Merge branch 'hw/advise-ng' into pu

* hw/advise-ng:
  advice: extract vadvise() from advise()
  advice: refactor advise API
diff --git a/.editorconfig b/.editorconfig
index 42cdc4b..f9d8196 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -4,7 +4,7 @@
 
 # The settings for C (*.c and *.h) files are mirrored in .clang-format.  Keep
 # them in sync.
-[*.{c,h,sh,perl,pl,pm}]
+[*.{c,h,sh,perl,pl,pm,txt}]
 indent_style = tab
 tab_width = 8
 
diff --git a/.gitignore b/.gitignore
index aebe7c0..bd2f49b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,7 @@
 /git-bisect--helper
 /git-blame
 /git-branch
+/git-bugreport
 /git-bundle
 /git-cat-file
 /git-check-attr
@@ -189,7 +190,9 @@
 /gitweb/gitweb.cgi
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
+/config-list.h
 /command-list.h
+/bugreport-config-safelist.h
 *.tar.gz
 *.dsc
 *.deb
diff --git a/.mailmap b/.mailmap
index 7c94418..73fd92e 100644
--- a/.mailmap
+++ b/.mailmap
@@ -59,6 +59,7 @@
 David Turner <novalis@novalis.org> <dturner@twopensource.com>
 David Turner <novalis@novalis.org> <dturner@twosigma.com>
 Derrick Stolee <dstolee@microsoft.com> <stolee@gmail.com>
+Derrick Stolee <dstolee@microsoft.com> Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
 Deskin Miller <deskinm@umich.edu>
 Đoàn Trần Công Danh <congdanhqx@gmail.com> Doan Tran Cong Danh
 Dirk Süsserott <newsletter@dirk.my1.cc>
@@ -109,6 +110,7 @@
 Joachim Berdal Haga <cjhaga@fys.uio.no>
 Joachim Jablon <joachim.jablon@people-doc.com> <ewjoachim@gmail.com>
 Johannes Schindelin <Johannes.Schindelin@gmx.de> <johannes.schindelin@gmx.de>
+Johannes Schindelin <Johannes.Schindelin@gmx.de> Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
 Johannes Sixt <j6t@kdbg.org> <J.Sixt@eudaptics.com>
 Johannes Sixt <j6t@kdbg.org> <j.sixt@viscovery.net>
 Johannes Sixt <j6t@kdbg.org> <johannes.sixt@telecom.at>
@@ -287,6 +289,7 @@
 YONETANI Tomokazu <y0n3t4n1@gmail.com> <qhwt+git@les.ath.cx>
 YONETANI Tomokazu <y0n3t4n1@gmail.com> <y0netan1@dragonflybsd.org>
 YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
+Yi-Jyun Pan <pan93412@gmail.com>
 # the two anonymous contributors are different persons:
 anonymous <linux@horizon.com>
 anonymous <linux@horizon.net>
diff --git a/.tsan-suppressions b/.tsan-suppressions
index 8c85014..5ba86d6 100644
--- a/.tsan-suppressions
+++ b/.tsan-suppressions
@@ -8,3 +8,9 @@
 # in practice it (hopefully!) doesn't matter.
 race:^want_color$
 race:^transfer_debug$
+
+# A boolean value, which tells whether the replace_map has been initialized or
+# not, is read racily with an update. As this variable is written to only once,
+# and it's OK if the value change right after reading it, this shouldn't be a
+# problem.
+race:^lookup_replace_object$
diff --git a/Documentation/MyFirstContribution.txt b/Documentation/MyFirstContribution.txt
index 35b9130..427274d 100644
--- a/Documentation/MyFirstContribution.txt
+++ b/Documentation/MyFirstContribution.txt
@@ -23,6 +23,42 @@
 - `Documentation/SubmittingPatches`
 - `Documentation/howto/new-command.txt`
 
+[[getting-help]]
+=== Getting Help
+
+If you get stuck, you can seek help in the following places.
+
+==== git@vger.kernel.org
+
+This is the main Git project mailing list where code reviews, version
+announcements, design discussions, and more take place. Those interested in
+contributing are welcome to post questions here. The Git list requires
+plain-text-only emails and prefers inline and bottom-posting when replying to
+mail; you will be CC'd in all replies to you. Optionally, you can subscribe to
+the list by sending an email to majordomo@vger.kernel.org with "subscribe git"
+in the body. The https://lore.kernel.org/git[archive] of this mailing list is
+available to view in a browser.
+
+==== https://groups.google.com/forum/#!forum/git-mentoring[git-mentoring@googlegroups.com]
+
+This mailing list is targeted to new contributors and was created as a place to
+post questions and receive answers outside of the public eye of the main list.
+Veteran contributors who are especially interested in helping mentor newcomers
+are present on the list. In order to avoid search indexers, group membership is
+required to view messages; anyone can join and no approval is required.
+
+==== https://webchat.freenode.net/#git-devel[#git-devel] on Freenode
+
+This IRC channel is for conversations between Git contributors. If someone is
+currently online and knows the answer to your question, you can receive help
+in real time. Otherwise, you can read the
+https://colabti.org/irclogger/irclogger_logs/git-devel[scrollback] to see
+whether someone answered you. IRC does not allow offline private messaging, so
+if you try to private message someone and then log out of IRC, they cannot
+respond to you. It's better to ask your questions in the channel so that you
+can be answered if you disconnect and so that others can learn from the
+conversation.
+
 [[getting-started]]
 == Getting Started
 
