txt
@@ -99,7 +99,7 @@
 	The remote refs to update.
 
 
-Specifying the Refs
+SPECIFYING THE REFS
 -------------------
 
 There are three ways to specify which refs to update on the
diff --git a/Documentation/git-shell.txt b/Documentation/git-shell.txt
index 54cf256..11361f3 100644
--- a/Documentation/git-shell.txt
+++ b/Documentation/git-shell.txt
@@ -62,8 +62,8 @@
 If a `no-interactive-login` command exists, then it is run and the
 interactive shell is aborted.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To disable interactive logins, displaying a greeting instead:
 
diff --git a/Documentation/git-shortlog.txt b/Documentation/git-shortlog.txt
index ee6c547..bc80905 100644
--- a/Documentation/git-shortlog.txt
+++ b/Documentation/git-shortlog.txt
@@ -8,8 +8,8 @@
 SYNOPSIS
 --------
 [verse]
+'git shortlog' [<options>] [<revision range>] [[--] <path>...]
 git log --pretty=short | 'git shortlog' [<options>]
-'git shortlog' [<options>] [<revision range>] [[\--] <path>...]
 
 DESCRIPTION
 -----------
@@ -69,11 +69,11 @@
 	ways to spell <revision range>, see the "Specifying Ranges"
 	section of linkgit:gitrevisions[7].
 
-[\--] <path>...::
+[--] <path>...::
 	Consider only commits that are enough to explain how the files
 	that match the specified paths came to be.
 +
-Paths may need to be prefixed with "\-- " to separate them from
+Paths may need to be prefixed with `--` to separate them from
 options or the revision range, when confusion arises.
 
 MAPPING AUTHORS
diff --git a/Documentation/git-show-branch.txt b/Documentation/git-show-branch.txt
index 7818e0f..262db04 100644
--- a/Documentation/git-show-branch.txt
+++ b/Documentation/git-show-branch.txt
@@ -173,8 +173,8 @@
 The current branch is "master".
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 If you keep your primary branches immediately under
 `refs/heads`, and topic branches in subdirectories of
diff --git a/Documentation/git-show-ref.txt b/Documentation/git-show-ref.txt
index c0aa871..d28e615 100644
--- a/Documentation/git-show-ref.txt
+++ b/Documentation/git-show-ref.txt
@@ -120,8 +120,8 @@
 ...
 -----------------------------------------------------------------------------
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To show all references called "master", whether tags or heads or anything
 else, and regardless of how deep in the reference naming hierarchy they are,
diff --git a/Documentation/git-show.txt b/Documentation/git-show.txt
index e73ef54..fcf528c 100644
--- a/Documentation/git-show.txt
+++ b/Documentation/git-show.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git show' [options] [<object>...]
+'git show' [<options>] [<object>...]
 
 DESCRIPTION
 -----------
@@ -77,7 +77,7 @@
 	Concatenates the contents of said Makefiles in the head
 	of the branch `master`.
 
-Discussion
+DISCUSSION
 ----------
 
 include::i18n.txt[]
diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt
index 6c230c0..c4467ff 100644
--- a/Documentation/git-status.txt
+++ b/Documentation/git-status.txt
@@ -113,7 +113,7 @@
 	- 'matching'    - Shows ignored files and directories matching an
 			  ignore pattern.
 +
-When 'matching' mode is specified, paths that explicity match an
+When 'matching' mode is specified, paths that explicitly match an
 ignored pattern are shown. If a directory matches an ignore pattern,
 then it is shown, but not paths contained in the ignored directory. If
 a directory does not match an ignore pattern, but all contents are
@@ -135,6 +135,16 @@
 	Display or do not display detailed ahead/behind counts for the
 	branch relative to its upstream branch.  Defaults to true.
 
+--renames::
+--no-renames::
+	Turn on/off rename detection regardless of user configuration.
+	See also linkgit:git-diff[1] `--no-renames`.
+
+--find-renames[=<n>]::
+	Turn on rename detection, optionally setting the similarity
+	threshold.
+	See also linkgit:git-diff[1] `--find-renames`.
+
 <pathspec>...::
 	See the 'pathspec' entry in linkgit:gitglossary[7].
 
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 71c5618..ef9d9d2 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -42,8 +42,8 @@
 when following the rules for relative URLs - because the evaluation
 of relative URLs in Git is identical to that of relative directories).
 +
-The default remote is the remote of the remote tracking branch
-of the current branch. If no such remote tracking branch exists or
+The default remote is the remote of the remote-tracking branch
+of the current branch. If no such remote-tracking branch exists or
 the HEAD is detached, "origin" is assumed to be the default remote.
 If the superproject doesn't have a default remote configured
 the superproject is its own authoritative upstream and the current
@@ -213,8 +213,8 @@
 	submodule URLs change upstream and you need to update your local
 	repositories accordingly.
 +
-"git submodule sync" synchronizes all submodules while
-"git submodule sync \-- A" synchronizes submodule "A" only.
+`git submodule sync` synchronizes all submodules while
+`git submodule sync -- A` synchronizes submodule "A" only.
 +
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and sync any nested submodules within.
@@ -239,6 +239,13 @@
 --quiet::
 	Only print error messages.
 
+--progress::
+	This option is only valid for add and update commands.
+	Progress status is reported on the standard error stream
+	by default when it is attached to a terminal, unless -q
+	is specified. This flag forces progress status even if the
+	standard error stream is not directed to a terminal.
+
 --all::
 	This option is only valid for the deinit command. Unregister all
 	submodules in the working tree.
@@ -362,7 +369,15 @@
 	this option will be passed to the linkgit:git-clone[1] command.
 +
 *NOTE*: Do *not* use this option unless you have read the note
-for linkgit:git-clone[1]'s `--reference` and `--shared` options carefully.
+for linkgit:git-clone[1]'s `--reference`, `--shared`, and `--dissociate`
+options carefully.
+
+--dissociate::
+	This option is only valid for add and update commands.  These
+	commands sometimes need to clone a remote repository. In this case,
+	this option will be passed to the linkgit:git-clone[1] command.
++
+*NOTE*: see the NOTE for the `--reference` option.
 
 --recursive::
 	This option is only valid for foreach, update, status and sync commands.
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index 636e090..7ea24fc 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git svn' <command> [options] [arguments]
+'git svn' <command> [<options>] [<arguments>]
 
 DESCRIPTION
 -----------
@@ -635,7 +635,8 @@
 
 -A<filename>::
 --authors-file=<filename>::
-	Syntax is compatible with the file used by 'git cvsimport':
+	Syntax is compatible with the file used by 'git cvsimport' but
+	an empty email address can be supplied with '<>':
 +
 ------------------------------------------------------------------------
 	loginname = Joe User <user@example.com>
@@ -654,8 +655,14 @@
 	If this option is specified, for each SVN committer name that
 	does not exist in the authors file, the given file is executed
 	with the committer name as the first argument.  The program is
-	expected to return a single line of the form "Name <email>",
-	which will be treated as if included in the authors file.
+	expected to return a single line of the form "Name <email>" or
+	"Name <>", which will be treated as if included in the authors
+	file.
++
+Due to historical reasons a relative 'filename' is first searched
+relative to the current directory for 'init' and 'clone' and relative
+to the root of the working tree for 'fetch'. If 'filename' is
+not found, it is searched like any other command in '$PATH'.
 +
 [verse]
 config key: svn.authorsProg
@@ -700,7 +707,7 @@
 config key: svn.useLogAuthor
 
 --add-author-from::
-	When committing to svn from Git (as part of 'commit-diff', 'set-tree' or 'dcommit'
+	When committing to svn from Git (as part of 'set-tree' or 'dcommit'
 	operations), if the existing log message doesn't already have a
 	`From:` or `Signed-off-by:` line, append a `From:` line based on the
 	Git commit's author string.  If you use this, then `--use-log-author`
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 1d17101..87c4288 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -34,8 +34,8 @@
 If `-m <msg>` or `-F <file>` is given and `-a`, `-s`, and `-u <keyid>`
 are absent, `-a` is implied.
 
-Otherwise just a tag reference for the SHA-1 object name of the commit object is
-created (i.e. a lightweight tag).
+Otherwise, a tag reference that points directly at the given object
+(i.e., a lightweight tag) is created.
 
 A GnuPG signed tag object will be created when `-s` or `-u
 <keyid>` is used.  When `-u <keyid>` is not used, the
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 3897a59..4e8e762 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -228,7 +228,7 @@
 	cleaner names.
 	The same applies to directories ending '/' and paths with '//'
 
-Using --refresh
+USING --REFRESH
 ---------------
 `--refresh` does not calculate a new sha1 file or bring the index
 up to date for mode/content changes. But what it *does* do is to
@@ -239,7 +239,7 @@
 For example, you'd want to do this after doing a 'git read-tree', to link
 up the stat index details with the proper files.
 
-Using --cacheinfo or --info-only
+USING --CACHEINFO OR --INFO-ONLY
 --------------------------------
 `--cacheinfo` is used to register a file that is not in the
 current working directory.  This is useful for minimum-checkout
@@ -261,7 +261,7 @@
 object database.
 
 
-Using --index-info
+USING --INDEX-INFO
 ------------------
 
 `--index-info` is a more powerful mechanism that lets you feed
@@ -317,7 +317,7 @@
 ------------
 
 
-Using ``assume unchanged'' bit
+USING ``ASSUME UNCHANGED'' BIT
 ------------------------------
 
 Many operations in Git depend on your filesystem to have an
@@ -350,7 +350,7 @@
 to mark them as "assume unchanged").
 
 
-Examples
+EXAMPLES
 --------
 To update and refresh only the files already checked out:
 
@@ -387,7 +387,7 @@
 <9> now it checks with lstat(2) and finds it has been changed.
 
 
-Skip-worktree bit
+SKIP-WORKTREE BIT
 -----------------
 
 Skip-worktree bit can be defined in one (long) sentence: When reading
@@ -407,7 +407,7 @@
 different from assume-unchanged bit's. Skip-worktree also takes
 precedence over assume-unchanged bit when both are set.
 
-Split index
+SPLIT INDEX
 -----------
 
 This mode is designed for repositories with very large indexes, and
@@ -432,7 +432,7 @@
 modification time is updated to the current time everytime a new split
 index based on the shared index file is either created or read from.
 
-Untracked cache
+UNTRACKED CACHE
 ---------------
 
 This cache is meant to speed up commands that involve determining
@@ -490,7 +490,7 @@
 status" run with `core.untrackedCache=false` to flush out the leftover
 bad data.
 
-File System Monitor
+FILE SYSTEM MONITOR
 -------------------
 
 This feature is intended to speed up git operations for repos that have
@@ -518,7 +518,7 @@
 a command reads the index. When `--[no-]fsmonitor` are used, the file
 system monitor is immediately added to or removed from the index.
 
-Configuration
+CONFIGURATION
 -------------
 
 The command honors `core.filemode` configuration variable.  If
diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 969bfab..bc8fdfd 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -120,7 +120,7 @@
 <ref> is updated or deleted atomically, a concurrent reader may
 still see a subset of the modifications.
 
-Logging Updates
+LOGGING UPDATES
 ---------------
 If config parameter "core.logAllRefUpdates" is true and the ref is one under
 "refs/heads/", "refs/remotes/", "refs/notes/", or the symbolic ref HEAD; or
diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt
index 44ff954..6072f93 100644
--- a/Documentation/git-var.txt
+++ b/Documentation/git-var.txt
@@ -23,14 +23,14 @@
 	as well. (However, the configuration variables listing functionality
 	is deprecated in favor of `git config -l`.)
 
-EXAMPLE
+EXAMPLES
 --------
 	$ git var GIT_AUTHOR_IDENT
 	Eric W. Biederman <ebiederm@lnxi.com> 1121223278 -0600
 
 
 VARIABLES
-----------
+---------
 GIT_AUTHOR_IDENT::
     The author of a piece of code.
 
diff --git a/Documentation/git-web--browse.txt b/Documentation/git-web--browse.txt
index 2d6b09a..fd952a5 100644
--- a/Documentation/git-web--browse.txt
+++ b/Documentation/git-web--browse.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git web{litdd}browse' [OPTIONS] URL/FILE ...
+'git web{litdd}browse' [<options>] <url|file>...
 
 DESCRIPTION
 -----------
@@ -84,7 +84,7 @@
 as a custom command and will use a shell eval to run the command with
 the URLs passed as arguments.
 
-Note about konqueror
+NOTE ABOUT KONQUEROR
 --------------------
 
 When 'konqueror' is specified by a command-line option or a
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index e7eb24a..afc6576 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -14,7 +14,7 @@
 'git worktree lock' [--reason <string>] <worktree>
 'git worktree move' <worktree> <new-path>
 'git worktree prune' [-n] [-v] [--expire <expire>]
-'git worktree remove' [--force] <worktree>
+'git worktree remove' [-f] <worktree>
 'git worktree unlock' <worktree>
 
 DESCRIPTION
@@ -27,11 +27,12 @@
 tree is associated with the repository.  This new working tree is called a
 "linked working tree" as opposed to the "main working tree" prepared by "git
 init" or "git clone".  A repository has one main working tree (if it's not a
-bare repository) and zero or more linked working trees.
+bare repository) and zero or more linked working trees. When you are done
+with a linked working tree, remove it with `git worktree remove`.
 
-When you are done with a linked working tree you can simply delete it.
-The working tree's administrative files in the repository (see
-"DETAILS" below) will eventually be removed automatically (see
+If a working tree is deleted without using `git worktree remove`, then
+its associated administrative files, which reside in the repository
+(see "DETAILS" below), will eventually be removed automatically (see
 `gc.worktreePruneExpire` in linkgit:git-config[1]), or you can run
 `git worktree prune` in the main or any linked working tree to
 clean up any stale administrative files.
@@ -60,8 +61,13 @@
 ------------
 +
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
-then, as a convenience, a new branch based at HEAD is created automatically,
-as if `-b $(basename <path>)` was specified.
+then, as a convenience, the new worktree is associated with a branch
+(call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
+doesn't exist, a new branch based on HEAD is automatically created as
+if `-b <branch>` was given.  If `<branch>` does exist, it will be
+checked out in the new worktree, if it's not checked out anywhere
+else, otherwise the command will refuse to create the worktree (unless
+`--force` is used).
 
 list::
 
@@ -106,7 +112,7 @@
 	By default, `add` refuses to create a new working tree when
 	`<commit-ish>` is a branch name and is already checked out by
 	another working tree and `remove` refuses to remove an unclean
-	working tree. This option overrides that safeguard.
+	working tree. This option overrides these safeguards.
 
 -b <new-branch>::
 -B <new-branch>::
@@ -232,7 +238,7 @@
 details on a single line with columns.  For example:
 
 ------------
-S git worktree list
+$ git worktree list
 /path/to/bare-source            (bare)
 /path/to/linked-worktree        abcd1234 [master]
 /path/to/other-linked-worktree  1234abc  (detached HEAD)
@@ -247,7 +253,7 @@
 example:
 
 ------------
-S git worktree list --porcelain
+$ git worktree list --porcelain
 worktree /path/to/bare-source
 bare
 
@@ -278,8 +284,7 @@
 # ... hack hack hack ...
 $ git commit -a -m 'emergency fix for boss'
 $ popd
-$ rm -rf ../temp
-$ git worktree prune
+$ git worktree remove ../temp
 ------------
 
 BUGS
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 4767860..dba7f0c 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -11,7 +11,7 @@
 [verse]
 'git' [--version] [--help] [-C <path>] [-c <name>=<value>]
     [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
-    [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
+    [-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare]
     [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
     [--super-prefix=<path>]
     <command> [<args>]
@@ -103,6 +103,7 @@
 	configuration options (see the "Configuration Mechanism" section
 	below).
 
+-P::
 --no-pager::
 	Do not pipe Git output into a pager.
 
@@ -163,6 +164,16 @@
 	Do not perform optional operations that require locks. This is
 	equivalent to setting the `GIT_OPTIONAL_LOCKS` to `0`.
 
+--list-cmds=group[,group...]::
+	List commands by group. This is an internal/experimental
+	option and may change or be removed in the future. Supported
+	groups are: builtins, parseopt (builtin commands that use
+	parse-options), main (all commands in libexec directory),
+	others (all other commands in `$PATH` that have git- prefix),
+	list-<category> (see categories in command-list.txt),
+	nohelpers (exclude helper commands), alias and config
+	(retrieve command list from config variable completion.commands)
+
 GIT COMMANDS
 ------------
 
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 1094fe2..92010b0 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitattributes - defining attributes per path
+gitattributes - Defining attributes per path
 
 SYNOPSIS
 --------
@@ -279,6 +279,94 @@
   catch potential problems early, safety triggers.
 
 
+`working-tree-encoding`
+^^^^^^^^^^^^^^^^^^^^^^^
+
+Git recognizes files encoded in ASCII or one of its supersets (e.g.
+UTF-8, ISO-8859-1, ...) as text files. Files encoded in certain other
+encodings (e.g. UTF-16) are interpreted as binary and consequently
+built-in Git text processing tools (e.g. 'git diff') as well as most Git
+web front ends do not visualize the contents of these files by default.
+
+In these cases you can tell Git the encoding of a file in the working
+directory with the `working-tree-encoding` attribute. If a file with this
+attribute is added to Git, then Git reencodes the content from the
+specified encoding to UTF-8. Finally, Git stores the UTF-8 encoded
+content in its internal data structure (called "the index"). On checkout
+the content is reencoded back to the specified encoding.
+
+Please note that using the `working-tree-encoding` attribute may have a
+number of pitfalls:
+
+- Alternative Git implementations (e.g. JGit or libgit2) and older Git
+  versions (as of March 2018) do not support the `working-tree-encoding`
+  attribute. If you decide to use the `working-tree-encoding` attribute
+  in your repository, then it is strongly recommended to ensure that all
+  clients working with the repository support it.
+
+  For example, Microsoft Visual Studio resources files (`*.rc`) or
+  PowerShell script files (`*.ps1`) are sometimes encoded in UTF-16.
+  If you declare `*.ps1` as files as UTF-16 and you add `foo.ps1` with
+  a `working-tree-encoding` enabled Git client, then `foo.ps1` will be
+  stored as UTF-8 internally. A client without `working-tree-encoding`
+  support will checkout `foo.ps1` as UTF-8 encoded file. This will
+  typically cause trouble for the users of this file.
+
+  If a Git client, that does not support the `working-tree-encoding`
+  attribute, adds a new file `bar.ps1`, then `bar.ps1` will be
+  stored "as-is" internally (in this example probably as UTF-16).
+  A client with `working-tree-encoding` support will interpret the
+  internal contents as UTF-8 and try to convert it to UTF-16 on checkout.
+  That operation will fail and cause an error.
+
+- Reencoding content to non-UTF encodings can cause errors as the
+  conversion might not be UTF-8 round trip safe. If you suspect your
+  encoding to not be round trip safe, then add it to
+  `core.checkRoundtripEncoding` to make Git check the round trip
+  encoding (see linkgit:git-config[1]). SHIFT-JIS (Japanese character
+  set) is known to have round trip issues with UTF-8 and is checked by
+  default.
+
+- Reencoding content requires resources that might slow down certain
+  Git operations (e.g 'git checkout' or 'git add').
+
+Use the `working-tree-encoding` attribute only if you cannot store a file
+in UTF-8 encoding and if you want Git to be able to process the content
+as text.
+
+As an example, use the following attributes if your '*.ps1' files are
+UTF-16 encoded with byte order mark (BOM) and you want Git to perform
+automatic line ending conversion based on your platform.
+
+------------------------
+*.ps1		text working-tree-encoding=UTF-16
+------------------------
+
+Use the following attributes if your '*.ps1' files are UTF-16 little
+endian encoded without BOM and you want Git to use Windows line endings
+in the working directory. Please note, it is highly recommended to
+explicitly define the line endings with `eol` if the `working-tree-encoding`
+attribute is used to avoid ambiguity.
+
+------------------------
+*.ps1		text working-tree-encoding=UTF-16LE eol=CRLF
+------------------------
+
+You can get a list of all available encodings on your platform with the
+following command:
+
+------------------------
+iconv --list
+------------------------
+
+If you do not know the encoding of a file, then you can use the `file`
+command to guess the encoding:
+
+------------------------
+file foo.ps1
+------------------------
+
+
 `ident`
 ^^^^^^^
 
@@ -1141,8 +1229,8 @@
 ------------
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 If you have these three `gitattributes` file:
 
diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
index 9f13266..592e06d 100644
--- a/Documentation/gitcli.txt
+++ b/Documentation/gitcli.txt
@@ -110,8 +110,8 @@
 +
 ---------------------------------------------
 $ git describe -h
-usage: git describe [options] <commit-ish>*
-   or: git describe [options] --dirty
+usage: git describe [<options>] <commit-ish>*
+   or: git describe [<options>] --dirty
 
     --contains            find the tag that comes after the commit
     --debug               debug search strategy on stderr
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index f877f7b..e3c283a 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -31,7 +31,7 @@
 arguments, and stdin. See the documentation for each hook below for
 details.
 
-'git init' may copy hooks to the new repository, depending on its
+`git init` may copy hooks to the new repository, depending on its
 configuration. See the "TEMPLATE DIRECTORY" section in
 linkgit:git-init[1] for details. When the rest of this document refers
 to "default hooks" it's talking about the default template shipped
@@ -45,9 +45,9 @@
 applypatch-msg
 ~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes a single
+This hook is invoked by linkgit:git-am[1].  It takes a single
 parameter, the name of the file that holds the proposed commit
-log message.  Exiting with a non-zero status causes 'git am' to abort
+log message.  Exiting with a non-zero status causes `git am` to abort
 before applying the patch.
 
 The hook is allowed to edit the message file in place, and can
@@ -61,7 +61,7 @@
 pre-applypatch
 ~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes no parameter, and is
+This hook is invoked by linkgit:git-am[1].  It takes no parameter, and is
 invoked after the patch is applied, but before a commit is made.
 
 If it exits with non-zero status, then the working tree will not be
@@ -76,33 +76,33 @@
 post-applypatch
 ~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes no parameter,
+This hook is invoked by linkgit:git-am[1].  It takes no parameter,
 and is invoked after the patch is applied and a commit is made.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git am'.
+the outcome of `git am`.
 
 pre-commit
 ~~~~~~~~~~
 
-This hook is invoked by 'git commit', and can be bypassed
+This hook is invoked by linkgit:git-commit[1], and can be bypassed
 with the `--no-verify` option.  It takes no parameters, and is
 invoked before obtaining the proposed commit log message and
 making a commit.  Exiting with a non-zero status from this script
-causes the 'git commit' command to abort before creating a commit.
+causes the `git commit` command to abort before creating a commit.
 
 The default 'pre-commit' hook, when enabled, catches introduction
 of lines with trailing whitespaces and aborts the commit when
 such a line is found.
 
-All the 'git commit' hooks are invoked with the environment
+All the `git commit` hooks are invoked with the environment
 variable `GIT_EDITOR=:` if the command will not bring up an editor
 to modify the commit message.
 
 prepare-commit-msg
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git commit' right after preparing the
+This hook is invoked by linkgit:git-commit[1] right after preparing the
 default log message, and before the editor is started.
 
 It takes one to three parameters.  The first is the name of the file
@@ -114,7 +114,7 @@
 (if a `.git/SQUASH_MSG` file exists); or `commit`, followed by
 a commit SHA-1 (if a `-c`, `-C` or `--amend` option was given).
 
-If the exit status is non-zero, 'git commit' will abort.
+If the exit status is non-zero, `git commit` will abort.
 
 The purpose of the hook is to edit the message file in place, and
 it is not suppressed by the `--no-verify` option.  A non-zero exit
@@ -127,7 +127,7 @@
 commit-msg
 ~~~~~~~~~~
 
-This hook is invoked by 'git commit' and 'git merge', and can be
+This hook is invoked by linkgit:git-commit[1] and linkgit:git-merge[1], and can be
 bypassed with the `--no-verify` option.  It takes a single parameter,
 the name of the file that holds the proposed commit log message.
 Exiting with a non-zero status causes the command to abort.
@@ -143,16 +143,16 @@
 post-commit
 ~~~~~~~~~~~
 
-This hook is invoked by 'git commit'. It takes no parameters, and is
+This hook is invoked by linkgit:git-commit[1]. It takes no parameters, and is
 invoked after a commit is made.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git commit'.
+the outcome of `git commit`.
 
 pre-rebase
 ~~~~~~~~~~
 
-This hook is called by 'git rebase' and can be used to prevent a
+This hook is called by linkgit:git-rebase[1] and can be used to prevent a
 branch from getting rebased.  The hook may be called with one or
 two parameters.  The first parameter is the upstream from which
 the series was forked.  The second parameter is the branch being
@@ -161,17 +161,17 @@
 post-checkout
 ~~~~~~~~~~~~~
 
-This hook is invoked when a 'git checkout' is run after having updated the
+This hook is invoked when a linkgit:git-checkout[1] is run after having updated the
 worktree.  The hook is given three parameters: the ref of the previous HEAD,
 the ref of the new HEAD (which may or may not have changed), and a flag
 indicating whether the checkout was a branch checkout (changing branches,
 flag=1) or a file checkout (retrieving a file from the index, flag=0).
-This hook cannot affect the outcome of 'git checkout'.
+This hook cannot affect the outcome of `git checkout`.
 
-It is also run after 'git clone', unless the --no-checkout (-n) option is
+It is also run after linkgit:git-clone[1], unless the `--no-checkout` (`-n`) option is
 used. The first parameter given to the hook is the null-ref, the second the
-ref of the new HEAD and the flag is always 1. Likewise for 'git worktree add'
-unless --no-checkout is used.
+ref of the new HEAD and the flag is always 1. Likewise for `git worktree add`
+unless `--no-checkout` is used.
 
 This hook can be used to perform repository validity checks, auto-display
 differences from the previous HEAD if different, or set working dir metadata
@@ -180,10 +180,10 @@
 post-merge
 ~~~~~~~~~~
 
-This hook is invoked by 'git merge', which happens when a 'git pull'
+This hook is invoked by linkgit:git-merge[1], which happens when a `git pull`
 is done on a local repository.  The hook takes a single parameter, a status
 flag specifying whether or not the merge being done was a squash merge.
-This hook cannot affect the outcome of 'git merge' and is not executed,
+This hook cannot affect the outcome of `git merge` and is not executed,
 if the merge failed due to conflicts.
 
 This hook can be used in conjunction with a corresponding pre-commit hook to
@@ -194,10 +194,10 @@
 pre-push
 ~~~~~~~~
 
-This hook is called by 'git push' and can be used to prevent a push from taking
-place.  The hook is called with two parameters which provide the name and
-location of the destination remote, if a named remote is not being used both
-values will be the same.
+This hook is called by linkgit:git-push[1] and can be used to prevent
+a push from taking place.  The hook is called with two parameters
+which provide the name and location of the destination remote, if a
+named remote is not being used both values will be the same.
 
 Information about what is to be pushed is provided on the hook's standard
 input with lines of the form:
@@ -216,7 +216,7 @@
 than a name which could be expanded (such as `HEAD~`, or a SHA-1) it will be
 supplied as it was originally given.
 
-If this hook exits with a non-zero status, 'git push' will abort without
+If this hook exits with a non-zero status, `git push` will abort without
 pushing anything.  Information about why the push is rejected may be sent
 to the user by writing to standard error.
 
@@ -224,8 +224,8 @@
 pre-receive
 ~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 Just before starting to update refs on the remote repository, the
 pre-receive hook is invoked.  Its exit status determines the success
 or failure of the update.
@@ -246,7 +246,7 @@
 still be prevented by the <<update,'update'>> hook.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The number of push options given on the command line of
@@ -265,8 +265,8 @@
 update
 ~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 Just before updating the ref on the remote repository, the update hook
 is invoked.  Its exit status determines the success or failure of
 the ref update.
@@ -279,7 +279,7 @@
  - and the new object name to be stored in the ref.
 
 A zero exit from the update hook allows the ref to be updated.
-Exiting with a non-zero status prevents 'git-receive-pack'
+Exiting with a non-zero status prevents `git receive-pack`
 from updating that ref.
 
 This hook can be used to prevent 'forced' update on certain refs by
@@ -299,7 +299,7 @@
 shell to restrict the user's access to only git commands.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The default 'update' hook, when enabled--and with
@@ -310,8 +310,8 @@
 post-receive
 ~~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 It executes on the remote repository once after all the refs have
 been updated.
 
@@ -320,7 +320,7 @@
 <<pre-receive,'pre-receive'>>
 hook does on its standard input.
 
-This hook does not affect the outcome of 'git-receive-pack', as it
+This hook does not affect the outcome of `git receive-pack`, as it
 is called after the real work is done.
 
 This supersedes the <<post-update,'post-update'>> hook in that it gets
@@ -328,7 +328,7 @@
 names.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The default 'post-receive' hook is empty, but there is
@@ -349,8 +349,8 @@
 post-update
 ~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 It executes on the remote repository once after all the refs have
 been updated.
 
@@ -358,7 +358,7 @@
 name of ref that was actually updated.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git-receive-pack'.
+the outcome of `git receive-pack`.
 
 The 'post-update' hook can tell what are the heads that were pushed,
 but it does not know what their original and updated values are,
@@ -368,20 +368,20 @@
 them.
 
 When enabled, the default 'post-update' hook runs
-'git update-server-info' to keep the information used by dumb
+`git update-server-info` to keep the information used by dumb
 transports (e.g., HTTP) up to date.  If you are publishing
 a Git repository that is accessible via HTTP, you should
 probably enable this hook.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 push-to-checkout
 ~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository, and when
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository, and when
 the push tries to update the branch that is currently checked out
 and the `receive.denyCurrentBranch` configuration variable is set to
 `updateInstead`.  Such a push by default is refused if the working
@@ -400,8 +400,8 @@
 exit with a zero status.
 
 For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
-in order to emulate 'git fetch' that is run in the reverse direction
-with `git push`, as the two-tree form of `read-tree -u -m` is
+in order to emulate `git fetch` that is run in the reverse direction
+with `git push`, as the two-tree form of `git read-tree -u -m` is
 essentially the same as `git checkout` that switches branches while
 keeping the local changes in the working tree that do not interfere
 with the difference between the branches.
@@ -410,15 +410,16 @@
 pre-auto-gc
 ~~~~~~~~~~~
 
-This hook is invoked by 'git gc --auto'. It takes no parameter, and
-exiting with non-zero status from this script causes the 'git gc --auto'
-to abort.
+This hook is invoked by `git gc --auto` (see linkgit:git-gc[1]). It
+takes no parameter, and exiting with non-zero status from this script
+causes the `git gc --auto` to abort.
 