diff --git a/Documentation/RelNotes/2.25.1.txt b/Documentation/RelNotes/2.25.1.txt
new file mode 100644
index 0000000..cd869b0
--- /dev/null
+++ b/Documentation/RelNotes/2.25.1.txt
@@ -0,0 +1,55 @@
+Git 2.25.1 Release Notes
+========================
+
+Fixes since v2.25
+-----------------
+
+ * "git commit" gives output similar to "git status" when there is
+   nothing to commit, but without honoring the advise.statusHints
+   configuration variable, which has been corrected.
+
+ * has_object_file() said "no" given an object registered to the
+   system via pretend_object_file(), making it inconsistent with
+   read_object_file(), causing lazy fetch to attempt fetching an
+   empty tree from promisor remotes.
+
+ * The code that tries to skip over the entries for the paths in a
+   single directory using the cache-tree was not careful enough
+   against corrupt index file.
+
+ * Complete an update to tutorial that encourages "git switch" over
+   "git checkout" that was done only half-way.
+
+ * Reduce unnecessary round-trip when running "ls-remote" over the
+   stateless RPC mechanism.
+
+ * "git restore --staged" did not correctly update the cache-tree
+   structure, resulting in bogus trees to be written afterwards, which
+   has been corrected.
+
+ * The code recently added to move to the entry beyond the ones in the
+   same directory in the index in the sparse-cone mode did not count
+   the number of entries to skip over incorrectly, which has been
+   corrected.
+
+ * Work around test breakages caused by custom regex engine used in
+   libasan, when address sanitizer is used with more recent versions
+   of gcc and clang.
+
+ * "git fetch --refmap=" option has got a better documentation.
+
+ * Corner case bugs in "git clean" that stems from a (necessarily for
+   performance reasons) awkward calling convention in the directory
+   enumeration API has been corrected.
+
+ * "git grep --no-index" should not get affected by the contents of
+   the .gitmodules file but when "--recurse-submodules" is given or
+   the "submodule.recurse" variable is set, it did.  Now these
+   settings are ignored in the "--no-index" mode.
+
+ * Technical details of the bundle format has been documented.
+
+ * Unhelpful warning messages during documentation build have been
+   squelched.
+
+Also contains various documentation updates, code clean-ups and minor fixups.
diff --git a/Documentation/RelNotes/2.26.0.txt b/Documentation/RelNotes/2.26.0.txt
new file mode 100644
index 0000000..52534dd
--- /dev/null
+++ b/Documentation/RelNotes/2.26.0.txt
@@ -0,0 +1,246 @@
+Git 2.26 Release Notes
+======================
+
+Updates since v2.25
+-------------------
+
+UI, Workflows & Features
+
+ * Sample credential helper for using .netrc has been updated to work
+   out of the box.
+
+ * gpg.minTrustLevel configuration variable has been introduced to
+   tell various signature verification codepaths the required minimum
+   trust level.
+
+ * The command line completion (in contrib/) learned to complete
+   subcommands and arguments to "git worktree".
+
+ * Disambiguation logic to tell revisions and pathspec apart has been
+   tweaked so that backslash-escaped glob special characters do not
+   count in the "wildcards are pathspec" rule.
+
+ * One effect of specifying where the GIT_DIR is (either with the
+   environment variable, or with the "git --git-dir=<where> cmd"
+   option) is to disable the repository discovery.  This has been
+   placed a bit more stress in the documentation, as new users often
+   get confused.
+
+ * Two help messages given when "git add" notices the user gave it
+   nothing to add have been updated to use advise() API.
+
+ * A new version of fsmonitor-watchman hook has been introduced, to
+   avoid races.
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * Tell .editorconfig that in this project, *.txt files are indented
+   with tabs.
+
+ * The test-lint machinery knew to check "VAR=VAL shell_function"
+   construct, but did not check "VAR= shell_funciton", which has been
+   corrected.
+
+ * Replace "git config --bool" calls with "git config --type=bool" in
+   sample templates.
+
+ * The effort to move "git-add--interactive" to C continues.
+
+ * Improve error message generation for "git submodule add".
+
+ * Preparation of test scripts for the day when the object names will
+   use SHA-256 continues.
+
+ * Warn programmers about pretend_object_file() that allows the code
+   to tentatively use in-core objects.
+
+ * The way "git pack-objects" reuses objects stored in existing pack
+   to generate its result has been improved.
+
+ * The transport protocol version 2 becomes the default one.
+
+ * Traditionally, we avoided threaded grep while searching in objects
+   (as opposed to files in the working tree) as accesses to the object
+   layer is not thread-safe.  This limitation is getting lifted.
+
+ * "git rebase -i" (and friends) used to unnecessarily check out the
+   tip of the branch to be rebased, which has been corrected.
+
+ * A low-level API function get_oid(), that accepts various ways to
+   name an object, used to issue end-user facing error messages
+   without l10n, which has been updated to be translatable.
+
+ * Unneeded connectivity check is now disabled in a partial clone when
+   fetching into it.
+
+ * Some rough edges in the sparse-checkout feature, especially around
+   the cone mode, have been cleaned up.
+
+ * The diff-* plumbing family of subcommands now pay attention to the
+   diff.wsErrorHighlight configuration, which has been ignored before;
+   this allows "git add -p" to also show the whitespace problems to
+   the end user.
+
+ * Some codepaths were given a repository instance as a parameter to
+   work in the repository, but passed the_repository instance to its
+   callees, which has been cleaned up (somewhat).
+
+
+Fixes since v2.25
+-----------------
+
+ * "git commit" gives output similar to "git status" when there is
+   nothing to commit, but without honoring the advise.statusHints
+   configuration variable, which has been corrected.
+   (merge 5c4f55f1f6 hw/commit-advise-while-rejecting later to maint).
+
+ * has_object_file() said "no" given an object registered to the
+   system via pretend_object_file(), making it inconsistent with
+   read_object_file(), causing lazy fetch to attempt fetching an
+   empty tree from promisor remotes.
+   (merge 9c8a294a1a jt/sha1-file-remove-oi-skip-cached later to maint).
+
+ * Complete an update to tutorial that encourages "git switch" over
+   "git checkout" that was done only half-way.
+   (merge 1a7e454dd6 hw/tutorial-favor-switch-over-checkout later to maint).
+
+ * C pedantry ;-) fix.
+   (merge 63ab08fb99 bc/run-command-nullness-after-free-fix later to maint).
+
+ * The code that tries to skip over the entries for the paths in a
+   single directory using the cache-tree was not careful enough
+   against corrupt index file.
+   (merge 573117dfa5 es/unpack-trees-oob-fix later to maint).
+
+ * Reduce unnecessary round-trip when running "ls-remote" over the
+   stateless RPC mechanism.
+   (merge 4d8cab95cc jk/no-flush-upon-disconnecting-slrpc-transport later to maint).
+
+ * "git restore --staged" did not correctly update the cache-tree
+   structure, resulting in bogus trees to be written afterwards, which
+   has been corrected.
+   (merge e701bab3e9 nd/switch-and-restore later to maint).
+
+ * The code recently added to move to the entry beyond the ones in the
+   same directory in the index in the sparse-cone mode did not count
+   the number of entries to skip over incorrectly, which has been
+   corrected.
+   (merge 7210ca4ee5 ds/sparse-cone later to maint).
+
+ * Rendering by "git log --graph" of ancestry lines leading to a merge
+   commit were made suboptimal to waste vertical space a bit with a
+   recent update, which has been corrected.
+   (merge c958d3bd0a ds/graph-horizontal-edges later to maint).
+
+ * Work around test breakages caused by custom regex engine used in
+   libasan, when address sanitizer is used with more recent versions
+   of gcc and clang.
+   (merge f65d07fffa jk/asan-build-fix later to maint).
+
+ * Minor bugfixes to "git add -i" that has recently been rewritten in C.
+   (merge 849e43cc18 js/builtin-add-i-cmds later to maint).
+
+ * "git fetch --refmap=" option has got a better documentation.
+   (merge b40a50264a ds/refmap-doc later to maint).
+
+ * "git checkout X" did not correctly fail when X is not a local
+   branch but could name more than one remote-tracking branches
+   (i.e. to be dwimmed as the starting point to create a corresponding
+   local branch), which has been corrected.
+   (merge fa74180d08 am/checkout-file-and-ref-ref-ambiguity later to maint).
+
+ * Corner case bugs in "git clean" that stems from a (necessarily for
+   performance reasons) awkward calling convention in the directory
+   enumeration API has been corrected.
+   (merge 0cbb60574e en/fill-directory-fixes-more later to maint).
+
+ * A fetch that is told to recursively fetch updates in submodules
+   inevitably produces reams of output, and it becomes hard to spot
+   error messages.  The command has been taught to enumerate
+   submodules that had errors at the end of the operation.
+   (merge 0222540827 es/fetch-show-failed-submodules-atend later to maint).
+
+ * The "--recurse-submodules" option of various subcommands did not
+   work well when run in an alternate worktree, which has been
+   corrected.
+   (merge a9472afb63 pb/recurse-submodule-in-worktree-fix later to maint).
+
+ * Futureproofing a test not to depend on the current implementation
+   detail.
+   (merge b54128bb0b jt/t5616-robustify later to maint).
+
+ * Running "git rm" on a submodule failed unnecessarily when
+   .gitmodules is only cache-dirty, which has been corrected.
+   (merge 7edee32985 dt/submodule-rm-with-stale-cache later to maint).
+
+ * C pedantry ;-) fix.
+   (merge cf82bff73f jk/clang-sanitizer-fixes later to maint).
+
+ * "git grep --no-index" should not get affected by the contents of
+   the .gitmodules file but when "--recurse-submodules" is given or
+   the "submodule.recurse" variable is set, it did.  Now these
+   settings are ignored in the "--no-index" mode.
+   (merge c56c48dd07 pb/do-not-recurse-grep-no-index later to maint).
+
+ * Technical details of the bundle format has been documented.
+   (merge 7378ec90e1 ms/doc-bundle-format later to maint).
+
+ * Unhelpful warning messages during documentation build have been squelched.
+   (merge 30183894ea js/ci-squelch-doc-warning later to maint).
+
+ * "git rebase -i" identifies existing commits in its todo file with
+   their abbreviated object name, which could become ambigous as it
+   goes to create new commits, and has a mechanism to avoid ambiguity
+   in the main part of its execution.  A few other cases however were
+   not covered by the protection against ambiguity, which has been
+   corrected.
+   (merge 26027625dd js/rebase-i-with-colliding-hash later to maint).
+
+ * Allow the rebase.missingCommitsCheck configuration to kick in when
+   "rebase --edit-todo" and "rebase --continue" restarts the procedure.
+   (merge 5a5445d878 ag/edit-todo-drop-check later to maint).
+
+ * The way "git submodule status" reports an initialized but not yet
+   populated submodule has not been reimplemented correctly when a
+   part of the "git submodule" command was rewritten in C, which has
+   been corrected.
+   (merge f38c92452d pk/status-of-uncloned-submodule later to maint).
+
+ * The code to automatically shrink the fan-out in the notes tree had
+   an off-by-one bug, which has been killed.
+   (merge dbc27477ff jh/notes-fanout-fix later to maint).
+
+ * The index-pack code now diagnoses a bad input packstream that
+   records the same object twice when it is used as delta base; the
+   code used to declare a software bug when encountering such an
+   input, but it is an input error.
+   (merge a21781011f jk/index-pack-dupfix later to maint).
+
+ * The code to compute the commit-graph has been taught to use a more
+   robust way to tell if two object directories refer to the same
+   thing.
+   (merge a7df60cac8 tb/commit-graph-object-dir later to maint).
+
+ * Other code cleanup, docfix, build fix, etc.
+   (merge 26f924d50e en/simplify-check-updates-in-unpack-trees later to maint).
+   (merge 065027ee1a en/string-list-can-be-custom-sorted later to maint).
+   (merge d0d0a357a1 am/update-pathspec-f-f-tests later to maint).
+   (merge f94f7bd00d am/test-pathspec-f-f-error-cases later to maint).
+   (merge e4837b4406 jk/test-fixes later to maint).
+   (merge a4ffbbbb99 rt/submodule-i18n later to maint).
+   (merge 856249c62a bc/actualmente later to maint).
+   (merge c513a958b6 ss/t6025-modernize later to maint).
+   (merge 69e104d70e bc/author-committer-doc later to maint).
+   (merge 7a2dc95cbc bc/misconception-doc later to maint).
+   (merge b441717256 dl/test-must-fail-fixes later to maint).
+   (merge d031049da3 mt/sparse-checkout-doc-update later to maint).
+   (merge 145136a95a jc/skip-prefix later to maint).
+   (merge eb31044ff7 jb/multi-pack-index-docfix later to maint).
+   (merge 04e5b3f0b4 km/submodule-doc-use-sm-path later to maint).
+   (merge e469afe158 ma/filter-branch-doc-caret later to maint).
+   (merge 395518cf7a jb/parse-options-message-fix later to maint).
+   (merge 303b3c1c46 es/submodule-fetch-message-fix later to maint).
+   (merge 9299f84921 ma/diff-doc-clarify-regexp-example later to maint).
+   (merge 2b0f19fa7a js/convert-typofix later to maint).
+   (merge 5290d45134 jk/alloc-cleanups later to maint).
diff --git a/Documentation/asciidoc.conf b/Documentation/asciidoc.conf
index 8fc4b67..663e064 100644
--- a/Documentation/asciidoc.conf
+++ b/Documentation/asciidoc.conf
@@ -6,9 +6,14 @@
 #
 # Show Git link as: <command>(<section>); if section is defined, else just show
 # the command.
+#
+# The annotate macro does nothing as far as rendering is
+# concerned -- we just grep for it in the sources to populate
+# things like the bugreport safelist.
 