 post-rewrite
 ~~~~~~~~~~~~
 
-This hook is invoked by commands that rewrite commits (`git commit
---amend`, 'git-rebase'; currently 'git-filter-branch' does 'not' call
+This hook is invoked by commands that rewrite commits
+(linkgit:git-commit[1] when called with `--amend` and
+linkgit:git-rebase[1]; currently `git filter-branch` does 'not' call
 it!).  Its first argument denotes the command it was invoked by:
 currently one of `amend` or `rebase`.  Further command-dependent
 arguments may be passed in the future.
@@ -450,16 +451,16 @@
 sendemail-validate
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git send-email'.  It takes a single parameter,
+This hook is invoked by linkgit:git-send-email[1].  It takes a single parameter,
 the name of the file that holds the e-mail to be sent.  Exiting with a
-non-zero status causes 'git send-email' to abort before sending any
+non-zero status causes `git send-email` to abort before sending any
 e-mails.
 
 fsmonitor-watchman
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked when the configuration option core.fsmonitor is
-set to .git/hooks/fsmonitor-watchman.  It takes two arguments, a version
+This hook is invoked when the configuration option `core.fsmonitor` is
+set to `.git/hooks/fsmonitor-watchman`.  It takes two arguments, a version
 (currently 1) and the time in elapsed nanoseconds since midnight,
 January 1, 1970.
 
@@ -478,7 +479,7 @@
 given.
 
 An optimized way to tell git "all files have changed" is to return
-the filename '/'.
+the filename `/`.
 
 The exit status determines whether git will use the data from the
 hook to limit its search.  On error, it will fall back to verifying
diff --git a/Documentation/gitk.txt b/Documentation/gitk.txt
index ca96c28..244cd01 100644
--- a/Documentation/gitk.txt
+++ b/Documentation/gitk.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'gitk' [<options>] [<revision range>] [\--] [<path>...]
+'gitk' [<options>] [<revision range>] [--] [<path>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
index ac44a15..4caf5d8 100644
--- a/Documentation/gitmodules.txt
+++ b/Documentation/gitmodules.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitmodules - defining submodule properties
+gitmodules - Defining submodule properties
 
 SYNOPSIS
 --------
diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index 4b8c93e..9d1459a 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -102,6 +102,14 @@
 +
 Supported commands: 'connect'.
 
+'stateless-connect'::
+	Experimental; for internal use only.
+	Can attempt to connect to a remote server for communication
+	using git's wire-protocol version 2.  See the documentation
+	for the stateless-connect command for more information.
++
+Supported commands: 'stateless-connect'.
+
 'push'::
 	Can discover remote refs and push local commits and the
 	history leading up to them to new or existing remote refs.
@@ -136,6 +144,14 @@
 +
 Supported commands: 'connect'.
 
+'stateless-connect'::
+	Experimental; for internal use only.
+	Can attempt to connect to a remote server for communication
+	using git's wire-protocol version 2.  See the documentation
+	for the stateless-connect command for more information.
++
+Supported commands: 'stateless-connect'.
+
 'fetch'::
 	Can discover remote refs and transfer objects reachable from
 	them to the local object store.
@@ -375,6 +391,22 @@
 +
 Supported if the helper has the "connect" capability.
 
+'stateless-connect' <service>::
+	Experimental; for internal use only.
+	Connects to the given remote service for communication using
+	git's wire-protocol version 2.  Valid replies to this command
+	are empty line (connection established), 'fallback' (no smart
+	transport support, fall back to dumb transports) and just
+	exiting with error message printed (can't connect, don't bother
+	trying to fall back).  After line feed terminating the positive
+	(empty) response, the output of the service starts.  Messages
+	(both request and response) must consist of zero or more
+	PKT-LINEs, terminating in a flush packet. The client must not
+	expect the server to store any state in between request-response
+	pairs.  After the connection ends, the remote helper exits.
++
+Supported if the helper has the "stateless-connect" capability.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without
diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt
index c60bcad..e85148f 100644
--- a/Documentation/gitrepository-layout.txt
+++ b/Documentation/gitrepository-layout.txt
@@ -275,11 +275,6 @@
 	or manually by `git worktree prune`. The file may contain a string
 	explaining why the repository is locked.
 
-worktrees/<id>/link::
-	If this file exists, it is a hard link to the linked .git
-	file. It is used to detect if the linked repository is
-	manually removed.
-
 SEE ALSO
 --------
 linkgit:git-init[1],
diff --git a/Documentation/gitrevisions.txt b/Documentation/gitrevisions.txt
index 27dec5b..1f6ccea 100644
--- a/Documentation/gitrevisions.txt
+++ b/Documentation/gitrevisions.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitrevisions - specifying revisions and ranges for Git
+gitrevisions - Specifying revisions and ranges for Git
 
 SYNOPSIS
 --------
diff --git a/Documentation/gitworkflows.txt b/Documentation/gitworkflows.txt
index 926e044..ca11c7b 100644
--- a/Documentation/gitworkflows.txt
+++ b/Documentation/gitworkflows.txt
@@ -107,7 +107,7 @@
 .Merge upwards
 [caption="Rule: "]
 =====================================
-Always commit your fixes to the oldest supported branch that require
+Always commit your fixes to the oldest supported branch that requires
 them.  Then (periodically) merge the integration branches upwards into each
 other.
 =====================================
diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index 6b8888d..6c2d23d 100644
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -463,7 +463,7 @@
 [[def_push]]push::
 	Pushing a <<def_branch,branch>> means to get the branch's
 	<<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
-	find out if it is a direct ancestor to the branch's local
+	find out if it is an ancestor to the branch's local
 	head ref, and in that case, putting all
 	objects, which are <<def_reachable,reachable>> from the local
 	head ref, and which are missing from the remote
diff --git a/Documentation/howto/recover-corrupted-object-harder.txt b/Documentation/howto/recover-corrupted-object-harder.txt
index 9c4cd09..8994e25 100644
--- a/Documentation/howto/recover-corrupted-object-harder.txt
+++ b/Documentation/howto/recover-corrupted-object-harder.txt
@@ -80,7 +80,7 @@
     # now add our object data
     cat object >>tmp.pack
     # and then append the pack trailer
-    /path/to/git.git/test-sha1 -b <tmp.pack >trailer
+    /path/to/git.git/t/helper/test-tool sha1 -b <tmp.pack >trailer
     cat trailer >>tmp.pack
 ------------
 
diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt
index 12b6bbf..662c271 100644
--- a/Documentation/merge-config.txt
+++ b/Documentation/merge-config.txt
@@ -35,7 +35,13 @@
 merge.renameLimit::
 	The number of files to consider when performing rename detection
 	during a merge; if not specified, defaults to the value of
-	diff.renameLimit.
+	diff.renameLimit. This setting has no effect if rename detection
+	is turned off.
+
+merge.renames::
+	Whether and how Git detects renames.  If set to "false",
+	rename detection is disabled. If set to "true", basic rename
+	detection is enabled.  Defaults to the value of diff.renames.
 
 merge.renormalize::
 	Tell Git that canonical representation of files in the
diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index 4a58aad..aa66cbe 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -23,8 +23,9 @@
 	causing mismerges by tests done on actual merge commits
 	taken from Linux 2.6 kernel development history.
 	Additionally this can detect and handle merges involving
-	renames.  This is the default merge strategy when
-	pulling or merging one branch.
+	renames, but currently cannot make use of detected
+	copies.  This is the default merge strategy when pulling
+	or merging one branch.
 +
 The 'recursive' strategy can take the following options:
 
@@ -84,12 +85,14 @@
 	`merge.renormalize` configuration variable.
 
 no-renames;;
-	Turn off rename detection.
+	Turn off rename detection. This overrides the `merge.renames`
+	configuration variable.
 	See also linkgit:git-diff[1] `--no-renames`.
 
 find-renames[=<n>];;
 	Turn on rename detection, optionally setting the similarity
-	threshold.  This is the default.
+	threshold.  This is the default. This overrides the
+	'merge.renames' configuration variable.
 	See also linkgit:git-diff[1] `--find-renames`.
 
 rename-threshold=<n>;;
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index dfcc49c..7d1bd44 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -7,6 +7,10 @@
 ones listed near the end of this list name trees and
 blobs contained in a commit.
 
+NOTE: This document shows the "raw" syntax as seen by git. The shell
+and other UIs might require additional quoting to protect special
+characters and to avoid word splitting.
+
 '<sha1>', e.g. 'dae86e1950b1277e545cee180551750029cfe735', 'dae86e'::
   The full SHA-1 object name (40-byte hexadecimal string), or
   a leading substring that is unique within the repository.
@@ -186,6 +190,8 @@
   is matched. ':/!-foo' performs a negative match, while ':/!!foo' matches a
   literal '!' character, followed by 'foo'. Any other sequence beginning with
   ':/!' is reserved for now.
+  Depending on the given text, the shell's word splitting rules might
+  require additional quoting.
 
 '<rev>:<path>', e.g. 'HEAD:README', ':README', 'master:./README'::
   A suffix ':' followed by a path names the blob or tree
@@ -345,6 +351,7 @@
 with each step in the notation's expansion and selection carefully
 spelt out:
 
+....
    Args   Expanded arguments    Selected commits
    D                            G H D
    D F                          G H I J D F
@@ -367,3 +374,4 @@
 	  = B ^B^1 ^B^2 ^B^3
 	  = B ^D ^E ^F          B
    F^! D  = F ^I ^J D           G H D F
+....
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 9a778b0..fa39ac9 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -47,21 +47,23 @@
 repo-specific one; by overwriting, the higher-priority repo-specific
 value is left at the end).
 
-The `git_config_with_options` function lets the caller examine config
+The `config_with_options` function lets the caller examine config
 while adjusting some of the default behavior of `git_config`. It should
 almost never be used by "regular" Git code that is looking up
 configuration variables. It is intended for advanced callers like
 `git-config`, which are intentionally tweaking the normal config-lookup
 process. It takes two extra parameters:
 
-`filename`::
-If this parameter is non-NULL, it specifies the name of a file to
-parse for configuration, rather than looking in the usual files. Regular
-`git_config` defaults to `NULL`.
+`config_source`::
+If this parameter is non-NULL, it specifies the source to parse for
+configuration, rather than looking in the usual files. See `struct
+git_config_source` in `config.h` for details. Regular `git_config` defaults
+to `NULL`.
 
-`respect_includes`::
-Specify whether include directives should be followed in parsed files.
-Regular `git_config` defaults to `1`.
+`opts`::
+Specify options to adjust the behavior of parsing config files. See `struct
+config_options` in `config.h` for details. As an example: regular `git_config`
+sets `opts.respect_includes` to `1` by default.
 
 Reading Specific Files
 ----------------------
diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt
index 7fae00f..4f44ca2 100644
--- a/Documentation/technical/api-directory-listing.txt
+++ b/Documentation/technical/api-directory-listing.txt
@@ -53,7 +53,7 @@
 	not be returned even if all of its contents are ignored. In
 	this case, the contents are returned as individual entries.
 +
-If this is set, files and directories that explicity match an ignore
+If this is set, files and directories that explicitly match an ignore
 pattern are reported. Implicity ignored directories (directories that
 do not match an ignore pattern, but whose contents are all ignored)
 are not reported, instead all of the contents are reported.
diff --git a/Documentation/technical/api-object-access.txt b/Documentation/technical/api-object-access.txt
index a1162e5..5b29622 100644
--- a/Documentation/technical/api-object-access.txt
+++ b/Documentation/technical/api-object-access.txt
@@ -1,7 +1,7 @@
 object access API
 =================
 
-Talk about <sha1_file.c> and <object.h> family, things like
+Talk about <sha1-file.c> and <object.h> family, things like
 
 * read_sha1_file()
 * read_object_with_reference()
diff --git a/Documentation/technical/api-oid-array.txt b/Documentation/technical/api-oid-array.txt
index b0c11f8..9febfb1 100644
--- a/Documentation/technical/api-oid-array.txt
+++ b/Documentation/technical/api-oid-array.txt
@@ -35,13 +35,18 @@
 	Free all memory associated with the array and return it to the
 	initial, empty state.
 
+`oid_array_for_each`::
+	Iterate over each element of the list, executing the callback
+	function for each one. Does not sort the list, so any custom
+	hash order is retained. If the callback returns a non-zero
+	value, the iteration ends immediately and the callback's
+	return is propagated; otherwise, 0 is returned.
+
 `oid_array_for_each_unique`::
-	Efficiently iterate over each unique element of the list,
-	executing the callback function for each one. If the array is
-	not sorted, this function has the side effect of sorting it. If
-	the callback returns a non-zero value, the iteration ends
-	immediately and the callback's return is propagated; otherwise,
-	0 is returned.
+	Iterate over each unique element of the list in sorted order,
+	but otherwise behave like `oid_array_for_each`. If the array
+	is not sorted, this function has the side effect of sorting
+	it.
 
 Examples
 --------
diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt
index ee907c4..fb06089 100644
--- a/Documentation/technical/api-submodule-config.txt
+++ b/Documentation/technical/api-submodule-config.txt
@@ -38,7 +38,7 @@
 Functions
 ---------
 
-`void submodule_free()`::
+`void submodule_free(struct repository *r)`::
 
 	Use these to free the internally cached values.
 
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
new file mode 100644
index 0000000..ad6af81
--- /dev/null
+++ b/Documentation/technical/commit-graph-format.txt
@@ -0,0 +1,97 @@
+Git commit graph format
+=======================
+
+The Git commit graph stores a list of commit OIDs and some associated
+metadata, including:
+
+- The generation number of the commit. Commits with no parents have
+  generation number 1; commits with parents have generation number
+  one more than the maximum generation number of its parents. We
+  reserve zero as special, and can be used to mark a generation
+  number invalid or as "not computed".
+
+- The root tree OID.
+
+- The commit date.
+
+- The parents of the commit, stored using positional references within
+  the graph file.
+
+These positional references are stored as unsigned 32-bit integers
+corresponding to the array position withing the list of commit OIDs. We
+use the most-significant bit for special purposes, so we can store at most
+(1 << 31) - 1 (around 2 billion) commits.
+
+== Commit graph files have the following format:
+
+In order to allow extensions that add extra data to the graph, we organize
+the body into "chunks" and provide a binary lookup table at the beginning
+of the body. The header includes certain values, such as number of chunks
+and hash type.
+
+All 4-byte numbers are in network order.
+
+HEADER:
+
+  4-byte signature:
+      The signature is: {'C', 'G', 'P', 'H'}
+
+  1-byte version number:
+      Currently, the only valid version is 1.
+
+  1-byte Hash Version (1 = SHA-1)
+      We infer the hash length (H) from this value.
+
+  1-byte number (C) of "chunks"
+
+  1-byte (reserved for later use)
+     Current clients should ignore this value.
+
+CHUNK LOOKUP:
+
+  (C + 1) * 12 bytes listing the table of contents for the chunks:
+      First 4 bytes describe the chunk id. Value 0 is a terminating label.
+      Other 8 bytes provide the byte-offset in current file for chunk to
+      start. (Chunks are ordered contiguously in the file, so you can infer
+      the length using the next chunk position if necessary.) Each chunk
+      ID appears at most once.
+
+  The remaining data in the body is described one chunk at a time, and
+  these chunks may be given in any order. Chunks are required unless
+  otherwise specified.
+
+CHUNK DATA:
+
+  OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes)
+      The ith entry, F[i], stores the number of OIDs with first
+      byte at most i. Thus F[255] stores the total
+      number of commits (N).
+
+  OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
+      The OIDs for all commits in the graph, sorted in ascending order.
+
+  Commit Data (ID: {'C', 'G', 'E', 'T' }) (N * (H + 16) bytes)
+    * The first H bytes are for the OID of the root tree.
+    * The next 8 bytes are for the positions of the first two parents
+      of the ith commit. Stores value 0xffffffff if no parent in that
+      position. If there are more than two parents, the second value
+      has its most-significant bit on and the other bits store an array
+      position into the Large Edge List chunk.
+    * The next 8 bytes store the generation number of the commit and
+      the commit time in seconds since EPOCH. The generation number
+      uses the higher 30 bits of the first 4 bytes, while the commit
+      time uses the 32 bits of the second 4 bytes, along with the lowest
+      2 bits of the lowest byte, storing the 33rd and 34th bit of the
+      commit time.
+
+  Large Edge List (ID: {'E', 'D', 'G', 'E'}) [Optional]
+      This list of 4-byte values store the second through nth parents for
+      all octopus merges. The second parent value in the commit data stores
+      an array position within this list along with the most-significant bit
+      on. Starting at that array position, iterate through this list of commit
+      positions for the parents until reaching a value with the most-significant
+      bit on. The other bits correspond to the position of the last parent.
+
+TRAILER:
+
+	H-byte HASH-checksum of all of the above.
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
new file mode 100644
index 0000000..0550c6d
--- /dev/null
+++ b/Documentation/technical/commit-graph.txt
@@ -0,0 +1,163 @@
+Git Commit Graph Design Notes
+=============================
+
+Git walks the commit graph for many reasons, including:
+
+1. Listing and filtering commit history.
+2. Computing merge bases.
+
+These operations can become slow as the commit count grows. The merge
+base calculation shows up in many user-facing commands, such as 'merge-base'
+or 'status' and can take minutes to compute depending on history shape.
+
+There are two main costs here:
+
+1. Decompressing and parsing commits.
+2. Walking the entire graph to satisfy topological order constraints.
+
+The commit graph file is a supplemental data structure that accelerates
+commit graph walks. If a user downgrades or disables the 'core.commitGraph'
+config setting, then the existing ODB is sufficient. The file is stored
+as "commit-graph" either in the .git/objects/info directory or in the info
+directory of an alternate.
+
+The commit graph file stores the commit graph structure along with some
+extra metadata to speed up graph walks. By listing commit OIDs in lexi-
+cographic order, we can identify an integer position for each commit and
+refer to the parents of a commit using those integer positions. We use
+binary search to find initial commits and then use the integer positions
+for fast lookups during the walk.
+
+A consumer may load the following info for a commit from the graph:
+
+1. The commit OID.
+2. The list of parents, along with their integer position.
+3. The commit date.
+4. The root tree OID.
+5. The generation number (see definition below).
+
+Values 1-4 satisfy the requirements of parse_commit_gently().
+
+Define the "generation number" of a commit recursively as follows:
+
+ * A commit with no parents (a root commit) has generation number one.
+
+ * A commit with at least one parent has generation number one more than
+   the largest generation number among its parents.
+
+Equivalently, the generation number of a commit A is one more than the
+length of a longest path from A to a root commit. The recursive definition
+is easier to use for computation and observing the following property:
+
+    If A and B are commits with generation numbers N and M, respectively,
+    and N <= M, then A cannot reach B. That is, we know without searching
+    that B is not an ancestor of A because it is further from a root commit
+    than A.
+
+    Conversely, when checking if A is an ancestor of B, then we only need
+    to walk commits until all commits on the walk boundary have generation
+    number at most N. If we walk commits using a priority queue seeded by
+    generation numbers, then we always expand the boundary commit with highest
+    generation number and can easily detect the stopping condition.
+
+This property can be used to significantly reduce the time it takes to
+walk commits and determine topological relationships. Without generation
+numbers, the general heuristic is the following:
+
+    If A and B are commits with commit time X and Y, respectively, and
+    X < Y, then A _probably_ cannot reach B.
+
+This heuristic is currently used whenever the computation is allowed to
+violate topological relationships due to clock skew (such as "git log"
+with default order), but is not used when the topological order is
+required (such as merge base calculations, "git log --graph").
+
+In practice, we expect some commits to be created recently and not stored
+in the commit graph. We can treat these commits as having "infinite"
+generation number and walk until reaching commits with known generation
+number.
+
+Design Details
+--------------
+
+- The commit graph file is stored in a file named 'commit-graph' in the
+  .git/objects/info directory. This could be stored in the info directory
+  of an alternate.
+
+- The core.commitGraph config setting must be on to consume graph files.
+
+- The file format includes parameters for the object ID hash function,
+  so a future change of hash algorithm does not require a change in format.
+
+Future Work
+-----------
+
+- The commit graph feature currently does not honor commit grafts. This can
+  be remedied by duplicating or refactoring the current graft logic.
+
+- The 'commit-graph' subcommand does not have a "verify" mode that is
+  necessary for integration with fsck.
+
+- The file format includes room for precomputed generation numbers. These
+  are not currently computed, so all generation numbers will be marked as
+  0 (or "uncomputed"). A later patch will include this calculation.
+
+- After computing and storing generation numbers, we must make graph
+  walks aware of generation numbers to gain the performance benefits they
+  enable. This will mostly be accomplished by swapping a commit-date-ordered
+  priority queue with one ordered by generation number. The following
+  operations are important candidates:
+
+    - paint_down_to_common()
+    - 'log --topo-order'
+
+- Currently, parse_commit_gently() requires filling in the root tree
+  object for a commit. This passes through lookup_tree() and consequently
+  lookup_object(). Also, it calls lookup_commit() when loading the parents.
+  These method calls check the ODB for object existence, even if the
+  consumer does not need the content. For example, we do not need the
+  tree contents when computing merge bases. Now that commit parsing is
+  removed from the computation time, these lookup operations are the
+  slowest operations keeping graph walks from being fast. Consider
+  loading these objects without verifying their existence in the ODB and
+  only loading them fully when consumers need them. Consider a method
+  such as "ensure_tree_loaded(commit)" that fully loads a tree before
+  using commit->tree.
+
+- The current design uses the 'commit-graph' subcommand to generate the graph.
+  When this feature stabilizes enough to recommend to most users, we should
+  add automatic graph writes to common operations that create many commits.
+  For example, one could compute a graph on 'clone', 'fetch', or 'repack'
+  commands.
+
+- A server could provide a commit graph file as part of the network protocol
+  to avoid extra calculations by clients. This feature is only of benefit if
+  the user is willing to trust the file, because verifying the file is correct
+  is as hard as computing it from scratch.
+
+Related Links
+-------------
+[0] https://bugs.chromium.org/p/git/issues/detail?id=8
+    Chromium work item for: Serialized Commit Graph
+
+[1] https://public-inbox.org/git/20110713070517.GC18566@sigill.intra.peff.net/
+    An abandoned patch that introduced generation numbers.
+
+[2] https://public-inbox.org/git/20170908033403.q7e6dj7benasrjes@sigill.intra.peff.net/
+    Discussion about generation numbers on commits and how they interact
+    with fsck.
+
+[3] https://public-inbox.org/git/20170908034739.4op3w4f2ma5s65ku@sigill.intra.peff.net/
+    More discussion about generation numbers and not storing them inside
+    commit objects. A valuable quote:
+
+    "I think we should be moving more in the direction of keeping
+     repo-local caches for optimizations. Reachability bitmaps have been
+     a big performance win. I think we should be doing the same with our
+     properties of commits. Not just generation numbers, but making it
+     cheap to access the graph structure without zlib-inflating whole
+     commit objects (i.e., packv4 or something like the "metapacks" I
+     proposed a few years ago)."
+
+[4] https://public-inbox.org/git/20180108154822.54829-1-git@jeffhostetler.com/T/#u
+    A patch to remove the ahead-behind calculation from 'status'.
diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt
index 417ba49..4ab6cd1 100644
--- a/Documentation/technical/hash-function-transition.txt
+++ b/Documentation/technical/hash-function-transition.txt
@@ -28,11 +28,30 @@
   address stored content.
 
 Over time some flaws in SHA-1 have been discovered by security
-researchers. https://shattered.io demonstrated a practical SHA-1 hash
-collision. As a result, SHA-1 cannot be considered cryptographically
-secure any more. This impacts the communication of hash values because
-we cannot trust that a given hash value represents the known good
-version of content that the speaker intended.
+researchers. On 23 February 2017 the SHAttered attack
+(https://shattered.io) demonstrated a practical SHA-1 hash collision.
+
+Git v2.13.0 and later subsequently moved to a hardened SHA-1
+implementation by default, which isn't vulnerable to the SHAttered
+attack.
+
+Thus Git has in effect already migrated to a new hash that isn't SHA-1
+and doesn't share its vulnerabilities, its new hash function just
+happens to produce exactly the same output for all known inputs,
+except two PDFs published by the SHAttered researchers, and the new
+implementation (written by those researchers) claims to detect future
+cryptanalytic collision attacks.
+
+Regardless, it's considered prudent to move past any variant of SHA-1
+to a new hash. There's no guarantee that future attacks on SHA-1 won't
+be published in the future, and those attacks may not have viable
+mitigations.
+
+If SHA-1 and its variants were to be truly broken, Git's hash function
+could not be considered cryptographically secure any more. This would
+impact the communication of hash values because we could not trust
+that a given hash value represented the known good version of content
+that the speaker intended.
 
 SHA-1 still possesses the other properties such as fast object lookup
 and safe error checking, but other hash functions are equally suitable
@@ -116,10 +135,15 @@
 		objectFormat = newhash
 		compatObjectFormat = sha1
 
-Specifying a repository format extension ensures that versions of Git
-not aware of NewHash do not try to operate on these repositories,
-instead producing an error message:
+The combination of setting `core.repositoryFormatVersion=1` and
+populating `extensions.*` ensures that all versions of Git later than
+`v0.99.9l` will die instead of trying to operate on the NewHash
+repository, instead producing an error message.
 
+	# Between v0.99.9l and v2.7.0
+	$ git status
+	fatal: Expected git repo version <= 0, found 1
+	# After v2.7.0
 	$ git status
 	fatal: unknown repository extensions found:
 		objectformat
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index 8e5bf60..70a99fd 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -36,6 +36,98 @@
 
   - The trailer records 20-byte SHA-1 checksum of all of the above.
 
+=== Object types
+
+Valid object types are:
+
+- OBJ_COMMIT (1)
+- OBJ_TREE (2)
+- OBJ_BLOB (3)
+- OBJ_TAG (4)
+- OBJ_OFS_DELTA (6)
+- OBJ_REF_DELTA (7)
+
+Type 5 is reserved for future expansion. Type 0 is invalid.
+
+=== Deltified representation
+
+Conceptually there are only four object types: commit, tree, tag and
+blob. However to save space, an object could be stored as a "delta" of
+another "base" object. These representations are assigned new types
+ofs-delta and ref-delta, which is only valid in a pack file.
+
+Both ofs-delta and ref-delta store the "delta" to be applied to
+another object (called 'base object') to reconstruct the object. The
+difference between them is, ref-delta directly encodes 20-byte base
+object name. If the base object is in the same pack, ofs-delta encodes
+the offset of the base object in the pack instead.
+
+The base object could also be deltified if it's in the same pack.
+Ref-delta can also refer to an object outside the pack (i.e. the
+so-called "thin pack"). When stored on disk however, the pack should
+be self contained to avoid cyclic dependency.
+
+The delta data is a sequence of instructions to reconstruct an object
+from the base object. If the base object is deltified, it must be
+converted to canonical form first. Each instruction appends more and
+more data to the target object until it's complete. There are two
+supported instructions so far: one for copy a byte range from the
+source object and one for inserting new data embedded in the
+instruction itself.
+
+Each instruction has variable length. Instruction type is determined
+by the seventh bit of the first octet. The following diagrams follow
+the convention in RFC 1951 (Deflate compressed data format).
+
+==== Instruction to copy from base object
+
+  +----------+---------+---------+---------+---------+-------+-------+-------+
+  | 1xxxxxxx | offset1 | offset2 | offset3 | offset4 | size1 | size2 | size3 |
+  +----------+---------+---------+---------+---------+-------+-------+-------+
+
+This is the instruction format to copy a byte range from the source
+object. It encodes the offset to copy from and the number of bytes to
+copy. Offset and size are in little-endian order.
+
+All offset and size bytes are optional. This is to reduce the
+instruction size when encoding small offsets or sizes. The first seven
+bits in the first octet determines which of the next seven octets is
+present. If bit zero is set, offset1 is present. If bit one is set
+offset2 is present and so on.
+
+Note that a more compact instruction does not change offset and size
+encoding. For example, if only offset2 is omitted like below, offset3
+still contains bits 16-23. It does not become offset2 and contains
+bits 8-15 even if it's right next to offset1.
+
+  +----------+---------+---------+
+  | 10000101 | offset1 | offset3 |
+  +----------+---------+---------+
+
+In its most compact form, this instruction only takes up one byte
+(0x80) with both offset and size omitted, which will have default
+values zero. There is another exception: size zero is automatically
+converted to 0x10000.
+
+==== Instruction to add new data
+
+  +----------+============+
+  | 0xxxxxxx |    data    |
+  +----------+============+
+
+This is the instruction to construct target object without the base
+object. The following data is appended to the target object. The first
+seven bits of the first octet determines the size of data in
+bytes. The size must be non-zero.
+
+==== Reserved instruction
+
+  +----------+============
+  | 00000000 |
+  +----------+============
+
+This is the instruction reserved for future expansion.
+
 == Original (version 1) pack-*.idx files have the following format:
 
   - The header consists of 256 4-byte network byte order
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
new file mode 100644
index 0000000..49bda76
--- /dev/null
+++ b/Documentation/technical/protocol-v2.txt
@@ -0,0 +1,414 @@
+ Git Wire Protocol, Version 2
+==============================
+
+This document presents a specification for a version 2 of Git's wire
+protocol.  Protocol v2 will improve upon v1 in the following ways:
+
+  * Instead of multiple service names, multiple commands will be
+    supported by a single service
+  * Easily extendable as capabilities are moved into their own section
+    of the protocol, no longer being hidden behind a NUL byte and
+    limited by the size of a pkt-line
+  * Separate out other information hidden behind NUL bytes (e.g. agent
+    string as a capability and symrefs can be requested using 'ls-refs')
+  * Reference advertisement will be omitted unless explicitly requested
+  * ls-refs command to explicitly request some refs
+  * Designed with http and stateless-rpc in mind.  With clear flush
+    semantics the http remote helper can simply act as a proxy
+
+In protocol v2 communication is command oriented.  When first contacting a
+server a list of capabilities will advertised.  Some of these capabilities
+will be commands which a client can request be executed.  Once a command
+has completed, a client can reuse the connection and request that other
+commands be executed.
+
+ Packet-Line Framing
+---------------------
+
+All communication is done using packet-line framing, just as in v1.  See
+`Documentation/technical/pack-protocol.txt` and
+`Documentation/technical/protocol-common.txt` for more information.
+
+In protocol v2 these special packets will have the following semantics:
+
+  * '0000' Flush Packet (flush-pkt) - indicates the end of a message
+  * '0001' Delimiter Packet (delim-pkt) - separates sections of a message
+
+ Initial Client Request
+------------------------
+
+In general a client can request to speak protocol v2 by sending
+`version=2` through the respective side-channel for the transport being
+used which inevitably sets `GIT_PROTOCOL`.  More information can be
+found in `pack-protocol.txt` and `http-protocol.txt`.  In all cases the
+response from the server is the capability advertisement.
+
+ Git Transport
+~~~~~~~~~~~~~~~
+
+When using the git:// transport, you can request to use protocol v2 by
+sending "version=2" as an extra parameter:
+
+   003egit-upload-pack /project.git\0host=myserver.com\0\0version=2\0
+
+ SSH and File Transport
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+When using either the ssh:// or file:// transport, the GIT_PROTOCOL
+environment variable must be set explicitly to include "version=2".
+
+ HTTP Transport
+~~~~~~~~~~~~~~~~
+
+When using the http:// or https:// transport a client makes a "smart"
+info/refs request as described in `http-protocol.txt` and requests that
+v2 be used by supplying "version=2" in the `Git-Protocol` header.
+
+   C: Git-Protocol: version=2
+   C:
+   C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
+
+A v2 server would reply:
+
+   S: 200 OK
+   S: <Some headers>
+   S: ...
+   S:
+   S: 000eversion 2\n
+   S: <capability-advertisement>
+
+Subsequent requests are then made directly to the service
+`$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack).
+
+ Capability Advertisement
+--------------------------
+
+A server which decides to communicate (based on a request from a client)
+using protocol version 2, notifies the client by sending a version string
+in its initial response followed by an advertisement of its capabilities.
+Each capability is a key with an optional value.  Clients must ignore all
+unknown keys.  Semantics of unknown values are left to the definition of
+each key.  Some capabilities will describe commands which can be requested
+to be executed by the client.
+
+    capability-advertisement = protocol-version
+			       capability-list
+			       flush-pkt
+
+    protocol-version = PKT-LINE("version 2" LF)
+    capability-list = *capability
+    capability = PKT-LINE(key[=value] LF)
+
+    key = 1*(ALPHA | DIGIT | "-_")
+    value = 1*(ALPHA | DIGIT | " -_.,?\/{}[]()<>!@#$%^&*+=:;")
+
+ Command Request
+-----------------
+
+After receiving the capability advertisement, a client can then issue a
+request to select the command it wants with any particular capabilities
+or arguments.  There is then an optional section where the client can
+provide any command specific parameters or queries.  Only a single
+command can be requested at a time.
+
+    request = empty-request | command-request
+    empty-request = flush-pkt
+    command-request = command
+		      capability-list
+		      [command-args]
+		      flush-pkt
+    command = PKT-LINE("command=" key LF)
+    command-args = delim-pkt
+		   *command-specific-arg
+
+    command-specific-args are packet line framed arguments defined by
+    each individual command.
+
+The server will then check to ensure that the client's request is
+comprised of a valid command as well as valid capabilities which were
+advertised.  If the request is valid the server will then execute the
+command.  A server MUST wait till it has received the client's entire
+request before issuing a response.  The format of the response is
+determined by the command being executed, but in all cases a flush-pkt
+indicates the end of the response.
+
+When a command has finished, and the client has received the entire
+response from the server, a client can either request that another
+command be executed or can terminate the connection.  A client may
+optionally send an empty request consisting of just a flush-pkt to
+indicate that no more requests will be made.
+
+ Capabilities
+--------------
+
+There are two different types of capabilities: normal capabilities,
+which can be used to to convey information or alter the behavior of a
+request, and commands, which are the core actions that a client wants to
+perform (fetch, push, etc).
+
+Protocol version 2 is stateless by default.  This means that all commands
+must only last a single round and be stateless from the perspective of the
+server side, unless the client has requested a capability indicating that
+state should be maintained by the server.  Clients MUST NOT require state
+management on the server side in order to function correctly.  This
+permits simple round-robin load-balancing on the server side, without
+needing to worry about state management.
+
+ agent
+~~~~~~~
+
+The server can advertise the `agent` capability with a value `X` (in the
+form `agent=X`) to notify the client that the server is running version
+`X`.  The client may optionally send its own agent string by including
+the `agent` capability with a value `Y` (in the form `agent=Y`) in its
+request to the server (but it MUST NOT do so if the server did not
+advertise the agent capability). The `X` and `Y` strings may contain any
+printable ASCII characters except space (i.e., the byte range 32 < x <
+127), and are typically of the form "package/version" (e.g.,
+"git/1.8.3.1"). The agent strings are purely informative for statistics
+and debugging purposes, and MUST NOT be used to programmatically assume
+the presence or absence of particular features.
+
+ ls-refs
+~~~~~~~~~
+
+`ls-refs` is the command used to request a reference advertisement in v2.
+Unlike the current reference advertisement, ls-refs takes in arguments
+which can be used to limit the refs sent from the server.
+
+Additional features not supported in the base command will be advertised
+as the value of the command in the capability advertisement in the form
+of a space separated list of features: "<command>=<feature 1> <feature 2>"
+
+ls-refs takes in the following arguments:
+
+    symrefs
+	In addition to the object pointed by it, show the underlying ref
+	pointed by it when showing a symbolic ref.
+    peel
+	Show peeled tags.
+    ref-prefix <prefix>
+	When specified, only references having a prefix matching one of
+	the provided prefixes are displayed.
+
+The output of ls-refs is as follows:
+
+    output = *ref
+	     flush-pkt
+    ref = PKT-LINE(obj-id SP refname *(SP ref-attribute) LF)
+    ref-attribute = (symref | peeled)
+    symref = "symref-target:" symref-target
+    peeled = "peeled:" obj-id
+
+ fetch
+~~~~~~~
+
+`fetch` is the command used to fetch a packfile in v2.  It can be looked
+at as a modified version of the v1 fetch where the ref-advertisement is
+stripped out (since the `ls-refs` command fills that role) and the
+message format is tweaked to eliminate redundancies and permit easy
+addition of future extensions.
+
+Additional features not supported in the base command will be advertised
+as the value of the command in the capability advertisement in the form
+of a space separated list of features: "<command>=<feature 1> <feature 2>"
+
+A `fetch` request can take the following arguments:
+
+    want <oid>
+	Indicates to the server an object which the client wants to
+	retrieve.  Wants can be anything and are not limited to
+	advertised objects.
+
+    have <oid>
+	Indicates to the server an object which the client has locally.
+	This allows the server to make a packfile which only contains
+	the objects that the client needs. Multiple 'have' lines can be
+	supplied.
+
+    done
+	Indicates to the server that negotiation should terminate (or
+	not even begin if performing a clone) and that the server should
+	use the information supplied in the request to construct the
+	packfile.
+
+    thin-pack
+	Request that a thin pack be sent, which is a pack with deltas
+	which reference base objects not contained within the pack (but
+	are known to exist at the receiving end). This can reduce the
+	network traffic significantly, but it requires the receiving end
+	to know how to "thicken" these packs by adding the missing bases
+	to the pack.
+
+    no-progress
+	Request that progress information that would normally be sent on
+	side-band channel 2, during the packfile transfer, should not be
+	sent.  However, the side-band channel 3 is still used for error
+	responses.
+
+    include-tag
+	Request that annotated tags should be sent if the objects they
+	point to are being sent.
+
+    ofs-delta
+	Indicate that the client understands PACKv2 with delta referring
+	to its base by position in pack rather than by an oid.  That is,
+	they can read OBJ_OFS_DELTA (ake type 6) in a packfile.
+
+If the 'shallow' feature is advertised the following arguments can be
+included in the clients request as well as the potential addition of the
+'shallow-info' section in the server's response as explained below.
+
+    shallow <oid>
+	A client must notify the server of all commits for which it only
+	has shallow copies (meaning that it doesn't have the parents of
+	a commit) by supplying a 'shallow <oid>' line for each such
+	object so that the server is aware of the limitations of the
+	client's history.  This is so that the server is aware that the
+	client may not have all objects reachable from such commits.
+
+    deepen <depth>
+	Requests that the fetch/clone should be shallow having a commit
+	depth of <depth> relative to the remote side.
+
+    deepen-relative
+	Requests that the semantics of the "deepen" command be changed
+	to indicate that the depth requested is relative to the client's
+	current shallow boundary, instead of relative to the requested
+	commits.
+
+    deepen-since <timestamp>
+	Requests that the shallow clone/fetch should be cut at a
+	specific time, instead of depth.  Internally it's equivalent to
+	doing "git rev-list --max-age=<timestamp>". Cannot be used with
+	"deepen".
+
+    deepen-not <rev>
+	Requests that the shallow clone/fetch should be cut at a
+	specific revision specified by '<rev>', instead of a depth.
+	Internally it's equivalent of doing "git rev-list --not <rev>".
+	Cannot be used with "deepen", but can be used with
+	"deepen-since".
+
+If the 'filter' feature is advertised, the following argument can be
+included in the client's request:
+
+    filter <filter-spec>
+	Request that various objects from the packfile be omitted
+	using one of several filtering techniques. These are intended
+	for use with partial clone and partial fetch operations. See
+	`rev-list` for possible "filter-spec" values.
+
+The response of `fetch` is broken into a number of sections separated by
+delimiter packets (0001), with each section beginning with its section
+header.
+
+    output = *section
+    section = (acknowledgments | shallow-info | packfile)
+	      (flush-pkt | delim-pkt)
+
+    acknowledgments = PKT-LINE("acknowledgments" LF)
+		      (nak | *ack)
+		      (ready)
+    ready = PKT-LINE("ready" LF)
+    nak = PKT-LINE("NAK" LF)
+    ack = PKT-LINE("ACK" SP obj-id LF)
+
+    shallow-info = PKT-LINE("shallow-info" LF)
+		   *PKT-LINE((shallow | unshallow) LF)
+    shallow = "shallow" SP obj-id
+    unshallow = "unshallow" SP obj-id
+
+    packfile = PKT-LINE("packfile" LF)
+	       *PKT-LINE(%x01-03 *%x00-ff)
+
+    acknowledgments section
+	* If the client determines that it is finished with negotiations
+	  by sending a "done" line, the acknowledgments sections MUST be
+	  omitted from the server's response.
+
+	* Always begins with the section header "acknowledgments"
+
+	* The server will respond with "NAK" if none of the object ids sent
+	  as have lines were common.
+
+	* The server will respond with "ACK obj-id" for all of the
+	  object ids sent as have lines which are common.
+
+	* A response cannot have both "ACK" lines as well as a "NAK"
+	  line.
+
+	* The server will respond with a "ready" line indicating that
+	  the server has found an acceptable common base and is ready to
+	  make and send a packfile (which will be found in the packfile
+	  section of the same response)
+
+	* If the server has found a suitable cut point and has decided
+	  to send a "ready" line, then the server can decide to (as an
+	  optimization) omit any "ACK" lines it would have sent during
+	  its response.  This is because the server will have already
+	  determined the objects it plans to send to the client and no
+	  further negotiation is needed.
+
+    shallow-info section
+	* If the client has requested a shallow fetch/clone, a shallow
+	  client requests a fetch or the server is shallow then the
+	  server's response may include a shallow-info section.  The
+	  shallow-info section will be included if (due to one of the
+	  above conditions) the server needs to inform the client of any
+	  shallow boundaries or adjustments to the clients already
+	  existing shallow boundaries.
+
+	* Always begins with the section header "shallow-info"
+
+	* If a positive depth is requested, the server will compute the
+	  set of commits which are no deeper than the desired depth.
+
+	* The server sends a "shallow obj-id" line for each commit whose
+	  parents will not be sent in the following packfile.
+
+	* The server sends an "unshallow obj-id" line for each commit
+	  which the client has indicated is shallow, but is no longer
+	  shallow as a result of the fetch (due to its parents being
+	  sent in the following packfile).
+
+	* The server MUST NOT send any "unshallow" lines for anything
+	  which the client has not indicated was shallow as a part of
+	  its request.
+
+	* This section is only included if a packfile section is also
+	  included in the response.
+
+    packfile section
+	* This section is only included if the client has sent 'want'
+	  lines in its request and either requested that no more
+	  negotiation be done by sending 'done' or if the server has
+	  decided it has found a sufficient cut point to produce a
+	  packfile.
+
+	* Always begins with the section header "packfile"
+
+	* The transmission of the packfile begins immediately after the
+	  section header
+
+	* The data transfer of the packfile is always multiplexed, using
+	  the same semantics of the 'side-band-64k' capability from
+	  protocol version 1.  This means that each packet, during the
+	  packfile data stream, is made up of a leading 4-byte pkt-line
+	  length (typical of the pkt-line format), followed by a 1-byte
+	  stream code, followed by the actual data.
+
+	  The stream code can be one of:
+		1 - pack data
+		2 - progress messages
+		3 - fatal error message just before stream aborts
+
+ server-option
+~~~~~~~~~~~~~~~
+
+If advertised, indicates that any number of server specific options can be
+included in a request.  This is done by sending each option as a
+"server-option=<option>" capability line in the capability-list section of
+a request.
+
+The provided options must not contain a NUL or LF character.
diff --git a/Documentation/technical/shallow.txt b/Documentation/technical/shallow.txt
index 5183b15..01dedfe 100644
--- a/Documentation/technical/shallow.txt
+++ b/Documentation/technical/shallow.txt
@@ -8,20 +8,22 @@
 these commits have no parents.
 *********************************************************
 
-The basic idea is to write the SHA-1s of shallow commits into
-$GIT_DIR/shallow, and handle its contents like the contents
-of $GIT_DIR/info/grafts (with the difference that shallow
-cannot contain parent information).
-
-This information is stored in a new file instead of grafts, or
-even the config, since the user should not touch that file
-at all (even throughout development of the shallow clone, it
-was never manually edited!).
+$GIT_DIR/shallow lists commit object names and tells Git to
+pretend as if they are root commits (e.g. "git log" traversal
+stops after showing them; "git fsck" does not complain saying
+the commits listed on their "parent" lines do not exist).
 
 Each line contains exactly one SHA-1. When read, a commit_graft
 will be constructed, which has nr_parent < 0 to make it easier
 to discern from user provided grafts.
 
+Note that the shallow feature could not be changed easily to
+use replace refs: a commit containing a `mergetag` is not allowed
+to be replaced, not even by a root commit. Such a commit can be
+made shallow, though. Also, having a `shallow` file explicitly
+listing all the commits made shallow makes it a *lot* easier to
+do shallow-specific things such as to deepen the history.
+
 Since fsck-objects relies on the library to read the objects,
 it honours shallow commits automatically.
 
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index bd6cd16..5998893 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.17.3
+DEF_VER=v2.18.1
 
 LF='
 '
diff --git a/Makefile b/Makefile
index a1d8775..e4b503d 100644
--- a/Makefile
+++ b/Makefile
@@ -29,10 +29,10 @@
 # Perl-compatible regular expressions instead of standard or extended
 # POSIX regular expressions.
 #
-# Currently USE_LIBPCRE is a synonym for USE_LIBPCRE1, define
-# USE_LIBPCRE2 instead if you'd like to use version 2 of the PCRE
-# library. The USE_LIBPCRE flag will likely be changed to mean v2 by
-# default in future releases.
+# USE_LIBPCRE is a synonym for USE_LIBPCRE2, define USE_LIBPCRE1
+# instead if you'd like to use the legacy version 1 of the PCRE
+# library. Support for version 1 will likely be removed in some future
+# release of Git, as upstream has all but abandoned it.
 #
 # When using USE_LIBPCRE1, define NO_LIBPCRE1_JIT if the PCRE v1
 # library is compiled without --enable-jit. We will auto-detect
@@ -335,6 +335,13 @@
 # when hardlinking a file to another name and unlinking the original file right
 # away (some NTFS drivers seem to zero the contents in that scenario).
 #
+# Define INSTALL_SYMLINKS if you prefer to have everything that can be
+# symlinked between bin/ and libexec/ to use relative symlinks between
+# the two. This option overrides NO_CROSS_DIRECTORY_HARDLINKS and
+# NO_INSTALL_HARDLINKS which will also use symlinking by indirection
+# within the same directory in some cases, INSTALL_SYMLINKS will
+# always symlink to the final target directly.
+#
 # Define NO_CROSS_DIRECTORY_HARDLINKS if you plan to distribute the installed
 # programs as a tar, where bin/ and libexec/ might be on different file systems.
 #
@@ -434,6 +441,49 @@
 #
 # When cross-compiling, define HOST_CPU as the canonical name of the CPU on
 # which the built Git will run (for instance "x86_64").
+#
+# Define RUNTIME_PREFIX to configure Git to resolve its ancillary tooling and
+# support files relative to the location of the runtime binary, rather than
+# hard-coding them into the binary. Git installations built with RUNTIME_PREFIX
+# can be moved to arbitrary filesystem locations. RUNTIME_PREFIX also causes
+# Perl scripts to use a modified entry point header allowing them to resolve
+# support files at runtime.
+#
+# When using RUNTIME_PREFIX, define HAVE_BSD_KERN_PROC_SYSCTL if your platform
+# supports the KERN_PROC BSD sysctl function.
+#
+# When using RUNTIME_PREFIX, define PROCFS_EXECUTABLE_PATH if your platform
+# mounts a "procfs" filesystem capable of resolving the path of the current
+# executable. If defined, this must be the canonical path for the "procfs"
+# current executable path.
+#
+# When using RUNTIME_PREFIX, define HAVE_NS_GET_EXECUTABLE_PATH if your platform
+# supports calling _NSGetExecutablePath to retrieve the path of the running
+# executable.
+#
+# When using RUNTIME_PREFIX, define HAVE_WPGMPTR if your platform offers
+# the global variable _wpgmptr containing the absolute path of the current
+# executable (this is the case on Windows).
+#
+# Define DEVELOPER to enable more compiler warnings. Compiler version
+# and family are auto detected, but could be overridden by defining
+# COMPILER_FEATURES (see config.mak.dev)
+#
+# When DEVELOPER is set, DEVOPTS can be used to control compiler
+# options.  This variable contains keywords separated by
+# whitespace. The following keywords are are recognized:
+#
+#    no-error:
+#
+#        suppresses the -Werror that implicitly comes with
+#        DEVELOPER=1. Useful for getting the full set of errors
+#        without immediately dying, or for logging them.
+#
+#    extra-all:
+#
+#        The DEVELOPER mode enables -Wextra with a few exceptions. By
+#        setting this flag the exceptions are removed, and all of
+#        -Wextra is used.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -442,15 +492,6 @@
 # CFLAGS and LDFLAGS are for the users to override from the command line.
 
 CFLAGS = -g -O2 -Wall
-DEVELOPER_CFLAGS = -Werror \
-	-Wdeclaration-after-statement \
-	-Wno-format-zero-length \
-	-Wold-style-definition \
-	-Woverflow \
-	-Wpointer-arith \
-	-Wstrict-prototypes \
-	-Wunused \
-	-Wvla
 LDFLAGS =
 ALL_CFLAGS = $(CPPFLAGS) $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS)
@@ -471,11 +512,12 @@
 #   mandir
 #   infodir
 #   htmldir
+#   localedir
+#   perllibdir
 # This can help installing the suite in a relocatable way.
 
 prefix = $(HOME)
-bindir_relative = bin
-bindir = $(prefix)/$(bindir_relative)
+bindir = $(prefix)/bin
 mandir = $(prefix)/share/man
 infodir = $(prefix)/share/info
 gitexecdir = libexec/git-core
@@ -492,9 +534,13 @@
 # DESTDIR =
 pathsep = :
 
+bindir_relative = $(patsubst $(prefix)/%,%,$(bindir))
 mandir_relative = $(patsubst $(prefix)/%,%,$(mandir))
 infodir_relative = $(patsubst $(prefix)/%,%,$(infodir))
+gitexecdir_relative = $(patsubst $(prefix)/%,%,$(gitexecdir))
+localedir_relative = $(patsubst $(prefix)/%,%,$(localedir))
 htmldir_relative = $(patsubst $(prefix)/%,%,$(htmldir))
+perllibdir_relative = $(patsubst $(prefix)/%,%,$(perllibdir))
 
 export prefix bindir sharedir sysconfdir gitwebdir perllibdir localedir
 
@@ -546,6 +592,7 @@
 SCRIPT_PYTHON =
 SCRIPT_SH =
 SCRIPT_LIB =
+TEST_BUILTINS_OBJS =
 TEST_PROGRAMS_NEED_X =
 
 # Having this variable in your environment would break pipelines because
@@ -643,7 +690,6 @@
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += shell.o
 PROGRAM_OBJS += show-index.o
-PROGRAM_OBJS += upload-pack.o
 PROGRAM_OBJS += remote-testsvn.o
 
 # Binary suffix, set to .exe for Windows builds
@@ -651,47 +697,50 @@
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
-TEST_PROGRAMS_NEED_X += test-chmtime
-TEST_PROGRAMS_NEED_X += test-ctype
-TEST_PROGRAMS_NEED_X += test-config
-TEST_PROGRAMS_NEED_X += test-date
-TEST_PROGRAMS_NEED_X += test-delta
-TEST_PROGRAMS_NEED_X += test-drop-caches
-TEST_PROGRAMS_NEED_X += test-dump-cache-tree
+TEST_BUILTINS_OBJS += test-chmtime.o
+TEST_BUILTINS_OBJS += test-config.o
+TEST_BUILTINS_OBJS += test-ctype.o
+TEST_BUILTINS_OBJS += test-date.o
+TEST_BUILTINS_OBJS += test-delta.o
+TEST_BUILTINS_OBJS += test-drop-caches.o
+TEST_BUILTINS_OBJS += test-dump-cache-tree.o
+TEST_BUILTINS_OBJS += test-dump-split-index.o
+TEST_BUILTINS_OBJS += test-example-decorate.o
+TEST_BUILTINS_OBJS += test-genrandom.o
+TEST_BUILTINS_OBJS += test-hashmap.o
+TEST_BUILTINS_OBJS += test-index-version.o
+TEST_BUILTINS_OBJS += test-lazy-init-name-hash.o
+TEST_BUILTINS_OBJS += test-match-trees.o
+TEST_BUILTINS_OBJS += test-mergesort.o
+TEST_BUILTINS_OBJS += test-mktemp.o
+TEST_BUILTINS_OBJS += test-online-cpus.o
+TEST_BUILTINS_OBJS += test-path-utils.o
+TEST_BUILTINS_OBJS += test-prio-queue.o
+TEST_BUILTINS_OBJS += test-read-cache.o
+TEST_BUILTINS_OBJS += test-ref-store.o
+TEST_BUILTINS_OBJS += test-regex.o
+TEST_BUILTINS_OBJS += test-revision-walking.o
+TEST_BUILTINS_OBJS += test-run-command.o
+TEST_BUILTINS_OBJS += test-scrap-cache-tree.o
+TEST_BUILTINS_OBJS += test-sha1-array.o
+TEST_BUILTINS_OBJS += test-sha1.o
+TEST_BUILTINS_OBJS += test-sigchain.o
+TEST_BUILTINS_OBJS += test-strcmp-offset.o
+TEST_BUILTINS_OBJS += test-string-list.o
+TEST_BUILTINS_OBJS += test-submodule-config.o
+TEST_BUILTINS_OBJS += test-subprocess.o
+TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
+TEST_BUILTINS_OBJS += test-wildmatch.o
+TEST_BUILTINS_OBJS += test-write-cache.o
+
 TEST_PROGRAMS_NEED_X += test-dump-fsmonitor
-TEST_PROGRAMS_NEED_X += test-dump-split-index
 TEST_PROGRAMS_NEED_X += test-dump-untracked-cache
-TEST_PROGRAMS_NEED_X += test-example-decorate
 TEST_PROGRAMS_NEED_X += test-fake-ssh
-TEST_PROGRAMS_NEED_X += test-genrandom
-TEST_PROGRAMS_NEED_X += test-hashmap
-TEST_PROGRAMS_NEED_X += test-index-version
-TEST_PROGRAMS_NEED_X += test-lazy-init-name-hash
 TEST_PROGRAMS_NEED_X += test-line-buffer
-TEST_PROGRAMS_NEED_X += test-match-trees
-TEST_PROGRAMS_NEED_X += test-mergesort
-TEST_PROGRAMS_NEED_X += test-mktemp
-TEST_PROGRAMS_NEED_X += test-online-cpus
 TEST_PROGRAMS_NEED_X += test-parse-options
-TEST_PROGRAMS_NEED_X += test-path-utils
-TEST_PROGRAMS_NEED_X += test-prio-queue
-TEST_PROGRAMS_NEED_X += test-read-cache
-TEST_PROGRAMS_NEED_X += test-write-cache
-TEST_PROGRAMS_NEED_X += test-ref-store
-TEST_PROGRAMS_NEED_X += test-regex
-TEST_PROGRAMS_NEED_X += test-revision-walking
-TEST_PROGRAMS_NEED_X += test-run-command
-TEST_PROGRAMS_NEED_X += test-scrap-cache-tree
-TEST_PROGRAMS_NEED_X += test-sha1
-TEST_PROGRAMS_NEED_X += test-sha1-array
-TEST_PROGRAMS_NEED_X += test-sigchain
-TEST_PROGRAMS_NEED_X += test-strcmp-offset
-TEST_PROGRAMS_NEED_X += test-string-list
-TEST_PROGRAMS_NEED_X += test-submodule-config
-TEST_PROGRAMS_NEED_X += test-subprocess
+TEST_PROGRAMS_NEED_X += test-pkt-line
 TEST_PROGRAMS_NEED_X += test-svn-fe
-TEST_PROGRAMS_NEED_X += test-urlmatch-normalization
-TEST_PROGRAMS_NEED_X += test-wildmatch
+TEST_PROGRAMS_NEED_X += test-tool
 
 TEST_PROGRAMS = $(patsubst %,t/helper/%$X,$(TEST_PROGRAMS_NEED_X))
 
@@ -746,7 +795,7 @@
 XDIFF_LIB = xdiff/lib.a
 VCSSVN_LIB = vcs-svn/lib.a
 
-GENERATED_H += common-cmds.h
+GENERATED_H += command-list.h
 
 LIB_H = $(shell $(FIND) . \
 	-name .git -prune -o \
@@ -772,11 +821,13 @@
 LIB_OBJS += bulk-checkin.o
 LIB_OBJS += bundle.o
 LIB_OBJS += cache-tree.o
+LIB_OBJS += chdir-notify.o
 LIB_OBJS += checkout.o
 LIB_OBJS += color.o
 LIB_OBJS += column.o
 LIB_OBJS += combine-diff.o
 LIB_OBJS += commit.o
+LIB_OBJS += commit-graph.o
 LIB_OBJS += compat/obstack.o
 LIB_OBJS += compat/terminal.o
 LIB_OBJS += config.o
@@ -807,7 +858,7 @@
 LIB_OBJS += ewah/ewah_bitmap.o
 LIB_OBJS += ewah/ewah_io.o
 LIB_OBJS += ewah/ewah_rlw.o
-LIB_OBJS += exec_cmd.o
+LIB_OBJS += exec-cmd.o
 LIB_OBJS += fetch-object.o
 LIB_OBJS += fetch-pack.o
 LIB_OBJS += fsck.o
@@ -830,9 +881,11 @@
 LIB_OBJS += ll-merge.o
 LIB_OBJS += lockfile.o
 LIB_OBJS += log-tree.o
+LIB_OBJS += ls-refs.o
 LIB_OBJS += mailinfo.o
 LIB_OBJS += mailmap.o
 LIB_OBJS += match-trees.o
+LIB_OBJS += mem-pool.o
 LIB_OBJS += merge.o
 LIB_OBJS += merge-blobs.o
 LIB_OBJS += merge-recursive.o
@@ -875,9 +928,10 @@
 LIB_OBJS += refs/iterator.o
 LIB_OBJS += refs/packed-backend.o
 LIB_OBJS += refs/ref-cache.o
+LIB_OBJS += refspec.o
 LIB_OBJS += ref-filter.o
 LIB_OBJS += remote.o
-LIB_OBJS += replace_object.o
+LIB_OBJS += replace-object.o
 LIB_OBJS += repository.o
 LIB_OBJS += rerere.o
 LIB_OBJS += resolve-undo.o
@@ -885,12 +939,13 @@
 LIB_OBJS += run-command.o
 LIB_OBJS += send-pack.o
 LIB_OBJS += sequencer.o
+LIB_OBJS += serve.o
 LIB_OBJS += server-info.o
 LIB_OBJS += setup.o
 LIB_OBJS += sha1-array.o
 LIB_OBJS += sha1-lookup.o
-LIB_OBJS += sha1_file.o
-LIB_OBJS += sha1_name.o
+LIB_OBJS += sha1-file.o
+LIB_OBJS += sha1-name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
 LIB_OBJS += sigchain.o
@@ -913,6 +968,7 @@
 LIB_OBJS += tree.o
 LIB_OBJS += tree-walk.o
 LIB_OBJS += unpack-trees.o
+LIB_OBJS += upload-pack.o
 LIB_OBJS += url.o
 LIB_OBJS += urlmatch.o
 LIB_OBJS += usage.o
@@ -925,7 +981,7 @@
 LIB_OBJS += wildmatch.o
 LIB_OBJS += worktree.o
 LIB_OBJS += wrapper.o
-LIB_OBJS += write_or_die.o
+LIB_OBJS += write-or-die.o
 LIB_OBJS += ws.o
 LIB_OBJS += wt-status.o
 LIB_OBJS += xdiff-interface.o
@@ -952,6 +1008,7 @@
 BUILTIN_OBJS += builtin/column.o
 BUILTIN_OBJS += builtin/commit-tree.o
 BUILTIN_OBJS += builtin/commit.o
+BUILTIN_OBJS += builtin/commit-graph.o
 BUILTIN_OBJS += builtin/config.o
 BUILTIN_OBJS += builtin/count-objects.o
 BUILTIN_OBJS += builtin/credential.o
@@ -1017,6 +1074,7 @@
 BUILTIN_OBJS += builtin/revert.o
 BUILTIN_OBJS += builtin/rm.o
 BUILTIN_OBJS += builtin/send-pack.o
+BUILTIN_OBJS += builtin/serve.o
 BUILTIN_OBJS += builtin/shortlog.o
 BUILTIN_OBJS += builtin/show-branch.o
 BUILTIN_OBJS += builtin/show-ref.o
@@ -1030,6 +1088,7 @@
 BUILTIN_OBJS += builtin/update-ref.o
 BUILTIN_OBJS += builtin/update-server-info.o
 BUILTIN_OBJS += builtin/upload-archive.o
+BUILTIN_OBJS += builtin/upload-pack.o
 BUILTIN_OBJS += builtin/var.o
 BUILTIN_OBJS += builtin/verify-commit.o
 BUILTIN_OBJS += builtin/verify-pack.o
@@ -1051,7 +1110,7 @@
 -include config.mak
 
 ifdef DEVELOPER
-CFLAGS += $(DEVELOPER_CFLAGS)
+include config.mak.dev
 endif
 
 comma := ,
@@ -1170,13 +1229,18 @@
 	COMPAT_OBJS += compat/basename.o
 endif
 
-USE_LIBPCRE1 ?= $(USE_LIBPCRE)
+USE_LIBPCRE2 ?= $(USE_LIBPCRE)
 
-ifneq (,$(USE_LIBPCRE1))
-	ifdef USE_LIBPCRE2
-$(error Only set USE_LIBPCRE1 (or its alias USE_LIBPCRE) or USE_LIBPCRE2, not both!)
+ifneq (,$(USE_LIBPCRE2))
+	ifdef USE_LIBPCRE1
+$(error Only set USE_LIBPCRE2 (or its alias USE_LIBPCRE) or USE_LIBPCRE1, not both!)
 	endif
 
+	BASIC_CFLAGS += -DUSE_LIBPCRE2
+	EXTLIBS += -lpcre2-8
+endif
+
+ifdef USE_LIBPCRE1
 	BASIC_CFLAGS += -DUSE_LIBPCRE1
 	EXTLIBS += -lpcre
 
@@ -1185,11 +1249,6 @@
 endif
 endif
 
-ifdef USE_LIBPCRE2
-	BASIC_CFLAGS += -DUSE_LIBPCRE2
-	EXTLIBS += -lpcre2-8
-endif
-
 ifdef LIBPCREDIR
 	BASIC_CFLAGS += -I$(LIBPCREDIR)/include
 	EXTLIBS += -L$(LIBPCREDIR)/$(lib) $(CC_LD_DYNPATH)$(LIBPCREDIR)/$(lib)
@@ -1292,17 +1351,19 @@
 	LIB_4_CRYPTO += -framework Security -framework CoreFoundation
 endif
 endif
-ifdef NEEDS_LIBICONV
-	ifdef ICONVDIR
-		BASIC_CFLAGS += -I$(ICONVDIR)/include
-		ICONV_LINK = -L$(ICONVDIR)/$(lib) $(CC_LD_DYNPATH)$(ICONVDIR)/$(lib)
-	else
-		ICONV_LINK =
+ifndef NO_ICONV
+	ifdef NEEDS_LIBICONV
+		ifdef ICONVDIR
+			BASIC_CFLAGS += -I$(ICONVDIR)/include
+			ICONV_LINK = -L$(ICONVDIR)/$(lib) $(CC_LD_DYNPATH)$(ICONVDIR)/$(lib)
+		else
+			ICONV_LINK =
+		endif
+		ifdef NEEDS_LIBINTL_BEFORE_LIBICONV
+			ICONV_LINK += -lintl
+		endif
+		EXTLIBS += $(ICONV_LINK) -liconv
 	endif
-	ifdef NEEDS_LIBINTL_BEFORE_LIBICONV
-		ICONV_LINK += -lintl
-	endif
-	EXTLIBS += $(ICONV_LINK) -liconv
 endif
 ifdef NEEDS_LIBGEN
 	EXTLIBS += -lgen
@@ -1652,10 +1713,27 @@
 	BASIC_CFLAGS += -DHAVE_BSD_SYSCTL
 endif
 
+ifdef HAVE_BSD_KERN_PROC_SYSCTL
+	BASIC_CFLAGS += -DHAVE_BSD_KERN_PROC_SYSCTL
+endif
+
 ifdef HAVE_GETDELIM
 	BASIC_CFLAGS += -DHAVE_GETDELIM
 endif
 
+ifneq ($(PROCFS_EXECUTABLE_PATH),)
+	procfs_executable_path_SQ = $(subst ','\'',$(PROCFS_EXECUTABLE_PATH))
+	BASIC_CFLAGS += '-DPROCFS_EXECUTABLE_PATH="$(procfs_executable_path_SQ)"'
+endif
+
+ifdef HAVE_NS_GET_EXECUTABLE_PATH
+	BASIC_CFLAGS += -DHAVE_NS_GET_EXECUTABLE_PATH
+endif
+
+ifdef HAVE_WPGMPTR
+	BASIC_CFLAGS += -DHAVE_WPGMPTR
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -1740,10 +1818,13 @@
 infodir_relative_SQ = $(subst ','\'',$(infodir_relative))
 perllibdir_SQ = $(subst ','\'',$(perllibdir))
 localedir_SQ = $(subst ','\'',$(localedir))
+localedir_relative_SQ = $(subst ','\'',$(localedir_relative))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
+gitexecdir_relative_SQ = $(subst ','\'',$(gitexecdir_relative))
 template_dir_SQ = $(subst ','\'',$(template_dir))
 htmldir_relative_SQ = $(subst ','\'',$(htmldir_relative))
 prefix_SQ = $(subst ','\'',$(prefix))
+perllibdir_relative_SQ = $(subst ','\'',$(perllibdir_relative))
 gitwebdir_SQ = $(subst ','\'',$(gitwebdir))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
@@ -1754,6 +1835,31 @@
 DIFF_SQ = $(subst ','\'',$(DIFF))
 PERLLIB_EXTRA_SQ = $(subst ','\'',$(PERLLIB_EXTRA))
 
+# RUNTIME_PREFIX's resolution logic requires resource paths to be expressed
+# relative to each other and share an installation path.
+#
+# This is a dependency in:
+# - Git's binary RUNTIME_PREFIX logic in (see "exec_cmd.c").
+# - The runtime prefix Perl header (see
+#   "perl/header_templates/runtime_prefix.template.pl").
+ifdef RUNTIME_PREFIX
+
+ifneq ($(filter /%,$(firstword $(gitexecdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative gitexecdir, not: $(gitexecdir))
+endif
+
+ifneq ($(filter /%,$(firstword $(localedir_relative))),)
+$(error RUNTIME_PREFIX requires a relative localedir, not: $(localedir))
+endif
+
+ifndef NO_PERL
+ifneq ($(filter /%,$(firstword $(perllibdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative perllibdir, not: $(perllibdir))
+endif
+endif
+
+endif
+
 # We must filter out any object files from $(GITLIBS),
 # as it is typically used like:
 #
@@ -1902,9 +2008,9 @@
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) \
 		$(filter %.o,$^) $(LIBS)
 
-help.sp help.s help.o: common-cmds.h
+help.sp help.s help.o: command-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: common-cmds.h GIT-PREFIX
+builtin/help.sp builtin/help.s builtin/help.o: command-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_HTML_PATH="$(htmldir_relative_SQ)"' \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
@@ -1923,9 +2029,9 @@
 	ln -s $< $@ 2>/dev/null || \
 	cp $< $@
 
-common-cmds.h: generate-cmdlist.sh command-list.txt
+command-list.h: generate-cmdlist.sh command-list.txt
 
-common-cmds.h: $(wildcard Documentation/git-*.txt)
+command-list.h: $(wildcard Documentation/git*.txt)
 	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
@@ -1974,27 +2080,44 @@
 # This makes sure we depend on the NO_PERL setting itself.
 $(SCRIPT_PERL_GEN): GIT-BUILD-OPTIONS
 
-ifndef NO_PERL
-$(SCRIPT_PERL_GEN):
+# Used for substitution in Perl modules. Disabled when using RUNTIME_PREFIX
+# since the locale directory is injected.
+perl_localedir_SQ = $(localedir_SQ)
 
+ifndef NO_PERL
+PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
 PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ):$(perllibdir_SQ)
-$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-VERSION-FILE
+
+PERL_DEFINES := $(PERL_PATH_SQ) $(PERLLIB_EXTRA_SQ) $(perllibdir_SQ)
+PERL_DEFINES += $(RUNTIME_PREFIX)
+
+# Support Perl runtime prefix. In this mode, a different header is installed
+# into Perl scripts.
+ifdef RUNTIME_PREFIX
+
+PERL_HEADER_TEMPLATE = perl/header_templates/runtime_prefix.template.pl
+
+# Don't export a fixed $(localedir) path; it will be resolved by the Perl header
+# at runtime.
+perl_localedir_SQ =
+
+endif
+
+PERL_DEFINES += $(gitexecdir) $(perllibdir) $(localedir)
+
+$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-PERL-HEADER GIT-VERSION-FILE
 	$(QUIET_GEN)$(RM) $@ $@+ && \
-	INSTLIBDIR='$(perllibdir_SQ)' && \
-	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
-	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
 	sed -e '1{' \
 	    -e '	s|#!.*perl|#!$(PERL_PATH_SQ)|' \
-	    -e '	h' \
-	    -e '	s=.*=use lib (split(/$(pathsep)/, $$ENV{GITPERLLIB} || "'"$$INSTLIBDIR"'"));=' \
-	    -e '	H' \
-	    -e '	x' \
+	    -e '	rGIT-PERL-HEADER' \
+	    -e '	G' \
 	    -e '}' \
 	    -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
 	    $< >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
 
+PERL_DEFINES := $(subst $(space),:,$(PERL_DEFINES))
 GIT-PERL-DEFINES: FORCE
 	@FLAGS='$(PERL_DEFINES)'; \
 	    if test x"$$FLAGS" != x"`cat $@ 2>/dev/null`" ; then \
@@ -2002,6 +2125,22 @@
 		echo "$$FLAGS" >$@; \
 	    fi
 
+GIT-PERL-HEADER: $(PERL_HEADER_TEMPLATE) GIT-PERL-DEFINES Makefile
+	$(QUIET_GEN)$(RM) $@ && \
+	INSTLIBDIR='$(perllibdir_SQ)' && \
+	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
+	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
+	sed -e 's=@@PATHSEP@@=$(pathsep)=g' \
+	    -e "s=@@INSTLIBDIR@@=$$INSTLIBDIR=g" \
+	    -e 's=@@PERLLIBDIR_REL@@=$(perllibdir_relative_SQ)=g' \
+	    -e 's=@@GITEXECDIR_REL@@=$(gitexecdir_relative_SQ)=g' \
+	    -e 's=@@LOCALEDIR_REL@@=$(localedir_relative_SQ)=g' \
+	    $< >$@+ && \
+	mv $@+ $@
+
+.PHONY: perllibdir
+perllibdir:
+	@echo '$(perllibdir_SQ)'
 
 .PHONY: gitweb
 gitweb:
@@ -2083,7 +2222,7 @@
 VCSSVN_OBJS += vcs-svn/svndiff.o
 VCSSVN_OBJS += vcs-svn/svndump.o
 
-TEST_OBJS := $(patsubst %$X,%.o,$(TEST_PROGRAMS))
+TEST_OBJS := $(patsubst %$X,%.o,$(TEST_PROGRAMS)) $(patsubst %,t/helper/%,$(TEST_BUILTINS_OBJS))
 OBJECTS := $(LIB_OBJS) $(BUILTIN_OBJS) $(PROGRAM_OBJS) $(TEST_OBJS) \
 	$(XDIFF_OBJS) \
 	$(VCSSVN_OBJS) \
@@ -2136,18 +2275,19 @@
 # Dependencies on header files, for platforms that do not support
 # the gcc -MMD option.
 #
-# Dependencies on automatically generated headers such as common-cmds.h
+# Dependencies on automatically generated headers such as command-list.h
 # should _not_ be included here, since they are necessary even when
 # building an object for the first time.
 
 $(OBJECTS): $(LIB_H)
 endif
 
-exec_cmd.sp exec_cmd.s exec_cmd.o: GIT-PREFIX
-exec_cmd.sp exec_cmd.s exec_cmd.o: EXTRA_CPPFLAGS = \
+exec-cmd.sp exec-cmd.s exec-cmd.o: GIT-PREFIX
+exec-cmd.sp exec-cmd.s exec-cmd.o: EXTRA_CPPFLAGS = \
 	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
+	'-DGIT_LOCALE_PATH="$(localedir_relative_SQ)"' \
 	'-DBINDIR="$(bindir_relative_SQ)"' \
-	'-DPREFIX="$(prefix_SQ)"'
+	'-DFALLBACK_RUNTIME_PREFIX="$(prefix_SQ)"'
 
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: GIT-PREFIX
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: EXTRA_CPPFLAGS = \
@@ -2163,7 +2303,7 @@
 
 gettext.sp gettext.s gettext.o: GIT-PREFIX
 gettext.sp gettext.s gettext.o: EXTRA_CPPFLAGS = \
-	-DGIT_LOCALE_PATH='"$(localedir_SQ)"'
+	-DGIT_LOCALE_PATH='"$(localedir_relative_SQ)"'
 
 http-push.sp http.sp http-walker.sp remote-curl.sp imap-send.sp: SPARSE_FLAGS += \
 	-DCURL_DISABLE_TYPECHECK
@@ -2323,7 +2463,7 @@
 
 perl/build/lib/%.pm: perl/%.pm
 	$(QUIET_GEN)mkdir -p $(dir $@) && \
-	sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
+	sed -e 's|@@LOCALEDIR@@|$(perl_localedir_SQ)|g' \
 	    -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \
 	< $< > $@
 
@@ -2494,10 +2634,12 @@
 
 .PRECIOUS: $(TEST_OBJS)
 
+t/helper/test-tool$X: $(patsubst %,t/helper/%,$(TEST_BUILTINS_OBJS))
+
 t/helper/test-%$X: t/helper/test-%.o GIT-LDFLAGS $(GITLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(filter %.a,$^) $(LIBS)
 
-check-sha1:: t/helper/test-sha1$X
+check-sha1:: t/helper/test-tool$X
 	t/helper/test-sha1.sh
 
 SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
@@ -2513,7 +2655,7 @@
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: common-cmds.h
+check: command-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
@@ -2606,35 +2748,44 @@
 
 	bindir=$$(cd '$(DESTDIR_SQ)$(bindir_SQ)' && pwd) && \
 	execdir=$$(cd '$(DESTDIR_SQ)$(gitexec_instdir_SQ)' && pwd) && \
+	destdir_from_execdir_SQ=$$(echo '$(gitexecdir_relative_SQ)' | sed -e 's|[^/][^/]*|..|g') && \
 	{ test "$$bindir/" = "$$execdir/" || \
 	  for p in git$X $(filter $(install_bindir_programs),$(ALL_PROGRAMS)); do \
 		$(RM) "$$execdir/$$p" && \
-		test -z "$(NO_INSTALL_HARDLINKS)$(NO_CROSS_DIRECTORY_HARDLINKS)" && \
-		ln "$$bindir/$$p" "$$execdir/$$p" 2>/dev/null || \
-		cp "$$bindir/$$p" "$$execdir/$$p" || exit; \
+		test -n "$(INSTALL_SYMLINKS)" && \
+		ln -s "$$destdir_from_execdir_SQ/$(bindir_relative_SQ)/$$p" "$$execdir/$$p" || \
+		{ test -z "$(NO_INSTALL_HARDLINKS)$(NO_CROSS_DIRECTORY_HARDLINKS)" && \
+		  ln "$$bindir/$$p" "$$execdir/$$p" 2>/dev/null || \
+		  cp "$$bindir/$$p" "$$execdir/$$p" || exit; } \
 	  done; \
 	} && \
 	for p in $(filter $(install_bindir_programs),$(BUILT_INS)); do \
 		$(RM) "$$bindir/$$p" && \
-		test -z "$(NO_INSTALL_HARDLINKS)" && \
-		ln "$$bindir/git$X" "$$bindir/$$p" 2>/dev/null || \
-		ln -s "git$X" "$$bindir/$$p" 2>/dev/null || \
-		cp "$$bindir/git$X" "$$bindir/$$p" || exit; \
+		test -n "$(INSTALL_SYMLINKS)" && \
+		ln -s "git$X" "$$bindir/$$p" || \
+		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
+		  ln "$$bindir/git$X" "$$bindir/$$p" 2>/dev/null || \
+		  ln -s "git$X" "$$bindir/$$p" 2>/dev/null || \
+		  cp "$$bindir/git$X" "$$bindir/$$p" || exit; } \
 	done && \
 	for p in $(BUILT_INS); do \
 		$(RM) "$$execdir/$$p" && \
-		test -z "$(NO_INSTALL_HARDLINKS)" && \
-		ln "$$execdir/git$X" "$$execdir/$$p" 2>/dev/null || \
-		ln -s "git$X" "$$execdir/$$p" 2>/dev/null || \
-		cp "$$execdir/git$X" "$$execdir/$$p" || exit; \
+		test -n "$(INSTALL_SYMLINKS)" && \
+		ln -s "$$destdir_from_execdir_SQ/$(bindir_relative_SQ)/git$X" "$$execdir/$$p" || \
+		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
+		  ln "$$execdir/git$X" "$$execdir/$$p" 2>/dev/null || \
+		  ln -s "git$X" "$$execdir/$$p" 2>/dev/null || \
+		  cp "$$execdir/git$X" "$$execdir/$$p" || exit; } \
 	done && \
 	remote_curl_aliases="$(REMOTE_CURL_ALIASES)" && \
 	for p in $$remote_curl_aliases; do \
 		$(RM) "$$execdir/$$p" && \
-		test -z "$(NO_INSTALL_HARDLINKS)" && \
-		ln "$$execdir/git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
-		ln -s "git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
-		cp "$$execdir/git-remote-http$X" "$$execdir/$$p" || exit; \
+		test -n "$(INSTALL_SYMLINKS)" && \
+		ln -s "git-remote-http$X" "$$execdir/$$p" || \
+		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
+		  ln "$$execdir/git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
+		  ln -s "git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
+		  cp "$$execdir/git-remote-http$X" "$$execdir/$$p" || exit; } \
 	done && \
 	./check_bindir "z$$bindir" "z$$execdir" "$$bindir/git-add$X"
 
@@ -2752,7 +2903,7 @@
 	$(RM) $(TEST_PROGRAMS) $(NO_INSTALL)
 	$(RM) -r bin-wrappers $(dep_dirs)
 	$(RM) -r po/build/
-	$(RM) *.pyc *.pyo */*.pyc */*.pyo common-cmds.h $(ETAGS_TARGET) tags cscope*
+	$(RM) *.pyc *.pyo */*.pyc */*.pyo command-list.h $(ETAGS_TARGET) tags cscope*
 	$(RM) -r $(GIT_TARNAME) .doc-tmp-dir
 	$(RM) $(GIT_TARNAME).tar.gz git-core_$(GIT_VERSION)-*.tar.gz
 	$(RM) $(htmldocs).tar.gz $(manpages).tar.gz
@@ -2770,7 +2921,7 @@
 endif
 	$(RM) GIT-VERSION-FILE GIT-CFLAGS GIT-LDFLAGS GIT-BUILD-OPTIONS
 	$(RM) GIT-USER-AGENT GIT-PREFIX
-	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PYTHON-VARS
+	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PERL-HEADER GIT-PYTHON-VARS
 
 .PHONY: all install profile-clean clean strip
 .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
diff --git a/README.md b/README.md
index f17af66..f920a42 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,9 @@
 available at <https://public-inbox.org/git/>,
 <http://marc.info/?l=git> and other archival sites.
 
+Issues which are security relevant should be disclosed privately to
+the Git Security mailing list <git-security@googlegroups.com>.
+
 The maintainer frequently sends the "What's cooking" reports that
 list the current status of various development topics to the mailing
 list.  The discussion following them give a good reference for
diff --git a/RelNotes b/RelNotes
index d14bdb5..392b0b3 120000
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.17.3.txt
\ No newline at end of file
+Documentation/RelNotes/2.18.1.txt
\ No newline at end of file
diff --git a/advice.c b/advice.c
index 406efc1..370a56d 100644
--- a/advice.c
+++ b/advice.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "config.h"
+#include "color.h"
 
 int advice_push_update_rejected = 1;
 int advice_push_non_ff_current = 1;
@@ -19,6 +20,34 @@
 int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
+int advice_graft_file_deprecated = 1;
+
+static int advice_use_color = -1;
+static char advice_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_YELLOW,	/* HINT */
+};
+
+enum color_advice {
+	ADVICE_COLOR_RESET = 0,
+	ADVICE_COLOR_HINT = 1,
+};
+
+static int parse_advise_color_slot(const char *slot)
+{
+	if (!strcasecmp(slot, "reset"))
+		return ADVICE_COLOR_RESET;
+	if (!strcasecmp(slot, "hint"))
+		return ADVICE_COLOR_HINT;
+	return -1;
+}
+
+static const char *advise_get_color(enum color_advice ix)
+{
+	if (want_color_stderr(advice_use_color))
+		return advice_colors[ix];
+	return "";
+}
 
 static struct {
 	const char *name;
@@ -42,6 +71,7 @@
 	{ "addembeddedrepo", &advice_add_embedded_repo },
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
+	{ "graftfiledeprecated", &advice_graft_file_deprecated },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
@@ -59,7 +89,10 @@
 
 	for (cp = buf.buf; *cp; cp = np) {
 		np = strchrnul(cp, '\n');
-		fprintf(stderr,	_("hint: %.*s\n"), (int)(np - cp), cp);
+		fprintf(stderr,	_("%shint: %.*s%s\n"),
+			advise_get_color(ADVICE_COLOR_HINT),
+			(int)(np - cp), cp,
+			advise_get_color(ADVICE_COLOR_RESET));
 		if (*np)
 			np++;
 	}
@@ -68,9 +101,23 @@
 
 int git_default_advice_config(const char *var, const char *value)
 {
-	const char *k;
+	const char *k, *slot_name;
 	int i;
 
+	if (!strcmp(var, "color.advice")) {
+		advice_use_color = git_config_colorbool(var, value);
+		return 0;
+	}
+
+	if (skip_prefix(var, "color.advice.", &slot_name)) {
+		int slot = parse_advise_color_slot(slot_name);
+		if (slot < 0)
+			return 0;
+		if (!value)
+			return config_error_nonbool(var);
+		return color_parse(value, advice_colors[slot]);
+	}
+
 	if (!skip_prefix(var, "advice.", &k))
 		return 0;
 
diff --git a/advice.h b/advice.h
index 70568fa..9f5064e 100644
--- a/advice.h
+++ b/advice.h
@@ -21,6 +21,7 @@
 extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
+extern int advice_graft_file_deprecated;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/alias.c b/alias.c
index bf146e5..a7e4e57 100644
--- a/alias.c
+++ b/alias.c
@@ -1,9 +1,12 @@
 #include "cache.h"
+#include "alias.h"
 #include "config.h"
+#include "string-list.h"
 
 struct config_alias_data {
 	const char *alias;
 	char *v;
+	struct string_list *list;
 };
 
 static int config_alias_cb(const char *key, const char *value, void *d)
@@ -11,8 +14,16 @@
 	struct config_alias_data *data = d;
 	const char *p;
 
-	if (skip_prefix(key, "alias.", &p) && !strcasecmp(p, data->alias))
-		return git_config_string((const char **)&data->v, key, value);
+	if (!skip_prefix(key, "alias.", &p))
+		return 0;
+
+	if (data->alias) {
+		if (!strcasecmp(p, data->alias))
+			return git_config_string((const char **)&data->v,
+						 key, value);
+	} else if (data->list) {
+		string_list_append(data->list, p);
+	}
 
 	return 0;
 }
@@ -26,6 +37,13 @@
 	return data.v;
 }
 
+void list_aliases(struct string_list *list)
+{
+	struct config_alias_data data = { NULL, NULL, list };
+
+	read_early_config(config_alias_cb, &data);
+}
+
 #define SPLIT_CMDLINE_BAD_ENDING 1
 #define SPLIT_CMDLINE_UNCLOSED_QUOTE 2
 static const char *split_cmdline_errors[] = {
diff --git a/alias.h b/alias.h
new file mode 100644
index 0000000..79933f2
--- /dev/null
+++ b/alias.h
@@ -0,0 +1,12 @@
+#ifndef __ALIAS_H__
+#define __ALIAS_H__
+
+struct string_list;
+
+char *alias_lookup(const char *alias);
+int split_cmdline(char *cmdline, const char ***argv);
+/* Takes a negative value returned by split_cmdline */
+const char *split_cmdline_strerror(int cmdline_errno);
+void list_aliases(struct string_list *list);
+
+#endif
diff --git a/alloc.c b/alloc.c
index 12afadf..cf4f8b6 100644
--- a/alloc.c
+++ b/alloc.c
@@ -93,6 +93,7 @@
 	struct commit *c = alloc_node(&commit_state, sizeof(struct commit));
 	c->object.type = OBJ_COMMIT;
 	c->index = alloc_commit_index();
+	c->graph_pos = COMMIT_NOT_FROM_GRAPH;
 	return c;
 }
 
diff --git a/apply.c b/apply.c
index 2d1cfe4..d79e615 100644
--- a/apply.c
+++ b/apply.c
@@ -2375,7 +2375,7 @@
 	if (postlen
 	    ? postlen < new_buf - postimage->buf
 	    : postimage->len < new_buf - postimage->buf)
-		die("BUG: caller miscounted postlen: asked %d, orig = %d, used = %d",
+		BUG("caller miscounted postlen: asked %d, orig = %d, used = %d",
 		    (int)postlen, (int) postimage->len, (int)(new_buf - postimage->buf));
 
 	/* Fix the length of the whole thing */
@@ -3180,7 +3180,7 @@
 		unsigned long size;
 		char *result;
 
-		result = read_sha1_file(oid.hash, &type, &size);
+		result = read_object_file(&oid, &type, &size);
 		if (!result)
 			return error(_("the necessary postimage %s for "
 				       "'%s' cannot be read"),
@@ -3242,7 +3242,7 @@
 		unsigned long sz;
 		char *result;
 
-		result = read_sha1_file(oid->hash, &type, &sz);
+		result = read_object_file(oid, &type, &sz);
 		if (!result)
 			return -1;
 		/* XXX read_sha1_file NUL-terminates */
@@ -3509,7 +3509,7 @@
 	unsigned mode = patch->new_mode;
 
 	if (!patch->is_new)
-		die("BUG: patch to %s is not a creation", patch->old_name);
+		BUG("patch to %s is not a creation", patch->old_name);
 
 	pos = cache_name_pos(name, strlen(name));
 	if (pos < 0)
@@ -4058,7 +4058,7 @@
 {
 	struct patch *patch;
 	struct index_state result = { NULL };
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	int res;
 
 	/* Once we start supporting the reverse patch, it may be
diff --git a/archive-tar.c b/archive-tar.c
index c6ed96e..b6f58dd 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -111,7 +111,7 @@
  * queues up writes, so that all our write(2) calls write exactly one
  * full block; pads writes to RECORDSIZE
  */
-static int stream_blocked(const unsigned char *sha1)
+static int stream_blocked(const struct object_id *oid)
 {
 	struct git_istream *st;
 	enum object_type type;
@@ -119,9 +119,9 @@
 	char buf[BLOCKSIZE];
 	ssize_t readlen;
 
-	st = open_istream(sha1, &type, &sz, NULL);
+	st = open_istream(oid, &type, &sz, NULL);
 	if (!st)
-		return error("cannot stream blob %s", sha1_to_hex(sha1));
+		return error("cannot stream blob %s", oid_to_hex(oid));
 	for (;;) {
 		readlen = read_istream(st, buf, sizeof(buf));
 		if (readlen <= 0)
@@ -218,7 +218,7 @@
 }
 
 static void write_extended_header(struct archiver_args *args,
-				  const unsigned char *sha1,
+				  const struct object_id *oid,
 				  const void *buffer, unsigned long size)
 {
 	struct ustar_header header;
@@ -226,14 +226,14 @@
 	memset(&header, 0, sizeof(header));
 	*header.typeflag = TYPEFLAG_EXT_HEADER;
 	mode = 0100666;
-	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", sha1_to_hex(sha1));
+	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
 	prepare_header(args, &header, mode, size);
 	write_blocked(&header, sizeof(header));
 	write_blocked(buffer, size);
 }
 
 static int write_tar_entry(struct archiver_args *args,
-			   const unsigned char *sha1,
+			   const struct object_id *oid,
 			   const char *path, size_t pathlen,
 			   unsigned int mode)
 {
@@ -257,7 +257,7 @@
 		mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 	} else {
 		return error("unsupported file mode: 0%o (SHA1: %s)",
-			     mode, sha1_to_hex(sha1));
+			     mode, oid_to_hex(oid));
 	}
 	if (pathlen > sizeof(header.name)) {
 		size_t plen = get_path_prefix(path, pathlen,
@@ -268,7 +268,7 @@
 			memcpy(header.name, path + plen + 1, rest);
 		} else {
 			xsnprintf(header.name, sizeof(header.name), "%s.data",
-				  sha1_to_hex(sha1));
+				  oid_to_hex(oid));
 			strbuf_append_ext_header(&ext_header, "path",
 						 path, pathlen);
 		}
@@ -276,14 +276,14 @@
 		memcpy(header.name, path, pathlen);
 
 	if (S_ISREG(mode) && !args->convert &&
-	    sha1_object_info(sha1, &size) == OBJ_BLOB &&
+	    oid_object_info(the_repository, oid, &size) == OBJ_BLOB &&
 	    size > big_file_threshold)
 		buffer = NULL;
 	else if (S_ISLNK(mode) || S_ISREG(mode)) {
 		enum object_type type;
-		buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
+		buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size);
 		if (!buffer)
-			return error("cannot read %s", sha1_to_hex(sha1));
+			return error("cannot read %s", oid_to_hex(oid));
 	} else {
 		buffer = NULL;
 		size = 0;
@@ -292,7 +292,7 @@
 	if (S_ISLNK(mode)) {
 		if (size > sizeof(header.linkname)) {
 			xsnprintf(header.linkname, sizeof(header.linkname),
-				  "see %s.paxheader", sha1_to_hex(sha1));
+				  "see %s.paxheader", oid_to_hex(oid));
 			strbuf_append_ext_header(&ext_header, "linkpath",
 			                         buffer, size);
 		} else
@@ -308,7 +308,7 @@
 	prepare_header(args, &header, mode, size_in_header);
 
 	if (ext_header.len > 0) {
-		write_extended_header(args, sha1, ext_header.buf,
+		write_extended_header(args, oid, ext_header.buf,
 				      ext_header.len);
 	}
 	strbuf_release(&ext_header);
@@ -317,7 +317,7 @@
 		if (buffer)
 			write_blocked(buffer, size);
 		else
-			err = stream_blocked(sha1);
+			err = stream_blocked(oid);
 	}
 	free(buffer);
 	return err;
@@ -441,7 +441,7 @@
 	int r;
 
 	if (!ar->data)
-		die("BUG: tar-filter archiver called with no filter defined");
+		BUG("tar-filter archiver called with no filter defined");
 
 	strbuf_addstr(&cmd, ar->data);
 	if (args->compression_level >= 0)
diff --git a/archive-zip.c b/archive-zip.c
index e8913e5..74f3fe9 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -276,7 +276,7 @@
 #define STREAM_BUFFER_SIZE (1024 * 16)
 
 static int write_zip_entry(struct archiver_args *args,
-			   const unsigned char *sha1,
+			   const struct object_id *oid,
 			   const char *path, size_t pathlen,
 			   unsigned int mode)
 {
@@ -314,7 +314,7 @@
 
 	if (pathlen > 0xffff) {
 		return error("path too long (%d chars, SHA1: %s): %s",
-				(int)pathlen, sha1_to_hex(sha1), path);
+				(int)pathlen, oid_to_hex(oid), path);
 	}
 
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
@@ -325,7 +325,8 @@
 		compressed_size = 0;
 		buffer = NULL;
 	} else if (S_ISREG(mode) || S_ISLNK(mode)) {
-		enum object_type type = sha1_object_info(sha1, &size);
+		enum object_type type = oid_object_info(the_repository, oid,
+							&size);
 
 		method = 0;
 		attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
@@ -337,18 +338,18 @@
 
 		if (S_ISREG(mode) && type == OBJ_BLOB && !args->convert &&
 		    size > big_file_threshold) {
-			stream = open_istream(sha1, &type, &size, NULL);
+			stream = open_istream(oid, &type, &size, NULL);
 			if (!stream)
 				return error("cannot stream blob %s",
-					     sha1_to_hex(sha1));
+					     oid_to_hex(oid));
 			flags |= ZIP_STREAM;
 			out = buffer = NULL;
 		} else {
-			buffer = sha1_file_to_archive(args, path, sha1, mode,
-						      &type, &size);
+			buffer = object_file_to_archive(args, path, oid, mode,
+							&type, &size);
 			if (!buffer)
 				return error("cannot read %s",
-					     sha1_to_hex(sha1));
+					     oid_to_hex(oid));
 			crc = crc32(crc, buffer, size);
 			is_binary = entry_is_binary(path_without_prefix,
 						    buffer, size);
@@ -357,7 +358,7 @@
 		compressed_size = (method == 0) ? size : 0;
 	} else {
 		return error("unsupported file mode: 0%o (SHA1: %s)", mode,
-				sha1_to_hex(sha1));
+				oid_to_hex(oid));
 	}
 
 	if (creator_version > max_creator_version)
diff --git a/archive.c b/archive.c
index 0b7b62a..4fe7bec 100644
--- a/archive.c
+++ b/archive.c
@@ -63,16 +63,16 @@
 	free(to_free);
 }
 
-void *sha1_file_to_archive(const struct archiver_args *args,
-			   const char *path, const unsigned char *sha1,
-			   unsigned int mode, enum object_type *type,
-			   unsigned long *sizep)
+void *object_file_to_archive(const struct archiver_args *args,
+			     const char *path, const struct object_id *oid,
+			     unsigned int mode, enum object_type *type,
+			     unsigned long *sizep)
 {
 	void *buffer;
 	const struct commit *commit = args->convert ? args->commit : NULL;
 
 	path += args->baselen;
-	buffer = read_sha1_file(sha1, type, sizep);
+	buffer = read_object_file(oid, type, sizep);
 	if (buffer && S_ISREG(mode)) {
 		struct strbuf buf = STRBUF_INIT;
 		size_t size = 0;
@@ -121,7 +121,7 @@
 	return check && ATTR_TRUE(check->items[1].value);
 }
 
-static int write_archive_entry(const unsigned char *sha1, const char *base,
+static int write_archive_entry(const struct object_id *oid, const char *base,
 		int baselen, const char *filename, unsigned mode, int stage,
 		void *context)
 {
@@ -153,7 +153,7 @@
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 		if (args->verbose)
 			fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
-		err = write_entry(args, sha1, path.buf, path.len, mode);
+		err = write_entry(args, oid, path.buf, path.len, mode);
 		if (err)
 			return err;
 		return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
@@ -161,7 +161,7 @@
 
 	if (args->verbose)
 		fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
-	return write_entry(args, sha1, path.buf, path.len, mode);
+	return write_entry(args, oid, path.buf, path.len, mode);
 }
 
 static void queue_directory(const unsigned char *sha1,
@@ -191,14 +191,14 @@
 	d->path[d->len - 1] = '\0'; /* no trailing slash */
 	ret =
 		write_directory(c) ||
-		write_archive_entry(d->oid.hash, d->path, d->baselen,
+		write_archive_entry(&d->oid, d->path, d->baselen,
 				    d->path + d->baselen, d->mode,
 				    d->stage, c) != READ_TREE_RECURSIVE;
 	free(d);
 	return ret ? -1 : 0;
 }
 
-static int queue_or_write_archive_entry(const unsigned char *sha1,
+static int queue_or_write_archive_entry(const struct object_id *oid,
 		struct strbuf *base, const char *filename,
 		unsigned mode, int stage, void *context)
 {
@@ -224,14 +224,14 @@
 
 		if (check_attr_export_ignore(check))
 			return 0;
-		queue_directory(sha1, base, filename,
+		queue_directory(oid->hash, base, filename,
 				mode, stage, c);
 		return READ_TREE_RECURSIVE;
 	}
 
 	if (write_directory(c))
 		return -1;
-	return write_archive_entry(sha1, base->buf, base->len, filename, mode,
+	return write_archive_entry(oid, base->buf, base->len, filename, mode,
 				   stage, context);
 }
 
@@ -250,7 +250,7 @@
 			len--;
 		if (args->verbose)
 			fprintf(stderr, "%.*s\n", (int)len, args->base);
-		err = write_entry(args, args->tree->object.oid.hash, args->base,
+		err = write_entry(args, &args->tree->object.oid, args->base,
 				  len, 040777);
 		if (err)
 			return err;
@@ -303,7 +303,7 @@
 	return NULL;
 }
 
-static int reject_entry(const unsigned char *sha1, struct strbuf *base,
+static int reject_entry(const struct object_id *oid, struct strbuf *base,
 			const char *filename, unsigned mode,
 			int stage, void *context)
 {
@@ -397,8 +397,8 @@
 		unsigned int mode;
 		int err;
 
-		err = get_tree_entry(tree->object.oid.hash, prefix,
-				     tree_oid.hash, &mode);
+		err = get_tree_entry(&tree->object.oid, prefix, &tree_oid,
+				     &mode);
 		if (err || !S_ISDIR(mode))
 			die("current working directory is untracked");
 
@@ -411,11 +411,9 @@
 }
 
 #define OPT__COMPR(s, v, h, p) \
-	{ OPTION_SET_INT, (s), NULL, (v), NULL, (h), \
-	  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, (p) }
+	OPT_SET_INT_F(s, NULL, v, h, p, PARSE_OPT_NONEG)
 #define OPT__COMPR_HIDDEN(s, v, p) \
-	{ OPTION_SET_INT, (s), NULL, (v), NULL, "", \
-	  PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN, NULL, (p) }
+	OPT_SET_INT_F(s, NULL, v, "", p, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN)
 
 static int parse_archive_args(int argc, const char **argv,
 		const struct archiver **ar, struct archiver_args *args,
diff --git a/archive.h b/archive.h
index 62d1d82..1f9954f 100644
--- a/archive.h
+++ b/archive.h
@@ -31,7 +31,7 @@
 extern void init_zip_archiver(void);
 
 typedef int (*write_archive_entry_fn_t)(struct archiver_args *args,
-					const unsigned char *sha1,
+					const struct object_id *oid,
 					const char *path, size_t pathlen,
 					unsigned int mode);
 
@@ -39,9 +39,9 @@
 extern int write_archive(int argc, const char **argv, const char *prefix, const char *name_hint, int remote);
 
 const char *archive_format_from_filename(const char *filename);
-extern void *sha1_file_to_archive(const struct archiver_args *args,
-				  const char *path, const unsigned char *sha1,
-				  unsigned int mode, enum object_type *type,