 [macros]
 (?su)[\\]?(?P<name>linkgit):(?P<target>\S*?)\[(?P<attrlist>.*?)\]=
+(?su)[\\]?(?P<name>annotate):(?P<target>\S*?)\[(?P<attrlist>.*?)\]=
 
 [attributes]
 asterisk=&#42;
@@ -28,6 +33,8 @@
 {0#<citerefentry>}
 {0#<refentrytitle>{target}</refentrytitle><manvolnum>{0}</manvolnum>}
 {0#</citerefentry>}
+[annotate-inlinemacro]
+{0#}
 endif::backend-docbook[]
 
 ifdef::backend-docbook[]
@@ -94,4 +101,6 @@
 git-relative-html-prefix=
 [linkgit-inlinemacro]
 <a href="{git-relative-html-prefix}{target}.html">{target}{0?({0})}</a>
+[annotate-inlinemacro]
+<!-- -->
 endif::backend-xhtml11[]
diff --git a/Documentation/asciidoctor-extensions.rb b/Documentation/asciidoctor-extensions.rb
index d906a00..03c80af 100644
--- a/Documentation/asciidoctor-extensions.rb
+++ b/Documentation/asciidoctor-extensions.rb
@@ -39,10 +39,17 @@
         output
       end
     end
+
+    class AnnotateProcessor < Asciidoctor::Extensions::InlineMacroProcessor
+      def process(parent, target, attrs)
+        ""
+      end
+    end
   end
 end
 
 Asciidoctor::Extensions.register do
   inline_macro Git::Documentation::LinkGitProcessor, :linkgit
   postprocessor Git::Documentation::DocumentPostProcessor
+  inline_macro Git::Documentation::AnnotateProcessor, :annotate
 end
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 83e7bba..08b13ba 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -263,7 +263,9 @@
 +
 The basic colors accepted are `normal`, `black`, `red`, `green`, `yellow`,
 `blue`, `magenta`, `cyan` and `white`.  The first color given is the
-foreground; the second is the background.
+foreground; the second is the background.  All the basic colors except
+`normal` have a bright variant that can be speficied by prefixing the
+color with `bright`, like `brightred`.
 +
 Colors may also be given as numbers between 0 and 255; these use ANSI
 256-color mode (but note that not all terminals may support this).  If
diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index 4be93f8..bdd37c3 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt
@@ -110,4 +110,10 @@
 	submoduleAlternateErrorStrategyDie::
 		Advice shown when a submodule.alternateErrorStrategy option
 		configured to "die" causes a fatal error.
+	addIgnoredFile::
+		Advice shown if a user attempts to add an ignored file to
+		the index.
+	addEmptyPathspec::
+		Advice shown if a user runs the add command without providing
+		the pathspec parameter.
 --
diff --git a/Documentation/config/branch.txt b/Documentation/config/branch.txt
index a592d52..cc5f324 100644
--- a/Documentation/config/branch.txt
+++ b/Documentation/config/branch.txt
@@ -81,15 +81,16 @@
 	"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'
+When `merges` (or just 'm'), 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` (deprecated in favor of `merges`), also pass
+When `preserve` (or just 'p', deprecated in favor of `merges`), also pass
 `--preserve-merges` along to 'git rebase' so that locally committed merge
 commits will not be flattened by running 'git pull'.
 +
-When the value is `interactive`, the rebase is run in interactive mode.
+When the value is `interactive` (or just 'i'), the rebase is run in interactive
+mode.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 9e440b1..74619a9 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -68,6 +68,17 @@
 	avoiding unnecessary processing of files that have not changed.
 	See the "fsmonitor-watchman" section of linkgit:githooks[5].
 
+core.fsmonitorHookVersion::
+	Sets the version of hook that is to be used when calling fsmonitor.
+	There are currently versions 1 and 2. When this is not set,
+	version 2 will be tried first and if it fails then version 1
+	will be tried. Version 1 uses a timestamp as input to determine
+	which files have changes since that time but some monitors
+	like watchman have race conditions when used with a timestamp.
+	Version 2 uses an opaque string so that the monitor can return
+	something that can be used to determine what files have changed
+	without race conditions.
+
 core.trustctime::
 	If false, the ctime differences between the index and the
 	working tree are ignored; useful when the inode change time
diff --git a/Documentation/config/gpg.txt b/Documentation/config/gpg.txt
index cce2c89..d94025c 100644
--- a/Documentation/config/gpg.txt
+++ b/Documentation/config/gpg.txt
@@ -18,3 +18,18 @@
 	chose. (see `gpg.program` and `gpg.format`) `gpg.program` can still
 	be used as a legacy synonym for `gpg.openpgp.program`. The default
 	value for `gpg.x509.program` is "gpgsm".
+
+gpg.minTrustLevel::
+	Specifies a minimum trust level for signature verification.  If
+	this option is unset, then signature verification for merge
+	operations require a key with at least `marginal` trust.  Other
+	operations that perform signature verification require a key
+	with at least `undefined` trust.  Setting this option overrides
+	the required trust-level for all operations.  Supported values,
+	in increasing order of significance:
++
+* `undefined`
+* `never`
+* `marginal`
+* `fully`
+* `ultimate`
diff --git a/Documentation/config/http.txt b/Documentation/config/http.txt
index 5a32f5b..e806033 100644
--- a/Documentation/config/http.txt
+++ b/Documentation/config/http.txt
@@ -71,7 +71,7 @@
 http.version::
 	Use the specified HTTP protocol version when communicating with a server.
 	If you want to force the default. The available and default version depend
-	on libcurl. Actually the possible values of
+	on libcurl. Currently the possible values of
 	this option are:
 
 	- HTTP/2
@@ -84,7 +84,7 @@
 	particular configuration of the crypto library in use. Internally
 	this sets the 'CURLOPT_SSL_VERSION' option; see the libcurl
 	documentation for more details on the format of this option and
-	for the ssl version supported. Actually the possible values of
+	for the ssl version supported. Currently the possible values of
 	this option are:
 
 	- sslv2
@@ -199,6 +199,14 @@
 	Transfer-Encoding: chunked is used to avoid creating a
 	massive pack file locally.  Default is 1 MiB, which is
 	sufficient for most requests.
++
+Note that raising this limit is only effective for disabling chunked
+transfer encoding and therefore should be used only where the remote
+server or a proxy only supports HTTP/1.0 or is noncompliant with the
+HTTP standard.  Raising this is not, in general, an effective solution
+for most push problems, but can increase memory consumption
+significantly since the entire buffer is allocated even for small
+pushes.
 
 http.lowSpeedLimit, http.lowSpeedTime::
 	If the HTTP transfer speed is less than 'http.lowSpeedLimit'
diff --git a/Documentation/config/merge.txt b/Documentation/config/merge.txt
index 6a31393..88b2912 100644
--- a/Documentation/config/merge.txt
+++ b/Documentation/config/merge.txt
@@ -70,6 +70,16 @@
 	Whether to print the diffstat between ORIG_HEAD and the merge result
 	at the end of the merge.  True by default.
 