-				  unsigned long *sizep);
+extern void *object_file_to_archive(const struct archiver_args *args,
+				    const char *path, const struct object_id *oid,
+				    unsigned int mode, enum object_type *type,
+				    unsigned long *sizep);
 
 #endif	/* ARCHIVE_H */
diff --git a/argv-array.c b/argv-array.c
index 5d370fa..f352ea9 100644
--- a/argv-array.c
+++ b/argv-array.c
@@ -21,12 +21,13 @@
 	array->argv[array->argc] = NULL;
 }
 
-void argv_array_push(struct argv_array *array, const char *value)
+const char *argv_array_push(struct argv_array *array, const char *value)
 {
 	argv_array_push_nodup(array, xstrdup(value));
+	return array->argv[array->argc - 1];
 }
 
-void argv_array_pushf(struct argv_array *array, const char *fmt, ...)
+const char *argv_array_pushf(struct argv_array *array, const char *fmt, ...)
 {
 	va_list ap;
 	struct strbuf v = STRBUF_INIT;
@@ -36,6 +37,7 @@
 	va_end(ap);
 
 	argv_array_push_nodup(array, strbuf_detach(&v, NULL));
+	return array->argv[array->argc - 1];
 }
 
 void argv_array_pushl(struct argv_array *array, ...)
@@ -64,6 +66,26 @@
 	array->argc--;
 }
 
+void argv_array_split(struct argv_array *array, const char *to_split)
+{
+	while (isspace(*to_split))
+		to_split++;
+	for (;;) {
+		const char *p = to_split;
+
+		if (!*p)
+			break;
+
+		while (*p && !isspace(*p))
+			p++;
+		argv_array_push_nodup(array, xstrndup(to_split, p - to_split));
+
+		while (isspace(*p))
+			p++;
+		to_split = p;
+	}
+}
+
 void argv_array_clear(struct argv_array *array)
 {
 	if (array->argv != empty_argv) {
diff --git a/argv-array.h b/argv-array.h
index 29056e4..a39ba43 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -12,13 +12,15 @@
 #define ARGV_ARRAY_INIT { empty_argv, 0, 0 }
 
 void argv_array_init(struct argv_array *);
-void argv_array_push(struct argv_array *, const char *);
+const char *argv_array_push(struct argv_array *, const char *);
 __attribute__((format (printf,2,3)))
-void argv_array_pushf(struct argv_array *, const char *fmt, ...);
+const char *argv_array_pushf(struct argv_array *, const char *fmt, ...);
 LAST_ARG_MUST_BE_NULL
 void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pushv(struct argv_array *, const char **);
 void argv_array_pop(struct argv_array *);
+/* Splits by whitespace; does not handle quoted arguments! */
+void argv_array_split(struct argv_array *, const char *);
 void argv_array_clear(struct argv_array *);
 const char **argv_array_detach(struct argv_array *);
 
diff --git a/attr.c b/attr.c
index dfc3a55..067fb9e 100644
--- a/attr.c
+++ b/attr.c
@@ -10,7 +10,7 @@
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "attr.h"
 #include "dir.h"
 #include "utf8.h"
@@ -157,7 +157,7 @@
 
 	size = hashmap_get_size(&map->map);
 	if (size < check->all_attrs_nr)
-		die("BUG: interned attributes shouldn't be deleted");
+		BUG("interned attributes shouldn't be deleted");
 
 	/*
 	 * If the number of attributes in the global dictionary has increased
@@ -541,7 +541,7 @@
 			break;
 
 	if (i >= check_vector.nr)
-		die("BUG: no entry found");
+		BUG("no entry found");
 
 	/* shift entries over */
 	for (; i < check_vector.nr - 1; i++)
@@ -599,11 +599,11 @@
 		const struct git_attr *attr;
 		param = va_arg(params, const char *);
 		if (!param)
-			die("BUG: counted %d != ended at %d",
+			BUG("counted %d != ended at %d",
 			    check->nr, cnt);
 		attr = git_attr(param);
 		if (!attr)
-			die("BUG: %s: not a valid attribute name", param);
+			BUG("%s: not a valid attribute name", param);
 		check->items[cnt].attr = attr;
 	}
 	va_end(params);
@@ -714,7 +714,7 @@
 			    struct index_state *istate)
 {
 	if (is_bare_repository() && new_direction != GIT_ATTR_INDEX)
-		die("BUG: non-INDEX attr direction in a bare repo");
+		BUG("non-INDEX attr direction in a bare repo");
 
 	if (new_direction != direction)
 		drop_all_attr_stacks();
diff --git a/bisect.c b/bisect.c
index f6d05bd..a579b50 100644
--- a/bisect.c
+++ b/bisect.c
@@ -132,7 +132,8 @@
 		unsigned flags = commit->object.flags;
 		enum object_type type;
 		unsigned long size;
-		char *buf = read_sha1_file(commit->object.oid.hash, &type, &size);
+		char *buf = read_object_file(&commit->object.oid, &type,
+					     &size);
 		const char *subject_start;
 		int subject_len;
 
@@ -144,10 +145,10 @@
 			fprintf(stderr, "%3d", weight(p));
 		else
 			fprintf(stderr, "---");
-		fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.oid.hash));
+		fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
 		for (pp = commit->parents; pp; pp = pp->next)
 			fprintf(stderr, " %.*s", 8,
-				sha1_to_hex(pp->item->object.oid.hash));
+				oid_to_hex(&pp->item->object.oid));
 
 		subject_len = find_commit_subject(buf, &subject_start);
 		if (subject_len)
diff --git a/blame.c b/blame.c
index 200e0ad..14d0e0b 100644
--- a/blame.c
+++ b/blame.c
@@ -80,8 +80,8 @@
 		struct object_id blob_oid;
 		unsigned mode;
 
-		if (!get_tree_entry(commit_oid->hash, path, blob_oid.hash, &mode) &&
-		    sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
+		if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
+		    oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
 			return;
 	}
 
@@ -297,8 +297,8 @@
 		    textconv_object(o->path, o->mode, &o->blob_oid, 1, &file->ptr, &file_size))
 			;
 		else
-			file->ptr = read_sha1_file(o->blob_oid.hash, &type,
-						   &file_size);
+			file->ptr = read_object_file(&o->blob_oid, &type,
+						     &file_size);
 		file->size = file_size;
 
 		if (!file->ptr)
@@ -502,11 +502,9 @@
 {
 	if (!is_null_oid(&origin->blob_oid))
 		return 0;
-	if (get_tree_entry(origin->commit->object.oid.hash,
-			   origin->path,
-			   origin->blob_oid.hash, &origin->mode))
+	if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
 		goto error_out;
-	if (sha1_object_info(origin->blob_oid.hash, NULL) != OBJ_BLOB)
+	if (oid_object_info(the_repository, &origin->blob_oid, NULL) != OBJ_BLOB)
 		goto error_out;
 	return 0;
  error_out:
@@ -553,10 +551,10 @@
 	diff_setup_done(&diff_opts);
 
 	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &origin->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(origin->commit),
 			      "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -622,10 +620,10 @@
 	diff_setup_done(&diff_opts);
 
 	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &origin->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(origin->commit),
 			      "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -1257,10 +1255,10 @@
 		diff_opts.flags.find_copies_harder = 1;
 
 	if (is_null_oid(&target->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &target->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(target->commit),
 			      "", &diff_opts);
 
 	if (!diff_opts.flags.find_copies_harder)
@@ -1808,7 +1806,7 @@
 			l->item = c;
 			if (add_decoration(&sb->revs->children,
 					   &c->parents->item->object, l))
-				die("BUG: not unique item in first-parent chain");
+				BUG("not unique item in first-parent chain");
 			c = c->parents->item;
 		}
 
@@ -1831,8 +1829,8 @@
 				    &sb->final_buf_size))
 			;
 		else
-			sb->final_buf = read_sha1_file(o->blob_oid.hash, &type,
-						       &sb->final_buf_size);
+			sb->final_buf = read_object_file(&o->blob_oid, &type,
+							 &sb->final_buf_size);
 
 		if (!sb->final_buf)
 			die(_("cannot read blob %s for path %s"),
diff --git a/branch.c b/branch.c
index 2672054..f967c98 100644
--- a/branch.c
+++ b/branch.c
@@ -3,12 +3,13 @@
 #include "config.h"
 #include "branch.h"
 #include "refs.h"
+#include "refspec.h"
 #include "remote.h"
 #include "commit.h"
 #include "worktree.h"
 
 struct tracking {
-	struct refspec spec;
+	struct refspec_item spec;
 	char *src;
 	const char *remote;
 	int matches;
@@ -218,8 +219,8 @@
 static int check_tracking_branch(struct remote *remote, void *cb_data)
 {
 	char *tracking_branch = cb_data;
-	struct refspec query;
-	memset(&query, 0, sizeof(struct refspec));
+	struct refspec_item query;
+	memset(&query, 0, sizeof(struct refspec_item));
 	query.dst = tracking_branch;
 	return !remote_find_tracking(remote, &query);
 }
diff --git a/builtin.h b/builtin.h
index 42378f3..4e0f647 100644
--- a/builtin.h
+++ b/builtin.h
@@ -149,6 +149,7 @@
 extern int cmd_clean(int argc, const char **argv, const char *prefix);
 extern int cmd_column(int argc, const char **argv, const char *prefix);
 extern int cmd_commit(int argc, const char **argv, const char *prefix);
+extern int cmd_commit_graph(int argc, const char **argv, const char *prefix);
 extern int cmd_commit_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_config(int argc, const char **argv, const char *prefix);
 extern int cmd_count_objects(int argc, const char **argv, const char *prefix);
@@ -215,6 +216,7 @@
 extern int cmd_revert(int argc, const char **argv, const char *prefix);
 extern int cmd_rm(int argc, const char **argv, const char *prefix);
 extern int cmd_send_pack(int argc, const char **argv, const char *prefix);
+extern int cmd_serve(int argc, const char **argv, const char *prefix);
 extern int cmd_shortlog(int argc, const char **argv, const char *prefix);
 extern int cmd_show(int argc, const char **argv, const char *prefix);
 extern int cmd_show_branch(int argc, const char **argv, const char *prefix);
@@ -231,6 +233,7 @@
 extern int cmd_update_server_info(int argc, const char **argv, const char *prefix);
 extern int cmd_upload_archive(int argc, const char **argv, const char *prefix);
 extern int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix);
+extern int cmd_upload_pack(int argc, const char **argv, const char *prefix);
 extern int cmd_var(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_commit(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_tag(int argc, const char **argv, const char *prefix);
diff --git a/builtin/add.c b/builtin/add.c
index 9ef7fb0..8a155dd 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -9,7 +9,7 @@
 #include "lockfile.h"
 #include "dir.h"
 #include "pathspec.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "cache-tree.h"
 #include "run-command.h"
 #include "parse-options.h"
@@ -265,8 +265,6 @@
 	return 0;
 }
 
-static struct lock_file lock_file;
-
 static const char ignore_error[] =
 N_("The following paths are ignored by one of your .gitignore files:\n");
 
@@ -393,6 +391,7 @@
 	int add_new_files;
 	int require_pathspec;
 	char *seen = NULL;
+	struct lock_file lock_file = LOCK_INIT;
 
 	git_config(add_config, NULL);
 
diff --git a/builtin/am.c b/builtin/am.c
index 1151b5c..2fc2d1e 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -6,7 +6,7 @@
 #include "cache.h"
 #include "config.h"
 #include "builtin.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 #include "dir.h"
 #include "run-command.h"
@@ -403,11 +403,11 @@
 	struct strbuf sb = STRBUF_INIT;
 
 	if (read_state_file(&sb, state, "next", 1) < 0)
-		die("BUG: state file 'next' does not exist");
+		BUG("state file 'next' does not exist");
 	state->cur = strtol(sb.buf, NULL, 10);
 
 	if (read_state_file(&sb, state, "last", 1) < 0)
-		die("BUG: state file 'last' does not exist");
+		BUG("state file 'last' does not exist");
 	state->last = strtol(sb.buf, NULL, 10);
 
 	if (read_author_script(state) < 0)
@@ -986,7 +986,7 @@
 	case PATCH_FORMAT_MBOXRD:
 		return split_mail_mbox(state, paths, keep_cr, 1);
 	default:
-		die("BUG: invalid patch_format");
+		BUG("invalid patch_format");
 	}
 	return -1;
 }
@@ -1041,7 +1041,7 @@
 		str = "b";
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	write_state_text(state, "keep", str);
@@ -1058,7 +1058,7 @@
 		str = "t";
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 	write_state_text(state, "scissors", str);
 
@@ -1216,7 +1216,7 @@
 		mi.keep_non_patch_brackets_in_subject = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	if (state->message_id)
@@ -1232,7 +1232,7 @@
 		mi.use_scissors = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 
 	mi.input = xfopen(mail, "r");
@@ -1463,7 +1463,7 @@
 	int options = 0;
 
 	if (init_apply_state(&apply_state, NULL))
-		die("BUG: init_apply_state() failed");
+		BUG("init_apply_state() failed");
 
 	argv_array_push(&apply_opts, "apply");
 	argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
@@ -1489,7 +1489,7 @@
 		apply_state.apply_verbosity = verbosity_silent;
 
 	if (check_apply_state(&apply_state, force_apply))
-		die("BUG: check_apply_state() failed");
+		BUG("check_apply_state() failed");
 
 	argv_array_push(&apply_paths, am_path(state, "patch"));
 
@@ -1542,7 +1542,7 @@
 	char *their_tree_name;
 
 	if (get_oid("HEAD", &our_tree) < 0)
-		hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&our_tree, the_hash_algo->empty_tree);
 
 	if (build_fake_ancestor(state, index_path))
 		return error("could not build fake ancestor");
@@ -1550,7 +1550,7 @@
 	discard_cache();
 	read_cache_from(index_path);
 
-	if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
+	if (write_index_as_tree(&orig_tree, &the_index, index_path, 0, NULL))
 		return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
 
 	say(state, stdout, _("Using index info to reconstruct a base tree..."));
@@ -1575,7 +1575,7 @@
 		return error(_("Did you hand edit your patch?\n"
 				"It does not apply to blobs recorded in its index."));
 
-	if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
+	if (write_index_as_tree(&their_tree, &the_index, index_path, 0, NULL))
 		return error("could not write tree");
 
 	say(state, stdout, _("Falling back to patching base and 3-way merge..."));
@@ -1626,7 +1626,7 @@
 	if (run_hook_le(NULL, "pre-applypatch", NULL))
 		exit(1);
 
-	if (write_cache_as_tree(tree.hash, 0, NULL))
+	if (write_cache_as_tree(&tree, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 
 	if (!get_oid_commit("HEAD", &parent)) {
@@ -1862,7 +1862,7 @@
 	 */
 	if (!state->rebasing) {
 		am_destroy(state);
-		close_all_packs();
+		close_all_packs(the_repository->objects);
 		run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 	}
 }
@@ -2004,7 +2004,7 @@
 	if (fast_forward_to(head_tree, head_tree, 1))
 		return -1;
 
-	if (write_cache_as_tree(index.hash, 0, NULL))
+	if (write_cache_as_tree(&index, 0, NULL))
 		return -1;
 
 	index_tree = parse_tree_indirect(&index);
@@ -2042,7 +2042,7 @@
 	am_rerere_clear();
 
 	if (get_oid("HEAD", &head))
-		hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&head, the_hash_algo->empty_tree);
 
 	if (clean_index(&head, &head))
 		die(_("failed to clean index"));
@@ -2105,11 +2105,11 @@
 	curr_branch = resolve_refdup("HEAD", 0, &curr_head, NULL);
 	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
-		hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&curr_head, the_hash_algo->empty_tree);
 
 	has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
 	if (!has_orig_head)
-		hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&orig_head, the_hash_algo->empty_tree);
 
 	clean_index(&curr_head, &orig_head);
 
@@ -2231,12 +2231,12 @@
 			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
 		OPT_BOOL('m', "message-id", &state.message_id,
 			N_("pass -m flag to git-mailinfo")),
-		{ OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
-		  N_("pass --keep-cr flag to git-mailsplit for mbox format"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
-		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
-		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+		OPT_SET_INT_F(0, "keep-cr", &keep_cr,
+			N_("pass --keep-cr flag to git-mailsplit for mbox format"),
+			1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "no-keep-cr", &keep_cr,
+			N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
+			0, PARSE_OPT_NONEG),
 		OPT_BOOL('c', "scissors", &state.scissors,
 			N_("strip everything before a scissors line")),
 		OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
@@ -2407,7 +2407,7 @@
 		ret = show_patch(&state);
 		break;
 	default:
-		die("BUG: invalid resume value");
+		BUG("invalid resume value");
 	}
 
 	am_state_release(&state);
diff --git a/builtin/blame.c b/builtin/blame.c
index 9dcb367..3295718 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -7,6 +7,7 @@
 
 #include "cache.h"
 #include "config.h"
+#include "color.h"
 #include "builtin.h"
 #include "commit.h"
 #include "diff.h"
@@ -23,6 +24,7 @@
 #include "dir.h"
 #include "progress.h"
 #include "blame.h"
+#include "string-list.h"
 
 static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");
 
@@ -46,6 +48,8 @@
 static int abbrev = -1;
 static int no_whole_file_rename;
 static int show_progress;
+static char repeated_meta_color[COLOR_MAXLEN];
+static int coloring_mode;
 
 static struct date_mode blame_date_mode = { DATE_ISO8601 };
 static size_t blame_date_width;
@@ -316,10 +320,12 @@
 #define OUTPUT_PORCELAIN	010
 #define OUTPUT_SHOW_NAME	020
 #define OUTPUT_SHOW_NUMBER	040
-#define OUTPUT_SHOW_SCORE      0100
-#define OUTPUT_NO_AUTHOR       0200
+#define OUTPUT_SHOW_SCORE	0100
+#define OUTPUT_NO_AUTHOR	0200
 #define OUTPUT_SHOW_EMAIL	0400
-#define OUTPUT_LINE_PORCELAIN 01000
+#define OUTPUT_LINE_PORCELAIN	01000
+#define OUTPUT_COLOR_LINE	02000
+#define OUTPUT_SHOW_AGE_WITH_COLOR	04000
 
 static void emit_porcelain_details(struct blame_origin *suspect, int repeat)
 {
@@ -367,6 +373,64 @@
 		putchar('\n');
 }
 
+static struct color_field {
+	timestamp_t hop;
+	char col[COLOR_MAXLEN];
+} *colorfield;
+static int colorfield_nr, colorfield_alloc;
+
+static void parse_color_fields(const char *s)
+{
+	struct string_list l = STRING_LIST_INIT_DUP;
+	struct string_list_item *item;
+	enum { EXPECT_DATE, EXPECT_COLOR } next = EXPECT_COLOR;
+
+	colorfield_nr = 0;
+
+	/* Ideally this would be stripped and split at the same time? */
+	string_list_split(&l, s, ',', -1);
+	ALLOC_GROW(colorfield, colorfield_nr + 1, colorfield_alloc);
+
+	for_each_string_list_item(item, &l) {
+		switch (next) {
+		case EXPECT_DATE:
+			colorfield[colorfield_nr].hop = approxidate(item->string);
+			next = EXPECT_COLOR;
+			colorfield_nr++;
+			ALLOC_GROW(colorfield, colorfield_nr + 1, colorfield_alloc);
+			break;
+		case EXPECT_COLOR:
+			if (color_parse(item->string, colorfield[colorfield_nr].col))
+				die(_("expecting a color: %s"), item->string);
+			next = EXPECT_DATE;
+			break;
+		}
+	}
+
+	if (next == EXPECT_COLOR)
+		die (_("must end with a color"));
+
+	colorfield[colorfield_nr].hop = TIME_MAX;
+	string_list_clear(&l, 0);
+}
+
+static void setup_default_color_by_age(void)
+{
+	parse_color_fields("blue,12 month ago,white,1 month ago,red");
+}
+
+static void determine_line_heat(struct blame_entry *ent, const char **dest_color)
+{
+	int i = 0;
+	struct commit_info ci;
+	get_commit_info(ent->suspect->commit, &ci, 1);
+
+	while (i < colorfield_nr && ci.author_time > colorfield[i].hop)
+		i++;
+
+	*dest_color = colorfield[i].col;
+}
+
 static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int opt)
 {
 	int cnt;
@@ -375,15 +439,35 @@
 	struct commit_info ci;
 	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
+	const char *default_color = NULL, *color = NULL, *reset = NULL;
 
 	get_commit_info(suspect->commit, &ci, 1);
 	oid_to_hex_r(hex, &suspect->commit->object.oid);
 
 	cp = blame_nth_line(sb, ent->lno);
+
+	if (opt & OUTPUT_SHOW_AGE_WITH_COLOR) {
+		determine_line_heat(ent, &default_color);
+		color = default_color;
+		reset = GIT_COLOR_RESET;
+	}
+
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
 		char ch;
 		int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? GIT_SHA1_HEXSZ : abbrev;
 
+		if (opt & OUTPUT_COLOR_LINE) {
+			if (cnt > 0) {
+				color = repeated_meta_color;
+				reset = GIT_COLOR_RESET;
+			} else  {
+				color = default_color ? default_color : NULL;
+				reset = default_color ? GIT_COLOR_RESET : NULL;
+			}
+		}
+		if (color)
+			fputs(color, stdout);
+
 		if (suspect->commit->object.flags & UNINTERESTING) {
 			if (blank_boundary)
 				memset(hex, ' ', length);
@@ -433,6 +517,8 @@
 			printf(" %*d) ",
 			       max_digits, ent->lno + 1 + cnt);
 		}
+		if (reset)
+			fputs(reset, stdout);
 		do {
 			ch = *cp++;
 			putchar(ch);
@@ -499,7 +585,7 @@
 
 static int update_auto_abbrev(int auto_abbrev, struct blame_origin *suspect)
 {
-	const char *uniq = find_unique_abbrev(suspect->commit->object.oid.hash,
+	const char *uniq = find_unique_abbrev(&suspect->commit->object.oid,
 					      auto_abbrev);
 	int len = strlen(uniq);
 	if (auto_abbrev < len)
@@ -607,6 +693,30 @@
 		parse_date_format(value, &blame_date_mode);
 		return 0;
 	}
+	if (!strcmp(var, "color.blame.repeatedlines")) {
+		if (color_parse_mem(value, strlen(value), repeated_meta_color))
+			warning(_("invalid color '%s' in color.blame.repeatedLines"),
+				value);
+		return 0;
+	}
+	if (!strcmp(var, "color.blame.highlightrecent")) {
+		parse_color_fields(value);
+		return 0;
+	}
+
+	if (!strcmp(var, "blame.coloring")) {
+		if (!strcmp(value, "repeatedLines")) {
+			coloring_mode |= OUTPUT_COLOR_LINE;
+		} else if (!strcmp(value, "highlightRecent")) {
+			coloring_mode |= OUTPUT_SHOW_AGE_WITH_COLOR;
+		} else if (!strcmp(value, "none")) {
+			coloring_mode &= ~(OUTPUT_COLOR_LINE |
+					    OUTPUT_SHOW_AGE_WITH_COLOR);
+		} else {
+			warning(_("invalid value for blame.coloring"));
+			return 0;
+		}
+	}
 
 	if (git_diff_heuristic_config(var, value, cb) < 0)
 		return -1;
@@ -655,7 +765,7 @@
 
 	if (get_oid(name, &oid))
 		return 0;
-	return OBJ_NONE < sha1_object_info(oid.hash, NULL);
+	return OBJ_NONE < oid_object_info(the_repository, &oid, NULL);
 }
 
 int cmd_blame(int argc, const char **argv, const char *prefix)
@@ -690,6 +800,8 @@
 		OPT_BIT('s', NULL, &output_option, N_("Suppress author name and timestamp (Default: off)"), OUTPUT_NO_AUTHOR),
 		OPT_BIT('e', "show-email", &output_option, N_("Show author email instead of name (Default: off)"), OUTPUT_SHOW_EMAIL),
 		OPT_BIT('w', NULL, &xdl_opts, N_("Ignore whitespace differences"), XDF_IGNORE_WHITESPACE),
+		OPT_BIT(0, "color-lines", &output_option, N_("color redundant metadata from previous line differently"), OUTPUT_COLOR_LINE),
+		OPT_BIT(0, "color-by-age", &output_option, N_("color lines by age"), OUTPUT_SHOW_AGE_WITH_COLOR),
 
 		/*
 		 * The following two options are parsed by parse_revision_opt()
@@ -714,6 +826,7 @@
 	unsigned int range_i;
 	long anchor;
 
+	setup_default_color_by_age();
 	git_config(git_blame_config, &output_option);
 	init_revisions(&revs, NULL);
 	revs.date_mode = blame_date_mode;
@@ -729,6 +842,7 @@
 	for (;;) {
 		switch (parse_options_step(&ctx, options, blame_opt_usage)) {
 		case PARSE_OPT_HELP:
+		case PARSE_OPT_ERROR:
 			exit(129);
 		case PARSE_OPT_DONE:
 			if (ctx.argv[0])
@@ -948,8 +1062,17 @@
 
 	blame_coalesce(&sb);
 
-	if (!(output_option & OUTPUT_PORCELAIN))
+	if (!(output_option & (OUTPUT_COLOR_LINE | OUTPUT_SHOW_AGE_WITH_COLOR)))
+		output_option |= coloring_mode;
+
+	if (!(output_option & OUTPUT_PORCELAIN)) {
 		find_alignment(&sb, &output_option);
+		if (!*repeated_meta_color &&
+		    (output_option & OUTPUT_COLOR_LINE))
+			strcpy(repeated_meta_color, GIT_COLOR_CYAN);
+	}
+	if (output_option & OUTPUT_ANNOTATE_COMPAT)
+		output_option &= ~(OUTPUT_COLOR_LINE | OUTPUT_SHOW_AGE_WITH_COLOR);
 
 	output(&sb, output_option);
 	free((void *)sb.final_buf);
diff --git a/builtin/branch.c b/builtin/branch.c
index 6d0cea9..5217ba3 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -273,7 +273,7 @@
 			       bname.buf,
 			       (flags & REF_ISBROKEN) ? "broken"
 			       : (flags & REF_ISSYMREF) ? target
-			       : find_unique_abbrev(oid.hash, DEFAULT_ABBREV));
+			       : find_unique_abbrev(&oid, DEFAULT_ABBREV));
 		}
 		delete_branch_config(bname.buf);
 
@@ -391,7 +391,6 @@
 	struct ref_array array;
 	int maxwidth = 0;
 	const char *remote_prefix = "";
-	struct strbuf out = STRBUF_INIT;
 	char *to_free = NULL;
 
 	/*
@@ -419,7 +418,10 @@
 	ref_array_sort(sorting, &array);
 
 	for (i = 0; i < array.nr; i++) {
-		format_ref_array_item(array.items[i], format, &out);
+		struct strbuf out = STRBUF_INIT;
+		struct strbuf err = STRBUF_INIT;
+		if (format_ref_array_item(array.items[i], format, &out, &err))
+			die("%s", err.buf);
 		if (column_active(colopts)) {
 			assert(!filter->verbose && "--column and --verbose are incompatible");
 			 /* format to a string_list to let print_columns() do its job */
@@ -428,6 +430,7 @@
 			fwrite(out.buf, 1, out.len, stdout);
 			putchar('\n');
 		}
+		strbuf_release(&err);
 		strbuf_release(&out);
 	}
 
@@ -497,7 +500,7 @@
 
 	if (!skip_prefix(oldref.buf, "refs/heads/", &interpreted_oldname) ||
 	    !skip_prefix(newref.buf, "refs/heads/", &interpreted_newname)) {
-		die("BUG: expected prefix missing for refs");
+		BUG("expected prefix missing for refs");
 	}
 
 	if (copy)
@@ -589,8 +592,8 @@
 		OPT__QUIET(&quiet, N_("suppress informational messages")),
 		OPT_SET_INT('t', "track",  &track, N_("set up tracking mode (see git-pull(1))"),
 			BRANCH_TRACK_EXPLICIT),
-		{ OPTION_SET_INT, 0, "set-upstream", &track, NULL, N_("do not use"),
-			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, BRANCH_TRACK_OVERRIDE },
+		OPT_SET_INT_F(0, "set-upstream", &track, N_("do not use"),
+			BRANCH_TRACK_OVERRIDE, PARSE_OPT_HIDDEN),
 		OPT_STRING('u', "set-upstream-to", &new_upstream, N_("upstream"), N_("change the upstream info")),
 		OPT_BOOL(0, "unset-upstream", &unset_upstream, N_("Unset the upstream info")),
 		OPT__COLOR(&branch_use_color, N_("use colored output")),
@@ -698,7 +701,7 @@
 		 * If no sorting parameter is given then we default to sorting
 		 * by 'refname'. This would give us an alphabetically sorted
 		 * array with the 'HEAD' ref at the beginning followed by
-		 * local branches 'refs/heads/...' and finally remote-tacking
+		 * local branches 'refs/heads/...' and finally remote-tracking
 		 * branches 'refs/remotes/...'.
 		 */
 		if (!sorting)
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index d90170f..665b581 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -32,7 +32,7 @@
 {
 	enum object_type type;
 
-	*buf = read_sha1_file(oid->hash, &type, size);
+	*buf = read_object_file(oid, &type, size);
 	if (!*buf)
 		return error(_("cannot read object %s '%s'"),
 			     oid_to_hex(oid), path);
@@ -77,7 +77,7 @@
 	switch (opt) {
 	case 't':
 		oi.type_name = &sb;
-		if (sha1_object_info_extended(oid.hash, &oi, flags) < 0)
+		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		if (sb.len) {
 			printf("%s\n", sb.buf);
@@ -88,7 +88,7 @@
 
 	case 's':
 		oi.sizep = &size;
-		if (sha1_object_info_extended(oid.hash, &oi, flags) < 0)
+		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		printf("%lu\n", size);
 		return 0;
@@ -116,7 +116,7 @@
 		/* else fallthrough */
 
 	case 'p':
-		type = sha1_object_info(oid.hash, NULL);
+		type = oid_object_info(the_repository, &oid, NULL);
 		if (type < 0)
 			die("Not a valid object name %s", obj_name);
 
@@ -130,7 +130,7 @@
 
 		if (type == OBJ_BLOB)
 			return stream_blob_to_fd(1, &oid, NULL, 0);
-		buf = read_sha1_file(oid.hash, &type, &size);
+		buf = read_object_file(&oid, &type, &size);
 		if (!buf)
 			die("Cannot read object %s", obj_name);
 
@@ -140,8 +140,9 @@
 	case 0:
 		if (type_from_string(exp_type) == OBJ_BLOB) {
 			struct object_id blob_oid;
-			if (sha1_object_info(oid.hash, NULL) == OBJ_TAG) {
-				char *buffer = read_sha1_file(oid.hash, &type, &size);
+			if (oid_object_info(the_repository, &oid, NULL) == OBJ_TAG) {
+				char *buffer = read_object_file(&oid, &type,
+								&size);
 				const char *target;
 				if (!skip_prefix(buffer, "object ", &target) ||
 				    get_oid_hex(target, &blob_oid))
@@ -150,7 +151,7 @@
 			} else
 				oidcpy(&blob_oid, &oid);
 
-			if (sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
+			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
 				return stream_blob_to_fd(1, &blob_oid, NULL, 0);
 			/*
 			 * we attempted to dereference a tag to a blob
@@ -159,7 +160,7 @@
 			 * fall-back to the usual case.
 			 */
 		}
-		buf = read_object_with_reference(oid.hash, exp_type, &size, NULL);
+		buf = read_object_with_reference(&oid, exp_type, &size, NULL);
 		break;
 
 	default:
@@ -304,13 +305,14 @@
 				enum object_type type;
 				if (!textconv_object(data->rest, 0100644, oid,
 						     1, &contents, &size))
-					contents = read_sha1_file(oid->hash, &type,
-								  &size);
+					contents = read_object_file(oid,
+								    &type,
+								    &size);
 				if (!contents)
 					die("could not convert '%s' %s",
 					    oid_to_hex(oid), data->rest);
 			} else
-				die("BUG: invalid cmdmode: %c", opt->cmdmode);
+				BUG("invalid cmdmode: %c", opt->cmdmode);
 			batch_write(opt, contents, size);
 			free(contents);
 		} else if (stream_blob_to_fd(1, oid, NULL, 0) < 0)
@@ -321,7 +323,7 @@
 		unsigned long size;
 		void *contents;
 
-		contents = read_sha1_file(oid->hash, &type, &size);
+		contents = read_object_file(oid, &type, &size);
 		if (!contents)
 			die("object %s disappeared", oid_to_hex(oid));
 		if (type != data->type)
@@ -340,8 +342,8 @@
 	struct strbuf buf = STRBUF_INIT;
 
 	if (!data->skip_object_info &&
-	    sha1_object_info_extended(data->oid.hash, &data->info,
-				      OBJECT_INFO_LOOKUP_REPLACE) < 0) {
+	    oid_object_info_extended(the_repository, &data->oid, &data->info,
+				     OBJECT_INFO_LOOKUP_REPLACE) < 0) {
 		printf("%s missing\n",
 		       obj_name ? obj_name : oid_to_hex(&data->oid));
 		fflush(stdout);
@@ -385,7 +387,7 @@
 			       (uintmax_t)strlen(obj_name), obj_name);
 			break;
 		default:
-			die("BUG: unknown get_sha1_with_context result %d\n",
+			BUG("unknown get_sha1_with_context result %d\n",
 			       result);
 			break;
 		}
diff --git a/builtin/checkout.c b/builtin/checkout.c
index d76e13c..2e1d237 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -66,7 +66,7 @@
 
 }
 
-static int update_some(const unsigned char *sha1, struct strbuf *base,
+static int update_some(const struct object_id *oid, struct strbuf *base,
 		const char *pathname, unsigned mode, int stage, void *context)
 {
 	int len;
@@ -78,7 +78,7 @@
 
 	len = base->len + strlen(pathname);
 	ce = xcalloc(1, cache_entry_size(len));
-	hashcpy(ce->oid.hash, sha1);
+	oidcpy(&ce->oid, oid);
 	memcpy(ce->name, base->buf, base->len);
 	memcpy(ce->name + base->len, pathname, len - base->len);
 	ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
@@ -405,10 +405,10 @@
 		pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 	if (print_sha1_ellipsis()) {
 		fprintf(stderr, "%s %s... %s\n", msg,
-			find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
+			find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 	} else {
 		fprintf(stderr, "%s %s %s\n", msg,
-			find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
+			find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 	}
 	strbuf_release(&sb);
 }
@@ -484,7 +484,8 @@
 
 	resolve_undo_clear();
 	if (opts->force) {
-		ret = reset_tree(new_branch_info->commit->tree, opts, 1, writeout_error);
+		ret = reset_tree(get_commit_tree(new_branch_info->commit),
+				 opts, 1, writeout_error);
 		if (ret)
 			return ret;
 	} else {
@@ -526,6 +527,7 @@
 		init_tree_desc(&trees[1], tree->buffer, tree->size);
 
 		ret = unpack_trees(2, trees, &topts);
+		clear_unpack_trees_porcelain(&topts);
 		if (ret == -1) {
 			/*
 			 * Unpack couldn't do a trivial merge; either
@@ -570,18 +572,23 @@
 			o.verbosity = 0;
 			work = write_tree_from_memory(&o);
 
-			ret = reset_tree(new_branch_info->commit->tree, opts, 1,
+			ret = reset_tree(get_commit_tree(new_branch_info->commit),
+					 opts, 1,
 					 writeout_error);
 			if (ret)
 				return ret;
 			o.ancestor = old_branch_info->name;
 			o.branch1 = new_branch_info->name;
 			o.branch2 = "local";
-			ret = merge_trees(&o, new_branch_info->commit->tree, work,
-				old_branch_info->commit->tree, &result);
+			ret = merge_trees(&o,
+					  get_commit_tree(new_branch_info->commit),
+					  work,
+					  get_commit_tree(old_branch_info->commit),
+					  &result);
 			if (ret < 0)
 				exit(128);
-			ret = reset_tree(new_branch_info->commit->tree, opts, 0,
+			ret = reset_tree(get_commit_tree(new_branch_info->commit),
+					 opts, 0,
 					 writeout_error);
 			strbuf_release(&o.obuf);
 			if (ret)
@@ -720,7 +727,7 @@
 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 {
 	strbuf_addstr(sb, "  ");
-	strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
+	strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
 	strbuf_addch(sb, ' ');
 	if (!parse_commit(commit))
 		pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
@@ -778,7 +785,7 @@
 			" git branch <new-branch-name> %s\n\n",
 			/* Give ngettext() the count */
 			lost),
-			find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
+			find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
 }
 
 /*
@@ -1002,7 +1009,7 @@
 		*source_tree = parse_tree_indirect(rev);
 	} else {
 		parse_commit_or_die(new_branch_info->commit);
-		*source_tree = new_branch_info->commit->tree;
+		*source_tree = get_commit_tree(new_branch_info->commit);
 	}
 
 	if (!*source_tree)                   /* case (1): want a tree */
diff --git a/builtin/clone.c b/builtin/clone.c
index 09fbca1..d0e0ff1 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -14,6 +14,7 @@
 #include "parse-options.h"
 #include "fetch-pack.h"
 #include "refs.h"
+#include "refspec.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "unpack-trees.h"
@@ -27,6 +28,7 @@
 #include "connected.h"
 #include "packfile.h"
 #include "list-objects-filter-options.h"
+#include "object-store.h"
 
 /*
  * Overall FIXMEs:
@@ -545,7 +547,7 @@
 }
 
 static struct ref *wanted_peer_refs(const struct ref *refs,
-		struct refspec *refspec)
+		struct refspec_item *refspec)
 {
 	struct ref *head = copy_ref(find_ref_by_name(refs, "HEAD"));
 	struct ref *local_refs = head;
@@ -822,7 +824,7 @@
 			} else if (remote_head_points_at) {
 				const char *head = remote_head_points_at->name;
 				if (!skip_prefix(head, "refs/heads/", &head))
-					die("BUG: remote HEAD points at non-head?");
+					BUG("remote HEAD points at non-head?");
 
 				strbuf_addf(&value, "+%s:%s%s", remote_head_points_at->name,
 						branch_top->buf, head);
@@ -893,8 +895,7 @@
 	int err = 0, complete_refs_before_fetch = 1;
 	int submodule_progress;
 
-	struct refspec *refspec;
-	const char *fetch_pattern;
+	struct refspec_item refspec;
 
 	fetch_if_missing = 0;
 
@@ -1076,8 +1077,7 @@
 	if (option_required_reference.nr || option_optional_reference.nr)
 		setup_reference();
 
-	fetch_pattern = value.buf;
-	refspec = parse_fetch_refspec(1, &fetch_pattern);
+	refspec_item_init(&refspec, value.buf, REFSPEC_FETCH);
 
 	strbuf_reset(&value);
 
@@ -1134,10 +1134,10 @@
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
-	refs = transport_get_remote_refs(transport);
+	refs = transport_get_remote_refs(transport, NULL);
 
 	if (refs) {
-		mapped_refs = wanted_peer_refs(refs, refspec);
+		mapped_refs = wanted_peer_refs(refs, &refspec);
 		/*
 		 * transport_get_remote_refs() may return refs with null sha-1
 		 * in mapped_refs (see struct transport->get_refs_list
@@ -1217,7 +1217,7 @@
 	transport_disconnect(transport);
 
 	if (option_dissociate) {
-		close_all_packs();
+		close_all_packs(the_repository->objects);
 		dissociate_from_references();
 	}
 
@@ -1231,6 +1231,6 @@
 	strbuf_release(&value);
 	junk_mode = JUNK_LEAVE_ALL;
 
-	free(refspec);
+	refspec_item_clear(&refspec);
 	return err;
 }
diff --git a/builtin/column.c b/builtin/column.c
index 0c3223d..5228ccf 100644
--- a/builtin/column.c
+++ b/builtin/column.c
@@ -42,7 +42,6 @@
 		git_config(column_config, NULL);
 
 	memset(&copts, 0, sizeof(copts));
-	copts.width = term_columns();
 	copts.padding = 1;
 	argc = parse_options(argc, argv, "", options, builtin_column_usage, 0);
 	if (argc)
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
new file mode 100644
index 0000000..37420ae
--- /dev/null
+++ b/builtin/commit-graph.c
@@ -0,0 +1,171 @@
+#include "builtin.h"
+#include "config.h"
+#include "dir.h"
+#include "lockfile.h"
+#include "parse-options.h"
+#include "commit-graph.h"
+
+static char const * const builtin_commit_graph_usage[] = {
+	N_("git commit-graph [--object-dir <objdir>]"),
+	N_("git commit-graph read [--object-dir <objdir>]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
+	NULL
+};
+
+static const char * const builtin_commit_graph_read_usage[] = {
+	N_("git commit-graph read [--object-dir <objdir>]"),
+	NULL
+};
+
+static const char * const builtin_commit_graph_write_usage[] = {
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
+	NULL
+};
+
+static struct opts_commit_graph {
+	const char *obj_dir;
+	int stdin_packs;
+	int stdin_commits;
+	int append;
+} opts;
+
+static int graph_read(int argc, const char **argv)
+{
+	struct commit_graph *graph = NULL;
+	char *graph_name;
+
+	static struct option builtin_commit_graph_read_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, NULL,
+			     builtin_commit_graph_read_options,
+			     builtin_commit_graph_read_usage, 0);
+
+	if (!opts.obj_dir)
+		opts.obj_dir = get_object_directory();
+
+	graph_name = get_commit_graph_filename(opts.obj_dir);
+	graph = load_commit_graph_one(graph_name);
+
+	if (!graph)
+		die("graph file %s does not exist", graph_name);
+	FREE_AND_NULL(graph_name);
+
+	printf("header: %08x %d %d %d %d\n",
+		ntohl(*(uint32_t*)graph->data),
+		*(unsigned char*)(graph->data + 4),
+		*(unsigned char*)(graph->data + 5),
+		*(unsigned char*)(graph->data + 6),
+		*(unsigned char*)(graph->data + 7));
+	printf("num_commits: %u\n", graph->num_commits);
+	printf("chunks:");
+
+	if (graph->chunk_oid_fanout)
+		printf(" oid_fanout");
+	if (graph->chunk_oid_lookup)
+		printf(" oid_lookup");
+	if (graph->chunk_commit_data)
+		printf(" commit_metadata");
+	if (graph->chunk_large_edges)
+		printf(" large_edges");
+	printf("\n");
+
+	return 0;
+}
+
+static int graph_write(int argc, const char **argv)
+{
+	const char **pack_indexes = NULL;
+	int packs_nr = 0;
+	const char **commit_hex = NULL;
+	int commits_nr = 0;
+	const char **lines = NULL;
+	int lines_nr = 0;
+	int lines_alloc = 0;
+
+	static struct option builtin_commit_graph_write_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
+			N_("scan pack-indexes listed by stdin for commits")),
+		OPT_BOOL(0, "stdin-commits", &opts.stdin_commits,
+			N_("start walk at commits listed by stdin")),
+		OPT_BOOL(0, "append", &opts.append,
+			N_("include all commits already in the commit-graph file")),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, NULL,
+			     builtin_commit_graph_write_options,
+			     builtin_commit_graph_write_usage, 0);
+
+	if (opts.stdin_packs && opts.stdin_commits)
+		die(_("cannot use both --stdin-commits and --stdin-packs"));
+	if (!opts.obj_dir)
+		opts.obj_dir = get_object_directory();
+
+	if (opts.stdin_packs || opts.stdin_commits) {
+		struct strbuf buf = STRBUF_INIT;
+		lines_nr = 0;
+		lines_alloc = 128;
+		ALLOC_ARRAY(lines, lines_alloc);
+
+		while (strbuf_getline(&buf, stdin) != EOF) {
+			ALLOC_GROW(lines, lines_nr + 1, lines_alloc);
+			lines[lines_nr++] = strbuf_detach(&buf, NULL);
+		}
+
+		if (opts.stdin_packs) {
+			pack_indexes = lines;
+			packs_nr = lines_nr;
+		}
+		if (opts.stdin_commits) {
+			commit_hex = lines;
+			commits_nr = lines_nr;
+		}
+	}
+
+	write_commit_graph(opts.obj_dir,
+			   pack_indexes,
+			   packs_nr,
+			   commit_hex,
+			   commits_nr,
+			   opts.append);
+
+	return 0;
+}
+
+int cmd_commit_graph(int argc, const char **argv, const char *prefix)
+{
+	static struct option builtin_commit_graph_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_END(),
+	};
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(builtin_commit_graph_usage,
+				   builtin_commit_graph_options);
+
+	git_config(git_default_config, NULL);
+	argc = parse_options(argc, argv, prefix,
+			     builtin_commit_graph_options,
+			     builtin_commit_graph_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (argc > 0) {
+		if (!strcmp(argv[0], "read"))
+			return graph_read(argc, argv);
+		if (!strcmp(argv[0], "write"))
+			return graph_write(argc, argv);
+	}
+
+	usage_with_options(builtin_commit_graph_usage,
+			   builtin_commit_graph_options);
+}
diff --git a/builtin/commit-tree.c b/builtin/commit-tree.c
index e5bdf57..ecf4219 100644
--- a/builtin/commit-tree.c
+++ b/builtin/commit-tree.c
@@ -58,7 +58,7 @@
 				usage(commit_tree_usage);
 			if (get_oid_commit(argv[i], &oid))
 				die("Not a valid object name %s", argv[i]);
-			assert_sha1_type(oid.hash, OBJ_COMMIT);
+			assert_oid_type(&oid, OBJ_COMMIT);
 			new_parent(lookup_commit(&oid), &parents);
 			continue;
 		}
diff --git a/builtin/commit.c b/builtin/commit.c
index 37fcb55..a842fea 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -143,6 +143,16 @@
 	return 0;
 }
 
+static int opt_parse_rename_score(const struct option *opt, const char *arg, int unset)
+{
+	const char **value = opt->value;
+	if (arg != NULL && *arg == '=')
+		arg = arg + 1;
+
+	*value = arg;
+	return 0;
+}
+
 static void determine_whence(struct wt_status *s)
 {
 	if (file_exists(git_path_merge_head()))
@@ -161,9 +171,9 @@
 static void status_init_config(struct wt_status *s, config_fn_t fn)
 {
 	wt_status_prepare(s);
+	init_diff_ui_defaults();
 	git_config(fn, s);
 	determine_whence(s);
-	init_diff_ui_defaults();
 	s->hints = advice_status_hints; /* must come after git_config() */
 }
 
@@ -218,8 +228,7 @@
 
 	if (with_tree) {
 		char *max_prefix = common_prefix(pattern);
-		overlay_tree_on_index(&the_index, with_tree,
-				      max_prefix ? max_prefix : prefix);
+		overlay_tree_on_index(&the_index, with_tree, max_prefix);
 		free(max_prefix);
 	}
 
@@ -496,7 +505,7 @@
 static void assert_split_ident(struct ident_split *id, const struct strbuf *buf)
 {
 	if (split_ident_line(id, buf->buf, buf->len) || !id->date_begin)
-		die("BUG: unable to parse our own ident: %s", buf->buf);
+		BUG("unable to parse our own ident: %s", buf->buf);
 }
 
 static void export_one(const char *var, const char *s, const char *e, int hack)
@@ -1260,11 +1269,31 @@
 			return error(_("Invalid untracked files mode '%s'"), v);
 		return 0;
 	}
+	if (!strcmp(k, "diff.renamelimit")) {
+		if (s->rename_limit == -1)
+			s->rename_limit = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "status.renamelimit")) {
+		s->rename_limit = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "diff.renames")) {
+		if (s->detect_rename == -1)
+			s->detect_rename = git_config_rename(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "status.renames")) {
+		s->detect_rename = git_config_rename(k, v);
+		return 0;
+	}
 	return git_diff_ui_config(k, v, NULL);
 }
 
 int cmd_status(int argc, const char **argv, const char *prefix)
 {
+	static int no_renames = -1;
+	static const char *rename_score_arg = (const char *)-1;
 	static struct wt_status s;
 	int fd;
 	struct object_id oid;
@@ -1298,6 +1327,10 @@
 		  N_("ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)"),
 		  PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
 		OPT_COLUMN(0, "column", &s.colopts, N_("list untracked files in columns")),
+		OPT_BOOL(0, "no-renames", &no_renames, N_("do not detect renames")),
+		{ OPTION_CALLBACK, 'M', "find-renames", &rename_score_arg,
+		  N_("n"), N_("detect renames, optionally set similarity index"),
+		  PARSE_OPT_OPTARG, opt_parse_rename_score },
 		OPT_END(),
 	};
 
@@ -1337,6 +1370,14 @@
 	s.ignore_submodule_arg = ignore_submodule_arg;
 	s.status_format = status_format;
 	s.verbose = verbose;
+	if (no_renames != -1)
+		s.detect_rename = !no_renames;
+	if ((intptr_t)rename_score_arg != -1) {
+		if (s.detect_rename < DIFF_DETECT_RENAME)
+			s.detect_rename = DIFF_DETECT_RENAME;
+		if (rename_score_arg)
+			s.rename_score = parse_rename_score(&rename_score_arg);
+	}
 
 	wt_status_collect(&s);
 
diff --git a/builtin/config.c b/builtin/config.c
index 01169dd..b29d26d 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -25,7 +25,8 @@
 
 static int use_global_config, use_system_config, use_local_config;
 static struct git_config_source given_config_source;
-static int actions, types;
+static int actions, type;
+static char *default_value;
 static int end_null;
 static int respect_includes_opt = -1;
 static struct config_options config_options;
@@ -55,11 +56,68 @@
 #define PAGING_ACTIONS (ACTION_LIST | ACTION_GET_ALL | \
 			ACTION_GET_REGEXP | ACTION_GET_URLMATCH)
 
-#define TYPE_BOOL (1<<0)
-#define TYPE_INT (1<<1)
-#define TYPE_BOOL_OR_INT (1<<2)
-#define TYPE_PATH (1<<3)
-#define TYPE_EXPIRY_DATE (1<<4)
+#define TYPE_BOOL		1
+#define TYPE_INT		2
+#define TYPE_BOOL_OR_INT	3
+#define TYPE_PATH		4
+#define TYPE_EXPIRY_DATE	5
+#define TYPE_COLOR		6
+
+#define OPT_CALLBACK_VALUE(s, l, v, h, i) \
+	{ OPTION_CALLBACK, (s), (l), (v), NULL, (h), PARSE_OPT_NOARG | \
+	PARSE_OPT_NONEG, option_parse_type, (i) }
+
+static struct option builtin_config_options[];
+
+static int option_parse_type(const struct option *opt, const char *arg,
+			     int unset)
+{
+	int new_type, *to_type;
+
+	if (unset) {
+		*((int *) opt->value) = 0;
+		return 0;
+	}
+
+	/*
+	 * To support '--<type>' style flags, begin with new_type equal to
+	 * opt->defval.
+	 */
+	new_type = opt->defval;
+	if (!new_type) {
+		if (!strcmp(arg, "bool"))
+			new_type = TYPE_BOOL;
+		else if (!strcmp(arg, "int"))
+			new_type = TYPE_INT;
+		else if (!strcmp(arg, "bool-or-int"))
+			new_type = TYPE_BOOL_OR_INT;
+		else if (!strcmp(arg, "path"))
+			new_type = TYPE_PATH;
+		else if (!strcmp(arg, "expiry-date"))
+			new_type = TYPE_EXPIRY_DATE;
+		else if (!strcmp(arg, "color"))
+			new_type = TYPE_COLOR;
+		else
+			die(_("unrecognized --type argument, %s"), arg);
+	}
+
+	to_type = opt->value;
+	if (*to_type && *to_type != new_type) {
+		/*
+		 * Complain when there is a new type not equal to the old type.
+		 * This allows for combinations like '--int --type=int' and
+		 * '--type=int --type=int', but disallows ones like '--type=bool
+		 * --int' and '--type=bool
+		 * --type=int'.
+		 */
+		error("only one type at a time.");
+		usage_with_options(builtin_config_usage,
+			builtin_config_options);
+	}
+	*to_type = new_type;
+
+	return 0;
+}
 
 static struct option builtin_config_options[] = {
 	OPT_GROUP(N_("Config file location")),
@@ -84,16 +142,18 @@
 	OPT_BIT(0, "get-color", &actions, N_("find the color configured: slot [default]"), ACTION_GET_COLOR),
 	OPT_BIT(0, "get-colorbool", &actions, N_("find the color setting: slot [stdout-is-tty]"), ACTION_GET_COLORBOOL),
 	OPT_GROUP(N_("Type")),
-	OPT_BIT(0, "bool", &types, N_("value is \"true\" or \"false\""), TYPE_BOOL),
-	OPT_BIT(0, "int", &types, N_("value is decimal number"), TYPE_INT),
-	OPT_BIT(0, "bool-or-int", &types, N_("value is --bool or --int"), TYPE_BOOL_OR_INT),
-	OPT_BIT(0, "path", &types, N_("value is a path (file or directory name)"), TYPE_PATH),
-	OPT_BIT(0, "expiry-date", &types, N_("value is an expiry date"), TYPE_EXPIRY_DATE),
+	OPT_CALLBACK('t', "type", &type, "", N_("value is given this type"), option_parse_type),
+	OPT_CALLBACK_VALUE(0, "bool", &type, N_("value is \"true\" or \"false\""), TYPE_BOOL),
+	OPT_CALLBACK_VALUE(0, "int", &type, N_("value is decimal number"), TYPE_INT),
+	OPT_CALLBACK_VALUE(0, "bool-or-int", &type, N_("value is --bool or --int"), TYPE_BOOL_OR_INT),