+merge.autoStash::
+	When set to true, automatically create a temporary stash entry
+	before the operation begins, and apply it after the operation
+	ends.  This means that you can run rebase on a dirty worktree.
+	However, use with care: the final stash application after a
+	successful rebase might result in non-trivial conflicts.
+	This option can be overridden by the `--no-autostash` and
+	`--autostash` options of linkgit:git-merge[1].
+	Defaults to false.
+
 merge.tool::
 	Controls which merge tool is used by linkgit:git-mergetool[1].
 	The list below shows the valid built-in values.
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 1d66f0c..0dac580 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -27,6 +27,13 @@
 all existing objects. You can force recompression by passing the -F option
 to linkgit:git-repack[1].
 
+pack.allowPackReuse::
+	When true, and when reachability bitmaps are enabled,
+	pack-objects will try to send parts of the bitmapped packfile
+	verbatim. This can reduce memory and CPU usage to serve fetches,
+	but might result in sending a slightly larger pack. Defaults to
+	true.
+
 pack.island::
 	An extended regular expression configuring a set of delta
 	islands. See "DELTA ISLANDS" in linkgit:git-pack-objects[1]
diff --git a/Documentation/config/protocol.txt b/Documentation/config/protocol.txt
index bfccc07..756591d 100644
--- a/Documentation/config/protocol.txt
+++ b/Documentation/config/protocol.txt
@@ -45,11 +45,10 @@
 --
 
 protocol.version::
-	Experimental. If set, clients will attempt to communicate with a
-	server using the specified protocol version.  If unset, no
-	attempt will be made by the client to communicate using a
-	particular protocol version, this results in protocol version 0
-	being used.
+	If set, clients will attempt to communicate with a server
+	using the specified protocol version.  If the server does
+	not support it, communication falls back to version 0.
+	If unset, the default is `2`.
 	Supported versions:
 +
 --
diff --git a/Documentation/config/pull.txt b/Documentation/config/pull.txt
index b87cab3..5404830 100644
--- a/Documentation/config/pull.txt
+++ b/Documentation/config/pull.txt
@@ -14,15 +14,16 @@
 	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'
+When `merges` (or just 'm'), 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` (deprecated in favor of `merges`), also pass
+When `preserve` (or just 'p', deprecated in favor of `merges`), also pass
 `--preserve-merges` along to 'git rebase' so that locally committed merge
 commits will not be flattened by running 'git pull'.
 +
-When the value is `interactive`, the rebase is run in interactive mode.
+When the value is `interactive` (or just 'i'), the rebase is run in interactive
+mode.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
diff --git a/Documentation/config/push.txt b/Documentation/config/push.txt
index 0a0e000..54871f8 100644
--- a/Documentation/config/push.txt
+++ b/Documentation/config/push.txt
@@ -1,6 +1,7 @@
 push.default::
 	Defines the action `git push` should take if no refspec is
-	explicitly given.  Different values are well-suited for
+	given (whether from the command-line, config, or elsewhere).
+	Different values are well-suited for
 	specific workflows; for instance, in a purely central workflow
 	(i.e. the fetch source is equal to the push destination),
 	`upstream` is probably what you want.  Possible values are:
@@ -8,7 +9,7 @@
 --
 
 * `nothing` - do not push anything (error out) unless a refspec is
-  explicitly given. This is primarily meant for people who want to
+  given. This is primarily meant for people who want to
   avoid mistakes by always being explicit.
 
 * `current` - push the current branch to update a branch with the same
diff --git a/Documentation/config/rebase.txt b/Documentation/config/rebase.txt
index d98e32d..7f7a07d 100644
--- a/Documentation/config/rebase.txt
+++ b/Documentation/config/rebase.txt
@@ -5,6 +5,12 @@
 	is always used. Setting this will emit a warning, to alert any
 	remaining users that setting this now does nothing.
 
+rebase.backend::
+	Default backend to use for rebasing.  Possible choices are
+	'apply' or 'merge'.  In the future, if the merge backend gains
+	all remaining capabilities of the apply backend, this setting
+	may become unused.
+
 rebase.stat::
 	Whether to show a diffstat of what changed upstream since the last
 	rebase. False by default.
diff --git a/Documentation/config/sendemail.txt b/Documentation/config/sendemail.txt
index 0006faf..fe27473 100644
--- a/Documentation/config/sendemail.txt
+++ b/Documentation/config/sendemail.txt
@@ -4,7 +4,7 @@
 	values in the 'sendemail' section. The default identity is
 	the value of `sendemail.identity`.
 
-sendemail.smtpEncryption::
+sendemail.smtpEncryption annotate:bugreport[include] ::
 	See linkgit:git-send-email[1] for description.  Note that this
 	setting is not subject to the 'identity' mechanism.
 
@@ -15,7 +15,7 @@
 	Path to ca-certificates (either a directory or a single file).
 	Set it to an empty string to disable certificate verification.
 
-sendemail.<identity>.*::
+sendemail.<identity>.* annotate:bugreport[exclude] ::
 	Identity-specific versions of the 'sendemail.*' parameters
 	found below, taking precedence over those when this
 	identity is selected, through either the command-line or
@@ -23,41 +23,41 @@
 
 sendemail.aliasesFile::
 sendemail.aliasFileType::
-sendemail.annotate::
-sendemail.bcc::
-sendemail.cc::
-sendemail.ccCmd::
-sendemail.chainReplyTo::
-sendemail.confirm::
-sendemail.envelopeSender::
-sendemail.from::
-sendemail.multiEdit::
-sendemail.signedoffbycc::
-sendemail.smtpPass::
-sendemail.suppresscc::
-sendemail.suppressFrom::
-sendemail.to::
-sendemail.tocmd::
-sendemail.smtpDomain::
-sendemail.smtpServer::
-sendemail.smtpServerPort::
-sendemail.smtpServerOption::
-sendemail.smtpUser::
-sendemail.thread::
-sendemail.transferEncoding::
-sendemail.validate::
-sendemail.xmailer::
+sendemail.annotate annotate:bugreport[include] ::
+sendemail.bcc annotate:bugreport[include] ::
+sendemail.cc annotate:bugreport[include] ::
+sendemail.ccCmd annotate:bugreport[include] ::
+sendemail.chainReplyTo annotate:bugreport[include] ::
+sendemail.confirm annotate:bugreport[include] ::
+sendemail.envelopeSender annotate:bugreport[include] ::
+sendemail.from annotate:bugreport[include] ::
+sendemail.multiEdit annotate:bugreport[include] ::
+sendemail.signedoffbycc annotate:bugreport[include] ::
+sendemail.smtpPass annotate:bugreport[exclude] ::
+sendemail.suppresscc annotate:bugreport[include] ::
+sendemail.suppressFrom annotate:bugreport[include] ::
+sendemail.to annotate:bugreport[include] ::
+sendemail.tocmd annotate:bugreport[include] ::
+sendemail.smtpDomain annotate:bugreport[include] ::
+sendemail.smtpServer annotate:bugreport[include] ::
+sendemail.smtpServerPort annotate:bugreport[include] ::
+sendemail.smtpServerOption annotate:bugreport[include] ::
+sendemail.smtpUser annotate:bugreport[exclude] ::
+sendemail.thread annotate:bugreport[include] ::
+sendemail.transferEncoding annotate:bugreport[include] ::
+sendemail.validate annotate:bugreport[include] ::
+sendemail.xmailer annotate:bugreport[include] ::
 	See linkgit:git-send-email[1] for description.
 
 sendemail.signedoffcc (deprecated)::
 	Deprecated alias for `sendemail.signedoffbycc`.
 
-sendemail.smtpBatchSize::
+sendemail.smtpBatchSize annotate:bugreport[include] ::
 	Number of messages to be sent per connection, after that a relogin
 	will happen.  If the value is 0 or undefined, send all messages in
 	one connection.
 	See also the `--batch-size` option of linkgit:git-send-email[1].
 
-sendemail.smtpReloginDelay::
+sendemail.smtpReloginDelay annotate:bugreport[include] ::
 	Seconds wait before reconnecting to smtp server.
 	See also the `--relogin-delay` option of linkgit:git-send-email[1].
diff --git a/Documentation/config/user.txt b/Documentation/config/user.txt
index 0557cbb..59aec7c 100644
--- a/Documentation/config/user.txt
+++ b/Documentation/config/user.txt
@@ -13,7 +13,12 @@
 	Also, all of these can be overridden by the `GIT_AUTHOR_NAME`,
 	`GIT_AUTHOR_EMAIL`, `GIT_COMMITTER_NAME`,
 	`GIT_COMMITTER_EMAIL` and `EMAIL` environment variables.
-	See linkgit:git-commit-tree[1] for more information.
++
+Note that the `name` forms of these variables conventionally refer to
+some form of a personal name.  See linkgit:git-commit[1] and the
+environment variables section of linkgit:git[1] for more information on
+these settings and the `credential.username` option if you're looking
+for authentication credentials instead.
 
 user.useConfigOnly::
 	Instruct Git to avoid trying to guess defaults for `user.email`
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 09faee3..bb31f0c 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -567,13 +567,13 @@
 file:
 +
 ----
-+    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
++    return frotz(nitfol, two->ptr, 1, 0);
 ...
--    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
+-    hit = frotz(nitfol, mf2.ptr, 1, 0);
 ----
 +
-While `git log -G"regexec\(regexp"` will show this commit, `git log
--S"regexec\(regexp" --pickaxe-regex` will not (because the number of
+While `git log -G"frotz\(nitfol"` will show this commit, `git log
+-S"frotz\(nitfol" --pickaxe-regex` will not (because the number of
 occurrences of that string did not change).
 +
 Unless `--text` is supplied patches of binary files without a textconv
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index a2f7862..a115a1a 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -139,7 +139,10 @@
 	specified refspec (can be given more than once) to map the
 	refs to remote-tracking branches, instead of the values of
 	`remote.*.fetch` configuration variables for the remote
-	repository.  See section on "Configured Remote-tracking
+	repository.  Providing an empty `<refspec>` to the
+	`--refmap` option causes Git to ignore the configured
+	refspecs and rely entirely on the refspecs supplied as
+	command-line arguments. See section on "Configured Remote-tracking
 	Branches" for details.
 
 -t::
diff --git a/Documentation/git-bugreport.txt b/Documentation/git-bugreport.txt
new file mode 100644
index 0000000..e870900
--- /dev/null
+++ b/Documentation/git-bugreport.txt
@@ -0,0 +1,55 @@
+git-bugreport(1)
+================
+
+NAME
+----
+git-bugreport - Collect information for user to file a bug report
+
+SYNOPSIS
+--------
+[verse]
+'git bugreport' [(-o | --output-directory) <path>] [(-s | --suffix) <format>]
+
+DESCRIPTION
+-----------
+Captures information about the user's machine, Git client, and repository state,
+as well as a form requesting information about the behavior the user observed,
+into a single text file which the user can then share, for example to the Git
+mailing list, in order to report an observed bug.
+
+The following information is requested from the user:
+
+ - Reproduction steps
+ - Expected behavior
+ - Actual behavior
+
+The following information is captured automatically:
+
+ - 'git version --build-options'
+ - uname sysname, release, version, and machine strings
+ - Compiler-specific info string
+ - 'git remote-https --build-info'
+ - $SHELL
+ - Selected config values
+ - A list of enabled hooks
+ - The number of loose objects in the repository
+ - The number of packs and packed objects in the repository
+ - A list of the contents of .git/objects/info (or equivalent)
+ - The number of valid and invalid alternates
+
+OPTIONS
+-------
+-o <path>::
+--output-directory <path>::
+	Place the resulting bug report file in `<path>` instead of the root of
+	the Git repository.
+
+-s <format>::
+--suffix <format>::
+	Specify an alternate suffix for the bugreport name, to create a file
+	named 'git-bugreport-<formatted suffix>'. This should take the form of a
+	link:strftime[3] format string; the current local time will be used.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
index bcd85c1..717d52c 100644
--- a/Documentation/git-commit-graph.txt
+++ b/Documentation/git-commit-graph.txt
@@ -26,7 +26,10 @@
 	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 in the `<dir>/info` directory and
-	the packfiles are expected to be in `<dir>/pack`.
+	the packfiles are expected to be in `<dir>/pack`. If the directory
+	could not be made into an absolute path, or does not match any known
+	object directory, `git commit-graph ...` will exit with non-zero
+	status.
 
 --[no-]progress::
 	Turn progress on/off explicitly. If neither is specified, progress is
@@ -36,29 +39,47 @@
 --------
 'write'::
 
-Write a commit-graph file based on the commits found in packfiles.
+Write a commit-graph file based on the specified sources of input:
 +
-With the `--stdin-packs` option, generate the new commit graph by
+With the `--input=stdin-packs` option, generate the new commit graph by
 walking objects only in the specified pack-indexes. (Cannot be combined
-with `--stdin-commits` or `--reachable`.)
+with `--input=stdin-commits` or `--input=reachable`.)
 +
-With the `--stdin-commits` option, generate the new commit graph by
-walking commits starting at the commits specified in stdin as a list
+With the `--input=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` or `--reachable`.)
+`--input=stdin-packs` or `--input=reachable`.)
 +
-With the `--reachable` option, generate the new commit graph by walking
-commits starting at all refs. (Cannot be combined with `--stdin-commits`
-or `--stdin-packs`.)
+With the `--input=reachable` option, generate the new commit graph by
+walking commits starting at all refs. (Cannot be combined with
+`--input=stdin-commits` or `--input=stdin-packs`.)
 +
-With the `--append` option, include all commits that are present in the
-existing commit-graph file.
+With the `--input=append` option, include all commits that are present
+in the existing commit-graph file.
 +
-With the `--split` option, write the commit-graph as a chain of multiple
-commit-graph files stored in `<dir>/info/commit-graphs`. The new commits
-not already in the commit-graph are added in a new "tip" file. This file
-is merged with the existing file if the following merge conditions are
-met:
+With the `--input=none` option, behave as if `--input=append` were
+given, but do not walk other packs to find additional commits.
++
+If none of the above options are given, then generate the new
+commit-graph by walking over all pack-indexes.
++
+With the `--split[=<strategy>]` option, write the commit-graph as a
+chain of multiple commit-graph files stored in
+`<dir>/info/commit-graphs`. Commit-graph layers are merged based on the
+strategy and other splitting options. The new commits not already in the
+commit-graph are added in a new "tip" file. This file is merged with the
+existing file if the following merge conditions are met:
++
+* If `--split=merge-always` is specified, then a merge is always
+conducted, and the remaining options are ignored. Conversely, if
+`--split=no-merge` is specified, a merge is never performed, and the
+remaining options are ignored. A bare `--split` defers to the remaining
+options.
++
+With the `--changed-paths` option, compute and write information about the
+paths changed between a commit and it's first parent. This operation can
+take a while on large repositories. It provides significant performance gains
+for getting history of a directory or a file with `git log -- <path>`.
 +
 * If `--size-multiple=<X>` is not specified, let `X` equal 2. If the new
 tip file would have `N` commits and the previous tip has `M` commits and
@@ -96,20 +117,20 @@
   using commits in `<pack-index>`.
 +
 ------------------------------------------------
-$ echo <pack-index> | git commit-graph write --stdin-packs
+$ echo <pack-index> | git commit-graph write --input=stdin-packs
 ------------------------------------------------
 
 * Write a commit-graph file containing all reachable commits.
 +
 ------------------------------------------------
-$ git show-ref -s | git commit-graph write --stdin-commits
+$ git show-ref -s | git commit-graph write --input=stdin-commits
 ------------------------------------------------
 
 * Write a commit-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
+$ git rev-parse HEAD | git commit-graph write --input=stdin-commits --input=append
 ------------------------------------------------
 
 
diff --git a/Documentation/git-commit-tree.txt b/Documentation/git-commit-tree.txt
index 4b90b9c..ec15ee8 100644
--- a/Documentation/git-commit-tree.txt
+++ b/Documentation/git-commit-tree.txt
@@ -69,7 +69,6 @@
 	Do not GPG-sign commit, to countermand a `--gpg-sign` option
 	given earlier on the command line.
 