+	OPT_CALLBACK_VALUE(0, "path", &type, N_("value is a path (file or directory name)"), TYPE_PATH),
+	OPT_CALLBACK_VALUE(0, "expiry-date", &type, N_("value is an expiry date"), TYPE_EXPIRY_DATE),
 	OPT_GROUP(N_("Other")),
 	OPT_BOOL('z', "null", &end_null, N_("terminate values with NUL byte")),
 	OPT_BOOL(0, "name-only", &omit_values, N_("show variable names only")),
 	OPT_BOOL(0, "includes", &respect_includes_opt, N_("respect include directives on lookup")),
 	OPT_BOOL(0, "show-origin", &show_origin, N_("show origin of config (file, standard input, blob, command line)")),
+	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
 	OPT_END(),
 };
 
@@ -149,30 +209,35 @@
 		if (show_keys)
 			strbuf_addch(buf, key_delim);
 
-		if (types == TYPE_INT)
+		if (type == TYPE_INT)
 			strbuf_addf(buf, "%"PRId64,
 				    git_config_int64(key_, value_ ? value_ : ""));
-		else if (types == TYPE_BOOL)
+		else if (type == TYPE_BOOL)
 			strbuf_addstr(buf, git_config_bool(key_, value_) ?
 				      "true" : "false");
-		else if (types == TYPE_BOOL_OR_INT) {
+		else if (type == TYPE_BOOL_OR_INT) {
 			int is_bool, v;
 			v = git_config_bool_or_int(key_, value_, &is_bool);
 			if (is_bool)
 				strbuf_addstr(buf, v ? "true" : "false");
 			else
 				strbuf_addf(buf, "%d", v);
-		} else if (types == TYPE_PATH) {
+		} else if (type == TYPE_PATH) {
 			const char *v;
 			if (git_config_pathname(&v, key_, value_) < 0)
 				return -1;
 			strbuf_addstr(buf, v);
 			free((char *)v);
-		} else if (types == TYPE_EXPIRY_DATE) {
+		} else if (type == TYPE_EXPIRY_DATE) {
 			timestamp_t t;
 			if (git_config_expiry_date(&t, key_, value_) < 0)
 				return -1;
 			strbuf_addf(buf, "%"PRItime, t);
+		} else if (type == TYPE_COLOR) {
+			char v[COLOR_MAXLEN];
+			if (git_config_color(v, key_, value_) < 0)
+				return -1;
+			strbuf_addstr(buf, v);
 		} else if (value_) {
 			strbuf_addstr(buf, value_);
 		} else {
@@ -258,6 +323,16 @@
 	config_with_options(collect_config, &values,
 			    &given_config_source, &config_options);
 
+	if (!values.nr && default_value) {
+		struct strbuf *item;
+		ALLOC_GROW(values.items, values.nr + 1, values.alloc);
+		item = &values.items[values.nr++];
+		strbuf_init(item, 0);
+		if (format_config(item, key_, default_value) < 0)
+			die(_("failed to format default config value: %s"),
+				default_value);
+	}
+
 	ret = !values.nr;
 
 	for (i = 0; i < values.nr; i++) {
@@ -287,7 +362,7 @@
 	if (!value)
 		return NULL;
 
-	if (types == 0 || types == TYPE_PATH || types == TYPE_EXPIRY_DATE)
+	if (type == 0 || type == TYPE_PATH || type == TYPE_EXPIRY_DATE)
 		/*
 		 * We don't do normalization for TYPE_PATH here: If
 		 * the path is like ~/foobar/, we prefer to store
@@ -296,11 +371,11 @@
 		 * Also don't do normalization for expiry dates.
 		 */
 		return xstrdup(value);
-	if (types == TYPE_INT)
+	if (type == TYPE_INT)
 		return xstrfmt("%"PRId64, git_config_int64(key, value));
-	if (types == TYPE_BOOL)
+	if (type == TYPE_BOOL)
 		return xstrdup(git_config_bool(key, value) ?  "true" : "false");
-	if (types == TYPE_BOOL_OR_INT) {
+	if (type == TYPE_BOOL_OR_INT) {
 		int is_bool, v;
 		v = git_config_bool_or_int(key, value, &is_bool);
 		if (!is_bool)
@@ -308,8 +383,22 @@
 		else
 			return xstrdup(v ? "true" : "false");
 	}
+	if (type == TYPE_COLOR) {
+		char v[COLOR_MAXLEN];
+		if (git_config_color(v, key, value))
+			die("cannot parse color '%s'", value);
 
-	die("BUG: cannot normalize type %d", types);
+		/*
+		 * The contents of `v` now contain an ANSI escape
+		 * sequence, not suitable for including within a
+		 * configuration file. Treat the above as a
+		 * "sanity-check", and return the given value, which we
+		 * know is representable as valid color code.
+		 */
+		return xstrdup(value);
+	}
+
+	BUG("cannot normalize type %d", type);
 }
 
 static int get_color_found;
@@ -513,6 +602,9 @@
 	if (use_local_config && nongit)
 		die(_("--local can only be used inside a git repository"));
 
+	if (given_config_source.blob && nongit)
+		die(_("--blob can only be used inside a git repository"));
+
 	if (given_config_source.file &&
 			!strcmp(given_config_source.file, "-")) {
 		given_config_source.file = NULL;
@@ -566,12 +658,7 @@
 		key_delim = '\n';
 	}
 
-	if (HAS_MULTI_BITS(types)) {
-		error("only one type at a time.");
-		usage_with_options(builtin_config_usage, builtin_config_options);
-	}
-
-	if ((actions & (ACTION_GET_COLOR|ACTION_GET_COLORBOOL)) && types) {
+	if ((actions & (ACTION_GET_COLOR|ACTION_GET_COLORBOOL)) && type) {
 		error("--get-color and variable type are incoherent");
 		usage_with_options(builtin_config_usage, builtin_config_options);
 	}
@@ -601,6 +688,12 @@
 		usage_with_options(builtin_config_usage, builtin_config_options);
 	}
 
+	if (default_value && !(actions & ACTION_GET)) {
+		error("--default is only applicable to --get");
+		usage_with_options(builtin_config_usage,
+			builtin_config_options);
+	}
+
 	if (actions & PAGING_ACTIONS)
 		setup_auto_pager("config", 1);
 
diff --git a/builtin/count-objects.c b/builtin/count-objects.c
index 3334381..d51e2ce 100644
--- a/builtin/count-objects.c
+++ b/builtin/count-objects.c
@@ -7,10 +7,12 @@
 #include "cache.h"
 #include "config.h"
 #include "dir.h"
+#include "repository.h"
 #include "builtin.h"
 #include "parse-options.h"
 #include "quote.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static unsigned long garbage;
 static off_t size_garbage;
@@ -64,7 +66,7 @@
 	else {
 		loose_size += on_disk_bytes(st);
 		loose++;
-		if (verbose && has_sha1_pack(oid->hash))
+		if (verbose && has_object_pack(oid))
 			packed_loose++;
 	}
 	return 0;
@@ -120,9 +122,8 @@
 		struct strbuf loose_buf = STRBUF_INIT;
 		struct strbuf pack_buf = STRBUF_INIT;
 		struct strbuf garbage_buf = STRBUF_INIT;
-		if (!packed_git)
-			prepare_packed_git();
-		for (p = packed_git; p; p = p->next) {
+
+		for (p = get_packed_git(the_repository); p; p = p->next) {
 			if (!p->pack_local)
 				continue;
 			if (open_pack_index(p))
diff --git a/builtin/describe.c b/builtin/describe.c
index e4869df..cf1ae77 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -6,7 +6,7 @@
 #include "blob.h"
 #include "refs.h"
 #include "builtin.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 #include "revision.h"
 #include "diff.h"
@@ -285,7 +285,7 @@
 
 static void append_suffix(int depth, const struct object_id *oid, struct strbuf *dst)
 {
-	strbuf_addf(dst, "-%d-g%s", depth, find_unique_abbrev(oid->hash, abbrev));
+	strbuf_addf(dst, "-%d-g%s", depth, find_unique_abbrev(oid, abbrev));
 }
 
 static void describe_commit(struct object_id *oid, struct strbuf *dst)
@@ -383,7 +383,7 @@
 	if (!match_cnt) {
 		struct object_id *cmit_oid = &cmit->object.oid;
 		if (always) {
-			strbuf_add_unique_abbrev(dst, cmit_oid->hash, abbrev);
+			strbuf_add_unique_abbrev(dst, cmit_oid, abbrev);
 			if (suffix)
 				strbuf_addstr(dst, suffix);
 			return;
@@ -502,7 +502,7 @@
 
 	if (cmit)
 		describe_commit(&oid, &sb);
-	else if (sha1_object_info(oid.hash, NULL) == OBJ_BLOB)
+	else if (oid_object_info(the_repository, &oid, NULL) == OBJ_BLOB)
 		describe_blob(oid, &sb);
 	else
 		die(_("%s is neither a commit nor blob"), arg);
@@ -612,7 +612,7 @@
 				suffix = broken;
 			}
 		} else if (dirty) {
-			static struct lock_file index_lock;
+			struct lock_file index_lock = LOCK_INIT;
 			struct rev_info revs;
 			struct argv_array args = ARGV_ARRAY_INIT;
 			int fd, result;
diff --git a/builtin/diff.c b/builtin/diff.c
index 16bfb22..bfefff3 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -398,7 +398,7 @@
 		if (!obj)
 			die(_("invalid object '%s' given."), name);
 		if (obj->type == OBJ_COMMIT)
-			obj = &((struct commit *)obj)->tree->object;
+			obj = &get_commit_tree(((struct commit *)obj))->object;
 
 		if (obj->type == OBJ_TREE) {
 			obj->flags |= flags;
diff --git a/builtin/difftool.c b/builtin/difftool.c
index bcc79d1..bc97d4a 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -15,7 +15,7 @@
 #include "config.h"
 #include "builtin.h"
 #include "run-command.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 #include "argv-array.h"
 #include "strbuf.h"
@@ -306,7 +306,7 @@
 	} else {
 		enum object_type type;
 		unsigned long size;
-		data = read_sha1_file(oid->hash, &type, &size);
+		data = read_object_file(oid, &type, &size);
 		if (!data)
 			die(_("could not read object %s for symlink %s"),
 				oid_to_hex(oid), path);
@@ -610,7 +610,7 @@
 			continue;
 
 		if (!indices_loaded) {
-			static struct lock_file lock;
+			struct lock_file lock = LOCK_INIT;
 			strbuf_reset(&buf);
 			strbuf_addf(&buf, "%s/wtindex", tmpdir);
 			if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
@@ -695,12 +695,11 @@
 			 N_("use `diff.guitool` instead of `diff.tool`")),
 		OPT_BOOL('d', "dir-diff", &dir_diff,
 			 N_("perform a full-directory diff")),
-		{ OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
+		OPT_SET_INT_F('y', "no-prompt", &prompt,
 			N_("do not prompt before launching a diff tool"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
-		{ OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
-			NULL, 1 },
+			0, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "prompt", &prompt, NULL,
+			1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 		OPT_BOOL(0, "symlinks", &symlinks,
 			 N_("use symlinks in dir-diff mode")),
 		OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 27b2cc1..6c97687 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -7,6 +7,7 @@
 #include "cache.h"
 #include "config.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "object.h"
 #include "tag.h"
@@ -35,8 +36,7 @@
 static int no_data;
 static int full_tree;
 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
-static struct refspec *refspecs;
-static int refspecs_nr;
+static struct refspec refspecs = REFSPEC_INIT_FETCH;
 static int anonymize;
 
 static int parse_opt_signed_tag_mode(const struct option *opt,
@@ -156,15 +156,14 @@
 	}
 }
 
-/* Since intptr_t is C99, we do not use it here */
-static inline uint32_t *mark_to_ptr(uint32_t mark)
+static inline void *mark_to_ptr(uint32_t mark)
 {
-	return ((uint32_t *)NULL) + mark;
+	return (void *)(uintptr_t)mark;
 }
 
 static inline uint32_t ptr_to_mark(void * mark)
 {
-	return (uint32_t *)mark - (uint32_t *)NULL;
+	return (uint32_t)(uintptr_t)mark;
 }
 
 static inline void mark_object(struct object *object, uint32_t mark)
@@ -237,10 +236,10 @@
 		object = (struct object *)lookup_blob(oid);
 		eaten = 0;
 	} else {
-		buf = read_sha1_file(oid->hash, &type, &size);
+		buf = read_object_file(oid, &type, &size);
 		if (!buf)
 			die ("Could not read blob %s", oid_to_hex(oid));
-		if (check_sha1_signature(oid->hash, buf, size, type_name(type)) < 0)
+		if (check_object_signature(oid, buf, size, type_name(type)) < 0)
 			die("sha1 mismatch in blob %s", oid_to_hex(oid));
 		object = parse_object_buffer(oid, type, size, buf, &eaten);
 	}
@@ -517,7 +516,7 @@
 	/* skip "committer", "author", "tagger", etc */
 	end_of_header = strchr(*beg, ' ');
 	if (!end_of_header)
-		die("BUG: malformed line fed to anonymize_ident_line: %.*s",
+		BUG("malformed line fed to anonymize_ident_line: %.*s",
 		    (int)(*end - *beg), *beg);
 	end_of_header++;
 	strbuf_add(out, *beg, end_of_header - *beg);
@@ -578,11 +577,11 @@
 	    get_object_mark(&commit->parents->item->object) != 0 &&
 	    !full_tree) {
 		parse_commit_or_die(commit->parents->item);
-		diff_tree_oid(&commit->parents->item->tree->object.oid,
-			      &commit->tree->object.oid, "", &rev->diffopt);
+		diff_tree_oid(get_commit_tree_oid(commit->parents->item),
+			      get_commit_tree_oid(commit), "", &rev->diffopt);
 	}
 	else
-		diff_root_tree_oid(&commit->tree->object.oid,
+		diff_root_tree_oid(get_commit_tree_oid(commit),
 				   "", &rev->diffopt);
 
 	/* Export the referenced blobs, and remember the marks. */
@@ -651,8 +650,11 @@
 	struct commit *commit;
 	while (commits->nr) {
 		commit = (struct commit *)object_array_pop(commits);
-		if (has_unshown_parent(commit))
+		if (has_unshown_parent(commit)) {
+			/* Queue again, to be handled later */
+			add_object_array(&commit->object, NULL, commits);
 			return;
+		}
 		handle_commit(commit, revs, paths_of_changed_objects);
 	}
 }
@@ -682,7 +684,7 @@
 		return;
 	}
 
-	buf = read_sha1_file(tag->object.oid.hash, &type, &size);
+	buf = read_object_file(&tag->object.oid, &type, &size);
 	if (!buf)
 		die ("Could not read tag %s", oid_to_hex(&tag->object.oid));
 	message = memmem(buf, size, "\n\n", 2);
@@ -826,9 +828,9 @@
 		if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 			continue;
 
-		if (refspecs) {
+		if (refspecs.nr) {
 			char *private;
-			private = apply_refspecs(refspecs, refspecs_nr, full_name);
+			private = apply_refspecs(&refspecs, full_name);
 			if (private) {
 				free(full_name);
 				full_name = private;
@@ -947,7 +949,7 @@
 		if (last_idnum < mark)
 			last_idnum = mark;
 
-		type = sha1_object_info(oid.hash, NULL);
+		type = oid_object_info(the_repository, &oid, NULL);
 		if (type < 0)
 			die("object not found: %s", oid_to_hex(&oid));
 
@@ -974,8 +976,8 @@
 static void handle_deletes(void)
 {
 	int i;
-	for (i = 0; i < refspecs_nr; i++) {
-		struct refspec *refspec = &refspecs[i];
+	for (i = 0; i < refspecs.nr; i++) {
+		struct refspec_item *refspec = &refspecs.items[i];
 		if (*refspec->src)
 			continue;
 
@@ -1036,18 +1038,12 @@
 		usage_with_options (fast_export_usage, options);
 
 	if (refspecs_list.nr) {
-		const char **refspecs_str;
 		int i;
 
-		ALLOC_ARRAY(refspecs_str, refspecs_list.nr);
 		for (i = 0; i < refspecs_list.nr; i++)
-			refspecs_str[i] = refspecs_list.items[i].string;
-
-		refspecs_nr = refspecs_list.nr;
-		refspecs = parse_fetch_refspec(refspecs_nr, refspecs_str);
+			refspec_append(&refspecs, refspecs_list.items[i].string);
 
 		string_list_clear(&refspecs_list, 1);
-		free(refspecs_str);
 	}
 
 	if (use_done_feature)
@@ -1086,7 +1082,7 @@
 	if (use_done_feature)
 		printf("done\n");
 
-	free_refspec(refspecs_nr, refspecs);
+	refspec_clear(&refspecs);
 
 	return 0;
 }
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index a7bc136..1a1bc63 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -4,6 +4,7 @@
 #include "remote.h"
 #include "connect.h"
 #include "sha1-array.h"
+#include "protocol.h"
 
 static const char fetch_pack_usage[] =
 "git fetch-pack [--all] [--stdin] [--quiet | -q] [--keep | -k] [--thin] "
@@ -52,6 +53,7 @@
 	struct fetch_pack_args args;
 	struct oid_array shallow = OID_ARRAY_INIT;
 	struct string_list deepen_not = STRING_LIST_INIT_DUP;
+	struct packet_reader reader;
 
 	fetch_if_missing = 0;
 
@@ -211,10 +213,24 @@
 		if (!conn)
 			return args.diag_url ? 0 : 1;
 	}
-	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL, &shallow);
+
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	switch (discover_version(&reader)) {
+	case protocol_v2:
+		die("support for protocol v2 not implemented yet");
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &ref, 0, NULL, &shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 
 	ref = fetch_pack(&args, fd, conn, ref, dest, sought, nr_sought,
-			 &shallow, pack_lockfile_ptr);
+			 &shallow, pack_lockfile_ptr, protocol_v0);
 	if (pack_lockfile) {
 		printf("lock %s\n", pack_lockfile);
 		fflush(stdout);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 6d73656..ea5b966 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -5,6 +5,7 @@
 #include "config.h"
 #include "repository.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "builtin.h"
 #include "string-list.h"
@@ -59,9 +60,9 @@
 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
 static int recurse_submodules_default = RECURSE_SUBMODULES_ON_DEMAND;
 static int shown_url = 0;
-static int refmap_alloc, refmap_nr;
-static const char **refmap_array;
+static struct refspec refmap = REFSPEC_INIT_FETCH;
 static struct list_objects_filter_options filter_options;
+static struct string_list server_options = STRING_LIST_INIT_DUP;
 
 static int git_fetch_config(const char *k, const char *v, void *cb)
 {
@@ -107,14 +108,12 @@
 
 static int parse_refmap_arg(const struct option *opt, const char *arg, int unset)
 {
-	ALLOC_GROW(refmap_array, refmap_nr + 1, refmap_alloc);
-
 	/*
 	 * "git fetch --refmap='' origin foo"
 	 * can be used to tell the command not to store anywhere
 	 */
-	if (*arg)
-		refmap_array[refmap_nr++] = arg;
+	refspec_append(&refmap, arg);
+
 	return 0;
 }
 
@@ -156,9 +155,9 @@
 			N_("deepen history of shallow clone, excluding rev")),
 	OPT_INTEGER(0, "deepen", &deepen_relative,
 		    N_("deepen history of shallow clone")),
-	{ OPTION_SET_INT, 0, "unshallow", &unshallow, NULL,
-		   N_("convert to a complete repository"),
-		   PARSE_OPT_NONEG | PARSE_OPT_NOARG, NULL, 1 },
+	OPT_SET_INT_F(0, "unshallow", &unshallow,
+		      N_("convert to a complete repository"),
+		      1, PARSE_OPT_NONEG),
 	{ OPTION_STRING, 0, "submodule-prefix", &submodule_prefix, N_("dir"),
 		   N_("prepend this to submodule path output"), PARSE_OPT_HIDDEN },
 	{ OPTION_CALLBACK, 0, "recurse-submodules-default",
@@ -170,6 +169,7 @@
 		 N_("accept refs that update .git/shallow")),
 	{ OPTION_CALLBACK, 0, "refmap", NULL, N_("refmap"),
 	  N_("specify fetch refmap"), PARSE_OPT_NONEG, parse_refmap_arg },
+	OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
 	OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
@@ -202,7 +202,7 @@
 
 	for (i = 0; i < branch->merge_nr; i++) {
 		struct ref *rm, **old_tail = *tail;
-		struct refspec refspec;
+		struct refspec_item refspec;
 
 		for (rm = *head; rm; rm = rm->next) {
 			if (branch_merge_matches(branch, i, rm->name)) {
@@ -264,7 +264,7 @@
 	struct string_list_item *item = NULL;
 
 	for_each_ref(add_existing, &existing_refs);
-	for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
+	for (ref = transport_get_remote_refs(transport, NULL); ref; ref = ref->next) {
 		if (!starts_with(ref->name, "refs/tags/"))
 			continue;
 
@@ -339,26 +339,40 @@
 }
 
 static struct ref *get_ref_map(struct transport *transport,
-			       struct refspec *refspecs, int refspec_count,
+			       struct refspec *rs,
 			       int tags, int *autotags)
 {
 	int i;
 	struct ref *rm;
 	struct ref *ref_map = NULL;
 	struct ref **tail = &ref_map;
+	struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
 
 	/* opportunistically-updated references: */
 	struct ref *orefs = NULL, **oref_tail = &orefs;
 
-	const struct ref *remote_refs = transport_get_remote_refs(transport);
+	const struct ref *remote_refs;
 
-	if (refspec_count) {
+	if (rs->nr)
+		refspec_ref_prefixes(rs, &ref_prefixes);
+	else if (transport->remote && transport->remote->fetch.nr)
+		refspec_ref_prefixes(&transport->remote->fetch, &ref_prefixes);
+
+	if (ref_prefixes.argc &&
+	    (tags == TAGS_SET || (tags == TAGS_DEFAULT && !rs->nr))) {
+		argv_array_push(&ref_prefixes, "refs/tags/");
+	}
+
+	remote_refs = transport_get_remote_refs(transport, &ref_prefixes);
+
+	argv_array_clear(&ref_prefixes);
+
+	if (rs->nr) {
 		struct refspec *fetch_refspec;
-		int fetch_refspec_nr;
 
-		for (i = 0; i < refspec_count; i++) {
-			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
-			if (refspecs[i].dst && refspecs[i].dst[0])
+		for (i = 0; i < rs->nr; i++) {
+			get_fetch_map(remote_refs, &rs->items[i], &tail, 0);
+			if (rs->items[i].dst && rs->items[i].dst[0])
 				*autotags = 1;
 		}
 		/* Merge everything on the command line (but not --tags) */
@@ -385,17 +399,14 @@
 		 * by ref_remove_duplicates() in favor of one of these
 		 * opportunistic entries with FETCH_HEAD_IGNORE.
 		 */
-		if (refmap_array) {
-			fetch_refspec = parse_fetch_refspec(refmap_nr, refmap_array);
-			fetch_refspec_nr = refmap_nr;
-		} else {
-			fetch_refspec = transport->remote->fetch;
-			fetch_refspec_nr = transport->remote->fetch_refspec_nr;
-		}
+		if (refmap.nr)
+			fetch_refspec = &refmap;
+		else
+			fetch_refspec = &transport->remote->fetch;
 
-		for (i = 0; i < fetch_refspec_nr; i++)
-			get_fetch_map(ref_map, &fetch_refspec[i], &oref_tail, 1);
-	} else if (refmap_array) {
+		for (i = 0; i < fetch_refspec->nr; i++)
+			get_fetch_map(ref_map, &fetch_refspec->items[i], &oref_tail, 1);
+	} else if (refmap.nr) {
 		die("--refmap option is only meaningful with command-line refspec(s).");
 	} else {
 		/* Use the defaults */
@@ -403,16 +414,16 @@
 		struct branch *branch = branch_get(NULL);
 		int has_merge = branch_has_merge_config(branch);
 		if (remote &&
-		    (remote->fetch_refspec_nr ||
+		    (remote->fetch.nr ||
 		     /* Note: has_merge implies non-NULL branch->remote_name */
 		     (has_merge && !strcmp(branch->remote_name, remote->name)))) {
-			for (i = 0; i < remote->fetch_refspec_nr; i++) {
-				get_fetch_map(remote_refs, &remote->fetch[i], &tail, 0);
-				if (remote->fetch[i].dst &&
-				    remote->fetch[i].dst[0])
+			for (i = 0; i < remote->fetch.nr; i++) {
+				get_fetch_map(remote_refs, &remote->fetch.items[i], &tail, 0);
+				if (remote->fetch.items[i].dst &&
+				    remote->fetch.items[i].dst[0])
 					*autotags = 1;
 				if (!i && !has_merge && ref_map &&
-				    !remote->fetch[0].pattern)
+				    !remote->fetch.items[0].pattern)
 					ref_map->fetch_head_status = FETCH_HEAD_MERGE;
 			}
 			/*
@@ -637,7 +648,7 @@
 	struct branch *current_branch = branch_get(NULL);
 	const char *pretty_ref = prettify_refname(ref->name);
 
-	type = sha1_object_info(ref->new_oid.hash, NULL);
+	type = oid_object_info(the_repository, &ref->new_oid, NULL);
 	if (type < 0)
 		die(_("object %s not found"), oid_to_hex(&ref->new_oid));
 
@@ -708,9 +719,9 @@
 	if (in_merge_bases(current, updated)) {
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
-		strbuf_add_unique_abbrev(&quickref, current->object.oid.hash, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "..");
-		strbuf_add_unique_abbrev(&quickref, ref->new_oid.hash, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
 			check_for_new_submodule_commits(&ref->new_oid);
@@ -723,9 +734,9 @@
 	} else if (force || ref->force) {
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
-		strbuf_add_unique_abbrev(&quickref, current->object.oid.hash, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "...");
-		strbuf_add_unique_abbrev(&quickref, ref->new_oid.hash, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
 			check_for_new_submodule_commits(&ref->new_oid);
@@ -947,11 +958,11 @@
 	return ret;
 }
 
-static int prune_refs(struct refspec *refs, int ref_count, struct ref *ref_map,
-		const char *raw_url)
+static int prune_refs(struct refspec *rs, struct ref *ref_map,
+		      const char *raw_url)
 {
 	int url_len, i, result = 0;
-	struct ref *ref, *stale_refs = get_stale_heads(refs, ref_count, ref_map);
+	struct ref *ref, *stale_refs = get_stale_heads(rs, ref_map);
 	char *url;
 	int summary_width = transport_summary_width(stale_refs);
 	const char *dangling_msg = dry_run
@@ -1097,7 +1108,7 @@
 }
 
 static int do_fetch(struct transport *transport,
-		    struct refspec *refs, int ref_count)
+		    struct refspec *rs)
 {
 	struct string_list existing_refs = STRING_LIST_INIT_DUP;
 	struct ref *ref_map;
@@ -1121,7 +1132,7 @@
 			goto cleanup;
 	}
 
-	ref_map = get_ref_map(transport, refs, ref_count, tags, &autotags);
+	ref_map = get_ref_map(transport, rs, tags, &autotags);
 	if (!update_head_ok)
 		check_not_current_branch(ref_map);
 
@@ -1145,11 +1156,10 @@
 		 * explicitly (via command line or configuration); we
 		 * don't care whether --tags was specified.
 		 */
-		if (ref_count) {
-			prune_refs(refs, ref_count, ref_map, transport->url);
+		if (rs->nr) {
+			prune_refs(rs, ref_map, transport->url);
 		} else {
-			prune_refs(transport->remote->fetch,
-				   transport->remote->fetch_refspec_nr,
+			prune_refs(&transport->remote->fetch,
 				   ref_map,
 				   transport->url);
 		}
@@ -1338,10 +1348,8 @@
 
 static int fetch_one(struct remote *remote, int argc, const char **argv, int prune_tags_ok)
 {
-	static const char **refs = NULL;
-	struct refspec *refspec;
-	int ref_nr = 0;
-	int j = 0;
+	struct refspec rs = REFSPEC_INIT_FETCH;
+	int i;
 	int exit_code;
 	int maybe_prune_tags;
 	int remote_via_config = remote_is_configured(remote, 0);
@@ -1374,37 +1382,34 @@
 
 	maybe_prune_tags = prune_tags_ok && prune_tags;
 	if (maybe_prune_tags && remote_via_config)
-		add_prune_tags_to_fetch_refspec(remote);
+		refspec_append(&remote->fetch, TAG_REFSPEC);
 
-	if (argc > 0 || (maybe_prune_tags && !remote_via_config)) {
-		size_t nr_alloc = st_add3(argc, maybe_prune_tags, 1);
-		refs = xcalloc(nr_alloc, sizeof(const char *));
-		if (maybe_prune_tags) {
-			refs[j++] = xstrdup("refs/tags/*:refs/tags/*");
-			ref_nr++;
+	if (maybe_prune_tags && (argc || !remote_via_config))
+		refspec_append(&rs, TAG_REFSPEC);
+
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(argv[i], "tag")) {
+			char *tag;
+			i++;
+			if (i >= argc)
+				die(_("You need to specify a tag name."));
+
+			tag = xstrfmt("refs/tags/%s:refs/tags/%s",
+				      argv[i], argv[i]);
+			refspec_append(&rs, tag);
+			free(tag);
+		} else {
+			refspec_append(&rs, argv[i]);
 		}
 	}
 
-	if (argc > 0) {
-		int i;
-		for (i = 0; i < argc; i++) {
-			if (!strcmp(argv[i], "tag")) {
-				i++;
-				if (i >= argc)
-					die(_("You need to specify a tag name."));
-				refs[j++] = xstrfmt("refs/tags/%s:refs/tags/%s",
-						    argv[i], argv[i]);
-			} else
-				refs[j++] = argv[i];
-			ref_nr++;
-		}
-	}
+	if (server_options.nr)
+		gtransport->server_options = &server_options;
 
 	sigchain_push_common(unlock_pack_on_signal);
 	atexit(unlock_pack);
-	refspec = parse_fetch_refspec(ref_nr, refs);
-	exit_code = do_fetch(gtransport, refspec, ref_nr);
-	free_refspec(ref_nr, refspec);
+	exit_code = do_fetch(gtransport, &rs);
+	refspec_clear(&rs);
 	transport_disconnect(gtransport);
 	gtransport = NULL;
 	return exit_code;
@@ -1516,7 +1521,7 @@
 
 	string_list_clear(&list, 0);
 
-	close_all_packs();
+	close_all_packs(the_repository->objects);
 
 	argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
 	if (verbosity < 0)
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 8e8a15e..bd680be 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -485,10 +485,10 @@
 	struct strbuf tagbuf = STRBUF_INIT;
 
 	for (i = 0; i < origins.nr; i++) {
-		unsigned char *sha1 = origins.items[i].util;
+		struct object_id *oid = origins.items[i].util;
 		enum object_type type;
 		unsigned long size, len;
-		char *buf = read_sha1_file(sha1, &type, &size);
+		char *buf = read_object_file(oid, &type, &size);
 		struct strbuf sig = STRBUF_INIT;
 
 		if (!buf || type != OBJ_TAG)
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 028aba5..3ad4f16 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "cache.h"
+#include "repository.h"
 #include "config.h"
 #include "commit.h"
 #include "tree.h"
@@ -16,6 +17,7 @@
 #include "streaming.h"
 #include "decorate.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define REACHABLE 0x0001
 #define SEEN      0x0002
@@ -65,7 +67,8 @@
 	const char *ret;
 
 	if (obj->type == OBJ_NONE) {
-		enum object_type type = sha1_object_info(obj->oid.hash, NULL);
+		enum object_type type = oid_object_info(the_repository,
+							&obj->oid, NULL);
 		if (type > 0)
 			object_as_type(obj, type, 0);
 	}
@@ -225,7 +228,7 @@
 	if (!(obj->flags & HAS_OBJ)) {
 		if (is_promisor_object(&obj->oid))
 			return;
-		if (has_sha1_pack(obj->oid.hash))
+		if (has_object_pack(&obj->oid))
 			return; /* it is in pack - forget about it */
 		printf("missing %s %s\n", printable_type(obj),
 			describe_object(obj));
@@ -512,7 +515,7 @@
 	void *contents;
 	int eaten;
 
-	if (read_loose_object(path, oid->hash, &type, &size, &contents) < 0) {
+	if (read_loose_object(path, oid, &type, &size, &contents) < 0) {
 		errors_found |= ERROR_OBJECT;
 		error("%s: object corrupt or missing: %s",
 		      oid_to_hex(oid), path);
@@ -717,9 +720,12 @@
 		for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
 		for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
 	} else {
+		struct alternate_object_database *alt_odb_list;
+
 		fsck_object_dir(get_object_directory());
 
-		prepare_alt_odb();
+		prepare_alt_odb(the_repository);
+		alt_odb_list = the_repository->objects->alt_odb_list;
 		for (alt = alt_odb_list; alt; alt = alt->next)
 			fsck_object_dir(alt->path);
 
@@ -728,10 +734,9 @@
 			uint32_t total = 0, count = 0;
 			struct progress *progress = NULL;
 
-			prepare_packed_git();
-
 			if (show_progress) {
-				for (p = packed_git; p; p = p->next) {
+				for (p = get_packed_git(the_repository); p;
+				     p = p->next) {
 					if (open_pack_index(p))
 						continue;
 					total += p->num_objects;
@@ -739,7 +744,8 @@
 
 				progress = start_progress(_("Checking objects"), total);
 			}
-			for (p = packed_git; p; p = p->next) {
+			for (p = get_packed_git(the_repository); p;
+			     p = p->next) {
 				/* verify gives error messages itself */
 				if (verify_pack(p, fsck_obj_buffer,
 						progress, count))
diff --git a/builtin/gc.c b/builtin/gc.c
index f51e5a6..ccfb1ce 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -11,6 +11,7 @@
  */
 
 #include "builtin.h"
+#include "repository.h"
 #include "config.h"
 #include "tempfile.h"
 #include "lockfile.h"
@@ -20,6 +21,11 @@
 #include "argv-array.h"
 #include "commit.h"
 #include "packfile.h"
+#include "object-store.h"
+#include "pack.h"
+#include "pack-objects.h"
+#include "blob.h"
+#include "tree.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -39,6 +45,8 @@
 static const char *gc_log_expire = "1.day.ago";
 static const char *prune_expire = "2.weeks.ago";
 static const char *prune_worktrees_expire = "3.months.ago";
+static unsigned long big_pack_threshold;
+static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
 
 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
 static struct argv_array reflog = ARGV_ARRAY_INIT;
@@ -126,6 +134,9 @@
 	git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
 	git_config_get_expiry("gc.logexpiry", &gc_log_expire);
 
+	git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
+	git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
+
 	git_config(git_default_config, NULL);
 }
 
@@ -164,6 +175,28 @@
 	return needed;
 }
 
+static struct packed_git *find_base_packs(struct string_list *packs,
+					  unsigned long limit)
+{
+	struct packed_git *p, *base = NULL;
+
+	for (p = get_packed_git(the_repository); p; p = p->next) {
+		if (!p->pack_local)
+			continue;
+		if (limit) {
+			if (p->pack_size >= limit)
+				string_list_append(packs, p->pack_name);
+		} else if (!base || base->pack_size < p->pack_size) {
+			base = p;
+		}
+	}
+
+	if (base)
+		string_list_append(packs, base->pack_name);
+
+	return base;
+}
+
 static int too_many_packs(void)
 {
 	struct packed_git *p;
@@ -172,8 +205,7 @@
 	if (gc_auto_pack_limit <= 0)
 		return 0;
 
-	prepare_packed_git();
-	for (cnt = 0, p = packed_git; p; p = p->next) {
+	for (cnt = 0, p = get_packed_git(the_repository); p; p = p->next) {
 		if (!p->pack_local)
 			continue;
 		if (p->pack_keep)
@@ -187,7 +219,86 @@
 	return gc_auto_pack_limit < cnt;
 }
 
-static void add_repack_all_option(void)
+static uint64_t total_ram(void)
+{
+#if defined(HAVE_SYSINFO)
+	struct sysinfo si;
+
+	if (!sysinfo(&si))
+		return si.totalram;
+#elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
+	int64_t physical_memory;
+	int mib[2];
+	size_t length;
+
+	mib[0] = CTL_HW;
+# if defined(HW_MEMSIZE)
+	mib[1] = HW_MEMSIZE;
+# else
+	mib[1] = HW_PHYSMEM;
+# endif
+	length = sizeof(int64_t);
+	if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
+		return physical_memory;
+#elif defined(GIT_WINDOWS_NATIVE)
+	MEMORYSTATUSEX memInfo;
+
+	memInfo.dwLength = sizeof(MEMORYSTATUSEX);
+	if (GlobalMemoryStatusEx(&memInfo))
+		return memInfo.ullTotalPhys;
+#endif
+	return 0;
+}
+
+static uint64_t estimate_repack_memory(struct packed_git *pack)
+{
+	unsigned long nr_objects = approximate_object_count();
+	size_t os_cache, heap;
+
+	if (!pack || !nr_objects)
+		return 0;
+
+	/*
+	 * First we have to scan through at least one pack.
+	 * Assume enough room in OS file cache to keep the entire pack
+	 * or we may accidentally evict data of other processes from
+	 * the cache.
+	 */
+	os_cache = pack->pack_size + pack->index_size;
+	/* then pack-objects needs lots more for book keeping */
+	heap = sizeof(struct object_entry) * nr_objects;
+	/*
+	 * internal rev-list --all --objects takes up some memory too,
+	 * let's say half of it is for blobs
+	 */
+	heap += sizeof(struct blob) * nr_objects / 2;
+	/*
+	 * and the other half is for trees (commits and tags are
+	 * usually insignificant)
+	 */
+	heap += sizeof(struct tree) * nr_objects / 2;
+	/* and then obj_hash[], underestimated in fact */
+	heap += sizeof(struct object *) * nr_objects;
+	/* revindex is used also */
+	heap += sizeof(struct revindex_entry) * nr_objects;
+	/*
+	 * read_sha1_file() (either at delta calculation phase, or
+	 * writing phase) also fills up the delta base cache
+	 */
+	heap += delta_base_cache_limit;
+	/* and of course pack-objects has its own delta cache */
+	heap += max_delta_cache_size;
+
+	return os_cache + heap;
+}
+
+static int keep_one_pack(struct string_list_item *item, void *data)
+{
+	argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
+	return 0;
+}
+
+static void add_repack_all_option(struct string_list *keep_pack)
 {
 	if (prune_expire && !strcmp(prune_expire, "now"))
 		argv_array_push(&repack, "-a");
@@ -196,6 +307,9 @@
 		if (prune_expire)
 			argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 	}
+
+	if (keep_pack)
+		for_each_string_list(keep_pack, keep_one_pack, NULL);
 }
 
 static void add_repack_incremental_option(void)
@@ -218,9 +332,35 @@
 	 * we run "repack -A -d -l".  Otherwise we tell the caller
 	 * there is no need.
 	 */
-	if (too_many_packs())
-		add_repack_all_option();
-	else if (too_many_loose_objects())
+	if (too_many_packs()) {
+		struct string_list keep_pack = STRING_LIST_INIT_NODUP;
+
+		if (big_pack_threshold) {
+			find_base_packs(&keep_pack, big_pack_threshold);
+			if (keep_pack.nr >= gc_auto_pack_limit) {
+				big_pack_threshold = 0;
+				string_list_clear(&keep_pack, 0);
+				find_base_packs(&keep_pack, 0);
+			}
+		} else {
+			struct packed_git *p = find_base_packs(&keep_pack, 0);
+			uint64_t mem_have, mem_want;
+
+			mem_have = total_ram();
+			mem_want = estimate_repack_memory(p);
+
+			/*
+			 * Only allow 1/2 of memory for pack-objects, leave
+			 * the rest for the OS and other processes in the
+			 * system.
+			 */
+			if (!mem_have || mem_want < mem_have / 2)
+				string_list_clear(&keep_pack, 0);
+		}
+
+		add_repack_all_option(&keep_pack);
+		string_list_clear(&keep_pack, 0);
+	} else if (too_many_loose_objects())
 		add_repack_incremental_option();
 	else
 		return 0;
@@ -233,7 +373,7 @@
 /* return NULL on success, else hostname running the gc */
 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 {
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	char my_host[HOST_NAME_MAX + 1];
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
@@ -353,6 +493,8 @@
 	const char *name;
 	pid_t pid;
 	int daemonized = 0;
+	int keep_base_pack = -1;
+	timestamp_t dummy;
 
 	struct option builtin_gc_options[] = {
 		OPT__QUIET(&quiet, N_("suppress progress reporting")),
@@ -365,6 +507,8 @@
 		OPT_BOOL_F(0, "force", &force,
 			   N_("force running gc even if there may be another gc running"),
 			   PARSE_OPT_NOCOMPLETE),
+		OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
+			 N_("repack all other packs except the largest pack")),
 		OPT_END()
 	};
 
@@ -381,7 +525,7 @@
 	/* default expiry time, overwritten in gc_config */
 	gc_config();
 	if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
-		die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
+		die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
 
 	if (pack_refs < 0)
 		pack_refs = !is_bare_repository();
@@ -391,6 +535,9 @@
 	if (argc > 0)
 		usage_with_options(builtin_gc_usage, builtin_gc_options);
 
+	if (prune_expire && parse_expiry_date(prune_expire, &dummy))
+		die(_("failed to parse prune expiry value %s"), prune_expire);
+
 	if (aggressive) {
 		argv_array_push(&repack, "-f");
 		if (aggressive_depth > 0)
@@ -430,8 +577,19 @@
 			 */
 			daemonized = !daemonize();
 		}
-	} else
-		add_repack_all_option();
+	} else {
+		struct string_list keep_pack = STRING_LIST_INIT_NODUP;
+
+		if (keep_base_pack != -1) {
+			if (keep_base_pack)
+				find_base_packs(&keep_pack, 0);
+		} else if (big_pack_threshold) {
+			find_base_packs(&keep_pack, big_pack_threshold);
+		}
+
+		add_repack_all_option(&keep_pack);
+		string_list_clear(&keep_pack, 0);
+	}
 
 	name = lock_repo_for_gc(force, &pid);
 	if (name) {
@@ -479,7 +637,7 @@
 		return error(FAILED_RUN, rerere.argv[0]);
 
 	report_garbage = report_pack_garbage;
-	reprepare_packed_git();
+	reprepare_packed_git(the_repository);
 	if (pack_garbage.nr > 0)
 		clean_pack_garbage();
 
diff --git a/builtin/grep.c b/builtin/grep.c
index 789a891..ee753a4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -22,6 +22,7 @@
 #include "pathspec.h"
 #include "submodule.h"
 #include "submodule-config.h"
+#include "object-store.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
@@ -306,7 +307,7 @@
 	void *data;
 
 	grep_read_lock();
-	data = read_sha1_file(oid->hash, type, size);
+	data = read_object_file(oid, type, size);
 	grep_read_unlock();
 	return data;
 }
@@ -439,7 +440,7 @@
 	 * object.
 	 */
 	grep_read_lock();
-	add_to_alternates_memory(submodule.objectdir);
+	add_to_alternates_memory(submodule.objects->objectdir);
 	grep_read_unlock();
 
 	if (oid) {
@@ -452,7 +453,7 @@
 		object = parse_object_or_die(oid, oid_to_hex(oid));
 
 		grep_read_lock();
-		data = read_object_with_reference(object->oid.hash, tree_type,
+		data = read_object_with_reference(&object->oid, tree_type,
 						  &size, NULL);
 		grep_read_unlock();
 
@@ -487,7 +488,8 @@
 		strbuf_addstr(&name, repo->submodule_prefix);
 	}
 
-	repo_read_index(repo);
+	if (repo_read_index(repo) < 0)
+		die("index file corrupt");
 
 	for (nr = 0; nr < repo->index->cache_nr; nr++) {
 		const struct cache_entry *ce = repo->index->cache[nr];
@@ -601,8 +603,7 @@
 }
 
 static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
-		       struct object *obj, const char *name, const char *path,
-		       struct repository *repo)
+		       struct object *obj, const char *name, const char *path)
 {
 	if (obj->type == OBJ_BLOB)
 		return grep_oid(opt, &obj->oid, name, 0, path);
@@ -614,7 +615,7 @@
 		int hit, len;
 
 		grep_read_lock();
-		data = read_object_with_reference(obj->oid.hash, tree_type,
+		data = read_object_with_reference(&obj->oid, tree_type,
 						  &size, NULL);
 		grep_read_unlock();
 
@@ -629,7 +630,7 @@
 		}
 		init_tree_desc(&tree, data, size);
 		hit = grep_tree(opt, pathspec, &tree, &base, base.len,
-				obj->type == OBJ_COMMIT, repo);
+				obj->type == OBJ_COMMIT, the_repository);
 		strbuf_release(&base);
 		free(data);
 		return hit;
@@ -638,7 +639,6 @@
 }
 
 static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
-			struct repository *repo,
 			const struct object_array *list)
 {
 	unsigned int i;
@@ -651,11 +651,11 @@
 
 		/* load the gitmodules file for this rev */
 		if (recurse_submodules) {
-			submodule_free();
+			submodule_free(the_repository);
 			gitmodules_config_oid(&real_obj->oid);
 		}
-		if (grep_object(opt, pathspec, real_obj, list->objects[i].name, list->objects[i].path,
-				repo)) {
+		if (grep_object(opt, pathspec, real_obj, list->objects[i].name,
+				list->objects[i].path)) {
 			hit = 1;
 			if (opt->status_only)
 				break;
@@ -886,9 +886,9 @@
 			   N_("indicate hit with exit status without output")),
 		OPT_BOOL(0, "all-match", &opt.all_match,
 			N_("show only matches from files that match all patterns")),
-		{ OPTION_SET_INT, 0, "debug", &opt.debug, NULL,
-		  N_("show parse tree for grep expression"),
-		  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1 },
+		OPT_SET_INT_F(0, "debug", &opt.debug,
+			      N_("show parse tree for grep expression"),
+			      1, PARSE_OPT_HIDDEN),
 		OPT_GROUP(""),
 		{ OPTION_STRING, 'O', "open-files-in-pager", &show_in_pager,
 			N_("pager"), N_("show matching files in the pager"),
@@ -1107,7 +1107,7 @@
 		if (cached)
 			die(_("both --cached and trees are given."));
 
-		hit = grep_objects(&opt, &pathspec, the_repository, &list);
+		hit = grep_objects(&opt, &pathspec, &list);
 	}
 
 	if (num_threads)
diff --git a/builtin/hash-object.c b/builtin/hash-object.c
index 526da5c..a9a3a19 100644
--- a/builtin/hash-object.c
+++ b/builtin/hash-object.c
@@ -9,7 +9,7 @@
 #include "blob.h"
 #include "quote.h"
 #include "parse-options.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 
 /*
  * This is to create corrupt objects for debugging and as such it
diff --git a/builtin/help.c b/builtin/help.c
index 598867c..58e0a55 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -4,11 +4,12 @@
 #include "cache.h"
 #include "config.h"
 #include "builtin.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 #include "run-command.h"
 #include "column.h"
 #include "help.h"
+#include "alias.h"
 
 #ifndef DEFAULT_HELP_FORMAT
 #define DEFAULT_HELP_FORMAT "man"
@@ -36,6 +37,7 @@
 
 static int show_all = 0;
 static int show_guides = 0;
+static int verbose;
 static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
 static int exclude_guides;
@@ -48,6 +50,7 @@
 			HELP_FORMAT_WEB),
 	OPT_SET_INT('i', "info", &help_format, N_("show info page"),
 			HELP_FORMAT_INFO),
+	OPT__VERBOSE(&verbose, N_("print command description")),
 	OPT_END(),
 };
 
@@ -400,38 +403,6 @@
 	open_html(page_path.buf);
 }
 
-static struct {
-	const char *name;
-	const char *help;
-} common_guides[] = {
-	{ "attributes", N_("Defining attributes per path") },
-	{ "everyday", N_("Everyday Git With 20 Commands Or So") },
-	{ "glossary", N_("A Git glossary") },
-	{ "ignore", N_("Specifies intentionally untracked files to ignore") },
-	{ "modules", N_("Defining submodule properties") },
-	{ "revisions", N_("Specifying revisions and ranges for Git") },
-	{ "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
-	{ "workflows", N_("An overview of recommended workflows with Git") },
-};
-
-static void list_common_guides_help(void)
-{
-	int i, longest = 0;
-
-	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
-		if (longest < strlen(common_guides[i].name))
-			longest = strlen(common_guides[i].name);
-	}
-
-	puts(_("The common Git guides are:\n"));
-	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
-		printf("   %s   ", common_guides[i].name);
-		mput_char(' ', longest - strlen(common_guides[i].name));
-		puts(_(common_guides[i].help));
-	}
-	putchar('\n');
-}
-
 static const char *check_git_cmd(const char* cmd)
 {
 	char *alias;
@@ -463,6 +434,11 @@
 
 	if (show_all) {
 		git_config(git_help_config, NULL);
+		if (verbose) {
+			setup_pager();
+			list_all_cmds_help();
+			return 0;
+		}
 		printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 		load_command_list("git-", &main_cmds, &other_cmds);
 		list_commands(colopts, &main_cmds, &other_cmds);
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 7b2f7c0..74fe297 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -9,10 +9,11 @@
 #include "tree.h"
 #include "progress.h"
 #include "fsck.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "streaming.h"
 #include "thread-utils.h"
 #include "packfile.h"
+#include "object-store.h"
 
 static const char index_pack_usage[] =
 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
@@ -59,7 +60,7 @@
 };
 
 struct ref_delta_entry {
-	unsigned char sha1[20];
+	struct object_id oid;
 	int obj_no;
 };
 
@@ -222,7 +223,7 @@
 
 	if (!(obj->flags & FLAG_CHECKED)) {
 		unsigned long size;
-		int type = sha1_object_info(obj->oid.hash, &size);
+		int type = oid_object_info(the_repository, &obj->oid, &size);
 		if (type <= 0)
 			die(_("did not receive expected object %s"),
 			      oid_to_hex(&obj->oid));
@@ -672,18 +673,18 @@
 	*last_index = last;
 }
 
-static int compare_ref_delta_bases(const unsigned char *sha1,
-				   const unsigned char *sha2,
+static int compare_ref_delta_bases(const struct object_id *oid1,
+				   const struct object_id *oid2,
 				   enum object_type type1,
 				   enum object_type type2)
 {
 	int cmp = type1 - type2;
 	if (cmp)
 		return cmp;
-	return hashcmp(sha1, sha2);
+	return oidcmp(oid1, oid2);
 }
 
-static int find_ref_delta(const unsigned char *sha1, enum object_type type)
+static int find_ref_delta(const struct object_id *oid, enum object_type type)
 {
 	int first = 0, last = nr_ref_deltas;
 
@@ -692,7 +693,7 @@
 		struct ref_delta_entry *delta = &ref_deltas[next];
 		int cmp;
 
-		cmp = compare_ref_delta_bases(sha1, delta->sha1,
+		cmp = compare_ref_delta_bases(oid, &delta->oid,
 					      type, objects[delta->obj_no].type);
 		if (!cmp)
 			return next;
@@ -705,11 +706,11 @@
 	return -first-1;
 }
 
-static void find_ref_delta_children(const unsigned char *sha1,
+static void find_ref_delta_children(const struct object_id *oid,
 				    int *first_index, int *last_index,
 				    enum object_type type)
 {
-	int first = find_ref_delta(sha1, type);
+	int first = find_ref_delta(oid, type);
 	int last = first;
 	int end = nr_ref_deltas - 1;
 
@@ -718,9 +719,9 @@
 		*last_index = -1;
 		return;
 	}
-	while (first > 0 && !hashcmp(ref_deltas[first - 1].sha1, sha1))
+	while (first > 0 && !oidcmp(&ref_deltas[first - 1].oid, oid))
 		--first;
-	while (last < end && !hashcmp(ref_deltas[last + 1].sha1, sha1))
+	while (last < end && !oidcmp(&ref_deltas[last + 1].oid, oid))
 		++last;
 	*first_index = first;
 	*last_index = last;
@@ -772,7 +773,7 @@
 
 	memset(&data, 0, sizeof(data));
 	data.entry = entry;
-	data.st = open_istream(entry->idx.oid.hash, &type, &size, NULL);
+	data.st = open_istream(&entry->idx.oid, &type, &size, NULL);
 	if (!data.st)
 		return -1;
 	if (size != entry->size || type != entry->type)
@@ -811,12 +812,12 @@
 		enum object_type has_type;
 		unsigned long has_size;
 		read_lock();
-		has_type = sha1_object_info(oid->hash, &has_size);
+		has_type = oid_object_info(the_repository, oid, &has_size);
 		if (has_type < 0)
 			die(_("cannot read existing object info %s"), oid_to_hex(oid));
 		if (has_type != type || has_size != size)
 			die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
-		has_data = read_sha1_file(oid->hash, &has_type, &has_size);
+		has_data = read_object_file(oid, &has_type, &has_size);
 		read_unlock();
 		if (!data)
 			data = new_data = get_data_from_pack(obj_entry);
@@ -868,7 +869,7 @@
 			if (obj->type == OBJ_COMMIT) {
 				struct commit *commit = (struct commit *) obj;
 				if (detach_commit_buffer(commit, NULL) != data)
-					die("BUG: parse_object_buffer transmogrified our buffer");
+					BUG("parse_object_buffer transmogrified our buffer");
 			}
 			obj->flags |= FLAG_CHECKED;
 		}
@@ -995,7 +996,7 @@
 						  struct base_data *prev_base)
 {
 	if (base->ref_last == -1 && base->ofs_last == -1) {
-		find_ref_delta_children(base->obj->idx.oid.hash,
+		find_ref_delta_children(&base->obj->idx.oid,