-
 Commit Information
 ------------------
 
@@ -79,26 +78,6 @@
 - author name, email and date
 - committer name and email and the commit time.
 
-While parent object ids are provided on the command line, author and
-committer information is taken from the following environment variables,
-if set:
-
-	GIT_AUTHOR_NAME
-	GIT_AUTHOR_EMAIL
-	GIT_AUTHOR_DATE
-	GIT_COMMITTER_NAME
-	GIT_COMMITTER_EMAIL
-	GIT_COMMITTER_DATE
-
-(nb "<", ">" and "\n"s are stripped)
-
-In case (some of) these environment variables are not set, the information
-is taken from the configuration items user.name and user.email, or, if not
-present, the environment variable EMAIL, or, if that is not set,
-system user name and the hostname used for outgoing mail (taken
-from `/etc/mailname` and falling back to the fully qualified hostname when
-that file does not exist).
-
 A commit comment is read from stdin. If a changelog
 entry is not provided via "<" redirection, 'git commit-tree' will just wait
 for one to be entered and terminated with ^D.
@@ -117,6 +96,7 @@
 SEE ALSO
 --------
 linkgit:git-write-tree[1]
+linkgit:git-commit[1]
 
 GIT
 ---
diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index ced5a9b..13f6539 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -367,9 +367,6 @@
 +
 For more details, see the 'pathspec' entry in linkgit:gitglossary[7].
 
-:git-commit: 1
-include::date-formats.txt[]
-
 EXAMPLES
 --------
 When recording your own work, the contents of modified files in
@@ -463,6 +460,43 @@
 should be recorded as a single commit.  In fact, the command
 refuses to run when given pathnames (but see `-i` option).
 
+COMMIT INFORMATION
+------------------
+
+Author and committer information is taken from the following environment
+variables, if set:
+
+	GIT_AUTHOR_NAME
+	GIT_AUTHOR_EMAIL
+	GIT_AUTHOR_DATE
+	GIT_COMMITTER_NAME
+	GIT_COMMITTER_EMAIL
+	GIT_COMMITTER_DATE
+
+(nb "<", ">" and "\n"s are stripped)
+
+The author and committer names are by convention some form of a personal name
+(that is, the name by which other humans refer to you), although Git does not
+enforce or require any particular form. Arbitrary Unicode may be used, subject
+to the constraints listed above. This name has no effect on authentication; for
+that, see the `credential.username` variable in linkgit:git-config[1].
+
+In case (some of) these environment variables are not set, the information
+is taken from the configuration items `user.name` and `user.email`, or, if not
+present, the environment variable EMAIL, or, if that is not set,
+system user name and the hostname used for outgoing mail (taken
+from `/etc/mailname` and falling back to the fully qualified hostname when
+that file does not exist).
+
+The `author.name` and `committer.name` and their corresponding email options
+override `user.name` and `user.email` if set and are overridden themselves by
+the environment variables.
+
+The typical usage is to set just the `user.name` and `user.email` variables;
+the other options are provided for more complex use cases.
+
+:git-commit: 1
+include::date-formats.txt[]
 
 DISCUSSION
 ----------
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index 899e92a..7573160 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -9,18 +9,18 @@
 SYNOPSIS
 --------
 [verse]
-'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] name [value [value_regex]]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-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>] [--show-origin] [--show-scope] [-z|--null] --get name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-z|--null] --get-all name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-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
 'git config' [<file-option>] --remove-section name
-'git config' [<file-option>] [--show-origin] [-z|--null] [--name-only] -l | --list
+'git config' [<file-option>] [--show-origin] [--show-scope] [-z|--null] [--name-only] -l | --list
 'git config' [<file-option>] --get-color name [default]
 'git config' [<file-option>] --get-colorbool name [stdout-is-tty]
 'git config' [<file-option>] -e | --edit
@@ -222,6 +222,11 @@
 	the actual origin (config file path, ref, or blob id if
 	applicable).
 
+--show-scope::
+	Similar to `--show-origin` in that it augments the output of
+	all queried config options with the scope of that value
+	(local, global, system, command).
+
 --get-colorbool name [stdout-is-tty]::
 
 	Find the color setting for `name` (e.g. `color.diff`) and output
diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index a530fef..40ba4aa 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -467,9 +467,9 @@
 
 * In editing files, git-filter-branch by design checks out each and
   every commit as it existed in the original repo.  If your repo has
-  10\^5 files and 10\^5 commits, but each commit only modifies 5
-  files, then git-filter-branch will make you do 10\^10 modifications,
-  despite only having (at most) 5*10^5 unique blobs.
+  `10^5` files and `10^5` commits, but each commit only modifies five
+  files, then git-filter-branch will make you do `10^10` modifications,
+  despite only having (at most) `5*10^5` unique blobs.
 
 * If you try and cheat and try to make git-filter-branch only work on
   files modified in a commit, then two things happen
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index c89fb56..ddb6acc 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -59,8 +59,8 @@
 	other than 'default'.
 
 grep.threads::
-	Number of grep worker threads to use.  If unset (or set to 0),
-	8 threads are used by default (for now).
+	Number of grep worker threads to use. If unset (or set to 0), Git will
+	use as many threads as the number of logical cores available.
 
 grep.fullName::
 	If set to true, enable `--full-name` option by default.
@@ -96,7 +96,8 @@
 	Recursively search in each submodule that has been initialized and
 	checked out in the repository.  When used in combination with the
 	<tree> option the prefix of all submodule output will be the name of
-	the parent project's <tree> object.
+	the parent project's <tree> object. This option has no effect
+	if `--no-index` is given.
 
 -a::
 --text::
@@ -347,6 +348,17 @@
 `git grep solution -- :^Documentation`::
 	Looks for `solution`, excluding files in `Documentation`.
 
+NOTES ON THREADS
+----------------
+
+The `--threads` option (and the grep.threads configuration) will be ignored when
+`--open-files-in-pager` is used, forcing a single-threaded execution.
+
+When grepping the object store (with `--cached` or giving tree objects), running
+with multiple threads might perform slower than single threaded if `--textconv`
+is given and there're too many text conversions. So if you experience low
+performance in this case, it might be desirable to use `--threads=1`.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
index 3494a1d..dab9609 100644
--- a/Documentation/git-p4.txt
+++ b/Documentation/git-p4.txt
@@ -374,14 +374,55 @@
     been submitted. Implies --disable-rebase. Can also be set with
     git-p4.disableP4Sync. Sync with origin/master still goes ahead if possible.
 
-Hook for submit
-~~~~~~~~~~~~~~~
+Hooks for submit
+----------------
+
+p4-pre-submit
+~~~~~~~~~~~~~
+
 The `p4-pre-submit` hook is executed if it exists and is executable.
 The hook takes no parameters and nothing from standard input. Exiting with
 non-zero status from this script prevents `git-p4 submit` from launching.
+It can be bypassed with the `--no-verify` command line option.
 
 One usage scenario is to run unit tests in the hook.
 