 					&base->ref_first, &base->ref_last,
 					OBJ_REF_DELTA);
 
@@ -1017,7 +1018,7 @@
 
 		if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
 					   base->obj->real_type))
-			die("BUG: child->real_type != OBJ_REF_DELTA");
+			BUG("child->real_type != OBJ_REF_DELTA");
 
 		resolve_delta(child, base, result);
 		if (base->ref_first == base->ref_last && base->ofs_last == -1)
@@ -1079,7 +1080,7 @@
 	const struct ref_delta_entry *delta_a = a;
 	const struct ref_delta_entry *delta_b = b;
 
-	return hashcmp(delta_a->sha1, delta_b->sha1);
+	return oidcmp(&delta_a->oid, &delta_b->oid);
 }
 
 static void resolve_base(struct object_entry *obj)
@@ -1145,7 +1146,7 @@
 			ofs_delta++;
 		} else if (obj->type == OBJ_REF_DELTA) {
 			ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
-			hashcpy(ref_deltas[nr_ref_deltas].sha1, ref_delta_oid.hash);
+			oidcpy(&ref_deltas[nr_ref_deltas].oid, &ref_delta_oid);
 			ref_deltas[nr_ref_deltas].obj_no = i;
 			nr_ref_deltas++;
 		} else if (!data) {
@@ -1273,7 +1274,7 @@
 			    nr_objects - nr_objects_initial);
 		stop_progress_msg(&progress, msg.buf);
 		strbuf_release(&msg);
-		hashclose(f, tail_hash, 0);
+		finalize_hashfile(f, tail_hash, 0);
 		hashcpy(read_hash, pack_hash);
 		fixup_pack_header_footer(output_fd, pack_hash,
 					 curr_pack, nr_objects,
@@ -1377,14 +1378,15 @@
 
 		if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 			continue;
-		base_obj->data = read_sha1_file(d->sha1, &type, &base_obj->size);
+		base_obj->data = read_object_file(&d->oid, &type,
+						  &base_obj->size);
 		if (!base_obj->data)
 			continue;
 
-		if (check_sha1_signature(d->sha1, base_obj->data,
+		if (check_object_signature(&d->oid, base_obj->data,
 				base_obj->size, type_name(type)))
-			die(_("local object %s is corrupt"), sha1_to_hex(d->sha1));
-		base_obj->obj = append_obj_to_pack(f, d->sha1,
+			die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
+		base_obj->obj = append_obj_to_pack(f, d->oid.hash,
 					base_obj->data, base_obj->size, type);
 		find_unresolved_deltas(base_obj);
 		display_progress(progress, nr_resolved_deltas);
@@ -1480,8 +1482,12 @@
 	} else
 		chmod(final_index_name, 0444);
 
-	if (do_fsck_object)
-		add_packed_git(final_index_name, strlen(final_index_name), 0);
+	if (do_fsck_object) {
+		struct packed_git *p;
+		p = add_packed_git(final_index_name, strlen(final_index_name), 0);
+		if (p)
+			install_packed_git(the_repository, p);
+	}
 
 	if (!from_stdin) {
 		printf("%s\n", sha1_to_hex(hash));
@@ -1547,12 +1553,13 @@
 {
 	const uint32_t *idx1, *idx2;
 	uint32_t i;
+	const uint32_t hashwords = the_hash_algo->rawsz / sizeof(uint32_t);
 
 	/* The address of the 4-byte offset table */
 	idx1 = (((const uint32_t *)p->index_data)
 		+ 2 /* 8-byte header */
 		+ 256 /* fan out */
-		+ 5 * p->num_objects /* 20-byte SHA-1 table */
+		+ hashwords * p->num_objects /* object ID table */
 		+ p->num_objects /* CRC32 table */
 		);
 
@@ -1597,7 +1604,7 @@
 	/*
 	 * Get rid of the idx file as we do not need it anymore.
 	 * NEEDSWORK: extract this bit from free_pack_by_name() in
-	 * sha1_file.c, perhaps?  It shouldn't matter very much as we
+	 * sha1-file.c, perhaps?  It shouldn't matter very much as we
 	 * know we haven't installed this pack (hence we never have
 	 * read anything from it).
 	 */
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 68ff4ad..4ecf909 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -7,7 +7,7 @@
 #include "config.h"
 #include "refs.h"
 #include "builtin.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 
 #ifndef DEFAULT_GIT_TEMPLATE_DIR
@@ -117,7 +117,7 @@
 
 	dir = opendir(template_path.buf);
 	if (!dir) {
-		warning(_("templates not found %s"), template_dir);
+		warning(_("templates not found in %s"), template_dir);
 		goto free_return;
 	}
 
@@ -391,7 +391,7 @@
 		else if (get_shared_repository() == PERM_EVERYBODY)
 			xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 		else
-			die("BUG: invalid value for shared_repository");
+			BUG("invalid value for shared_repository");
 		git_config_set("core.sharedrepository", buf);
 		git_config_set("receive.denyNonFastforwards", "true");
 	}
diff --git a/builtin/log.c b/builtin/log.c
index 94ee177..4686f68 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -518,7 +518,7 @@
 {
 	unsigned long size;
 	enum object_type type;
-	char *buf = read_sha1_file(oid->hash, &type, &size);
+	char *buf = read_object_file(oid, &type, &size);
 	int offset = 0;
 
 	if (!buf)
@@ -541,7 +541,7 @@
 	return 0;
 }
 
-static int show_tree_object(const unsigned char *sha1,
+static int show_tree_object(const struct object_id *oid,
 		struct strbuf *base,
 		const char *pathname, unsigned mode, int stage, void *context)
 {
@@ -1019,7 +1019,7 @@
 	    open_next_file(NULL, rev->numbered_files ? NULL : "cover-letter", rev, quiet))
 		return;
 
-	log_write_email_headers(rev, head, &pp.after_subject, &need_8bit_cte);
+	log_write_email_headers(rev, head, &pp.after_subject, &need_8bit_cte, 0);
 
 	for (i = 0; !need_8bit_cte && i < nr; i++) {
 		const char *buf = get_commit_buffer(list[i], NULL);
@@ -1067,8 +1067,8 @@
 
 	diff_setup_done(&opts);
 
-	diff_tree_oid(&origin->tree->object.oid,
-		      &head->tree->object.oid,
+	diff_tree_oid(get_commit_tree_oid(origin),
+		      get_commit_tree_oid(head),
 		      "", &opts);
 	diffcore_std(&opts);
 	diff_flush(&opts);
@@ -1474,9 +1474,9 @@
 			 N_("output all-zero hash in From header")),
 		OPT_BOOL(0, "ignore-if-in-upstream", &ignore_if_in_upstream,
 			 N_("don't include a patch matching a commit upstream")),
-		{ OPTION_SET_INT, 'p', "no-stat", &use_patch_format, NULL,
-		  N_("show patch format instead of default (patch + stat)"),
-		  PARSE_OPT_NONEG | PARSE_OPT_NOARG, NULL, 1},
+		OPT_SET_INT_F('p', "no-stat", &use_patch_format,
+			      N_("show patch format instead of default (patch + stat)"),
+			      1, PARSE_OPT_NONEG),
 		OPT_GROUP(N_("Messaging")),
 		{ OPTION_CALLBACK, 0, "add-header", NULL, N_("header"),
 			    N_("add email header"), 0, header_callback },
@@ -1873,12 +1873,12 @@
 {
 	if (!verbose) {
 		fprintf(file, "%c %s\n", sign,
-		       find_unique_abbrev(commit->object.oid.hash, abbrev));
+		       find_unique_abbrev(&commit->object.oid, abbrev));
 	} else {
 		struct strbuf buf = STRBUF_INIT;
 		pp_commit_easy(CMIT_FMT_ONELINE, commit, &buf);
 		fprintf(file, "%c %s %s\n", sign,
-		       find_unique_abbrev(commit->object.oid.hash, abbrev),
+		       find_unique_abbrev(&commit->object.oid, abbrev),
 		       buf.buf);
 		strbuf_release(&buf);
 	}
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 2fc836e..88bb201 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -166,7 +166,7 @@
 				 */
 				pos = index_name_pos(istate, ent->name, ent->len);
 				if (0 <= pos)
-					die("BUG: killed-file %.*s not found",
+					BUG("killed-file %.*s not found",
 						ent->len, ent->name);
 				pos = -pos - 1;
 				while (pos < istate->cache_nr &&
@@ -240,7 +240,7 @@
 			printf("%s%06o %s %d\t",
 			       tag,
 			       ce->ce_mode,
-			       find_unique_abbrev(ce->oid.hash, abbrev),
+			       find_unique_abbrev(&ce->oid, abbrev),
 			       ce_stage(ce));
 		}
 		write_eolinfo(repo->index, ce, fullname);
@@ -271,7 +271,7 @@
 			if (!ui->mode[i])
 				continue;
 			printf("%s%06o %s %d\t", tag_resolve_undo, ui->mode[i],
-			       find_unique_abbrev(ui->sha1[i], abbrev),
+			       find_unique_abbrev(&ui->oid[i], abbrev),
 			       i + 1);
 			write_name(path);
 		}
@@ -556,9 +556,9 @@
 		{ OPTION_CALLBACK, 0, "exclude-standard", &dir, NULL,
 			N_("add the standard git exclusions"),
 			PARSE_OPT_NOARG, option_parse_exclude_standard },
-		{ OPTION_SET_INT, 0, "full-name", &prefix_len, NULL,
-			N_("make the output relative to the project top directory"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL },
+		OPT_SET_INT_F(0, "full-name", &prefix_len,
+			      N_("make the output relative to the project top directory"),
+			      0, PARSE_OPT_NONEG),
 		OPT_BOOL(0, "recurse-submodules", &recurse_submodules,
 			N_("recurse through submodules")),
 		OPT_BOOL(0, "error-unmatch", &error_unmatch,
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 540d564..1a25df7 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -1,7 +1,9 @@
 #include "builtin.h"
 #include "cache.h"
 #include "transport.h"
+#include "ref-filter.h"
 #include "remote.h"
+#include "refs.h"
 
 static const char * const ls_remote_usage[] = {
 	N_("git ls-remote [--heads] [--tags] [--refs] [--upload-pack=<exec>]\n"
@@ -43,10 +45,15 @@
 	int show_symref_target = 0;
 	const char *uploadpack = NULL;
 	const char **pattern = NULL;
+	struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
+	int i;
+	struct string_list server_options = STRING_LIST_INIT_DUP;
 
 	struct remote *remote;
 	struct transport *transport;
 	const struct ref *ref;
+	struct ref_array ref_array;
+	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
 
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("do not print remote URL")),
@@ -60,14 +67,19 @@
 		OPT_BIT(0, "refs", &flags, N_("do not show peeled tags"), REF_NORMAL),
 		OPT_BOOL(0, "get-url", &get_url,
 			 N_("take url.<base>.insteadOf into account")),
+		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
+			     N_("field name to sort on"), &parse_opt_ref_sorting),
 		OPT_SET_INT_F(0, "exit-code", &status,
 			      N_("exit with exit code 2 if no matching refs are found"),
 			      2, PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL(0, "symref", &show_symref_target,
 			 N_("show underlying ref in addition to the object pointed by it")),
+		OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
 		OPT_END()
 	};
 
+	memset(&ref_array, 0, sizeof(ref_array));
+
 	argc = parse_options(argc, argv, prefix, options, ls_remote_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 	dest = argv[0];
@@ -75,8 +87,17 @@
 	if (argc > 1) {
 		int i;
 		pattern = xcalloc(argc, sizeof(const char *));
-		for (i = 1; i < argc; i++)
+		for (i = 1; i < argc; i++) {
+			const char *glob;
 			pattern[i - 1] = xstrfmt("*/%s", argv[i]);
+
+			glob = strchr(argv[i], '*');
+			if (glob)
+				argv_array_pushf(&ref_prefixes, "%.*s",
+						 (int)(glob - argv[i]), argv[i]);
+			else
+				expand_ref_prefix(&ref_prefixes, argv[i]);
+		}
 	}
 
 	remote = remote_get(dest);
@@ -90,28 +111,46 @@
 
 	if (get_url) {
 		printf("%s\n", *remote->url);
+		UNLEAK(sorting);
 		return 0;
 	}
 
 	transport = transport_get(remote, NULL);
 	if (uploadpack != NULL)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK, uploadpack);
+	if (server_options.nr)
+		transport->server_options = &server_options;
 
-	ref = transport_get_remote_refs(transport);
-	if (transport_disconnect(transport))
+	ref = transport_get_remote_refs(transport, &ref_prefixes);
+	if (transport_disconnect(transport)) {
+		UNLEAK(sorting);
 		return 1;
+	}
 
 	if (!dest && !quiet)
 		fprintf(stderr, "From %s\n", *remote->url);
 	for ( ; ref; ref = ref->next) {
+		struct ref_array_item *item;
 		if (!check_ref_type(ref, flags))
 			continue;
 		if (!tail_match(pattern, ref->name))
 			continue;
+		item = ref_array_push(&ref_array, ref->name, &ref->old_oid);
+		item->symref = xstrdup_or_null(ref->symref);
+	}
+
+	if (sorting)
+		ref_array_sort(sorting, &ref_array);
+
+	for (i = 0; i < ref_array.nr; i++) {
+		const struct ref_array_item *ref = ref_array.items[i];
 		if (show_symref_target && ref->symref)
-			printf("ref: %s\t%s\n", ref->symref, ref->name);
-		printf("%s\t%s\n", oid_to_hex(&ref->old_oid), ref->name);
+			printf("ref: %s\t%s\n", ref->symref, ref->refname);
+		printf("%s\t%s\n", oid_to_hex(&ref->objectname), ref->refname);
 		status = 0; /* we found something */
 	}
+
+	UNLEAK(sorting);
+	UNLEAK(ref_array);
 	return status;
 }
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index ef96540..409da4e 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -60,7 +60,7 @@
 	return 0;
 }
 
-static int show_tree(const unsigned char *sha1, struct strbuf *base,
+static int show_tree(const struct object_id *oid, struct strbuf *base,
 		const char *pathname, unsigned mode, int stage, void *context)
 {
 	int retval = 0;
@@ -94,7 +94,7 @@
 			char size_text[24];
 			if (!strcmp(type, blob_type)) {
 				unsigned long size;
-				if (sha1_object_info(sha1, &size) == OBJ_BAD)
+				if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
 					xsnprintf(size_text, sizeof(size_text),
 						  "BAD");
 				else
@@ -103,11 +103,11 @@
 			} else
 				xsnprintf(size_text, sizeof(size_text), "-");
 			printf("%06o %s %s %7s\t", mode, type,
-			       find_unique_abbrev(sha1, abbrev),
+			       find_unique_abbrev(oid, abbrev),
 			       size_text);
 		} else
 			printf("%06o %s %s\t", mode, type,
-			       find_unique_abbrev(sha1, abbrev));
+			       find_unique_abbrev(oid, abbrev));
 	}
 	baselen = base->len;
 	strbuf_addstr(base, pathname);
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index d01ddec..bf01e05 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -2,7 +2,7 @@
 #include "tree-walk.h"
 #include "xdiff-interface.h"
 #include "blob.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "merge-blobs.h"
 
 static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
@@ -60,7 +60,7 @@
 	const char *path = entry->path;
 
 	if (!entry->stage)
-		return read_sha1_file(entry->blob->object.oid.hash, &type, size);
+		return read_object_file(&entry->blob->object.oid, &type, size);
 	base = NULL;
 	if (entry->stage == 1) {
 		base = entry->blob;
@@ -82,7 +82,8 @@
 	enum object_type type;
 	while (entry) {
 		if (entry->stage == 2)
-			return read_sha1_file(entry->blob->object.oid.hash, &type, size);
+			return read_object_file(&entry->blob->object.oid,
+						&type, size);
 		entry = entry->link;
 	}
 	return NULL;
diff --git a/builtin/merge.c b/builtin/merge.c
index ee050a4..b00d6f4 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -14,6 +14,7 @@
 #include "run-command.h"
 #include "diff.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "diffcore.h"
 #include "revision.h"
@@ -34,6 +35,7 @@
 #include "string-list.h"
 #include "packfile.h"
 #include "tag.h"
+#include "alias.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -213,9 +215,9 @@
 	OPT_BOOL('e', "edit", &option_edit,
 		N_("edit message before committing")),
 	OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
-	{ OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
-		N_("abort if fast-forward is not possible"),
-		PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
+	OPT_SET_INT_F(0, "ff-only", &fast_forward,
+		      N_("abort if fast-forward is not possible"),
+		      FF_ONLY, PARSE_OPT_NONEG),
 	OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 	OPT_BOOL(0, "verify-signatures", &verify_signatures,
 		N_("verify that the named commit has a valid GPG signature")),
@@ -280,7 +282,7 @@
 	return rc;
 }
 
-static void read_empty(unsigned const char *sha1, int verbose)
+static void read_empty(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[7];
@@ -290,15 +292,15 @@
 		args[i++] = "-v";
 	args[i++] = "-m";
 	args[i++] = "-u";
-	args[i++] = EMPTY_TREE_SHA1_HEX;
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = empty_tree_oid_hex();
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
 		die(_("read-tree failed"));
 }
 
-static void reset_hard(unsigned const char *sha1, int verbose)
+static void reset_hard(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[6];
@@ -308,7 +310,7 @@
 		args[i++] = "-v";
 	args[i++] = "--reset";
 	args[i++] = "-u";
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
@@ -324,7 +326,7 @@
 	if (is_null_oid(stash))
 		return;
 
-	reset_hard(head->hash, 1);
+	reset_hard(head, 1);
 
 	args[2] = oid_to_hex(stash);
 
@@ -412,7 +414,7 @@
 			 * We ignore errors in 'gc --auto', since the
 			 * user should see them.
 			 */
-			close_all_packs();
+			close_all_packs(the_repository->objects);
 			run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 		}
 	}
@@ -639,7 +641,7 @@
 
 static void write_tree_trivial(struct object_id *oid)
 {
-	if (write_cache_as_tree(oid->hash, 0, NULL))
+	if (write_cache_as_tree(oid, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 }
 
@@ -647,7 +649,7 @@
 			      struct commit_list *remoteheads,
 			      struct commit *head)
 {
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	const char *head_arg = "HEAD";
 
 	hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
@@ -805,7 +807,7 @@
 {
 	struct object_id result_tree, result_commit;
 	struct commit_list *parents, **pptr = &parents;
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 
 	hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
 	refresh_cache(REFRESH_QUIET);
@@ -1297,7 +1299,7 @@
 		if (remoteheads->next)
 			die(_("Can merge only exactly one commit into empty head"));
 		remote_head_oid = &remoteheads->item->object.oid;
-		read_empty(remote_head_oid->hash, 0);
+		read_empty(remote_head_oid, 0);
 		update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 		goto done;
@@ -1324,7 +1326,7 @@
 
 			check_commit_signature(commit, &signature_check);
 
-			find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
+			find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
 			switch (signature_check.result) {
 			case 'G':
 				break;
@@ -1417,9 +1419,9 @@
 
 		if (verbosity >= 0) {
 			printf(_("Updating %s..%s\n"),
-			       find_unique_abbrev(head_commit->object.oid.hash,
+			       find_unique_abbrev(&head_commit->object.oid,
 						  DEFAULT_ABBREV),
-			       find_unique_abbrev(remoteheads->item->object.oid.hash,
+			       find_unique_abbrev(&remoteheads->item->object.oid,
 						  DEFAULT_ABBREV));
 		}
 		strbuf_addstr(&msg, "Fast-forward");
diff --git a/builtin/mktag.c b/builtin/mktag.c
index beb5528..82a6e86 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "tag.h"
+#include "replace-object.h"
 
 /*
  * A signature file has a very simple fixed format: four lines
@@ -18,17 +19,17 @@
 /*
  * We refuse to tag something we can't verify. Just because.
  */
-static int verify_object(const unsigned char *sha1, const char *expected_type)
+static int verify_object(const struct object_id *oid, const char *expected_type)
 {
 	int ret = -1;
 	enum object_type type;
 	unsigned long size;
-	void *buffer = read_sha1_file(sha1, &type, &size);
-	const unsigned char *repl = lookup_replace_object(sha1);
+	void *buffer = read_object_file(oid, &type, &size);
+	const struct object_id *repl = lookup_replace_object(the_repository, oid);
 
 	if (buffer) {
 		if (type == type_from_string(expected_type))
-			ret = check_sha1_signature(repl, buffer, size, expected_type);
+			ret = check_object_signature(repl, buffer, size, expected_type);
 		free(buffer);
 	}
 	return ret;
@@ -38,8 +39,8 @@
 {
 	int typelen;
 	char type[20];
-	unsigned char sha1[20];
-	const char *object, *type_line, *tag_line, *tagger_line, *lb, *rb;
+	struct object_id oid;
+	const char *object, *type_line, *tag_line, *tagger_line, *lb, *rb, *p;
 	size_t len;
 
 	if (size < 84)
@@ -52,11 +53,11 @@
 	if (memcmp(object, "object ", 7))
 		return error("char%d: does not start with \"object \"", 0);
 
-	if (get_sha1_hex(object + 7, sha1))
+	if (parse_oid_hex(object + 7, &oid, &p))
 		return error("char%d: could not get SHA1 hash", 7);
 
 	/* Verify type line */
-	type_line = object + 48;
+	type_line = p + 1;
 	if (memcmp(type_line - 1, "\ntype ", 6))
 		return error("char%d: could not find \"\\ntype \"", 47);
 
@@ -80,8 +81,8 @@
 	type[typelen] = 0;
 
 	/* Verify that the object matches */
-	if (verify_object(sha1, type))
-		return error("char%d: could not verify object %s", 7, sha1_to_hex(sha1));
+	if (verify_object(&oid, type))
+		return error("char%d: could not verify object %s", 7, oid_to_hex(&oid));
 
 	/* Verify the tag-name: we don't allow control characters or spaces in it */
 	tag_line += 4;
diff --git a/builtin/mktree.c b/builtin/mktree.c
index f5f3c0e..bb76b46 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c
@@ -10,13 +10,13 @@
 
 static struct treeent {
 	unsigned mode;
-	unsigned char sha1[20];
+	struct object_id oid;
 	int len;
 	char name[FLEX_ARRAY];
 } **entries;
 static int alloc, used;
 
-static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
+static void append_to_tree(unsigned mode, struct object_id *oid, char *path)
 {
 	struct treeent *ent;
 	size_t len = strlen(path);
@@ -26,7 +26,7 @@
 	FLEX_ALLOC_MEM(ent, name, path, len);
 	ent->mode = mode;
 	ent->len = len;
-	hashcpy(ent->sha1, sha1);
+	oidcpy(&ent->oid, oid);
 
 	ALLOC_GROW(entries, used + 1, alloc);
 	entries[used++] = ent;
@@ -54,7 +54,7 @@
 	for (i = 0; i < used; i++) {
 		struct treeent *ent = entries[i];
 		strbuf_addf(&buf, "%o %s%c", ent->mode, ent->name, '\0');
-		strbuf_add(&buf, ent->sha1, 20);
+		strbuf_add(&buf, ent->oid.hash, the_hash_algo->rawsz);
 	}
 
 	write_object_file(buf.buf, buf.len, tree_type, oid);
@@ -69,11 +69,12 @@
 static void mktree_line(char *buf, size_t len, int nul_term_line, int allow_missing)
 {
 	char *ptr, *ntr;
+	const char *p;
 	unsigned mode;
 	enum object_type mode_type; /* object type derived from mode */
 	enum object_type obj_type; /* object type derived from sha */
 	char *path, *to_free = NULL;
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	ptr = buf;
 	/*
@@ -85,9 +86,8 @@
 		die("input format error: %s", buf);
 	ptr = ntr + 1; /* type */
 	ntr = strchr(ptr, ' ');
-	if (!ntr || buf + len <= ntr + 40 ||
-	    ntr[41] != '\t' ||
-	    get_sha1_hex(ntr + 1, sha1))
+	if (!ntr || parse_oid_hex(ntr + 1, &oid, &p) ||
+	    *p != '\t')
 		die("input format error: %s", buf);
 
 	/* It is perfectly normal if we do not have a commit from a submodule */
@@ -116,12 +116,12 @@
 	}
 
 	/* Check the type of object identified by sha1 */
-	obj_type = sha1_object_info(sha1, NULL);
+	obj_type = oid_object_info(the_repository, &oid, NULL);
 	if (obj_type < 0) {
 		if (allow_missing) {
 			; /* no problem - missing objects are presumed to be of the right type */
 		} else {
-			die("entry '%s' object %s is unavailable", path, sha1_to_hex(sha1));
+			die("entry '%s' object %s is unavailable", path, oid_to_hex(&oid));
 		}
 	} else {
 		if (obj_type != mode_type) {
@@ -131,11 +131,11 @@
 			 * because the new tree entry will never be correct.
 			 */
 			die("entry '%s' object %s is a %s but specified type was (%s)",
-				path, sha1_to_hex(sha1), type_name(obj_type), type_name(mode_type));
+				path, oid_to_hex(&oid), type_name(obj_type), type_name(mode_type));
 		}
 	}
 
-	append_to_tree(mode, sha1, path);
+	append_to_tree(mode, &oid, path);
 	free(to_free);
 }
 
diff --git a/builtin/mv.c b/builtin/mv.c
index 6d141f7..80bb967 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -72,7 +72,6 @@
 	return path;
 }
 
-static struct lock_file lock_file;
 #define SUBMODULE_WITH_GITDIR ((const char *)1)
 
 static void prepare_move_submodule(const char *src, int first,
@@ -131,6 +130,7 @@
 	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
 	struct stat st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
+	struct lock_file lock_file = LOCK_INIT;
 
 	git_config(git_default_config, NULL);
 
@@ -276,10 +276,12 @@
 			die_errno(_("renaming '%s' failed"), src);
 		}
 		if (submodule_gitfile[i]) {
-			if (submodule_gitfile[i] != SUBMODULE_WITH_GITDIR)
-				connect_work_tree_and_git_dir(dst, submodule_gitfile[i]);
 			if (!update_path_in_gitmodules(src, dst))
 				gitmodules_modified = 1;
+			if (submodule_gitfile[i] != SUBMODULE_WITH_GITDIR)
+				connect_work_tree_and_git_dir(dst,
+							      submodule_gitfile[i],
+							      1);
 		}
 
 		if (mode == WORKING_DIRECTORY)
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 9e088eb..387ddf8 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -328,7 +328,7 @@
 	else if (allow_undefined)
 		printf("undefined\n");
 	else if (always)
-		printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
+		printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
 	else
 		die("cannot describe '%s'", oid_to_hex(oid));
 	strbuf_release(&buf);
diff --git a/builtin/notes.c b/builtin/notes.c
index 6d2fda4..6981e2d 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -14,7 +14,7 @@
 #include "blob.h"
 #include "pretty.h"
 #include "refs.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "run-command.h"
 #include "parse-options.h"
 #include "string-list.h"
@@ -118,11 +118,11 @@
 	return 0;
 }
 
-static void copy_obj_to_fd(int fd, const unsigned char *sha1)
+static void copy_obj_to_fd(int fd, const struct object_id *oid)
 {
 	unsigned long size;
 	enum object_type type;
-	char *buf = read_sha1_file(sha1, &type, &size);
+	char *buf = read_object_file(oid, &type, &size);
 	if (buf) {
 		if (size)
 			write_or_die(fd, buf, size);
@@ -162,7 +162,7 @@
 }
 
 static void prepare_note_data(const struct object_id *object, struct note_data *d,
-		const unsigned char *old_note)
+		const struct object_id *old_note)
 {
 	if (d->use_editor || !d->given) {
 		int fd;
@@ -253,7 +253,7 @@
 
 	if (get_oid(arg, &object))
 		die(_("failed to resolve '%s' as a valid ref."), arg);
-	if (!(buf = read_sha1_file(object.hash, &type, &len))) {
+	if (!(buf = read_object_file(&object, &type, &len))) {
 		free(buf);
 		die(_("failed to read object '%s'."), arg);
 	}
@@ -457,11 +457,11 @@
 			oid_to_hex(&object));
 	}
 
-	prepare_note_data(&object, &d, note ? note->hash : NULL);
+	prepare_note_data(&object, &d, note);
 	if (d.buf.len || allow_empty) {
 		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
-			die("BUG: combine_notes_overwrite failed");
+			BUG("combine_notes_overwrite failed");
 		commit_notes(t, "Notes added by 'git notes add'");
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
@@ -544,7 +544,7 @@
 	}
 
 	if (add_note(t, &object, from_note, combine_notes_overwrite))
-		die("BUG: combine_notes_overwrite failed");
+		BUG("combine_notes_overwrite failed");
 	commit_notes(t, "Notes added by 'git notes copy'");
 out:
 	free_notes(t);
@@ -602,13 +602,13 @@
 	t = init_notes_check(argv[0], NOTES_INIT_WRITABLE);
 	note = get_note(t, &object);
 
-	prepare_note_data(&object, &d, edit && note ? note->hash : NULL);
+	prepare_note_data(&object, &d, edit && note ? note : NULL);
 
 	if (note && !edit) {
 		/* Append buf to previous note contents */
 		unsigned long size;
 		enum object_type type;
-		char *prev_buf = read_sha1_file(note->hash, &type, &size);
+		char *prev_buf = read_object_file(note, &type, &size);
 
 		strbuf_grow(&d.buf, size + 1);
 		if (d.buf.len && prev_buf && size)
@@ -621,7 +621,7 @@
 	if (d.buf.len || allow_empty) {
 		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
-			die("BUG: combine_notes_overwrite failed");
+			BUG("combine_notes_overwrite failed");
 		logmsg = xstrfmt("Notes added by 'git notes %s'", argv[0]);
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
@@ -778,13 +778,13 @@
 			   N_("resolve notes conflicts using the given strategy "
 			      "(manual/ours/theirs/union/cat_sort_uniq)")),
 		OPT_GROUP(N_("Committing unmerged notes")),
-		{ OPTION_SET_INT, 0, "commit", &do_commit, NULL,
-			N_("finalize notes merge by committing unmerged notes"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
+		OPT_SET_INT_F(0, "commit", &do_commit,
+			      N_("finalize notes merge by committing unmerged notes"),
+			      1, PARSE_OPT_NONEG),
 		OPT_GROUP(N_("Aborting notes merge resolution")),
-		{ OPTION_SET_INT, 0, "abort", &do_abort, NULL,
-			N_("abort notes merge"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
+		OPT_SET_INT_F(0, "abort", &do_abort,
+			      N_("abort notes merge"),
+			      1, PARSE_OPT_NONEG),
 		OPT_END()
 	};
 
@@ -831,7 +831,7 @@
 		const char *short_ref = NULL;
 
 		if (!skip_prefix(o.local_ref, "refs/notes/", &short_ref))
-			die("BUG: local ref %s is outside of refs/notes/",
+			BUG("local ref %s is outside of refs/notes/",
 			    o.local_ref);
 
 		strbuf_addf(&merge_key, "notes.%s.mergeStrategy", short_ref);
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index e9d3cfb..71056d8 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "cache.h"
+#include "repository.h"
 #include "config.h"
 #include "attr.h"
 #include "object.h"
@@ -28,6 +29,20 @@
 #include "argv-array.h"
 #include "list.h"
 #include "packfile.h"
+#include "object-store.h"
+#include "dir.h"
+
+#define IN_PACK(obj) oe_in_pack(&to_pack, obj)
+#define SIZE(obj) oe_size(&to_pack, obj)
+#define SET_SIZE(obj,size) oe_set_size(&to_pack, obj, size)
+#define DELTA_SIZE(obj) oe_delta_size(&to_pack, obj)
+#define DELTA(obj) oe_delta(&to_pack, obj)
+#define DELTA_CHILD(obj) oe_delta_child(&to_pack, obj)
+#define DELTA_SIBLING(obj) oe_delta_sibling(&to_pack, obj)
+#define SET_DELTA(obj, val) oe_set_delta(&to_pack, obj, val)
+#define SET_DELTA_SIZE(obj, val) oe_set_delta_size(&to_pack, obj, val)
+#define SET_DELTA_CHILD(obj, val) oe_set_delta_child(&to_pack, obj, val)
+#define SET_DELTA_SIBLING(obj, val) oe_set_delta_sibling(&to_pack, obj, val)
 
 static const char *pack_usage[] = {
 	N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
@@ -43,7 +58,7 @@
 static struct packing_data to_pack;
 
 static struct pack_idx_entry **written_list;
-static uint32_t nr_result, nr_written;
+static uint32_t nr_result, nr_written, nr_seen;
 
 static int non_empty;
 static int reuse_delta = 1, reuse_object = 1;
@@ -53,7 +68,8 @@
 static int local;
 static int have_non_local_packs;
 static int incremental;
-static int ignore_packed_keep;
+static int ignore_packed_keep_on_disk;
+static int ignore_packed_keep_in_core;
 static int allow_ofs_delta;
 static struct pack_idx_option pack_idx_opts;
 static const char *base_name;
@@ -78,7 +94,7 @@
 static int exclude_promisor_objects;
 
 static unsigned long delta_cache_size = 0;
-static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
+static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
 static unsigned long cache_max_small_delta_size = 1000;
 
 static unsigned long window_memory_limit = 0;
@@ -122,17 +138,17 @@
 	void *buf, *base_buf, *delta_buf;
 	enum object_type type;
 
-	buf = read_sha1_file(entry->idx.oid.hash, &type, &size);
+	buf = read_object_file(&entry->idx.oid, &type, &size);
 	if (!buf)
 		die("unable to read %s", oid_to_hex(&entry->idx.oid));
-	base_buf = read_sha1_file(entry->delta->idx.oid.hash, &type,
-				  &base_size);
+	base_buf = read_object_file(&DELTA(entry)->idx.oid, &type,
+				    &base_size);
 	if (!base_buf)
 		die("unable to read %s",
-		    oid_to_hex(&entry->delta->idx.oid));
+		    oid_to_hex(&DELTA(entry)->idx.oid));
 	delta_buf = diff_delta(base_buf, base_size,
 			       buf, size, &delta_size, 0);
-	if (!delta_buf || delta_size != entry->delta_size)
+	if (!delta_buf || delta_size != DELTA_SIZE(entry))
 		die("delta size changed");
 	free(buf);
 	free(base_buf);
@@ -263,15 +279,15 @@
 	enum object_type type;
 	void *buf;
 	struct git_istream *st = NULL;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (!usable_delta) {
-		if (entry->type == OBJ_BLOB &&
-		    entry->size > big_file_threshold &&
-		    (st = open_istream(entry->idx.oid.hash, &type, &size, NULL)) != NULL)
+		if (oe_type(entry) == OBJ_BLOB &&
+		    oe_size_greater_than(&to_pack, entry, big_file_threshold) &&
+		    (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 			buf = NULL;
 		else {
-			buf = read_sha1_file(entry->idx.oid.hash, &type,
-					     &size);
+			buf = read_object_file(&entry->idx.oid, &type, &size);
 			if (!buf)
 				die(_("unable to read %s"),
 				    oid_to_hex(&entry->idx.oid));
@@ -283,15 +299,15 @@
 		FREE_AND_NULL(entry->delta_data);
 		entry->z_delta_size = 0;
 	} else if (entry->delta_data) {
-		size = entry->delta_size;
+		size = DELTA_SIZE(entry);
 		buf = entry->delta_data;
 		entry->delta_data = NULL;
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	} else {
 		buf = get_delta(entry);
-		size = entry->delta_size;
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+		size = DELTA_SIZE(entry);
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	}
 
@@ -315,12 +331,12 @@
 		 * encoding of the relative offset for the delta
 		 * base from this object's position in the pack.
 		 */
-		off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+		off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 		unsigned pos = sizeof(dheader) - 1;
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -332,19 +348,19 @@
 	} else if (type == OBJ_REF_DELTA) {
 		/*
 		 * Deltas with a base reference contain
-		 * an additional 20 bytes for the base sha1.
+		 * additional bytes for the base object ID.
 		 */
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -367,21 +383,23 @@
 static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 				unsigned long limit, int usable_delta)
 {
-	struct packed_git *p = entry->in_pack;
+	struct packed_git *p = IN_PACK(entry);
 	struct pack_window *w_curs = NULL;
 	struct revindex_entry *revidx;
 	off_t offset;
-	enum object_type type = entry->type;
+	enum object_type type = oe_type(entry);
 	off_t datalen;
 	unsigned char header[MAX_PACK_OBJECT_HEADER],
 		      dheader[MAX_PACK_OBJECT_HEADER];
 	unsigned hdrlen;
+	const unsigned hashsz = the_hash_algo->rawsz;
+	unsigned long entry_size = SIZE(entry);
 
-	if (entry->delta)
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+	if (DELTA(entry))
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	hdrlen = encode_in_pack_object_header(header, sizeof(header),
-					      type, entry->size);
+					      type, entry_size);
 
 	offset = entry->in_pack_offset;
 	revidx = find_pack_revindex(p, offset);
@@ -398,7 +416,7 @@
 	datalen -= entry->in_pack_header_size;
 
 	if (!pack_to_stdout && p->index_version == 1 &&
-	    check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
+	    check_pack_inflate(p, &w_curs, offset, datalen, entry_size)) {
 		error("corrupt packed object for %s",
 		      oid_to_hex(&entry->idx.oid));
 		unuse_pack(&w_curs);
@@ -406,12 +424,12 @@
 	}
 
 	if (type == OBJ_OFS_DELTA) {
-		off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+		off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 		unsigned pos = sizeof(dheader) - 1;
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -420,16 +438,16 @@
 		hdrlen += sizeof(dheader) - pos;
 		reused_delta++;
 	} else if (type == OBJ_REF_DELTA) {
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 		reused_delta++;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -465,28 +483,29 @@
 	else
 		limit = pack_size_limit - write_offset;
 
-	if (!entry->delta)
+	if (!DELTA(entry))
 		usable_delta = 0;	/* no delta */
 	else if (!pack_size_limit)
 	       usable_delta = 1;	/* unlimited packfile */
-	else if (entry->delta->idx.offset == (off_t)-1)
+	else if (DELTA(entry)->idx.offset == (off_t)-1)
 		usable_delta = 0;	/* base was written to another pack */
-	else if (entry->delta->idx.offset)
+	else if (DELTA(entry)->idx.offset)
 		usable_delta = 1;	/* base already exists in this pack */
 	else
 		usable_delta = 0;	/* base could end up in another pack */
 
 	if (!reuse_object)
 		to_reuse = 0;	/* explicit */
-	else if (!entry->in_pack)
+	else if (!IN_PACK(entry))
 		to_reuse = 0;	/* can't reuse what we don't have */
-	else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
+	else if (oe_type(entry) == OBJ_REF_DELTA ||
+		 oe_type(entry) == OBJ_OFS_DELTA)
 				/* check_object() decided it for us ... */
 		to_reuse = usable_delta;
 				/* ... but pack split may override that */
-	else if (entry->type != entry->in_pack_type)
+	else if (oe_type(entry) != entry->in_pack_type)
 		to_reuse = 0;	/* pack has delta which is unusable */
-	else if (entry->delta)
+	else if (DELTA(entry))
 		to_reuse = 0;	/* we want to pack afresh */
 	else
 		to_reuse = 1;	/* we have it in-pack undeltified,
@@ -538,12 +557,12 @@
 	}
 
 	/* if we are deltified, write out base object first. */
-	if (e->delta) {
+	if (DELTA(e)) {
 		e->idx.offset = 1; /* now recurse */
-		switch (write_one(f, e->delta, offset)) {
+		switch (write_one(f, DELTA(e), offset)) {
 		case WRITE_ONE_RECURSIVE:
 			/* we cannot depend on this one */
-			e->delta = NULL;
+			SET_DELTA(e, NULL);
 			break;
 		default:
 			break;
@@ -605,34 +624,34 @@
 			/* add this node... */
 			add_to_write_order(wo, endp, e);
 			/* all its siblings... */
-			for (s = e->delta_sibling; s; s = s->delta_sibling) {
+			for (s = DELTA_SIBLING(e); s; s = DELTA_SIBLING(s)) {
 				add_to_write_order(wo, endp, s);
 			}
 		}
 		/* drop down a level to add left subtree nodes if possible */
-		if (e->delta_child) {
+		if (DELTA_CHILD(e)) {
 			add_to_order = 1;
-			e = e->delta_child;
+			e = DELTA_CHILD(e);
 		} else {
 			add_to_order = 0;
 			/* our sibling might have some children, it is next */
-			if (e->delta_sibling) {
-				e = e->delta_sibling;
+			if (DELTA_SIBLING(e)) {
+				e = DELTA_SIBLING(e);
 				continue;
 			}
 			/* go back to our parent node */
-			e = e->delta;
-			while (e && !e->delta_sibling) {
+			e = DELTA(e);
+			while (e && !DELTA_SIBLING(e)) {
 				/* we're on the right side of a subtree, keep
 				 * going up until we can go right again */
-				e = e->delta;
+				e = DELTA(e);
 			}
 			if (!e) {
 				/* done- we hit our original root node */
 				return;
 			}
 			/* pass it off to sibling at this level */
-			e = e->delta_sibling;
+			e = DELTA_SIBLING(e);
 		}
 	};
 }
@@ -643,7 +662,7 @@
 {
 	struct object_entry *root;
 
-	for (root = e; root->delta; root = root->delta)
+	for (root = e; DELTA(root); root = DELTA(root))
 		; /* nothing */
 	add_descendants_to_write_order(wo, endp, root);
 }
@@ -658,8 +677,8 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		objects[i].tagged = 0;
 		objects[i].filled = 0;
-		objects[i].delta_child = NULL;
-		objects[i].delta_sibling = NULL;
+		SET_DELTA_CHILD(&objects[i], NULL);
+		SET_DELTA_SIBLING(&objects[i], NULL);
 	}
 
 	/*
@@ -669,11 +688,11 @@
 	 */
 	for (i = to_pack.nr_objects; i > 0;) {
 		struct object_entry *e = &objects[--i];
-		if (!e->delta)
+		if (!DELTA(e))
 			continue;
 		/* Mark me as the first child */
-		e->delta_sibling = e->delta->delta_child;
-		e->delta->delta_child = e;
+		e->delta_sibling_idx = DELTA(e)->delta_child_idx;
+		SET_DELTA_CHILD(DELTA(e), e);
 	}
 
 	/*
@@ -705,8 +724,8 @@
 	 * And then all remaining commits and tags.
 	 */
 	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (objects[i].type != OBJ_COMMIT &&
-		    objects[i].type != OBJ_TAG)
+		if (oe_type(&objects[i]) != OBJ_COMMIT &&
+		    oe_type(&objects[i]) != OBJ_TAG)
 			continue;
 		add_to_write_order(wo, &wo_end, &objects[i]);
 	}
@@ -715,7 +734,7 @@
 	 * And then all the trees.
 	 */
 	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (objects[i].type != OBJ_TREE)
+		if (oe_type(&objects[i]) != OBJ_TREE)
 			continue;
 		add_to_write_order(wo, &wo_end, &objects[i]);
 	}
@@ -752,7 +771,7 @@
 		die_errno("unable to seek in reused packfile");
 
 	if (reuse_packfile_offset < 0)
-		reuse_packfile_offset = reuse_packfile->pack_size - 20;
+		reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 
 	total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 
@@ -837,11 +856,11 @@
 		 * If so, rewrite it like in fast-import
 		 */
 		if (pack_to_stdout) {
-			hashclose(f, oid.hash, CSUM_CLOSE);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE);
 		} else if (nr_written == nr_remaining) {
-			hashclose(f, oid.hash, CSUM_FSYNC);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 		} else {
-			int fd = hashclose(f, oid.hash, 0);
+			int fd = finalize_hashfile(f, oid.hash, 0);
 			fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 						 nr_written, oid.hash, offset);
 			close(fd);
@@ -878,7 +897,8 @@
 
 			if (write_bitmap_index) {
 				bitmap_writer_set_checksum(oid.hash);
-				bitmap_writer_build_type_index(written_list, nr_written);
+				bitmap_writer_build_type_index(
+					&to_pack, written_list, nr_written);
 			}
 
 			finish_tmp_packfile(&tmpname, pack_tmp_name,
@@ -982,13 +1002,16 @@
 	 * Otherwise, we signal "-1" at the end to tell the caller that we do
 	 * not know either way, and it needs to check more packs.
 	 */
-	if (!ignore_packed_keep &&
+	if (!ignore_packed_keep_on_disk &&
+	    !ignore_packed_keep_in_core &&
 	    (!local || !have_non_local_packs))
 		return 1;
 
 	if (local && !p->pack_local)
 		return 0;
-	if (ignore_packed_keep && p->pack_local && p->pack_keep)
+	if (p->pack_local &&
+	    ((ignore_packed_keep_on_disk && p->pack_keep) ||
+	     (ignore_packed_keep_in_core && p->pack_keep_in_core)))
 		return 0;
 
 	/* we don't know yet; keep looking for more packs */
@@ -1012,7 +1035,7 @@
 	int want;
 	struct list_head *pos;
 
-	if (!exclude && local && has_loose_object_nonlocal(oid->hash))
+	if (!exclude && local && has_loose_object_nonlocal(oid))
 		return 0;
 
 	/*
@@ -1025,8 +1048,7 @@
 		if (want != -1)
 			return want;
 	}
-
-	list_for_each(pos, &packed_git_mru) {
+	list_for_each(pos, get_packed_git_mru(the_repository)) {
 		struct packed_git *p = list_entry(pos, struct packed_git, mru);
 		off_t offset;
 
@@ -1044,7 +1066,8 @@
 			}
 			want = want_found_object(exclude, p);
 			if (!exclude && want > 0)
-				list_move(&p->mru, &packed_git_mru);
+				list_move(&p->mru,
+					  get_packed_git_mru(the_repository));
 			if (want != -1)
 				return want;
 		}
@@ -1066,14 +1089,13 @@
 
 	entry = packlist_alloc(&to_pack, oid->hash, index_pos);
 	entry->hash = hash;
-	if (type)
-		entry->type = type;
+	oe_set_type(entry, type);
 	if (exclude)
 		entry->preferred_base = 1;
 	else
 		nr_result++;
 	if (found_pack) {
-		entry->in_pack = found_pack;
+		oe_set_in_pack(&to_pack, entry, found_pack);
 		entry->in_pack_offset = found_offset;
 	}
 
@@ -1091,6 +1113,8 @@
 	off_t found_offset = 0;
 	uint32_t index_pos;
 
+	display_progress(progress_state, ++nr_seen);
+
 	if (have_duplicate_entry(oid, exclude, &index_pos))
 		return 0;
 
@@ -1106,8 +1130,6 @@
 	create_object_entry(oid, type, pack_name_hash(name),
 			    exclude, name && no_try_delta(name),
 			    index_pos, found_pack, found_offset);
-
-	display_progress(progress_state, nr_result);
 	return 1;
 }
 
@@ -1118,6 +1140,8 @@
 {
 	uint32_t index_pos;
 
+	display_progress(progress_state, ++nr_seen);
+
 	if (have_duplicate_entry(oid, 0, &index_pos))
 		return 0;
 
@@ -1125,8 +1149,6 @@
 		return 0;
 
 	create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
-
-	display_progress(progress_state, nr_result);
 	return 1;
 }
 
@@ -1190,7 +1212,7 @@
 	/* Did not find one.  Either we got a bogus request or
 	 * we need to read and perhaps cache.
 	 */
-	data = read_sha1_file(oid->hash, &type, &size);
+	data = read_object_file(oid, &type, &size);
 	if (!data)
 		return NULL;
 	if (type != OBJ_TREE) {
@@ -1351,7 +1373,7 @@
 	if (window <= num_preferred_base++)
 		return;
 
-	data = read_object_with_reference(oid->hash, tree_type, &size, tree_oid.hash);
+	data = read_object_with_reference(oid, tree_type, &size, &tree_oid);
 	if (!data)
 		return;
 
@@ -1398,8 +1420,10 @@
 
 static void check_object(struct object_entry *entry)
 {
-	if (entry->in_pack) {
-		struct packed_git *p = entry->in_pack;
+	unsigned long canonical_size;
+
+	if (IN_PACK(entry)) {
+		struct packed_git *p = IN_PACK(entry);
 		struct pack_window *w_curs = NULL;
 		const unsigned char *base_ref = NULL;
 		struct object_entry *base_entry;
@@ -1407,6 +1431,8 @@
 		unsigned long avail;
 		off_t ofs;
 		unsigned char *buf, c;
+		enum object_type type;
+		unsigned long in_pack_size;
 
 		buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
 
@@ -1415,11 +1441,15 @@
 		 * since non-delta representations could still be reused.
 		 */
 		used = unpack_object_header_buffer(buf, avail,
-						   &entry->in_pack_type,
-						   &entry->size);
+						   &type,
+						   &in_pack_size);
 		if (used == 0)
 			goto give_up;
 
+		if (type < 0)
+			BUG("invalid type %d", type);
+		entry->in_pack_type = type;
+
 		/*
 		 * Determine if this is a delta and if so whether we can
 		 * reuse it or not.  Otherwise let's find out as cheaply as
@@ -1428,9 +1458,10 @@
 		switch (entry->in_pack_type) {
 		default:
 			/* Not a delta hence we've already got all we need. */
-			entry->type = entry->in_pack_type;
+			oe_set_type(entry, entry->in_pack_type);
+			SET_SIZE(entry, in_pack_size);
 			entry->in_pack_header_size = used;
-			if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
+			if (oe_type(entry) < OBJ_COMMIT || oe_type(entry) > OBJ_BLOB)
 				goto give_up;
 			unuse_pack(&w_curs);
 			return;
@@ -1438,7 +1469,7 @@
 			if (reuse_delta && !entry->preferred_base)
 				base_ref = use_pack(p, &w_curs,
 						entry->in_pack_offset + used, NULL);
-			entry->in_pack_header_size = used + 20;
+			entry->in_pack_header_size = used + the_hash_algo->rawsz;
 			break;
 		case OBJ_OFS_DELTA:
 			buf = use_pack(p, &w_curs,
@@ -1484,25 +1515,29 @@
 			 * deltify other objects against, in order to avoid
 			 * circular deltas.
 			 */
-			entry->type = entry->in_pack_type;
-			entry->delta = base_entry;
-			entry->delta_size = entry->size;
-			entry->delta_sibling = base_entry->delta_child;
-			base_entry->delta_child = entry;
+			oe_set_type(entry, entry->in_pack_type);
+			SET_SIZE(entry, in_pack_size); /* delta size */
+			SET_DELTA(entry, base_entry);
+			SET_DELTA_SIZE(entry, in_pack_size);
+			entry->delta_sibling_idx = base_entry->delta_child_idx;
+			SET_DELTA_CHILD(base_entry, entry);
 			unuse_pack(&w_curs);
 			return;
 		}
 
-		if (entry->type) {
+		if (oe_type(entry)) {
+			off_t delta_pos;
+
 			/*
 			 * This must be a delta and we already know what the
 			 * final object type is.  Let's extract the actual
 			 * object size from the delta header.
 			 */
-			entry->size = get_size_from_delta(p, &w_curs,
-					entry->in_pack_offset + entry->in_pack_header_size);
-			if (entry->size == 0)
+			delta_pos = entry->in_pack_offset + entry->in_pack_header_size;
+			canonical_size = get_size_from_delta(p, &w_curs, delta_pos);
+			if (canonical_size == 0)
 				goto give_up;
+			SET_SIZE(entry, canonical_size);
 			unuse_pack(&w_curs);
 			return;
 		}
@@ -1516,27 +1551,34 @@
 		unuse_pack(&w_curs);
 	}
 
-	entry->type = sha1_object_info(entry->idx.oid.hash, &entry->size);
-	/*
-	 * The error condition is checked in prepare_pack().  This is
-	 * to permit a missing preferred base object to be ignored
-	 * as a preferred base.  Doing so can result in a larger
-	 * pack file, but the transfer will still take place.
-	 */
+	oe_set_type(entry,
+		    oid_object_info(the_repository, &entry->idx.oid, &canonical_size));
+	if (entry->type_valid) {
+		SET_SIZE(entry, canonical_size);
+	} else {
+		/*
+		 * Bad object type is checked in prepare_pack().  This is
+		 * to permit a missing preferred base object to be ignored
+		 * as a preferred base.  Doing so can result in a larger
+		 * pack file, but the transfer will still take place.
+		 */
+	}
 }
 
 static int pack_offset_sort(const void *_a, const void *_b)
 {
 	const struct object_entry *a = *(struct object_entry **)_a;
 	const struct object_entry *b = *(struct object_entry **)_b;
+	const struct packed_git *a_in_pack = IN_PACK(a);
+	const struct packed_git *b_in_pack = IN_PACK(b);
 
 	/* avoid filesystem trashing with loose objects */
-	if (!a->in_pack && !b->in_pack)
+	if (!a_in_pack && !b_in_pack)
 		return oidcmp(&a->idx.oid, &b->idx.oid);
 
-	if (a->in_pack < b->in_pack)
+	if (a_in_pack < b_in_pack)
 		return -1;
-	if (a->in_pack > b->in_pack)
+	if (a_in_pack > b_in_pack)
 		return 1;
 	return a->in_pack_offset < b->in_pack_offset ? -1 :
 			(a->in_pack_offset > b->in_pack_offset);
@@ -1557,30 +1599,37 @@
  */
 static void drop_reused_delta(struct object_entry *entry)
 {
-	struct object_entry **p = &entry->delta->delta_child;
+	unsigned *idx = &to_pack.objects[entry->delta_idx - 1].delta_child_idx;
 	struct object_info oi = OBJECT_INFO_INIT;
+	enum object_type type;
+	unsigned long size;
 
-	while (*p) {
-		if (*p == entry)
-			*p = (*p)->delta_sibling;
+	while (*idx) {
+		struct object_entry *oe = &to_pack.objects[*idx - 1];
+
+		if (oe == entry)
+			*idx = oe->delta_sibling_idx;
 		else
-			p = &(*p)->delta_sibling;
+			idx = &oe->delta_sibling_idx;
 	}
-	entry->delta = NULL;
+	SET_DELTA(entry, NULL);
 	entry->depth = 0;
 
-	oi.sizep = &entry->size;
-	oi.typep = &entry->type;
-	if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0) {
+	oi.sizep = &size;
+	oi.typep = &type;
+	if (packed_object_info(the_repository, IN_PACK(entry), entry->in_pack_offset, &oi) < 0) {
 		/*
 		 * We failed to get the info from this pack for some reason;
 		 * fall back to sha1_object_info, which may find another copy.
-		 * And if that fails, the error will be recorded in entry->type
+		 * And if that fails, the error will be recorded in oe_type(entry)
 		 * and dealt with in prepare_pack().
 		 */
-		entry->type = sha1_object_info(entry->idx.oid.hash,
-					       &entry->size);
+		oe_set_type(entry,
+			    oid_object_info(the_repository, &entry->idx.oid, &size));
+	} else {
+		oe_set_type(entry, type);
 	}
+	SET_SIZE(entry, size);
 }
 
 /*
@@ -1604,7 +1653,7 @@
 
 	for (cur = entry, total_depth = 0;
 	     cur;
-	     cur = cur->delta, total_depth++) {
+	     cur = DELTA(cur), total_depth++) {
 		if (cur->dfs_state == DFS_DONE) {
 			/*
 			 * We've already seen this object and know it isn't
@@ -1621,7 +1670,7 @@
 		 * is a bug.
 		 */
 		if (cur->dfs_state != DFS_NONE)
-			die("BUG: confusing delta dfs state in first pass: %d",
+			BUG("confusing delta dfs state in first pass: %d",
 			    cur->dfs_state);
 
 		/*
@@ -1629,7 +1678,7 @@
 		 * it's not a delta, we're done traversing, but we'll mark it
 		 * done to save time on future traversals.
 		 */
-		if (!cur->delta) {
+		if (!DELTA(cur)) {
 			cur->dfs_state = DFS_DONE;
 			break;
 		}
@@ -1652,7 +1701,7 @@
 		 * We keep all commits in the chain that we examined.
 		 */
 		cur->dfs_state = DFS_ACTIVE;
-		if (cur->delta->dfs_state == DFS_ACTIVE) {
+		if (DELTA(cur)->dfs_state == DFS_ACTIVE) {
 			drop_reused_delta(cur);
 			cur->dfs_state = DFS_DONE;
 			break;
@@ -1667,7 +1716,7 @@
 	 * an extra "next" pointer to keep going after we reset cur->delta.
 	 */
 	for (cur = entry; cur; cur = next) {
-		next = cur->delta;
+		next = DELTA(cur);
 
 		/*
 		 * We should have a chain of zero or more ACTIVE states down to
@@ -1678,7 +1727,7 @@
 		if (cur->dfs_state == DFS_DONE)
 			break;
 		else if (cur->dfs_state != DFS_ACTIVE)
-			die("BUG: confusing delta dfs state in second pass: %d",
+			BUG("confusing delta dfs state in second pass: %d",
 			    cur->dfs_state);
 
 		/*
@@ -1712,6 +1761,10 @@
 	uint32_t i;
 	struct object_entry **sorted_by_offset;
 
+	if (progress)
+		progress_state = start_progress(_("Counting objects"),
+						to_pack.nr_objects);
+
 	sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
 	for (i = 0; i < to_pack.nr_objects; i++)
 		sorted_by_offset[i] = to_pack.objects + i;
@@ -1720,9 +1773,12 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		struct object_entry *entry = sorted_by_offset[i];
 		check_object(entry);
-		if (big_file_threshold < entry->size)
+		if (entry->type_valid &&
+		    oe_size_greater_than(&to_pack, entry, big_file_threshold))
 			entry->no_try_delta = 1;
+		display_progress(progress_state, i + 1);
 	}
+	stop_progress(&progress_state);
 
 	/*
 	 * This must happen in a second pass, since we rely on the delta
@@ -1747,10 +1803,14 @@
 {
 	const struct object_entry *a = *(struct object_entry **)_a;
 	const struct object_entry *b = *(struct object_entry **)_b;
+	enum object_type a_type = oe_type(a);
+	enum object_type b_type = oe_type(b);
+	unsigned long a_size = SIZE(a);
+	unsigned long b_size = SIZE(b);
 
-	if (a->type > b->type)
+	if (a_type > b_type)
 		return -1;
-	if (a->type < b->type)
+	if (a_type < b_type)
 		return 1;
 	if (a->hash > b->hash)
 		return -1;
@@ -1760,9 +1820,9 @@
 		return -1;
 	if (a->preferred_base < b->preferred_base)
 		return 1;
-	if (a->size > b->size)
+	if (a_size > b_size)
 		return -1;
-	if (a->size < b->size)
+	if (a_size < b_size)
 		return 1;
 	return a < b ? -1 : (a > b);  /* newest first */
 }
@@ -1815,6 +1875,46 @@
 
 #endif
 
+/*
+ * Return the size of the object without doing any delta
+ * reconstruction (so non-deltas are true object sizes, but deltas
+ * return the size of the delta data).
+ */
+unsigned long oe_get_size_slow(struct packing_data *pack,
+			       const struct object_entry *e)
+{
+	struct packed_git *p;
+	struct pack_window *w_curs;
+	unsigned char *buf;
+	enum object_type type;
+	unsigned long used, avail, size;
+
+	if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
+		read_lock();
+		if (oid_object_info(the_repository, &e->idx.oid, &size) < 0)
+			die(_("unable to get size of %s"),
+			    oid_to_hex(&e->idx.oid));
+		read_unlock();
+		return size;
+	}
+
+	p = oe_in_pack(pack, e);
+	if (!p)
+		BUG("when e->type is a delta, it must belong to a pack");
+
+	read_lock();
+	w_curs = NULL;
+	buf = use_pack(p, &w_curs, e->in_pack_offset, &avail);
+	used = unpack_object_header_buffer(buf, avail, &type, &size);
+	if (used == 0)
+		die(_("unable to parse object header of %s"),
+		    oid_to_hex(&e->idx.oid));
+
+	unuse_pack(&w_curs);
+	read_unlock();
+	return size;
+}
+
 static int try_delta(struct unpacked *trg, struct unpacked *src,
 		     unsigned max_depth, unsigned long *mem_usage)
 {
@@ -1826,7 +1926,7 @@
 	void *delta_buf;
 
 	/* Don't bother doing diffs between different types */
-	if (trg_entry->type != src_entry->type)
+	if (oe_type(trg_entry) != oe_type(src_entry))
 		return -1;
 
 	/*
@@ -1837,8 +1937,8 @@
 	 * it, we will still save the transfer cost, as we already know
 	 * the other side has it and we won't send src_entry at all.
 	 */
-	if (reuse_delta && trg_entry->in_pack &&
-	    trg_entry->in_pack == src_entry->in_pack &&
+	if (reuse_delta && IN_PACK(trg_entry) &&
+	    IN_PACK(trg_entry) == IN_PACK(src_entry) &&
 	    !src_entry->preferred_base &&
 	    trg_entry->in_pack_type != OBJ_REF_DELTA &&
 	    trg_entry->in_pack_type != OBJ_OFS_DELTA)
@@ -1849,19 +1949,19 @@
 		return 0;
 
 	/* Now some size filtering heuristics. */
-	trg_size = trg_entry->size;
-	if (!trg_entry->delta) {
-		max_size = trg_size/2 - 20;
+	trg_size = SIZE(trg_entry);
+	if (!DELTA(trg_entry)) {
+		max_size = trg_size/2 - the_hash_algo->rawsz;
 		ref_depth = 1;
 	} else {
-		max_size = trg_entry->delta_size;
+		max_size = DELTA_SIZE(trg_entry);
 		ref_depth = trg->depth;
 	}
 	max_size = (uint64_t)max_size * (max_depth - src->depth) /
 						(max_depth - ref_depth + 1);
 	if (max_size == 0)
 		return 0;
-	src_size = src_entry->size;
+	src_size = SIZE(src_entry);
 	sizediff = src_size < trg_size ? trg_size - src_size : 0;
 	if (sizediff >= max_size)
 		return 0;
@@ -1871,8 +1971,7 @@
 	/* Load data if not already done */
 	if (!trg->data) {
 		read_lock();
-		trg->data = read_sha1_file(trg_entry->idx.oid.hash, &type,
-					   &sz);
+		trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
 		read_unlock();
 		if (!trg->data)
 			die("object %s cannot be read",
@@ -1885,8 +1984,7 @@
 	}
 	if (!src->data) {
 		read_lock();
-		src->data = read_sha1_file(src_entry->idx.oid.hash, &type,
-					   &sz);
+		src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
 		read_unlock();
 		if (!src->data) {
 			if (src_entry->preferred_base) {
@@ -1925,10 +2023,14 @@
 	delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
 	if (!delta_buf)
 		return 0;
+	if (delta_size >= (1U << OE_DELTA_SIZE_BITS)) {
+		free(delta_buf);
+		return 0;
+	}
 
-	if (trg_entry->delta) {
+	if (DELTA(trg_entry)) {
 		/* Prefer only shallower same-sized deltas. */
-		if (delta_size == trg_entry->delta_size &&
+		if (delta_size == DELTA_SIZE(trg_entry) &&
 		    src->depth + 1 >= trg->depth) {
 			free(delta_buf);
 			return 0;
@@ -1943,7 +2045,7 @@
 	free(trg_entry->delta_data);
 	cache_lock();
 	if (trg_entry->delta_data) {
-		delta_cache_size -= trg_entry->delta_size;
+		delta_cache_size -= DELTA_SIZE(trg_entry);
 		trg_entry->delta_data = NULL;
 	}
 	if (delta_cacheable(src_size, trg_size, delta_size)) {
@@ -1955,8 +2057,8 @@
 		free(delta_buf);
 	}
 
-	trg_entry->delta = src_entry;
-	trg_entry->delta_size = delta_size;
+	SET_DELTA(trg_entry, src_entry);
+	SET_DELTA_SIZE(trg_entry, delta_size);
 	trg->depth = src->depth + 1;
 
 	return 1;
@@ -1964,13 +2066,13 @@
 
 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 {
-	struct object_entry *child = me->delta_child;
+	struct object_entry *child = DELTA_CHILD(me);
 	unsigned int m = n;
 	while (child) {
 		unsigned int c = check_delta_limit(child, n + 1);
 		if (m < c)
 			m = c;
-		child = child->delta_sibling;
+		child = DELTA_SIBLING(child);
 	}
 	return m;
 }
@@ -1981,7 +2083,7 @@
 	free_delta_index(n->index);
 	n->index = NULL;
 	if (n->data) {
-		freed_mem += n->entry->size;
+		freed_mem += SIZE(n->entry);
 		FREE_AND_NULL(n->data);
 	}
 	n->entry = NULL;
@@ -2039,7 +2141,7 @@
 		 * otherwise they would become too deep.
 		 */
 		max_depth = depth;
-		if (entry->delta_child) {
+		if (DELTA_CHILD(entry)) {
 			max_depth -= check_delta_limit(entry, 0);
 			if (max_depth <= 0)
 				goto next;
@@ -2077,19 +2179,26 @@
 		 * between writes at that moment.
 		 */
 		if (entry->delta_data && !pack_to_stdout) {
-			entry->z_delta_size = do_compress(&entry->delta_data,
-							  entry->delta_size);
-			cache_lock();
-			delta_cache_size -= entry->delta_size;
-			delta_cache_size += entry->z_delta_size;
-			cache_unlock();
+			unsigned long size;
+
+			size = do_compress(&entry->delta_data, DELTA_SIZE(entry));
+			if (size < (1U << OE_Z_DELTA_BITS)) {
+				entry->z_delta_size = size;
+				cache_lock();
+				delta_cache_size -= DELTA_SIZE(entry);
+				delta_cache_size += entry->z_delta_size;
+				cache_unlock();
+			} else {
+				FREE_AND_NULL(entry->delta_data);
+				entry->z_delta_size = 0;
+			}
 		}
 
 		/* if we made n a delta, and if n is already at max
 		 * depth, leaving it in the window is pointless.  we
 		 * should evict it first.
 		 */
-		if (entry->delta && max_depth <= n->depth)
+		if (DELTA(entry) && max_depth <= n->depth)
 			continue;
 
 		/*
@@ -2097,7 +2206,7 @@
 		 * currently deltified object, to keep it longer.  It will
 		 * be the first base object to be attempted next.
 		 */
-		if (entry->delta) {
+		if (DELTA(entry)) {
 			struct unpacked swap = array[best_base];
 			int dist = (window + idx - best_base) % window;
 			int dst = best_base;
@@ -2418,13 +2527,14 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		struct object_entry *entry = to_pack.objects + i;
 
-		if (entry->delta)
+		if (DELTA(entry))
 			/* This happens if we decided to reuse existing
 			 * delta from a pack.  "reuse_delta &&" is implied.
 			 */
 			continue;
 
-		if (entry->size < 50)
+		if (!entry->type_valid ||
+		    oe_size_less_than(&to_pack, entry, 50))
 			continue;
 
 		if (entry->no_try_delta)
@@ -2432,11 +2542,11 @@
 
 		if (!entry->preferred_base) {
 			nr_deltas++;
-			if (entry->type < 0)
+			if (oe_type(entry) < 0)
 				die("unable to get type of object %s",
 				    oid_to_hex(&entry->idx.oid));
 		} else {
-			if (entry->type < 0) {
+			if (oe_type(entry) < 0) {
 				/*
 				 * This object is not found, but we
 				 * don't have to include it anyway.
@@ -2545,7 +2655,7 @@
 			die("expected object ID, got garbage:\n %s", line);
 
 		add_preferred_base_object(p + 1);
-		add_object_entry(&oid, 0, p + 1, 0);
+		add_object_entry(&oid, OBJ_NONE, p + 1, 0);
 	}
 }
 
@@ -2674,11 +2784,11 @@
 
 	memset(&in_pack, 0, sizeof(in_pack));
 
-	for (p = packed_git; p; p = p->next) {
+	for (p = get_packed_git(the_repository); p; p = p->next) {
 		struct object_id oid;
 		struct object *o;
 
-		if (!p->pack_local || p->pack_keep)
+		if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
 			continue;
 		if (open_pack_index(p))
 			die("cannot open pack index");
@@ -2709,7 +2819,7 @@
 static int add_loose_object(const struct object_id *oid, const char *path,
 			    void *data)
 {
-	enum object_type type = sha1_object_info(oid->hash, NULL);
+	enum object_type type = oid_object_info(the_repository, oid, NULL);
 
 	if (type < 0) {
 		warning("loose object at %s could not be examined", path);
@@ -2737,16 +2847,18 @@
 	static struct packed_git *last_found = (void *)1;
 	struct packed_git *p;
 
-	p = (last_found != (void *)1) ? last_found : packed_git;
+	p = (last_found != (void *)1) ? last_found :
+					get_packed_git(the_repository);
 
 	while (p) {
-		if ((!p->pack_local || p->pack_keep) &&
+		if ((!p->pack_local || p->pack_keep ||
+				p->pack_keep_in_core) &&
 			find_pack_entry_one(oid->hash, p)) {
 			last_found = p;
 			return 1;
 		}
 		if (p == last_found)
-			p = packed_git;
+			p = get_packed_git(the_repository);
 		else
 			p = p->next;
 		if (p == last_found)
@@ -2782,8 +2894,8 @@
 	uint32_t i;
 	struct object_id oid;
 
-	for (p = packed_git; p; p = p->next) {
-		if (!p->pack_local || p->pack_keep)
+	for (p = get_packed_git(the_repository); p; p = p->next) {
+		if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
 			continue;
 
 		if (open_pack_index(p))
@@ -2809,7 +2921,8 @@
 {
 	return pack_to_stdout &&
 	       allow_ofs_delta &&
-	       !ignore_packed_keep &&
+	       !ignore_packed_keep_on_disk &&
+	       !ignore_packed_keep_in_core &&
 	       (!local || !have_non_local_packs) &&
 	       !incremental;
 }
@@ -2918,6 +3031,32 @@
 	oid_array_clear(&recent_objects);
 }
 
+static void add_extra_kept_packs(const struct string_list *names)
+{
+	struct packed_git *p;
+
+	if (!names->nr)
+		return;
+
+	for (p = get_packed_git(the_repository); p; p = p->next) {
+		const char *name = basename(p->pack_name);
+		int i;
+
+		if (!p->pack_local)
+			continue;
+
+		for (i = 0; i < names->nr; i++)
+			if (!fspathcmp(name, names->items[i].string))
+				break;
+
+		if (i < names->nr) {
+			p->pack_keep_in_core = 1;
+			ignore_packed_keep_in_core = 1;
+			continue;
+		}
+	}
+}
+
 static int option_parse_index_version(const struct option *opt,
 				      const char *arg, int unset)
 {
@@ -2957,6 +3096,7 @@
 	struct argv_array rp = ARGV_ARRAY_INIT;
 	int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
 	int rev_list_index = 0;
+	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
 	struct option pack_objects_options[] = {
 		OPT_SET_INT('q', "quiet", &progress,
 			    N_("do not show progress meter"), 0),
@@ -2994,18 +3134,18 @@
 			 N_("do not create an empty pack output")),
 		OPT_BOOL(0, "revs", &use_internal_rev_list,
 			 N_("read revision arguments from standard input")),
-		{ OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
-		  N_("limit the objects to those that are not yet packed"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
-		  N_("include objects reachable from any reference"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
-		  N_("include objects referred by reflog entries"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
-		  N_("include objects referred to by the index"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
+		OPT_SET_INT_F(0, "unpacked", &rev_list_unpacked,
+			      N_("limit the objects to those that are not yet packed"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "all", &rev_list_all,
+			      N_("include objects reachable from any reference"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "reflog", &rev_list_reflog,
+			      N_("include objects referred by reflog entries"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "indexed-objects", &rev_list_index,
+			      N_("include objects referred to by the index"),
+			      1, PARSE_OPT_NONEG),
 		OPT_BOOL(0, "stdout", &pack_to_stdout,
 			 N_("output pack to stdout")),
 		OPT_BOOL(0, "include-tag", &include_tag,
@@ -3021,8 +3161,10 @@
 			 N_("create thin packs")),
 		OPT_BOOL(0, "shallow", &shallow,
 			 N_("create packs suitable for shallow fetches")),
-		OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
+		OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep_on_disk,
 			 N_("ignore packs that have companion .keep file")),
+		OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
+				N_("ignore this pack")),
 		OPT_INTEGER(0, "compression", &pack_compression_level,
 			    N_("pack compression level")),
 		OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
@@ -3040,6 +3182,9 @@
 		OPT_END(),
 	};
 
+	if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
+		BUG("too many dfs states, increase OE_DFS_STATE_BITS");
+
 	check_replace_refs = 0;
 
 	reset_pack_idx_option(&pack_idx_opts);
@@ -3056,6 +3201,17 @@
 	if (pack_to_stdout != !base_name || argc)
 		usage_with_options(pack_usage, pack_objects_options);
 
+	if (depth >= (1 << OE_DEPTH_BITS)) {
+		warning(_("delta chain depth %d is too deep, forcing %d"),
+			depth, (1 << OE_DEPTH_BITS) - 1);
+		depth = (1 << OE_DEPTH_BITS) - 1;
+	}
+	if (cache_max_small_delta_size >= (1U << OE_Z_DELTA_BITS)) {
+		warning(_("pack.deltaCacheLimit is too high, forcing %d"),
+			(1U << OE_Z_DELTA_BITS) - 1);
+		cache_max_small_delta_size = (1U << OE_Z_DELTA_BITS) - 1;
+	}
+
 	argv_array_push(&rp, "pack-objects");
 	if (thin) {
 		use_internal_rev_list = 1;
@@ -3087,6 +3243,8 @@
 		fetch_if_missing = 0;
 		argv_array_push(&rp, "--exclude-promisor-objects");
 	}
+	if (unpack_unreachable || keep_unreachable || pack_loose_unreachable)
+		use_internal_rev_list = 1;
 
 	if (!reuse_object)
 		reuse_delta = 0;
@@ -3150,23 +3308,23 @@
 	if (progress && all_progress_implied)
 		progress = 2;
 
-	prepare_packed_git();
-	if (ignore_packed_keep) {
+	add_extra_kept_packs(&keep_pack_list);
+	if (ignore_packed_keep_on_disk) {
 		struct packed_git *p;
-		for (p = packed_git; p; p = p->next)
+		for (p = get_packed_git(the_repository); p; p = p->next)
 			if (p->pack_local && p->pack_keep)
 				break;
 		if (!p) /* no keep-able packs found */
-			ignore_packed_keep = 0;
+			ignore_packed_keep_on_disk = 0;
 	}
 	if (local) {
 		/*
-		 * unlike ignore_packed_keep above, we do not want to
-		 * unset "local" based on looking at packs, as it
-		 * also covers non-local objects
+		 * unlike ignore_packed_keep_on_disk above, we do not
+		 * want to unset "local" based on looking at packs, as
+		 * it also covers non-local objects
 		 */
 		struct packed_git *p;
-		for (p = packed_git; p; p = p->next) {
+		for (p = get_packed_git(the_repository); p; p = p->next) {
 			if (!p->pack_local) {
 				have_non_local_packs = 1;
 				break;
@@ -3174,8 +3332,10 @@
 		}
 	}
 
+	prepare_packing_data(&to_pack);
+
 	if (progress)
-		progress_state = start_progress(_("Counting objects"), 0);
+		progress_state = start_progress(_("Enumerating objects"), 0);
 	if (!use_internal_rev_list)
 		read_object_list_from_stdin();
 	else {
diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index 991e1bb..0494dce 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -7,7 +7,9 @@
 */
 
 #include "builtin.h"
+#include "repository.h"
 #include "packfile.h"
+#include "object-store.h"
 
 #define BLKSIZE 512
 
@@ -18,7 +20,7 @@
 
 struct llist_item {
 	struct llist_item *next;
-	const unsigned char *sha1;
+	const struct object_id *oid;
 };
 static struct llist {
 	struct llist_item *front;
@@ -88,14 +90,14 @@
 		return ret;
 
 	new_item = ret->front = llist_item_get();
-	new_item->sha1 = list->front->sha1;
+	new_item->oid = list->front->oid;
 
 	old_item = list->front->next;
 	while (old_item) {
 		prev = new_item;
 		new_item = llist_item_get();
 		prev->next = new_item;
-		new_item->sha1 = old_item->sha1;
+		new_item->oid = old_item->oid;
 		old_item = old_item->next;
 	}
 	new_item->next = NULL;
@@ -106,10 +108,10 @@
 
 static inline struct llist_item *llist_insert(struct llist *list,
 					      struct llist_item *after,
-					       const unsigned char *sha1)
+					      const struct object_id *oid)
 {
 	struct llist_item *new_item = llist_item_get();
-	new_item->sha1 = sha1;
+	new_item->oid = oid;
 	new_item->next = NULL;
 
 	if (after != NULL) {
@@ -129,21 +131,21 @@
 }
 
 static inline struct llist_item *llist_insert_back(struct llist *list,
-						   const unsigned char *sha1)
+						   const struct object_id *oid)
 {
-	return llist_insert(list, list->back, sha1);
+	return llist_insert(list, list->back, oid);
 }
 
 static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
-			const unsigned char *sha1, struct llist_item *hint)
+			const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev = NULL, *l;
 
 	l = (hint == NULL) ? list->front : hint;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) { /* we insert before this entry */
-			return llist_insert(list, prev, sha1);
+			return llist_insert(list, prev, oid);
 		}
 		if (!cmp) { /* already exists */
 			return l;
@@ -152,11 +154,11 @@
 		l = l->next;
 	}
 	/* insert at the end */
-	return llist_insert_back(list, sha1);
+	return llist_insert_back(list, oid);
 }
 
 /* returns a pointer to an item in front of sha1 */
-static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
+static inline struct llist_item * llist_sorted_remove(struct llist *list, const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev, *l;
 
@@ -164,7 +166,7 @@
 	l = (hint == NULL) ? list->front : hint;
 	prev = NULL;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) /* not in list, since sorted */
 			return prev;
 		if (!cmp) { /* found */
@@ -199,7 +201,7 @@
 	b = B->front;
 
 	while (b) {
-		hint = llist_sorted_remove(A, b->sha1, hint);
+		hint = llist_sorted_remove(A, b->oid, hint);
 		b = b->next;
 	}
 }
@@ -250,13 +252,14 @@
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
 	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->pack->index_data;
 	p2_base = p2->pack->index_data;
 	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
-	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
-	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->pack->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->pack->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->pack->num_objects * p1_step &&
 	       p2_off < p2->pack->num_objects * p2_step)
@@ -265,9 +268,11 @@
 		/* cmp ~ p1 - p2 */
 		if (cmp == 0) {
 			p1_hint = llist_sorted_remove(p1->unique_objects,
-					p1_base + p1_off, p1_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p1_hint);
 			p2_hint = llist_sorted_remove(p2->unique_objects,
-					p1_base + p1_off, p2_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p2_hint);
 			p1_off += p1_step;
 			p2_off += p2_step;
 			continue;
@@ -357,13 +362,14 @@
 	size_t ret = 0;
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->index_data;
 	p2_base = p2->index_data;
 	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
-	p1_step = (p1->index_version < 2) ? 24 : 20;
-	p2_step = (p2->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->num_objects * p1_step &&
 	       p2_off < p2->num_objects * p2_step)
@@ -497,7 +503,7 @@
 		l = pl->all_objects->front;
 		while (l) {
 			hint = llist_insert_sorted_unique(all_objects,
-							  l->sha1, hint);
+							  l->oid, hint);
 			l = l->next;
 		}
 		pl = pl->next;
@@ -556,9 +562,9 @@
 
 	base = p->index_data;
 	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
-	step = (p->index_version < 2) ? 24 : 20;
+	step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
 	while (off < p->num_objects * step) {
-		llist_insert_back(l.all_objects, base + off);
+		llist_insert_back(l.all_objects, (const struct object_id *)(base + off));
 		off += step;
 	}
 	/* this list will be pruned in cmp_two_packs later */
@@ -571,7 +577,7 @@
 
 static struct pack_list * add_pack_file(const char *filename)
 {
-	struct packed_git *p = packed_git;
+	struct packed_git *p = get_packed_git(the_repository);
 
 	if (strlen(filename) < 40)
 		die("Bad pack filename: %s", filename);
@@ -586,7 +592,7 @@
 
 static void load_all(void)
 {
-	struct packed_git *p = packed_git;
+	struct packed_git *p = get_packed_git(the_repository);
 
 	while (p) {
 		add_pack(p);
@@ -599,8 +605,8 @@
 	int i;
 	struct pack_list *min, *red, *pl;
 	struct llist *ignore;
-	unsigned char *sha1;
-	char buf[42]; /* 40 byte sha1 + \n + \0 */
+	struct object_id *oid;
+	char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(pack_redundant_usage);
@@ -629,8 +635,6 @@
 			break;
 	}
 
-	prepare_packed_git();
-
 	if (load_all_packs)
 		load_all();
 	else
@@ -650,10 +654,10 @@
 	llist_init(&ignore);
 	if (!isatty(0)) {
 		while (fgets(buf, sizeof(buf), stdin)) {
-			sha1 = xmalloc(20);
-			if (get_sha1_hex(buf, sha1))
-				die("Bad sha1 on stdin: %s", buf);
-			llist_insert_sorted_unique(ignore, sha1, NULL);
+			oid = xmalloc(sizeof(*oid));
+			if (get_oid_hex(buf, oid))
+				die("Bad object ID on stdin: %s", buf);
+			llist_insert_sorted_unique(ignore, oid, NULL);
 		}
 	}
 	llist_sorted_difference_inplace(all_objects, ignore);
diff --git a/builtin/pack-refs.c b/builtin/pack-refs.c
index b106a39..f335356 100644
--- a/builtin/pack-refs.c
+++ b/builtin/pack-refs.c
@@ -1,6 +1,7 @@
 #include "builtin.h"
 #include "parse-options.h"
 #include "refs.h"
+#include "repository.h"
 
 static char const * const pack_refs_usage[] = {
 	N_("git pack-refs [<options>]"),
@@ -17,5 +18,5 @@
 	};
 	if (parse_options(argc, argv, prefix, opts, pack_refs_usage, 0))
 		usage_with_options(pack_refs_usage, opts);
-	return refs_pack_refs(get_main_ref_store(), flags);
+	return refs_pack_refs(get_main_ref_store(the_repository), flags);
 }
diff --git a/builtin/prune-packed.c b/builtin/prune-packed.c
index 4192381..4ff525e 100644
--- a/builtin/prune-packed.c
+++ b/builtin/prune-packed.c
@@ -25,7 +25,7 @@
 {
 	int *opts = data;
 
-	if (!has_sha1_pack(oid->hash))
+	if (!has_object_pack(oid))
 		return 0;
 
 	if (*opts & PRUNE_PACKED_DRY_RUN)
diff --git a/builtin/prune.c b/builtin/prune.c
index 4394d01..518ffbe 100644
--- a/builtin/prune.c
+++ b/builtin/prune.c
@@ -50,7 +50,8 @@
 	if (st.st_mtime > expire)
 		return 0;
 	if (show_only || verbose) {
-		enum object_type type = sha1_object_info(oid->hash, NULL);
+		enum object_type type = oid_object_info(the_repository, oid,
+							NULL);
 		printf("%s %s\n", oid_to_hex(oid),
 		       (type > 0) ? type_name(type) : "unknown");
 	}
diff --git a/builtin/pull.c b/builtin/pull.c
index e32d6cd..49cc3be 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -9,12 +9,13 @@
 #include "config.h"
 #include "builtin.h"
 #include "parse-options.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "run-command.h"
 #include "sha1-array.h"
 #include "remote.h"
 #include "dir.h"
 #include "refs.h"
+#include "refspec.h"
 #include "revision.h"
 #include "submodule.h"
 #include "submodule-config.h"
@@ -27,14 +28,16 @@
 	REBASE_FALSE = 0,
 	REBASE_TRUE,
 	REBASE_PRESERVE,
+	REBASE_MERGES,
 	REBASE_INTERACTIVE
 };
 
 /**
  * Parses the value of --rebase. If value is a false value, returns
  * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
- * "preserve", returns REBASE_PRESERVE. If value is a invalid value, dies with
- * a fatal error if fatal is true, otherwise returns REBASE_INVALID.
+ * "merges", returns REBASE_MERGES. If value is "preserve", returns
+ * REBASE_PRESERVE. If value is a invalid value, dies with a fatal error if
+ * fatal is true, otherwise returns REBASE_INVALID.
  */
 static enum rebase_type parse_config_rebase(const char *key, const char *value,
 		int fatal)
@@ -47,6 +50,8 @@
 		return REBASE_TRUE;
 	else if (!strcmp(value, "preserve"))
 		return REBASE_PRESERVE;
+	else if (!strcmp(value, "merges"))
+		return REBASE_MERGES;
 	else if (!strcmp(value, "interactive"))
 		return REBASE_INTERACTIVE;
 
@@ -130,7 +135,7 @@
 	/* Options passed to git-merge or git-rebase */
 	OPT_GROUP(N_("Options related to merging")),
 	{ OPTION_CALLBACK, 'r', "rebase", &opt_rebase,
-	  "false|true|preserve|interactive",
+	  "false|true|merges|preserve|interactive",
 	  N_("incorporate changes by rebasing rather than merging"),
 	  PARSE_OPT_OPTARG, parse_opt_rebase },
 	OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
@@ -539,7 +544,7 @@
 		argv_array_push(&args, repo);
 		argv_array_pushv(&args, refspecs);
 	} else if (*refspecs)
-		die("BUG: refspecs without repo?");
+		BUG("refspecs without repo?");
 	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 	argv_array_clear(&args);
 	return ret;
@@ -668,19 +673,19 @@
 }
 
 /**
- * Derives the remote tracking branch from the remote and refspec.
+ * Derives the remote-tracking branch from the remote and refspec.
  *
  * FIXME: The current implementation assumes the default mapping of
  * refs/heads/<branch_name> to refs/remotes/<remote_name>/<branch_name>.
  */
 static const char *get_tracking_branch(const char *remote, const char *refspec)
 {
-	struct refspec *spec;
+	struct refspec_item spec;
 	const char *spec_src;
 	const char *merge_branch;
 
-	spec = parse_fetch_refspec(1, &refspec);
-	spec_src = spec->src;
+	refspec_item_init(&spec, refspec, REFSPEC_FETCH);
+	spec_src = spec.src;
 	if (!*spec_src || !strcmp(spec_src, "HEAD"))
 		spec_src = "HEAD";
 	else if (skip_prefix(spec_src, "heads/", &spec_src))
@@ -700,13 +705,13 @@
 	} else
 		merge_branch = NULL;
 
-	free_refspec(1, spec);
+	refspec_item_clear(&spec);
 	return merge_branch;
 }
 
 /**
  * Given the repo and refspecs, sets fork_point to the point at which the
- * current branch forked from its remote tracking branch. Returns 0 on success,
+ * current branch forked from its remote-tracking branch. Returns 0 on success,
  * -1 on failure.
  */
 static int get_rebase_fork_point(struct object_id *fork_point, const char *repo,
@@ -800,7 +805,9 @@
 	argv_push_verbosity(&args);
 
 	/* Options passed to git-rebase */
-	if (opt_rebase == REBASE_PRESERVE)
+	if (opt_rebase == REBASE_MERGES)
+		argv_array_push(&args, "--rebase-merges");
+	else if (opt_rebase == REBASE_PRESERVE)
 		argv_array_push(&args, "--preserve-merges");
 	else if (opt_rebase == REBASE_INTERACTIVE)
 		argv_array_push(&args, "--interactive");
diff --git a/builtin/push.c b/builtin/push.c
index 013c20d..9cd8e8c 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -4,6 +4,7 @@
 #include "cache.h"
 #include "config.h"
 #include "refs.h"
+#include "refspec.h"
 #include "run-command.h"
 #include "builtin.h"
 #include "remote.h"
@@ -12,12 +13,40 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "send-pack.h"
+#include "color.h"
 
 static const char * const push_usage[] = {
 	N_("git push [<options>] [<repository> [<refspec>...]]"),
 	NULL,
 };
 
+static int push_use_color = -1;
+static char push_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_RED,	/* ERROR */
+};
+
+enum color_push {
+	PUSH_COLOR_RESET = 0,
+	PUSH_COLOR_ERROR = 1
+};
+
+static int parse_push_color_slot(const char *slot)
+{
+	if (!strcasecmp(slot, "reset"))
+		return PUSH_COLOR_RESET;
+	if (!strcasecmp(slot, "error"))
+		return PUSH_COLOR_ERROR;
+	return -1;
+}
+
+static const char *push_get_color(enum color_push ix)
+{
+	if (want_color_stderr(push_use_color))
+		return push_colors[ix];
+	return "";
+}
+
 static int thin = 1;
 static int deleterefs;
 static const char *receivepack;
@@ -28,19 +57,10 @@
 
 static struct push_cas_option cas;
 
-static const char **refspec;
-static int refspec_nr;
-static int refspec_alloc;
+static struct refspec rs = REFSPEC_INIT_PUSH;
 
 static struct string_list push_options_config = STRING_LIST_INIT_DUP;
 
-static void add_refspec(const char *ref)
-{
-	refspec_nr++;
-	ALLOC_GROW(refspec, refspec_nr, refspec_alloc);
-	refspec[refspec_nr-1] = ref;
-}
-
 static const char *map_refspec(const char *ref,
 			       struct remote *remote, struct ref *local_refs)
 {
@@ -50,12 +70,11 @@
 	if (count_refspec_match(ref, local_refs, &matched) != 1)
 		return ref;
 
-	if (remote->push) {
-		struct refspec query;
-		memset(&query, 0, sizeof(struct refspec));
+	if (remote->push.nr) {
+		struct refspec_item query;
+		memset(&query, 0, sizeof(struct refspec_item));
 		query.src = matched->name;
-		if (!query_refspecs(remote->push, remote->push_refspec_nr, &query) &&
-		    query.dst) {
+		if (!query_refspecs(&remote->push, &query) && query.dst) {
 			struct strbuf buf = STRBUF_INIT;
 			strbuf_addf(&buf, "%s%s:%s",
 				    query.force ? "+" : "",
@@ -110,7 +129,7 @@
 			}
 			ref = map_refspec(ref, remote, local_refs);
 		}
-		add_refspec(ref);
+		refspec_append(&rs, ref);
 	}
 }
 
@@ -198,7 +217,7 @@
 	}
 
 	strbuf_addf(&refspec, "%s:%s", branch->refname, branch->merge[0]->src);
-	add_refspec(refspec.buf);
+	refspec_append(&rs, refspec.buf);
 }
 
 static void setup_push_current(struct remote *remote, struct branch *branch)
@@ -208,7 +227,7 @@
 	if (!branch)
 		die(_(message_detached_head_die), remote->name);
 	strbuf_addf(&refspec, "%s:%s", branch->refname, branch->refname);
-	add_refspec(refspec.buf);
+	refspec_append(&rs, refspec.buf);
 }
 
 static int is_workflow_triangular(struct remote *remote)
@@ -225,7 +244,7 @@
 	switch (push_default) {
 	default:
 	case PUSH_DEFAULT_MATCHING:
-		add_refspec(":");
+		refspec_append(&rs, ":");
 		break;
 
 	case PUSH_DEFAULT_UNSPECIFIED:
@@ -313,7 +332,8 @@
 	advise(_(message_advice_ref_needs_force));
 }
 
-static int push_with_options(struct transport *transport, int flags)
+static int push_with_options(struct transport *transport, struct refspec *rs,
+			     int flags)
 {
 	int err;
 	unsigned int reject_reasons;
@@ -335,10 +355,12 @@
 
 	if (verbosity > 0)
 		fprintf(stderr, _("Pushing to %s\n"), transport->url);
-	err = transport_push(transport, refspec_nr, refspec, flags,
-			     &reject_reasons);
-	if (err != 0)
+	err = transport_push(transport, rs, flags, &reject_reasons);
+	if (err != 0) {
+		fprintf(stderr, "%s", push_get_color(PUSH_COLOR_ERROR));
 		error(_("failed to push some refs to '%s'"), transport->url);
+		fprintf(stderr, "%s", push_get_color(PUSH_COLOR_RESET));
+	}
 
 	err |= transport_disconnect(transport);
 	if (!err)
@@ -366,6 +388,7 @@
 	struct remote *remote = pushremote_get(repo);
 	const char **url;
 	int url_nr;
+	struct refspec *push_refspec = &rs;
 
 	if (!remote) {
 		if (repo)
@@ -386,27 +409,9 @@
 	if (push_options->nr)
 		flags |= TRANSPORT_PUSH_OPTIONS;
 
-	if ((flags & TRANSPORT_PUSH_ALL) && refspec) {
-		if (!strcmp(*refspec, "refs/tags/*"))
-			return error(_("--all and --tags are incompatible"));
-		return error(_("--all can't be combined with refspecs"));
-	}
-
-	if ((flags & TRANSPORT_PUSH_MIRROR) && refspec) {
-		if (!strcmp(*refspec, "refs/tags/*"))
-			return error(_("--mirror and --tags are incompatible"));
-		return error(_("--mirror can't be combined with refspecs"));
-	}
-
-	if ((flags & (TRANSPORT_PUSH_ALL|TRANSPORT_PUSH_MIRROR)) ==
-				(TRANSPORT_PUSH_ALL|TRANSPORT_PUSH_MIRROR)) {
-		return error(_("--all and --mirror are incompatible"));
-	}
-
-	if (!refspec && !(flags & TRANSPORT_PUSH_ALL)) {
-		if (remote->push_refspec_nr) {
-			refspec = remote->push_refspec;
-			refspec_nr = remote->push_refspec_nr;
+	if (!push_refspec->nr && !(flags & TRANSPORT_PUSH_ALL)) {
+		if (remote->push.nr) {
+			push_refspec = &remote->push;
 		} else if (!(flags & TRANSPORT_PUSH_MIRROR))
 			setup_default_push_refspecs(remote);
 	}
@@ -418,7 +423,7 @@
 				transport_get(remote, url[i]);
 			if (flags & TRANSPORT_PUSH_OPTIONS)
 				transport->push_options = push_options;
-			if (push_with_options(transport, flags))
+			if (push_with_options(transport, push_refspec, flags))
 				errs++;
 		}
 	} else {
@@ -426,7 +431,7 @@
 			transport_get(remote, NULL);
 		if (flags & TRANSPORT_PUSH_OPTIONS)
 			transport->push_options = push_options;
-		if (push_with_options(transport, flags))
+		if (push_with_options(transport, push_refspec, flags))
 			errs++;
 	}
 	return !!errs;
@@ -467,6 +472,7 @@
 
 static int git_push_config(const char *k, const char *v, void *cb)
 {
+	const char *slot_name;
 	int *flags = cb;
 	int status;
 
@@ -514,6 +520,16 @@
 			else
 				string_list_append(&push_options_config, v);
 		return 0;
+	} else if (!strcmp(k, "color.push")) {
+		push_use_color = git_config_colorbool(k, v);
+		return 0;
+	} else if (skip_prefix(k, "color.push.", &slot_name)) {
+		int slot = parse_push_color_slot(slot_name);
+		if (slot < 0)
+			return 0;
+		if (!v)
+			return config_error_nonbool(k);
+		return color_parse(v, push_colors[slot]);
 	}
 
 	return git_default_config(k, v, NULL);
@@ -583,6 +599,20 @@
 		die(_("--delete is incompatible with --all, --mirror and --tags"));
 	if (deleterefs && argc < 2)
 		die(_("--delete doesn't make sense without any refs"));
+	if (flags & TRANSPORT_PUSH_ALL) {
+		if (tags)
+			die(_("--all and --tags are incompatible"));
+		if (argc >= 2)
+			die(_("--all can't be combined with refspecs"));
+	}
+	if (flags & TRANSPORT_PUSH_MIRROR) {
+		if (tags)
+			die(_("--mirror and --tags are incompatible"));
+		if (argc >= 2)
+			die(_("--mirror can't be combined with refspecs"));
+	}
+	if ((flags & TRANSPORT_PUSH_ALL) && (flags & TRANSPORT_PUSH_MIRROR))
+		die(_("--all and --mirror are incompatible"));
 
 	if (recurse_submodules == RECURSE_SUBMODULES_CHECK)
 		flags |= TRANSPORT_RECURSE_SUBMODULES_CHECK;
@@ -592,7 +622,7 @@
 		flags |= TRANSPORT_RECURSE_SUBMODULES_ONLY;
 
 	if (tags)
-		add_refspec("refs/tags/*");
+		refspec_append(&rs, "refs/tags/*");
 
 	if (argc > 0) {
 		repo = argv[0];
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index bf87a27..ebc43eb 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -107,8 +107,6 @@
 	return git_default_config(var, value, cb);
 }
 
-static struct lock_file lock_file;
-
 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 {
 	int i, stage = 0;
@@ -116,6 +114,7 @@
 	struct tree_desc t[MAX_UNPACK_TREES];
 	struct unpack_trees_options opts;
 	int prefix_set = 0;
+	struct lock_file lock_file = LOCK_INIT;
 	const struct option read_tree_options[] = {
 		{ OPTION_CALLBACK, 0, "index-output", NULL, N_("file"),
 		  N_("write resulting index to <file>"),
diff --git a/builtin/rebase--helper.c b/builtin/rebase--helper.c
index ad07470..f7c2a5f 100644
--- a/builtin/rebase--helper.c
+++ b/builtin/rebase--helper.c
@@ -12,8 +12,8 @@
 int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts = REPLAY_OPTS_INIT;
-	unsigned flags = 0, keep_empty = 0;
-	int abbreviate_commands = 0;
+	unsigned flags = 0, keep_empty = 0, rebase_merges = 0;
+	int abbreviate_commands = 0, rebase_cousins = -1;
 	enum {
 		CONTINUE = 1, ABORT, MAKE_SCRIPT, SHORTEN_OIDS, EXPAND_OIDS,
 		CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH,
@@ -24,6 +24,9 @@
 		OPT_BOOL(0, "keep-empty", &keep_empty, N_("keep empty commits")),
 		OPT_BOOL(0, "allow-empty-message", &opts.allow_empty_message,
 			N_("allow commits with empty messages")),
+		OPT_BOOL(0, "rebase-merges", &rebase_merges, N_("rebase merge commits")),
+		OPT_BOOL(0, "rebase-cousins", &rebase_cousins,
+			 N_("keep original branch points of cousins")),
 		OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
 				CONTINUE),
 		OPT_CMDMODE(0, "abort", &command, N_("abort rebase"),
@@ -57,8 +60,14 @@
 
 	flags |= keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
 	flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
+	flags |= rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
+	flags |= rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
 	flags |= command == SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
 
+	if (rebase_cousins >= 0 && !rebase_merges)
+		warning(_("--[no-]rebase-cousins has no effect without "
+			  "--rebase-merges"));
+
 	if (command == CONTINUE && argc == 1)
 		return !!sequencer_continue(&opts);
 	if (command == ABORT && argc == 1)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 75e7f18..68d36e0 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "repository.h"
 #include "config.h"
 #include "lockfile.h"
 #include "pack.h"
@@ -6,7 +7,7 @@
 #include "pkt-line.h"
 #include "sideband.h"
 #include "run-command.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "commit.h"
 #include "object.h"
 #include "remote.h"
@@ -453,21 +454,21 @@
 	/* RFC 2104 2. (6) & (7) */
 	git_SHA1_Init(&ctx);
 	git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
-	git_SHA1_Update(&ctx, out, 20);
+	git_SHA1_Update(&ctx, out, GIT_SHA1_RAWSZ);
 	git_SHA1_Final(out, &ctx);
 }
 
 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
 {
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
+	unsigned char sha1[GIT_SHA1_RAWSZ];
 
 	strbuf_addf(&buf, "%s:%"PRItime, path, stamp);
 	hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
 	strbuf_release(&buf);
 
 	/* RFC 2104 5. HMAC-SHA1-80 */
-	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));
+	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, GIT_SHA1_HEXSZ, sha1_to_hex(sha1));
 	return strbuf_detach(&buf, NULL);
 }
 
@@ -875,7 +876,7 @@
 static int command_singleton_iterator(void *cb_data, struct object_id *oid);
 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 {
-	static struct lock_file shallow_lock;
+	struct lock_file shallow_lock = LOCK_INIT;
 	struct oid_array extra = OID_ARRAY_INIT;
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	uint32_t mask = 1 << (cmd->index % 32);
@@ -967,7 +968,7 @@
 		return "Working directory has unstaged changes";
 
 	/* diff-index with either HEAD or an empty tree */
-	diff_index[4] = head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX;
+	diff_index[4] = head_has_history() ? "HEAD" : empty_tree_oid_hex();
 
 	child_process_init(&child);
 	child.argv = diff_index;
@@ -1242,11 +1243,11 @@
 	rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 		 " its target '%s' (%s..%s)",
 		 cmd->ref_name,
-		 find_unique_abbrev(cmd->old_oid.hash, DEFAULT_ABBREV),
-		 find_unique_abbrev(cmd->new_oid.hash, DEFAULT_ABBREV),
+		 find_unique_abbrev(&cmd->old_oid, DEFAULT_ABBREV),
+		 find_unique_abbrev(&cmd->new_oid, DEFAULT_ABBREV),
 		 dst_cmd->ref_name,
-		 find_unique_abbrev(dst_cmd->old_oid.hash, DEFAULT_ABBREV),
-		 find_unique_abbrev(dst_cmd->new_oid.hash, DEFAULT_ABBREV));
+		 find_unique_abbrev(&dst_cmd->old_oid, DEFAULT_ABBREV),
+		 find_unique_abbrev(&dst_cmd->new_oid, DEFAULT_ABBREV));
 
 	cmd->error_string = dst_cmd->error_string =
 		"inconsistent aliased update";
@@ -1377,7 +1378,7 @@
 		}
 	}
 	if (!checked_connectivity)
-		die("BUG: connectivity check skipped???");
+		BUG("connectivity check skipped???");
 }
 
 static void execute_commands_non_atomic(struct command *commands,
@@ -1778,7 +1779,7 @@
 		status = finish_command(&child);
 		if (status)
 			return "index-pack abnormal exit";
-		reprepare_packed_git();
+		reprepare_packed_git(the_repository);
 	}
 	return NULL;
 }
@@ -1964,6 +1965,12 @@
 		unpack_limit = receive_unpack_limit;
 
 	switch (determine_protocol_version_server()) {
+	case protocol_v2:
+		/*
+		 * push support for protocol v2 has not been implemented yet,
+		 * so ignore the request to use v2 and fallback to using v0.
+		 */
+		break;
 	case protocol_v1:
 		/*
 		 * v1 is just the original protocol with a version string,
@@ -2027,7 +2034,7 @@
 			proc.git_cmd = 1;
 			proc.argv = argv_gc_auto;
 
-			close_all_packs();
+			close_all_packs(the_repository->objects);
 			if (!start_command(&proc)) {
 				if (use_sideband)
 					copy_to_sideband(proc.err, -1, NULL);
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 4719a53..a48984d 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -75,7 +75,7 @@
 	if (!tree->buffer) {
 		enum object_type type;
 		unsigned long size;
-		void *data = read_sha1_file(oid->hash, &type, &size);
+		void *data = read_object_file(oid, &type, &size);
 		if (!data) {
 			tree->object.flags |= INCOMPLETE;
 			return 0;
@@ -154,7 +154,7 @@
 		for (i = 0; i < found.nr; i++) {
 			struct commit *c =
 				(struct commit *)found.objects[i].item;
-			if (!tree_is_complete(&c->tree->object.oid)) {
+			if (!tree_is_complete(get_commit_tree_oid(c))) {
 				is_incomplete = 1;
 				c->object.flags |= INCOMPLETE;
 			}
diff --git a/builtin/remote.c b/builtin/remote.c
index 805ffc0..1a82d85 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -7,6 +7,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 #include "refs.h"
+#include "refspec.h"
 #include "argv-array.h"
 
 static const char * const builtin_remote_usage[] = {
@@ -245,7 +246,9 @@
 struct branch_info {
 	char *remote_name;
 	struct string_list merge;
-	enum { NO_REBASE, NORMAL_REBASE, INTERACTIVE_REBASE } rebase;
+	enum {
+		NO_REBASE, NORMAL_REBASE, INTERACTIVE_REBASE, REBASE_MERGES
+	} rebase;
 };
 
 static struct string_list branch_list = STRING_LIST_INIT_NODUP;
@@ -306,6 +309,8 @@
 				info->rebase = v;
 			else if (!strcmp(value, "preserve"))
 				info->rebase = NORMAL_REBASE;
+			else if (!strcmp(value, "merges"))
+				info->rebase = REBASE_MERGES;
 			else if (!strcmp(value, "interactive"))
 				info->rebase = INTERACTIVE_REBASE;
 		}
@@ -332,10 +337,10 @@
 	struct ref *ref, *stale_refs;
 	int i;
 
-	for (i = 0; i < states->remote->fetch_refspec_nr; i++)
-		if (get_fetch_map(remote_refs, states->remote->fetch + i, &tail, 1))
+	for (i = 0; i < states->remote->fetch.nr; i++)
+		if (get_fetch_map(remote_refs, &states->remote->fetch.items[i], &tail, 1))
 			die(_("Could not get fetch map for refspec %s"),
-				states->remote->fetch_refspec[i]);
+				states->remote->fetch.raw[i]);
 
 	states->new_refs.strdup_strings = 1;
 	states->tracked.strdup_strings = 1;
@@ -346,8 +351,7 @@
 		else
 			string_list_append(&states->tracked, abbrev_branch(ref->name));
 	}
-	stale_refs = get_stale_heads(states->remote->fetch,
-				     states->remote->fetch_refspec_nr, fetch_map);
+	stale_refs = get_stale_heads(&states->remote->fetch, fetch_map);
 	for (ref = stale_refs; ref; ref = ref->next) {
 		struct string_list_item *item =
 			string_list_append(&states->stale, abbrev_branch(ref->name));
@@ -387,8 +391,7 @@
 	local_refs = get_local_heads();
 	push_map = copy_ref_list(remote_refs);
 
-	match_push_refs(local_refs, &push_map, remote->push_refspec_nr,
-			remote->push_refspec, MATCH_REFS_NONE);
+	match_push_refs(local_refs, &push_map, &remote->push, MATCH_REFS_NONE);
 
 	states->push.strdup_strings = 1;
 	for (ref = push_map; ref; ref = ref->next) {
@@ -434,14 +437,14 @@
 		return 0;
 
 	states->push.strdup_strings = 1;
-	if (!remote->push_refspec_nr) {
+	if (!remote->push.nr) {
 		item = string_list_append(&states->push, _("(matching)"));
 		info = item->util = xcalloc(1, sizeof(struct push_info));
 		info->status = PUSH_STATUS_NOTQUERIED;
 		info->dest = xstrdup(item->string);
 	}
-	for (i = 0; i < remote->push_refspec_nr; i++) {