+p4-prepare-changelist
+~~~~~~~~~~~~~~~~~~~~~
+
+The `p4-prepare-changelist` hook is executed right after preparing
+the default changelist message and before the editor is started.
+It takes one parameter, the name of the file that contains the
+changelist text. Exiting with a non-zero status from the script
+will abort the process.
+
+The purpose of the hook is to edit the message file in place,
+and it is not supressed by the `--no-verify` option. This hook
+is called even if `--prepare-p4-only` is set.
+
+p4-changelist
+~~~~~~~~~~~~~
+
+The `p4-changelist` hook is executed after the changelist
+message has been edited by the user. It can be bypassed with the
+`--no-verify` option. It takes a single parameter, the name
+of the file that holds the proposed changelist text. Exiting
+with a non-zero status causes the command to abort.
+
+The hook is allowed to edit the changelist file and can be used
+to normalize the text into some project standard format. It can
+also be used to refuse the Submit after inspect the message file.
+
+p4-post-changelist
+~~~~~~~~~~~~~~~~~~
+
+The `p4-post-changelist` hook is invoked after the submit has
+successfully occured in P4. It takes no parameters and is meant
+primarily for notification and cannot affect the outcome of the
+git p4 submit action.
+
+
+
 Rebase options
 ~~~~~~~~~~~~~~
 These options can be used to modify 'git p4 rebase' behavior.
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index dfb901f..ba3772d 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -133,15 +133,6 @@
 --no-rebase::
 	Override earlier --rebase.
 
---autostash::
---no-autostash::
-	Before starting rebase, stash local modifications away (see
-	linkgit:git-stash[1]) if needed, and apply the stash entry when
-	done. `--no-autostash` is useful to override the `rebase.autoStash`
-	configuration variable (see linkgit:git-config[1]).
-+
-This option is only valid when "--rebase" is used.
-
 Options related to fetching
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 0c4f038..8c1f4b8 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -258,16 +258,45 @@
 	original branch. The index and working tree are also left
 	unchanged as a result.
 
---keep-empty::
-	Keep the commits that do not change anything from its
-	parents in the result.
+--apply:
+	Use applying strategies to rebase (calling `git-am`
+	internally).  This option may become a no-op in the future
+	once the merge backend handles everything the apply one does.
 +
 See also INCOMPATIBLE OPTIONS below.
 
+--empty={drop,keep,ask}::
+	How to handle commits that are not empty to start and are not
+	clean cherry-picks of any upstream commit, but which become
+	empty after rebasing (because they contain a subset of already
+	upstream changes).  With drop (the default), commits that
+	become empty are dropped.  With keep, such commits are kept.
+	With ask (implied by --interactive), the rebase will halt when
+	an empty commit is applied allowing you to choose whether to
+	drop it, edit files more, or just commit the empty changes.
+	Other options, like --exec, will use the default of drop unless
+	-i/--interactive is explicitly specified.
++
+Note that commits which start empty are kept, and commits which are
+clean cherry-picks (as determined by `git log --cherry-mark ...`) are
+always dropped.
++
+See also INCOMPATIBLE OPTIONS below.
+
+--keep-empty::
+	No-op.  Rebasing commits that started empty (had no change
+	relative to their parent) used to fail and this option would
+	override that behavior, allowing commits with empty changes to
+	be rebased.  Now commits with no changes do not cause rebasing
+	to halt.
++
+See also BEHAVIORAL DIFFERENCES and INCOMPATIBLE OPTIONS below.
+
 --allow-empty-message::
-	By default, rebasing commits with an empty message will fail.
-	This option overrides that behavior, allowing commits with empty
-	messages to be rebased.
+	No-op.  Rebasing commits with an empty message used to fail
+	and this option would override that behavior, allowing commits
+	with empty messages to be rebased.  Now commits with an empty
+	message do not cause rebasing to halt.
 +
 See also INCOMPATIBLE OPTIONS below.
 
@@ -286,7 +315,7 @@
 --merge::
 	Use merging strategies to rebase.  When the recursive (default) merge
 	strategy is used, this allows rebase to be aware of renames on the
-	upstream side.
+	upstream side.  This is the default.
 +
 Note that a rebase merge works by replaying each commit from the working
 branch on top of the <upstream> branch.  Because of this, when a merge
@@ -356,7 +385,7 @@
 	Ensure at least <n> lines of surrounding context match before
 	and after each change.  When fewer lines of surrounding
 	context exist they all must match.  By default no context is
-	ever ignored.
+	ever ignored.  Implies --apply.
 +
 See also INCOMPATIBLE OPTIONS below.
 
@@ -394,8 +423,9 @@
 
 --ignore-whitespace::
 --whitespace=<option>::
-	These flag are passed to the 'git apply' program
+	These flags are passed to the 'git apply' program
 	(see linkgit:git-apply[1]) that applies the patch.
+	Implies --apply.
 +
 See also INCOMPATIBLE OPTIONS below.
 
@@ -539,10 +569,11 @@
 
 The following options:
 
+ * --apply
  * --committer-date-is-author-date
  * --ignore-date
- * --whitespace
  * --ignore-whitespace
+ * --whitespace
  * -C
 
 are incompatible with the following options:
@@ -557,6 +588,7 @@
  * --interactive
  * --exec
  * --keep-empty
+ * --empty=
  * --edit-todo
  * --root when used in combination with --onto
 
@@ -565,33 +597,127 @@
  * --preserve-merges and --interactive
  * --preserve-merges and --signoff
  * --preserve-merges and --rebase-merges
+ * --preserve-merges and --empty=
  * --keep-base and --onto
  * --keep-base and --root
 
 BEHAVIORAL DIFFERENCES
 -----------------------
 
-There are some subtle differences how the backends behave.
+git rebase has two primary backends: apply and merge.  (The apply
+backend used to known as the 'am' backend, but the name led to
+confusion as it looks like a verb instead of a noun.  Also, the merge
+backend used to be known as the interactive backend, but it is now
+used for non-interactive cases as well.  Both were renamed based on
+lower-level functionality that underpinned each.) There are some
+subtle differences in how these two backends behave:
 
 Empty commits
 ~~~~~~~~~~~~~
 
-The am backend drops any "empty" commits, regardless of whether the
-commit started empty (had no changes relative to its parent to
-start with) or ended empty (all changes were already applied
-upstream in other commits).
+The apply backend unfortunately drops intentionally empty commits, i.e.
+commits that started empty, though these are rare in practice.  It
+also drops commits that become empty and has no option for controlling
+this behavior.
 
-The interactive backend drops commits by default that
-started empty and halts if it hits a commit that ended up empty.
-The `--keep-empty` option exists for the interactive backend to allow
-it to keep commits that started empty.
+The merge backend keeps intentionally empty commits.  Similar to the
+apply backend, by default the merge backend drops commits that become
+empty unless -i/--interactive is specified (in which case it stops and
+asks the user what to do).  The merge backend also has an
+--empty={drop,keep,ask} option for changing the behavior of handling
+commits that become empty.
 
 Directory rename detection
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Directory rename heuristics are enabled in the merge and interactive
-backends.  Due to the lack of accurate tree information, directory
-rename detection is disabled in the am backend.
+Due to the lack of accurate tree information (arising from
+constructing fake ancestors with the limited information available in
+patches), directory rename detection is disabled in the apply backend.
+Disabled directory rename detection means that if one side of history
+renames a directory and the other adds new files to the old directory,
+then the new files will be left behind in the old directory without
+any warning at the time of rebasing that you may want to move these
+files into the new directory.
+
+Directory rename detection works with the merge backend to provide you
+warnings in such cases.
+
+Context
+~~~~~~~
+
+The apply backend works by creating a sequence of patches (by calling
+`format-patch` internally), and then applying the patches in sequence
+(calling `am` internally).  Patches are composed of multiple hunks,
+each with line numbers, a context region, and the actual changes.  The
+line numbers have to be taken with some fuzz, since the other side
+will likely have inserted or deleted lines earlier in the file.  The
+context region is meant to help find how to adjust the line numbers in
+order to apply the changes to the right lines.  However, if multiple
+areas of the code have the same surrounding lines of context, the
+wrong one can be picked.  There are real-world cases where this has
+caused commits to be reapplied incorrectly with no conflicts reported.
+Setting diff.context to a larger value may prevent such types of
+problems, but increases the chance of spurious conflicts (since it
+will require more lines of matching context to apply).
+
+The merge backend works with a full copy of each relevant file,
+insulating it from these types of problems.
+
+Labelling of conflicts markers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When there are content conflicts, the merge machinery tries to
+annotate each side's conflict markers with the commits where the
+content came from.  Since the apply backend drops the original
+information about the rebased commits and their parents (and instead
+generates new fake commits based off limited information in the
+generated patches), those commits cannot be identified; instead it has
+to fall back to a commit summary.  Also, when merge.conflictStyle is
+set to diff3, the apply backend will use "constructed merge base" to
+label the content from the merge base, and thus provide no information
+about the merge base commit whatsoever.
+
+The merge backend works with the full commits on both sides of history
+and thus has no such limitations.
+
+Hooks
+~~~~~
+
+The apply backend has not traditionally called the post-commit hook,
+while the merge backend has.  However, this was by accident of
+implementation rather than by design.  Both backends should have the
+same behavior, though it is not clear which one is correct.
+
+Interruptability
+~~~~~~~~~~~~~~~~
+
+The apply backend has safety problems with an ill-timed interrupt; if
+the user presses Ctrl-C at the wrong time to try to abort the rebase,
+the rebase can enter a state where it cannot be aborted with a
+subsequent `git rebase --abort`.  The merge backend does not appear to
+suffer from the same shortcoming.  (See
+https://lore.kernel.org/git/20200207132152.GC2868@szeder.dev/ for
+details.)
+
+Miscellaneous differences
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+There are a few more behavioral differences that most folks would
+probably consider inconsequential but which are mentioned for
+completeness:
+
+* Reflog: The two backends will use different wording when describing
+  the changes made in the reflog, though both will make use of the
+  word "rebase".
+
+* Progress, informational, and error messages: The two backends
+  provide slightly different progress and informational messages.
+  Also, the apply backend writes error messages (such as "Your files
+  would be overwritten...") to stdout, while the merge backend writes
+  them to stderr.
+
+* State directories: The two backends keep their state in different
+  directories under .git/
 