-		struct refspec *spec = remote->push + i;
+	for (i = 0; i < remote->push.nr; i++) {
+		const struct refspec_item *spec = &remote->push.items[i];
 		if (spec->matching)
 			item = string_list_append(&states->push, _("(matching)"));
 		else if (strlen(spec->src))
@@ -461,7 +464,7 @@
 {
 	struct ref *ref, *matches;
 	struct ref *fetch_map = NULL, **fetch_map_tail = &fetch_map;
-	struct refspec refspec;
+	struct refspec_item refspec;
 
 	refspec.force = 0;
 	refspec.pattern = 1;
@@ -514,7 +517,7 @@
 	const struct object_id *oid, int flags, void *cb_data)
 {
 	struct branches_for_remote *branches = cb_data;
-	struct refspec refspec;
+	struct refspec_item refspec;
 	struct known_remote *kr;
 
 	memset(&refspec, 0, sizeof(refspec));
@@ -585,12 +588,12 @@
 		git_config_set_multivar(buf.buf, remote->url[i], "^$", 0);
 	strbuf_reset(&buf);
 	strbuf_addf(&buf, "remote.%s.push", remote->name);
-	for (i = 0; i < remote->push_refspec_nr; i++)
-		git_config_set_multivar(buf.buf, remote->push_refspec[i], "^$", 0);
+	for (i = 0; i < remote->push.raw_nr; i++)
+		git_config_set_multivar(buf.buf, remote->push.raw[i], "^$", 0);
 	strbuf_reset(&buf);
 	strbuf_addf(&buf, "remote.%s.fetch", remote->name);
-	for (i = 0; i < remote->fetch_refspec_nr; i++)
-		git_config_set_multivar(buf.buf, remote->fetch_refspec[i], "^$", 0);
+	for (i = 0; i < remote->fetch.raw_nr; i++)
+		git_config_set_multivar(buf.buf, remote->fetch.raw[i], "^$", 0);
 	if (remote->origin == REMOTE_REMOTES)
 		unlink_or_warn(git_path("remotes/%s", remote->name));
 	else if (remote->origin == REMOTE_BRANCHES)
@@ -645,11 +648,11 @@
 	strbuf_addf(&buf, "remote.%s.fetch", rename.new_name);
 	git_config_set_multivar(buf.buf, NULL, NULL, 1);
 	strbuf_addf(&old_remote_context, ":refs/remotes/%s/", rename.old_name);
-	for (i = 0; i < oldremote->fetch_refspec_nr; i++) {
+	for (i = 0; i < oldremote->fetch.raw_nr; i++) {
 		char *ptr;
 
 		strbuf_reset(&buf2);
-		strbuf_addstr(&buf2, oldremote->fetch_refspec[i]);
+		strbuf_addstr(&buf2, oldremote->fetch.raw[i]);
 		ptr = strstr(buf2.buf, old_remote_context.buf);
 		if (ptr) {
 			refspec_updated = 1;
@@ -833,7 +836,7 @@
 	const struct object_id *oid, int flags, void *cb_data)
 {
 	struct ref_states *states = cb_data;
-	struct refspec refspec;
+	struct refspec_item refspec;
 
 	if (flags & REF_ISSYMREF)
 		return 0;
@@ -862,7 +865,7 @@
 	if (query) {
 		transport = transport_get(states->remote, states->remote->url_nr > 0 ?
 			states->remote->url[0] : NULL);
-		remote_refs = transport_get_remote_refs(transport);
+		remote_refs = transport_get_remote_refs(transport, NULL);
 		transport_disconnect(transport);
 
 		states->queried = 1;
@@ -963,9 +966,15 @@
 
 	printf("    %-*s ", show_info->width, item->string);
 	if (branch_info->rebase) {
-		printf_ln(branch_info->rebase == INTERACTIVE_REBASE
-			  ? _("rebases interactively onto remote %s")
-			  : _("rebases onto remote %s"), merge->items[0].string);
+		const char *msg;
+		if (branch_info->rebase == INTERACTIVE_REBASE)
+			msg = _("rebases interactively onto remote %s");
+		else if (branch_info->rebase == REBASE_MERGES)
+			msg = _("rebases interactively (with merges) onto "
+				"remote %s");
+		else
+			msg = _("rebases onto remote %s");
+		printf_ln(msg, merge->items[0].string);
 		return 0;
 	} else if (show_info->any_rebase) {
 		printf_ln(_(" merges with remote %s"), merge->items[0].string);
diff --git a/builtin/repack.c b/builtin/repack.c
index 7bdb401..6c636e1 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -86,7 +86,8 @@
  * have a corresponding .keep or .promisor file. These packs are not to
  * be kept if we are going to pack everything into one file.
  */
-static void get_non_kept_pack_filenames(struct string_list *fname_list)
+static void get_non_kept_pack_filenames(struct string_list *fname_list,
+					const struct string_list *extra_keep)
 {
 	DIR *dir;
 	struct dirent *e;
@@ -97,6 +98,14 @@
 
 	while ((e = readdir(dir)) != NULL) {
 		size_t len;
+		int i;
+
+		for (i = 0; i < extra_keep->nr; i++)
+			if (!fspathcmp(e->d_name, extra_keep->items[i].string))
+				break;
+		if (extra_keep->nr > 0 && i < extra_keep->nr)
+			continue;
+
 		if (!strip_suffix(e->d_name, ".pack", &len))
 			continue;
 
@@ -148,7 +157,7 @@
 	struct string_list rollback = STRING_LIST_INIT_NODUP;
 	struct string_list existing_packs = STRING_LIST_INIT_DUP;
 	struct strbuf line = STRBUF_INIT;
-	int ext, ret, failed;
+	int i, ext, ret, failed;
 	FILE *out;
 
 	/* variables to be filled by option parsing */
@@ -160,6 +169,7 @@
 	const char *depth = NULL;
 	const char *threads = NULL;
 	const char *max_pack_size = NULL;
+	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
 	int no_reuse_delta = 0, no_reuse_object = 0;
 	int no_update_server_info = 0;
 	int quiet = 0;
@@ -200,6 +210,8 @@
 				N_("maximum size of each packfile")),
 		OPT_BOOL(0, "pack-kept-objects", &pack_kept_objects,
 				N_("repack objects in packs marked with .keep")),
+		OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
+				N_("do not repack this pack")),
 		OPT_END()
 	};
 
@@ -230,6 +242,9 @@
 	argv_array_push(&cmd.args, "--keep-true-parents");
 	if (!pack_kept_objects)
 		argv_array_push(&cmd.args, "--honor-pack-keep");
+	for (i = 0; i < keep_pack_list.nr; i++)
+		argv_array_pushf(&cmd.args, "--keep-pack=%s",
+				 keep_pack_list.items[i].string);
 	argv_array_push(&cmd.args, "--non-empty");
 	argv_array_push(&cmd.args, "--all");
 	argv_array_push(&cmd.args, "--reflog");
@@ -254,7 +269,7 @@
 		argv_array_push(&cmd.args, "--write-bitmap-index");
 
 	if (pack_everything & ALL_INTO_ONE) {
-		get_non_kept_pack_filenames(&existing_packs);
+		get_non_kept_pack_filenames(&existing_packs, &keep_pack_list);
 
 		if (existing_packs.nr && delete_redundant) {
 			if (unpack_unreachable) {
diff --git a/builtin/replace.c b/builtin/replace.c
index 482f120..6da2411 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -14,12 +14,15 @@
 #include "refs.h"
 #include "parse-options.h"
 #include "run-command.h"
+#include "object-store.h"
+#include "repository.h"
 #include "tag.h"
 
 static const char * const git_replace_usage[] = {
 	N_("git replace [-f] <object> <replacement>"),
 	N_("git replace [-f] --edit <object>"),
 	N_("git replace [-f] --graft <commit> [<parent>...]"),
+	N_("git replace [-f] --convert-graft-file"),
 	N_("git replace -d <object>..."),
 	N_("git replace [--format=<format>] [-l [<pattern>]]"),
 	NULL
@@ -53,8 +56,9 @@
 			if (get_oid(refname, &object))
 				return error("Failed to resolve '%s' as a valid ref.", refname);
 
-			obj_type = sha1_object_info(object.hash, NULL);
-			repl_type = sha1_object_info(oid->hash, NULL);
+			obj_type = oid_object_info(the_repository, &object,
+						   NULL);
+			repl_type = oid_object_info(the_repository, oid, NULL);
 
 			printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
 			       oid_to_hex(oid), type_name(repl_type));
@@ -79,11 +83,11 @@
 	else if (!strcmp(format, "long"))
 		data.format = REPLACE_FORMAT_LONG;
 	else
-		die("invalid replace format '%s'\n"
-		    "valid formats are 'short', 'medium' and 'long'\n",
-		    format);
+		return error("invalid replace format '%s'\n"
+			     "valid formats are 'short', 'medium' and 'long'\n",
+			     format);
 
-	for_each_replace_ref(show_reference, (void *)&data);
+	for_each_replace_ref(the_repository, show_reference, (void *)&data);
 
 	return 0;
 }
@@ -134,7 +138,7 @@
 	return 0;
 }
 
-static void check_ref_valid(struct object_id *object,
+static int check_ref_valid(struct object_id *object,
 			    struct object_id *prev,
 			    struct strbuf *ref,
 			    int force)
@@ -142,12 +146,13 @@
 	strbuf_reset(ref);
 	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 	if (check_refname_format(ref->buf, 0))
-		die("'%s' is not a valid ref name.", ref->buf);
+		return error("'%s' is not a valid ref name.", ref->buf);
 
 	if (read_ref(ref->buf, prev))
 		oidclr(prev);
 	else if (!force)
-		die("replace ref '%s' already exists", ref->buf);
+		return error("replace ref '%s' already exists", ref->buf);
+	return 0;
 }
 
 static int replace_object_oid(const char *object_ref,
@@ -161,28 +166,33 @@
 	struct strbuf ref = STRBUF_INIT;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
+	int res = 0;
 
-	obj_type = sha1_object_info(object->hash, NULL);
-	repl_type = sha1_object_info(repl->hash, NULL);
+	obj_type = oid_object_info(the_repository, object, NULL);
+	repl_type = oid_object_info(the_repository, repl, NULL);
 	if (!force && obj_type != repl_type)
-		die("Objects must be of the same type.\n"
-		    "'%s' points to a replaced object of type '%s'\n"
-		    "while '%s' points to a replacement object of type '%s'.",
-		    object_ref, type_name(obj_type),
-		    replace_ref, type_name(repl_type));
+		return error("Objects must be of the same type.\n"
+			     "'%s' points to a replaced object of type '%s'\n"
+			     "while '%s' points to a replacement object of "
+			     "type '%s'.",
+			     object_ref, type_name(obj_type),
+			     replace_ref, type_name(repl_type));
 
-	check_ref_valid(object, &prev, &ref, force);
+	if (check_ref_valid(object, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref.buf, repl, &prev,
 				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
-		die("%s", err.buf);
+		res = error("%s", err.buf);
 
 	ref_transaction_free(transaction);
 	strbuf_release(&ref);
-	return 0;
+	return res;
 }
 
 static int replace_object(const char *object_ref, const char *replace_ref, int force)
@@ -190,9 +200,11 @@
 	struct object_id object, repl;
 
 	if (get_oid(object_ref, &object))
-		die("Failed to resolve '%s' as a valid ref.", object_ref);
+		return error("Failed to resolve '%s' as a valid ref.",
+			     object_ref);
 	if (get_oid(replace_ref, &repl))
-		die("Failed to resolve '%s' as a valid ref.", replace_ref);
+		return error("Failed to resolve '%s' as a valid ref.",
+			     replace_ref);
 
 	return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 }
@@ -202,7 +214,7 @@
  * If "raw" is true, then the object's raw contents are printed according to
  * "type". Otherwise, we pretty-print the contents for human editing.
  */
-static void export_object(const struct object_id *oid, enum object_type type,
+static int export_object(const struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
@@ -210,7 +222,7 @@
 
 	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 	if (fd < 0)
-		die_errno("unable to open %s for writing", filename);
+		return error_errno("unable to open %s for writing", filename);
 
 	argv_array_push(&cmd.args, "--no-replace-objects");
 	argv_array_push(&cmd.args, "cat-file");
@@ -223,7 +235,8 @@
 	cmd.out = fd;
 
 	if (run_command(&cmd))
-		die("cat-file reported failure");
+		return error("cat-file reported failure");
+	return 0;
 }
 
 /*
@@ -231,14 +244,14 @@
  * interpreting it as "type", and writing the result to the object database.
  * The sha1 of the written object is returned via sha1.
  */
-static void import_object(struct object_id *oid, enum object_type type,
+static int import_object(struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	int fd;
 
 	fd = open(filename, O_RDONLY);
 	if (fd < 0)
-		die_errno("unable to open %s for reading", filename);
+		return error_errno("unable to open %s for reading", filename);
 
 	if (!raw && type == OBJ_TREE) {
 		const char *argv[] = { "mktree", NULL };
@@ -250,27 +263,40 @@
 		cmd.in = fd;
 		cmd.out = -1;
 
-		if (start_command(&cmd))
-			die("unable to spawn mktree");
+		if (start_command(&cmd)) {
+			close(fd);
+			return error("unable to spawn mktree");
+		}
 
-		if (strbuf_read(&result, cmd.out, 41) < 0)
-			die_errno("unable to read from mktree");
+		if (strbuf_read(&result, cmd.out, 41) < 0) {
+			error_errno("unable to read from mktree");
+			close(fd);
+			close(cmd.out);
+			return -1;
+		}
 		close(cmd.out);
 
-		if (finish_command(&cmd))
-			die("mktree reported failure");
-		if (get_oid_hex(result.buf, oid) < 0)
-			die("mktree did not return an object name");
+		if (finish_command(&cmd)) {
+			strbuf_release(&result);
+			return error("mktree reported failure");
+		}
+		if (get_oid_hex(result.buf, oid) < 0) {
+			strbuf_release(&result);
+			return error("mktree did not return an object name");
+		}
 
 		strbuf_release(&result);
 	} else {
 		struct stat st;
 		int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 
-		if (fstat(fd, &st) < 0)
-			die_errno("unable to fstat %s", filename);
+		if (fstat(fd, &st) < 0) {
+			error_errno("unable to fstat %s", filename);
+			close(fd);
+			return -1;
+		}
 		if (index_fd(oid, fd, &st, type, NULL, flags) < 0)
-			die("unable to write object to database");
+			return error("unable to write object to database");
 		/* index_fd close()s fd for us */
 	}
 
@@ -278,30 +304,43 @@
 	 * No need to close(fd) here; both run-command and index-fd
 	 * will have done it for us.
 	 */
+	return 0;
 }
 
 static int edit_and_replace(const char *object_ref, int force, int raw)
 {
-	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
+	char *tmpfile;
 	enum object_type type;
 	struct object_id old_oid, new_oid, prev;
 	struct strbuf ref = STRBUF_INIT;
 
 	if (get_oid(object_ref, &old_oid) < 0)
-		die("Not a valid object name: '%s'", object_ref);
+		return error("Not a valid object name: '%s'", object_ref);
 
-	type = sha1_object_info(old_oid.hash, NULL);
+	type = oid_object_info(the_repository, &old_oid, NULL);
 	if (type < 0)
-		die("unable to get object type for %s", oid_to_hex(&old_oid));
+		return error("unable to get object type for %s",
+			     oid_to_hex(&old_oid));
 
-	check_ref_valid(&old_oid, &prev, &ref, force);
+	if (check_ref_valid(&old_oid, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
 	strbuf_release(&ref);
 
-	export_object(&old_oid, type, raw, tmpfile);
-	if (launch_editor(tmpfile, NULL, NULL) < 0)
-		die("editing object file failed");
-	import_object(&new_oid, type, raw, tmpfile);
-
+	tmpfile = git_pathdup("REPLACE_EDITOBJ");
+	if (export_object(&old_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
+	if (launch_editor(tmpfile, NULL, NULL) < 0) {
+		free(tmpfile);
+		return error("editing object file failed");
+	}
+	if (import_object(&new_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
 	free(tmpfile);
 
 	if (!oidcmp(&old_oid, &new_oid))
@@ -310,7 +349,7 @@
 	return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 }
 
-static void replace_parents(struct strbuf *buf, int argc, const char **argv)
+static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 {
 	struct strbuf new_parents = STRBUF_INIT;
 	const char *parent_start, *parent_end;
@@ -327,9 +366,15 @@
 	/* prepare new parents */
 	for (i = 0; i < argc; i++) {
 		struct object_id oid;
-		if (get_oid(argv[i], &oid) < 0)
-			die(_("Not a valid object name: '%s'"), argv[i]);
-		lookup_commit_or_die(&oid, argv[i]);
+		if (get_oid(argv[i], &oid) < 0) {
+			strbuf_release(&new_parents);
+			return error(_("Not a valid object name: '%s'"),
+				     argv[i]);
+		}
+		if (!lookup_commit_reference(&oid)) {
+			strbuf_release(&new_parents);
+			return error(_("could not parse %s"), argv[i]);
+		}
 		strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
 	}
 
@@ -338,6 +383,7 @@
 		      new_parents.buf, new_parents.len);
 
 	strbuf_release(&new_parents);
+	return 0;
 }
 
 struct check_mergetag_data {
@@ -345,7 +391,7 @@
 	const char **argv;
 };
 
-static void check_one_mergetag(struct commit *commit,
+static int check_one_mergetag(struct commit *commit,
 			       struct commit_extra_header *extra,
 			       void *data)
 {
@@ -358,33 +404,35 @@
 	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
 	tag = lookup_tag(&tag_oid);
 	if (!tag)
-		die(_("bad mergetag in commit '%s'"), ref);
+		return error(_("bad mergetag in commit '%s'"), ref);
 	if (parse_tag_buffer(tag, extra->value, extra->len))
-		die(_("malformed mergetag in commit '%s'"), ref);
+		return error(_("malformed mergetag in commit '%s'"), ref);
 
 	/* iterate over new parents */
 	for (i = 1; i < mergetag_data->argc; i++) {
 		struct object_id oid;
 		if (get_oid(mergetag_data->argv[i], &oid) < 0)
-			die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
+			return error(_("Not a valid object name: '%s'"),
+				     mergetag_data->argv[i]);
 		if (!oidcmp(&tag->tagged->oid, &oid))
-			return; /* found */
+			return 0; /* found */
 	}
 
-	die(_("original commit '%s' contains mergetag '%s' that is discarded; "
-	      "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
+	return error(_("original commit '%s' contains mergetag '%s' that is "
+		       "discarded; use --edit instead of --graft"), ref,
+		     oid_to_hex(&tag_oid));
 }
 
-static void check_mergetags(struct commit *commit, int argc, const char **argv)
+static int check_mergetags(struct commit *commit, int argc, const char **argv)
 {
 	struct check_mergetag_data mergetag_data;
 
 	mergetag_data.argc = argc;
 	mergetag_data.argv = argv;
-	for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
+	return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 }
 
-static int create_graft(int argc, const char **argv, int force)
+static int create_graft(int argc, const char **argv, int force, int gentle)
 {
 	struct object_id old_oid, new_oid;
 	const char *old_ref = argv[0];
@@ -394,33 +442,81 @@
 	unsigned long size;
 
 	if (get_oid(old_ref, &old_oid) < 0)
-		die(_("Not a valid object name: '%s'"), old_ref);
-	commit = lookup_commit_or_die(&old_oid, old_ref);
+		return error(_("Not a valid object name: '%s'"), old_ref);
+	commit = lookup_commit_reference(&old_oid);
+	if (!commit)
+		return error(_("could not parse %s"), old_ref);
 
 	buffer = get_commit_buffer(commit, &size);
 	strbuf_add(&buf, buffer, size);
 	unuse_commit_buffer(commit, buffer);
 
-	replace_parents(&buf, argc - 1, &argv[1]);
+	if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
+		strbuf_release(&buf);
+		return -1;
+	}
 
 	if (remove_signature(&buf)) {
 		warning(_("the original commit '%s' has a gpg signature."), old_ref);
 		warning(_("the signature will be removed in the replacement commit!"));
 	}
 
-	check_mergetags(commit, argc, argv);
+	if (check_mergetags(commit, argc, argv)) {
+		strbuf_release(&buf);
+		return -1;
+	}
 
-	if (write_object_file(buf.buf, buf.len, commit_type, &new_oid))
-		die(_("could not write replacement commit for: '%s'"), old_ref);
+	if (write_object_file(buf.buf, buf.len, commit_type, &new_oid)) {
+		strbuf_release(&buf);
+		return error(_("could not write replacement commit for: '%s'"),
+			     old_ref);
+	}
 
 	strbuf_release(&buf);
 
-	if (!oidcmp(&old_oid, &new_oid))
+	if (!oidcmp(&old_oid, &new_oid)) {
+		if (gentle) {
+			warning("graft for '%s' unnecessary", oid_to_hex(&old_oid));
+			return 0;
+		}
 		return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
+	}
 
 	return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
 }
 
+static int convert_graft_file(int force)
+{
+	const char *graft_file = get_graft_file();
+	FILE *fp = fopen_or_warn(graft_file, "r");
+	struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
+	struct argv_array args = ARGV_ARRAY_INIT;
+
+	if (!fp)
+		return -1;
+
+	while (strbuf_getline(&buf, fp) != EOF) {
+		if (*buf.buf == '#')
+			continue;
+
+		argv_array_split(&args, buf.buf);
+		if (args.argc && create_graft(args.argc, args.argv, force, 1))
+			strbuf_addf(&err, "\n\t%s", buf.buf);
+		argv_array_clear(&args);
+	}
+	fclose(fp);
+
+	strbuf_release(&buf);
+
+	if (!err.len)
+		return unlink_or_warn(graft_file);
+
+	warning(_("could not convert the following graft(s):\n%s"), err.buf);
+	strbuf_release(&err);
+
+	return -1;
+}
+
 int cmd_replace(int argc, const char **argv, const char *prefix)
 {
 	int force = 0;
@@ -432,6 +528,7 @@
 		MODE_DELETE,
 		MODE_EDIT,
 		MODE_GRAFT,
+		MODE_CONVERT_GRAFT_FILE,
 		MODE_REPLACE
 	} cmdmode = MODE_UNSPECIFIED;
 	struct option options[] = {
@@ -439,6 +536,7 @@
 		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 		OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 		OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
+		OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
 		OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
@@ -461,7 +559,8 @@
 	if (force &&
 	    cmdmode != MODE_REPLACE &&
 	    cmdmode != MODE_EDIT &&
-	    cmdmode != MODE_GRAFT)
+	    cmdmode != MODE_GRAFT &&
+	    cmdmode != MODE_CONVERT_GRAFT_FILE)
 		usage_msg_opt("-f only makes sense when writing a replacement",
 			      git_replace_usage, options);
 
@@ -492,7 +591,13 @@
 		if (argc < 1)
 			usage_msg_opt("-g needs at least one argument",
 				      git_replace_usage, options);
-		return create_graft(argc, argv, force);
+		return create_graft(argc, argv, force, 0);
+
+	case MODE_CONVERT_GRAFT_FILE:
+		if (argc != 0)
+			usage_msg_opt("--convert-graft-file takes no argument",
+				      git_replace_usage, options);
+		return !!convert_graft_file(force);
 
 	case MODE_LIST:
 		if (argc > 1)
@@ -501,6 +606,6 @@
 		return list_replace_refs(argv[0], format);
 
 	default:
-		die("BUG: invalid cmdmode %d", (int)cmdmode);
+		BUG("invalid cmdmode %d", (int)cmdmode);
 	}
 }
diff --git a/builtin/reset.c b/builtin/reset.c
index 5da0f75..a862c70 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -109,7 +109,7 @@
 	struct strbuf buf = STRBUF_INIT;
 
 	printf(_("HEAD is now at %s"),
-		find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
+		find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
 
 	pp_commit_easy(CMIT_FMT_ONELINE, commit, &buf);
 	if (buf.len > 0)
@@ -314,7 +314,7 @@
 	unborn = !strcmp(rev, "HEAD") && get_oid("HEAD", &oid);
 	if (unborn) {
 		/* reset on unborn branch: treat as reset to empty tree */
-		hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&oid, the_hash_algo->empty_tree);
 	} else if (!pathspec.nr) {
 		struct commit *commit;
 		if (get_oid_committish(rev, &oid))
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 6f5b9b0..fadd3ec 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -108,7 +108,7 @@
 	if (!revs->graph)
 		fputs(get_revision_mark(revs, commit), stdout);
 	if (revs->abbrev_commit && revs->abbrev)
-		fputs(find_unique_abbrev(commit->object.oid.hash, revs->abbrev),
+		fputs(find_unique_abbrev(&commit->object.oid, revs->abbrev),
 		      stdout);
 	else
 		fputs(oid_to_hex(&commit->object.oid), stdout);
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index a1e680b..4f49e96 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -159,7 +159,7 @@
 		}
 	}
 	else if (abbrev)
-		show_with_type(type, find_unique_abbrev(oid->hash, abbrev));
+		show_with_type(type, find_unique_abbrev(oid, abbrev));
 	else
 		show_with_type(type, oid_to_hex(oid));
 }
@@ -282,6 +282,10 @@
 			struct commit *a, *b;
 			a = lookup_commit_reference(&start_oid);
 			b = lookup_commit_reference(&end_oid);
+			if (!a || !b) {
+				*dotdot = '.';
+				return 0;
+			}
 			exclude = get_merge_bases(a, b);
 			while (exclude) {
 				struct commit *commit = pop_commit(&exclude);
@@ -328,12 +332,12 @@
 		return 0;
 
 	*dotdot = 0;
-	if (get_oid_committish(arg, &oid)) {
+	if (get_oid_committish(arg, &oid) ||
+	    !(commit = lookup_commit_reference(&oid))) {
 		*dotdot = '^';
 		return 0;
 	}
 
-	commit = lookup_commit_reference(&oid);
 	if (exclude_parent &&
 	    exclude_parent > commit_list_count(commit->parents)) {
 		*dotdot = '^';
@@ -887,8 +891,8 @@
 				if (read_cache() < 0)
 					die(_("Could not read the index"));
 				if (the_index.split_index) {
-					const unsigned char *sha1 = the_index.split_index->base_sha1;
-					const char *path = git_path("sharedindex.%s", sha1_to_hex(sha1));
+					const struct object_id *oid = &the_index.split_index->base_oid;
+					const char *path = git_path("sharedindex.%s", oid_to_hex(oid));
 					strbuf_reset(&buf);
 					puts(relative_path(path, prefix, &buf));
 				}
diff --git a/builtin/rm.c b/builtin/rm.c
index 4447bb4..65b448e 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -178,7 +178,7 @@
 		 * way as changed from the HEAD.
 		 */
 		if (no_head
-		     || get_tree_entry(head->hash, name, oid.hash, &mode)
+		     || get_tree_entry(head, name, &oid, &mode)
 		     || ce->ce_mode != create_ce_mode(mode)
 		     || oidcmp(&ce->oid, &oid))
 			staged_changes = 1;
@@ -233,8 +233,6 @@
 	return errs;
 }
 
-static struct lock_file lock_file;
-
 static int show_only = 0, force = 0, index_only = 0, recursive = 0, quiet = 0;
 static int ignore_unmatch = 0;
 
@@ -251,6 +249,7 @@
 
 int cmd_rm(int argc, const char **argv, const char *prefix)
 {
+	struct lock_file lock_file = LOCK_INIT;
 	int i;
 	struct pathspec pathspec;
 	char *seen;
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index fc4f0bb..4923b10 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -14,6 +14,7 @@
 #include "sha1-array.h"
 #include "gpg-interface.h"
 #include "gettext.h"
+#include "protocol.h"
 
 static const char * const send_pack_usage[] = {
 	N_("git send-pack [--all | --mirror] [--dry-run] [--force] "
@@ -125,8 +126,7 @@
 
 int cmd_send_pack(int argc, const char **argv, const char *prefix)
 {
-	int i, nr_refspecs = 0;
-	const char **refspecs = NULL;
+	struct refspec rs = REFSPEC_INIT_PUSH;
 	const char *remote_name = NULL;
 	struct remote *remote = NULL;
 	const char *dest = NULL;
@@ -154,6 +154,7 @@
 	int progress = -1;
 	int from_stdin = 0;
 	struct push_cas_option cas = {0};
+	struct packet_reader reader;
 
 	struct option options[] = {
 		OPT__VERBOSITY(&verbose),
@@ -187,8 +188,7 @@
 	argc = parse_options(argc, argv, prefix, options, send_pack_usage, 0);
 	if (argc > 0) {
 		dest = argv[0];
-		refspecs = (const char **)(argv + 1);
-		nr_refspecs = argc - 1;
+		refspec_appendn(&rs, argv + 1, argc - 1);
 	}
 
 	if (!dest)
@@ -207,31 +207,23 @@
 	args.push_options = push_options.nr ? &push_options : NULL;
 
 	if (from_stdin) {
-		struct argv_array all_refspecs = ARGV_ARRAY_INIT;
-
-		for (i = 0; i < nr_refspecs; i++)
-			argv_array_push(&all_refspecs, refspecs[i]);
-
 		if (args.stateless_rpc) {
 			const char *buf;
 			while ((buf = packet_read_line(0, NULL)))
-				argv_array_push(&all_refspecs, buf);
+				refspec_append(&rs, buf);
 		} else {
 			struct strbuf line = STRBUF_INIT;
 			while (strbuf_getline(&line, stdin) != EOF)
-				argv_array_push(&all_refspecs, line.buf);
+				refspec_append(&rs, line.buf);
 			strbuf_release(&line);
 		}
-
-		refspecs = all_refspecs.argv;
-		nr_refspecs = all_refspecs.argc;
 	}
 
 	/*
 	 * --all and --mirror are incompatible; neither makes sense
 	 * with any refspecs.
 	 */
-	if ((nr_refspecs > 0 && (send_all || args.send_mirror)) ||
+	if ((rs.nr > 0 && (send_all || args.send_mirror)) ||
 	    (send_all && args.send_mirror))
 		usage_with_options(send_pack_usage, options);
 
@@ -256,10 +248,22 @@
 			args.verbose ? CONNECT_VERBOSE : 0);
 	}
 
-	get_remote_heads(fd[0], NULL, 0, &remote_refs, REF_NORMAL,
-			 &extra_have, &shallow);
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
 
-	transport_verify_remote_names(nr_refspecs, refspecs);
+	switch (discover_version(&reader)) {
+	case protocol_v2:
+		die("support for protocol v2 not implemented yet");
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &remote_refs, REF_NORMAL,
+				 &extra_have, &shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 
 	local_refs = get_local_heads();
 
@@ -271,7 +275,7 @@
 		flags |= MATCH_REFS_MIRROR;
 
 	/* match them up */
-	if (match_push_refs(local_refs, &remote_refs, nr_refspecs, refspecs, flags))
+	if (match_push_refs(local_refs, &remote_refs, &rs, flags))
 		return -1;
 
 	if (!is_empty_cas(&cas))
diff --git a/builtin/serve.c b/builtin/serve.c
new file mode 100644
index 0000000..d3fd240
--- /dev/null
+++ b/builtin/serve.c
@@ -0,0 +1,30 @@
+#include "cache.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "serve.h"
+
+static char const * const serve_usage[] = {
+	N_("git serve [<options>]"),
+	NULL
+};
+
+int cmd_serve(int argc, const char **argv, const char *prefix)
+{
+	struct serve_options opts = SERVE_OPTIONS_INIT;
+
+	struct option options[] = {
+		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+			 N_("quit after a single request/response exchange")),
+		OPT_BOOL(0, "advertise-capabilities", &opts.advertise_capabilities,
+			 N_("exit immediately after advertising capabilities")),
+		OPT_END()
+	};
+
+	/* ignore all unknown cmdline switches for now */
+	argc = parse_options(argc, argv, prefix, options, serve_usage,
+			     PARSE_OPT_KEEP_DASHDASH |
+			     PARSE_OPT_KEEP_UNKNOWN);
+	serve(&opts);
+
+	return 0;
+}
diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index e29875b..608d6ba 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -11,7 +11,8 @@
 #include "parse-options.h"
 
 static char const * const shortlog_usage[] = {
-	N_("git shortlog [<options>] [<revision-range>] [[--] [<path>...]]"),
+	N_("git shortlog [<options>] [<revision-range>] [[--] <path>...]"),
+	N_("git log --pretty=short | git shortlog [<options>]"),
 	NULL
 };
 
@@ -283,6 +284,7 @@
 	for (;;) {
 		switch (parse_options_step(&ctx, options, shortlog_usage)) {
 		case PARSE_OPT_HELP:
+		case PARSE_OPT_ERROR:
 			exit(129);
 		case PARSE_OPT_DONE:
 			goto parse_done;
@@ -292,6 +294,11 @@
 parse_done:
 	argc = parse_options_end(&ctx);
 
+	if (nongit && argc > 1) {
+		error(_("too many arguments given outside repository"));
+		usage_with_options(shortlog_usage, options);
+	}
+
 	if (setup_revisions(argc, argv, &rev, NULL) != 1) {
 		error(_("unrecognized argument: %s"), argv[1]);
 		usage_with_options(shortlog_usage, options);
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index e8a4aa4..6c2148b 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -292,7 +292,7 @@
 		}
 		else
 			printf("[%s] ",
-			       find_unique_abbrev(commit->object.oid.hash,
+			       find_unique_abbrev(&commit->object.oid,
 						  DEFAULT_ABBREV));
 	}
 	puts(pretty_str);
diff --git a/builtin/show-ref.c b/builtin/show-ref.c
index 41e5e71..f2eb1a7 100644
--- a/builtin/show-ref.c
+++ b/builtin/show-ref.c
@@ -29,7 +29,7 @@
 	if (quiet)
 		return;
 
-	hex = find_unique_abbrev(oid->hash, abbrev);
+	hex = find_unique_abbrev(oid, abbrev);
 	if (hash_only)
 		printf("%s\n", hex);
 	else
@@ -39,7 +39,7 @@
 		return;
 
 	if (!peel_ref(refname, &peeled)) {
-		hex = find_unique_abbrev(peeled.hash, abbrev);
+		hex = find_unique_abbrev(&peeled, abbrev);
 		printf("%s %s^{}\n", hex, refname);
 	}
 }
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index cd75c7f..05e5ed3 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -12,10 +12,12 @@
 #include "run-command.h"
 #include "remote.h"
 #include "refs.h"
+#include "refspec.h"
 #include "connect.h"
 #include "revision.h"
 #include "diffcore.h"
 #include "diff.h"
+#include "object-store.h"
 #include "dir.h"
 
 #define OPT_QUIET (1 << 0)
@@ -455,7 +457,7 @@
 
 	displaypath = get_submodule_displaypath(path, prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -596,8 +598,12 @@
 
 	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
 
-	if (state == ' ' || state == '+')
-		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+	if (state == ' ' || state == '+') {
+		const char *name = compute_rev_name(path, oid_to_hex(oid));
+
+		if (name)
+			printf(" (%s)", name);
+	}
 
 	printf("\n");
 }
@@ -622,7 +628,7 @@
 	struct rev_info rev;
 	int diff_files_result;
 
-	if (!submodule_from_path(&null_oid, path))
+	if (!submodule_from_path(the_repository, &null_oid, path))
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
 		      path);
 
@@ -655,9 +661,13 @@
 			     displaypath);
 	} else if (!(flags & OPT_CACHED)) {
 		struct object_id oid;
+		struct ref_store *refs = get_submodule_ref_store(path);
 
-		if (refs_head_ref(get_submodule_ref_store(path),
-				  handle_submodule_head_ref, &oid))
+		if (!refs) {
+			print_status(flags, '-', path, ce_oid, displaypath);
+			goto cleanup;
+		}
+		if (refs_head_ref(refs, handle_submodule_head_ref, &oid))
 			die(_("could not resolve HEAD ref inside the "
 			      "submodule '%s'"), path);
 
@@ -742,7 +752,7 @@
 	if (argc != 2)
 		usage(_("git submodule--helper name <path>"));
 
-	sub = submodule_from_path(&null_oid, argv[1]);
+	sub = submodule_from_path(the_repository, &null_oid, argv[1]);
 
 	if (!sub)
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
@@ -773,7 +783,7 @@
 	if (!is_submodule_active(the_repository, path))
 		return;
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (sub && sub->url) {
 		if (starts_with_dot_dot_slash(sub->url) ||
@@ -926,7 +936,7 @@
 	struct strbuf sb_config = STRBUF_INIT;
 	char *sub_git_dir = xstrfmt("%s/.git", path);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (!sub || !sub->name)
 		goto cleanup;
@@ -1057,7 +1067,7 @@
 }
 
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
-			   const char *depth, struct string_list *reference,
+			   const char *depth, struct string_list *reference, int dissociate,
 			   int quiet, int progress)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -1076,6 +1086,8 @@
 			argv_array_pushl(&cp.args, "--reference",
 					 item->string, NULL);
 	}
+	if (dissociate)
+		argv_array_push(&cp.args, "--dissociate");
 	if (gitdir && *gitdir)
 		argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
 
@@ -1192,7 +1204,7 @@
 	char *p, *path = NULL, *sm_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
-	int require_init = 0;
+	int dissociate = 0, require_init = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
 
 	struct option module_clone_options[] = {
@@ -1211,6 +1223,8 @@
 		OPT_STRING_LIST(0, "reference", &reference,
 			   N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &depth,
 			   N_("string"),
 			   N_("depth for shallow clones")),
@@ -1256,7 +1270,7 @@
 
 		prepare_possible_alternates(name, &reference);
 
-		if (clone_submodule(path, sm_gitdir, url, depth, &reference,
+		if (clone_submodule(path, sm_gitdir, url, depth, &reference, dissociate,
 				    quiet, progress))
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
@@ -1270,8 +1284,7 @@
 		strbuf_reset(&sb);
 	}
 
-	/* Connect module worktree and git dir */
-	connect_work_tree_and_git_dir(path, sm_gitdir);
+	connect_work_tree_and_git_dir(path, sm_gitdir, 0);
 
 	p = git_pathdup_submodule(path, "config");
 	if (!p)
@@ -1311,6 +1324,7 @@
 	int quiet;
 	int recommend_shallow;
 	struct string_list references;
+	int dissociate;
 	unsigned require_init;
 	const char *depth;
 	const char *recursive_prefix;
@@ -1327,7 +1341,7 @@
 	int failed_clones_nr, failed_clones_alloc;
 };
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
+	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, 0, \
 	NULL, NULL, NULL, \
 	STRING_LIST_INIT_DUP, 0, NULL, 0, 0}
 
@@ -1379,7 +1393,7 @@
 		goto cleanup;
 	}
 
-	sub = submodule_from_path(&null_oid, ce->name);
+	sub = submodule_from_path(the_repository, &null_oid, ce->name);
 
 	if (suc->recursive_prefix)
 		displaypath = relative_path(suc->recursive_prefix,
@@ -1456,6 +1470,8 @@
 		for_each_string_list_item(item, &suc->references)
 			argv_array_pushl(&child->args, "--reference", item->string, NULL);
 	}
+	if (suc->dissociate)
+		argv_array_push(&child->args, "--dissociate");
 	if (suc->depth)
 		argv_array_push(&child->args, suc->depth);
 
@@ -1589,6 +1605,8 @@
 			   N_("rebase, merge, checkout or none")),
 		OPT_STRING_LIST(0, "reference", &suc.references, N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &suc.dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &suc.depth, "<depth>",
 			   N_("Create a shallow clone truncated to the "
 			      "specified number of revisions")),
@@ -1666,7 +1684,7 @@
 	const char *branch = NULL;
 	char *key;
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 	if (!sub)
 		return NULL;
 
@@ -1751,13 +1769,14 @@
 
 	/* Check the refspec */
 	if (argc > 2) {
-		int i, refspec_nr = argc - 2;
+		int i;
 		struct ref *local_refs = get_local_heads();
-		struct refspec *refspec = parse_push_refspec(refspec_nr,
-							     argv + 2);
+		struct refspec refspec = REFSPEC_INIT_PUSH;
 
-		for (i = 0; i < refspec_nr; i++) {
-			struct refspec *rs = refspec + i;
+		refspec_appendn(&refspec, argv + 2, argc - 2);
+
+		for (i = 0; i < refspec.nr; i++) {
+			const struct refspec_item *rs = &refspec.items[i];
 
 			if (rs->pattern || rs->matching)
 				continue;
@@ -1784,7 +1803,7 @@
 				    rs->src);
 			}
 		}
-		free_refspec(refspec_nr, refspec);
+		refspec_clear(&refspec);
 	}
 	free(head);
 
diff --git a/builtin/tag.c b/builtin/tag.c
index da18669..5d0dd11 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -99,7 +99,8 @@
 {
 	if (delete_ref(NULL, ref, oid, 0))
 		return 1;
-	printf(_("Deleted tag '%s' (was %s)\n"), name, find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
+	printf(_("Deleted tag '%s' (was %s)\n"), name,
+	       find_unique_abbrev(oid, DEFAULT_ABBREV));
 	return 0;
 }
 
@@ -117,7 +118,7 @@
 		return -1;
 
 	if (format->format)
-		pretty_print_ref(name, oid->hash, format);
+		pretty_print_ref(name, oid, format);
 
 	return 0;
 }
@@ -167,7 +168,7 @@
 	enum object_type type;
 	char *buf, *sp;
 
-	buf = read_sha1_file(oid->hash, &type, &size);
+	buf = read_object_file(oid, &type, &size);
 	if (!buf)
 		return;
 	/* skip header */
@@ -211,7 +212,7 @@
 	struct strbuf header = STRBUF_INIT;
 	char *path = NULL;
 
-	type = sha1_object_info(object->hash, NULL);
+	type = oid_object_info(the_repository, object, NULL);
 	if (type <= OBJ_NONE)
 	    die(_("bad object type."));
 
@@ -293,17 +294,17 @@
 		strbuf_addstr(sb, rla);
 	} else {
 		strbuf_addstr(sb, "tag: tagging ");
-		strbuf_add_unique_abbrev(sb, oid->hash, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(sb, oid, DEFAULT_ABBREV);
 	}
 
 	strbuf_addstr(sb, " (");
-	type = sha1_object_info(oid->hash, NULL);
+	type = oid_object_info(the_repository, oid, NULL);
 	switch (type) {
 	default:
 		strbuf_addstr(sb, "object of unknown type");
 		break;
 	case OBJ_COMMIT:
-		if ((buf = read_sha1_file(oid->hash, &type, &size)) != NULL) {
+		if ((buf = read_object_file(oid, &type, &size)) != NULL) {
 			subject_len = find_commit_subject(buf, &subject_start);
 			strbuf_insert(sb, sb->len, subject_start, subject_len);
 		} else {
@@ -558,7 +559,8 @@
 		die("%s", err.buf);
 	ref_transaction_free(transaction);
 	if (force && !is_null_oid(&prev) && oidcmp(&prev, &object))
-		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev.hash, DEFAULT_ABBREV));
+		printf(_("Updated tag '%s' (was %s)\n"), tag,
+		       find_unique_abbrev(&prev, DEFAULT_ABBREV));
 
 	UNLEAK(buf);
 	UNLEAK(ref);
diff --git a/builtin/unpack-file.c b/builtin/unpack-file.c
index 32e0155..300eb59 100644
--- a/builtin/unpack-file.c
+++ b/builtin/unpack-file.c
@@ -9,7 +9,7 @@
 	unsigned long size;
 	int fd;
 
-	buf = read_sha1_file(oid->hash, &type, &size);
+	buf = read_object_file(oid, &type, &size);
 	if (!buf || type != OBJ_BLOB)
 		die("unable to read blob object %s", oid_to_hex(oid));
 
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index c8f1406..6e81ca8 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -199,7 +199,7 @@
 
 	if (!(obj->flags & FLAG_OPEN)) {
 		unsigned long size;
-		int type = sha1_object_info(obj->oid.hash, &size);
+		int type = oid_object_info(the_repository, &obj->oid, &size);
 		if (type != obj->type || type <= 0)
 			die("object of unexpected type");
 		obj->flags |= FLAG_WRITTEN;
@@ -423,7 +423,7 @@
 	if (resolve_against_held(nr, &base_oid, delta_data, delta_size))
 		return;
 
-	base = read_sha1_file(base_oid.hash, &type, &base_size);
+	base = read_object_file(&base_oid, &type, &base_size);
 	if (!base) {
 		error("failed to read delta-pack base object %s",
 		      oid_to_hex(&base_oid));
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 1af8a00..a8709a2 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -602,7 +602,7 @@
 	int size;
 	struct cache_entry *ce;
 
-	if (get_tree_entry(ent->hash, path, oid.hash, &mode)) {
+	if (get_tree_entry(ent, path, &oid, &mode)) {
 		if (which)
 			error("%s: not in %s branch.", path, which);
 		return NULL;
@@ -1069,6 +1069,7 @@
 			break;
 		switch (parseopt_state) {
 		case PARSE_OPT_HELP:
+		case PARSE_OPT_ERROR:
 			exit(129);
 		case PARSE_OPT_NON_OPTION:
 		case PARSE_OPT_DONE:
@@ -1173,7 +1174,7 @@
 		report(_("Untracked cache enabled for '%s'"), get_git_work_tree());
 		break;
 	default:
-		die("BUG: bad untracked_cache value: %d", untracked_cache);
+		BUG("bad untracked_cache value: %d", untracked_cache);
 	}
 
 	if (fsmonitor > 0) {
diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
new file mode 100644
index 0000000..decde5a
--- /dev/null
+++ b/builtin/upload-pack.c
@@ -0,0 +1,74 @@
+#include "cache.h"
+#include "builtin.h"
+#include "exec-cmd.h"
+#include "pkt-line.h"
+#include "parse-options.h"
+#include "protocol.h"
+#include "upload-pack.h"
+#include "serve.h"
+
+static const char * const upload_pack_usage[] = {
+	N_("git upload-pack [<options>] <dir>"),
+	NULL
+};
+
+int cmd_upload_pack(int argc, const char **argv, const char *prefix)
+{
+	const char *dir;
+	int strict = 0;
+	struct upload_pack_options opts = { 0 };
+	struct serve_options serve_opts = SERVE_OPTIONS_INIT;
+	struct option options[] = {
+		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+			 N_("quit after a single request/response exchange")),
+		OPT_BOOL(0, "advertise-refs", &opts.advertise_refs,
+			 N_("exit immediately after initial ref advertisement")),
+		OPT_BOOL(0, "strict", &strict,
+			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
+		OPT_INTEGER(0, "timeout", &opts.timeout,
+			    N_("interrupt transfer after <n> seconds of inactivity")),
+		OPT_END()
+	};
+
+	packet_trace_identity("upload-pack");
+	check_replace_refs = 0;
+
+	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);
+
+	if (argc != 1)
+		usage_with_options(upload_pack_usage, options);
+
+	if (opts.timeout)
+		opts.daemon_mode = 1;
+
+	setup_path();
+
+	dir = argv[0];
+
+	if (!enter_repo(dir, strict))
+		die("'%s' does not appear to be a git repository", dir);
+
+	switch (determine_protocol_version_server()) {
+	case protocol_v2:
+		serve_opts.advertise_capabilities = opts.advertise_refs;
+		serve_opts.stateless_rpc = opts.stateless_rpc;
+		serve(&serve_opts);
+		break;
+	case protocol_v1:
+		/*
+		 * v1 is just the original protocol with a version string,
+		 * so just fall through after writing the version string.
+		 */
+		if (opts.advertise_refs || !opts.stateless_rpc)
+			packet_write_fmt(1, "version 1\n");
+
+		/* fallthrough */
+	case protocol_v0:
+		upload_pack(&opts);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
+
+	return 0;
+}
diff --git a/builtin/verify-commit.c b/builtin/verify-commit.c
index 05315ea..dcdaada 100644
--- a/builtin/verify-commit.c
+++ b/builtin/verify-commit.c
@@ -44,7 +44,7 @@
 	if (get_oid(name, &oid))
 		return error("commit '%s' not found.", name);
 
-	buf = read_sha1_file(oid.hash, &type, &size);
+	buf = read_object_file(&oid, &type, &size);
 	if (!buf)
 		return error("%s: unable to read file.", name);
 	if (type != OBJ_COMMIT)
diff --git a/builtin/verify-tag.c b/builtin/verify-tag.c
index ad7b79f..6fa04b7 100644
--- a/builtin/verify-tag.c
+++ b/builtin/verify-tag.c
@@ -72,7 +72,7 @@
 		}
 
 		if (format.format)
-			pretty_print_ref(name, oid.hash, &format);
+			pretty_print_ref(name, &oid, &format);
 	}
 	return had_error;
 }
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 670555d..5c7d2bb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -29,8 +29,6 @@
 	int detach;
 	int checkout;
 	int keep_locked;
-	const char *new_branch;
-	int force_new_branch;
 };
 
 static int show_only;
@@ -101,16 +99,9 @@
 	}
 	path[len] = '\0';
 	if (!file_exists(path)) {
-		struct stat st_link;
 		free(path);
-		/*
-		 * the repo is moved manually and has not been
-		 * accessed since?
-		 */
-		if (!stat(git_path("worktrees/%s/link", id), &st_link) &&
-		    st_link.st_nlink > 1)
-			return 0;
-		if (st.st_mtime <= expire) {
+		if (stat(git_path("worktrees/%s/index", id), &st) ||
+		    st.st_mtime <= expire) {
 			strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
 			return 1;
 		} else {
@@ -305,8 +296,6 @@
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
 
-	fprintf_ln(stderr, _("Preparing %s (identifier %s)"), path, name);
-
 	argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
 	argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
 	cp.git_cmd = 1;
@@ -373,18 +362,75 @@
 	return ret;
 }
 
+static void print_preparing_worktree_line(int detach,
+					  const char *branch,
+					  const char *new_branch,
+					  int force_new_branch)
+{
+	if (force_new_branch) {
+		struct commit *commit = lookup_commit_reference_by_name(new_branch);
+		if (!commit)
+			printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+		else
+			printf_ln(_("Preparing worktree (resetting branch '%s'; was at %s)"),
+				  new_branch,
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+	} else if (new_branch) {
+		printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+	} else {
+		struct strbuf s = STRBUF_INIT;
+		if (!detach && !strbuf_check_branch_ref(&s, branch) &&
+		    ref_exists(s.buf))
+			printf_ln(_("Preparing worktree (checking out '%s')"),
+				  branch);
+		else {
+			struct commit *commit = lookup_commit_reference_by_name(branch);
+			if (!commit)
+				die(_("invalid reference: %s"), branch);
+			printf_ln(_("Preparing worktree (detached HEAD %s)"),
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+		}
+		strbuf_release(&s);
+	}
+}
+
+static const char *dwim_branch(const char *path, const char **new_branch)
+{
+	int n;
+	const char *s = worktree_basename(path, &n);
+	const char *branchname = xstrndup(s, n);
+	struct strbuf ref = STRBUF_INIT;
+
+	UNLEAK(branchname);
+	if (!strbuf_check_branch_ref(&ref, branchname) &&
+	    ref_exists(ref.buf)) {
+		strbuf_release(&ref);
+		return branchname;
+	}
+
+	*new_branch = branchname;
+	if (guess_remote) {
+		struct object_id oid;
+		const char *remote =
+			unique_tracking_name(*new_branch, &oid);
+		return remote;
+	}
+	return NULL;
+}
+
 static int add(int ac, const char **av, const char *prefix)
 {
 	struct add_opts opts;
 	const char *new_branch_force = NULL;
 	char *path;
 	const char *branch;
+	const char *new_branch = NULL;
 	const char *opt_track = NULL;
 	struct option options[] = {
 		OPT__FORCE(&opts.force,
 			   N_("checkout <branch> even if already checked out in other worktree"),
 			   PARSE_OPT_NOCOMPLETE),
-		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
+		OPT_STRING('b', NULL, &new_branch, N_("branch"),
 			   N_("create a new branch")),
 		OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
 			   N_("create or reset a branch")),
@@ -402,7 +448,7 @@
 	memset(&opts, 0, sizeof(opts));
 	opts.checkout = 1;
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
-	if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
+	if (!!opts.detach + !!new_branch + !!new_branch_force > 1)
 		die(_("-b, -B, and --detach are mutually exclusive"));
 	if (ac < 1 || ac > 2)
 		usage_with_options(worktree_usage, options);
@@ -413,33 +459,25 @@
 	if (!strcmp(branch, "-"))
 		branch = "@{-1}";
 
-	opts.force_new_branch = !!new_branch_force;