 include::merge-strategies.txt[]
 
diff --git a/Documentation/git-rm.txt b/Documentation/git-rm.txt
index b5c4622..ab75036 100644
--- a/Documentation/git-rm.txt
+++ b/Documentation/git-rm.txt
@@ -8,16 +8,18 @@
 SYNOPSIS
 --------
 [verse]
-'git rm' [-f | --force] [-n] [-r] [--cached] [--ignore-unmatch] [--quiet] [--] <file>...
+'git rm' [-f | --force] [-n] [-r] [--cached] [--ignore-unmatch]
+	  [--quiet] [--pathspec-from-file=<file> [--pathspec-file-nul]]
+	  [--] [<pathspec>...]
 
 DESCRIPTION
 -----------
-Remove files from the index, or from the working tree and the index.
-`git rm` will not remove a file from just your working directory.
-(There is no option to remove a file only from the working tree
-and yet keep it in the index; use `/bin/rm` if you want to do that.)
-The files being removed have to be identical to the tip of the branch,
-and no updates to their contents can be staged in the index,
+Remove files matching pathspec from the index, or from the working tree
+and the index. `git rm` will not remove a file from just your working
+directory. (There is no option to remove a file only from the working
+tree and yet keep it in the index; use `/bin/rm` if you want to do
+that.) The files being removed have to be identical to the tip of the
+branch, and no updates to their contents can be staged in the index,
 though that default behavior can be overridden with the `-f` option.
 When `--cached` is given, the staged content has to
 match either the tip of the branch or the file on disk,
@@ -26,15 +28,20 @@
 
 OPTIONS
 -------
-<file>...::
-	Files to remove.  Fileglobs (e.g. `*.c`) can be given to
-	remove all matching files.  If you want Git to expand
-	file glob characters, you may need to shell-escape them.
-	A leading directory name
-	(e.g. `dir` to remove `dir/file1` and `dir/file2`) can be
-	given to remove all files in the directory, and recursively
-	all sub-directories,
-	but this requires the `-r` option to be explicitly given.
+<pathspec>...::
+	Files to remove.  A leading directory name (e.g. `dir` to remove
+	`dir/file1` and `dir/file2`) can be given to remove all files in
+	the directory, and recursively all sub-directories, but this
+	requires the `-r` option to be explicitly given.
++
+The command removes only the paths that are known to Git.
++
+File globbing matches across directory boundaries.  Thus, given two
+directories `d` and `d2`, there is a difference between using
+`git rm 'd*'` and `git rm 'd/*'`, as the former will also remove all
+of directory `d2`.
++
+For more details, see the 'pathspec' entry in linkgit:gitglossary[7].
 
 -f::
 --force::
@@ -68,19 +75,19 @@
 	`git rm` normally outputs one line (in the form of an `rm` command)
 	for each file removed. This option suppresses that output.
 
+--pathspec-from-file=<file>::
+	Pathspec is passed in `<file>` instead of commandline args. If
+	`<file>` is exactly `-` then standard input is used. Pathspec
+	elements are separated by LF or CR/LF. Pathspec elements can be
+	quoted as explained for the configuration variable `core.quotePath`
+	(see linkgit:git-config[1]). See also `--pathspec-file-nul` and
+	global `--literal-pathspecs`.
 
-DISCUSSION
-----------
+--pathspec-file-nul::
+	Only meaningful with `--pathspec-from-file`. Pathspec elements are
+	separated with NUL character and all other characters are taken
+	literally (including newlines and quotes).
 
-The <file> list given to the command can be exact pathnames,
-file glob patterns, or leading directory names.  The command
-removes only the paths that are known to Git.  Giving the name of
-a file that you have not told Git about does not remove that file.
-
-File globbing matches across directory boundaries.  Thus, given
-two directories `d` and `d2`, there is a difference between
-using `git rm 'd*'` and `git rm 'd/*'`, as the former will
-also remove all of directory `d2`.
 
 REMOVING FILES THAT HAVE DISAPPEARED FROM THE FILESYSTEM
 --------------------------------------------------------
diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
index 974ade2..c0342e5 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -41,6 +41,10 @@
 To avoid interfering with other worktrees, it first enables the
 `extensions.worktreeConfig` setting and makes sure to set the
 `core.sparseCheckout` setting in the worktree-specific config file.
++
+When `--cone` is provided, the `core.sparseCheckoutCone` setting is
+also set, allowing for better performance with a limited set of
+patterns (see 'CONE PATTERN SET' below).
 
 'set'::
 	Write a set of patterns to the sparse-checkout file, as given as
@@ -50,6 +54,21 @@
 +
 When the `--stdin` option is provided, the patterns are read from
 standard in as a newline-delimited list instead of from the arguments.
++
+When `core.sparseCheckoutCone` is enabled, the input list is considered a
+list of directories instead of sparse-checkout patterns. The command writes
+patterns to the sparse-checkout file to include all files contained in those
+directories (recursively) as well as files that are siblings of ancestor
+directories. The input format matches the output of `git ls-tree --name-only`.
+This includes interpreting pathnames that begin with a double quote (") as
+C-style quoted strings.
+
+'add'::
+	Update the sparse-checkout file to include additional patterns.
+	By default, these patterns are read from the command-line arguments,
+	but they can be read from stdin using the `--stdin` option. When
+	`core.sparseCheckoutCone` is enabled, the given patterns are interpreted
+	as directory names as in the 'set' subcommand.
 
 'disable'::
 	Disable the `core.sparseCheckout` config setting, and restore the
@@ -106,7 +125,7 @@
 inclusion/exclusion rules. These can result in O(N*M) pattern matches when
 updating the index, where N is the number of patterns and M is the number
 of paths in the index. To combat this performance issue, a more restricted
-pattern set is allowed when `core.spareCheckoutCone` is enabled.
+pattern set is allowed when `core.sparseCheckoutCone` is enabled.
 
 The accepted patterns in the cone pattern set are:
 
@@ -128,9 +147,12 @@
 ----------------
 
 This says "include everything in root, but nothing two levels below root."
-If we then add the folder `A/B/C` as a recursive pattern, the folders `A` and
-`A/B` are added as parent patterns. The resulting sparse-checkout file is
-now
+
+When in cone mode, the `git sparse-checkout set` subcommand takes a list of
+directories instead of a list of sparse-checkout patterns. In this mode,
+the command `git sparse-checkout set A/B/C` sets the directory `A/B/C` as
+a recursive pattern, the directories `A` and `A/B` are added as parent
+patterns. The resulting sparse-checkout file is now
 
 ----------------
 /*
diff --git a/Documentation/git-stash.txt b/Documentation/git-stash.txt
index 53e1a12..79949f8 100644
--- a/Documentation/git-stash.txt
+++ b/Documentation/git-stash.txt
@@ -15,6 +15,7 @@
 'git stash' branch <branchname> [<stash>]
 'git stash' [push [-p|--patch] [-k|--[no-]keep-index] [-q|--quiet]
 	     [-u|--include-untracked] [-a|--all] [-m|--message <message>]
+	     [--pathspec-from-file=<file> [--pathspec-file-nul]]
 	     [--] [<pathspec>...]]
 'git stash' clear
 'git stash' create [<message>]
@@ -43,10 +44,10 @@
 is also possible). Stashes may also be referenced by specifying just the
 stash index (e.g. the integer `n` is equivalent to `stash@{n}`).
 
-OPTIONS
--------
+COMMANDS
+--------
 
-push [-p|--patch] [-k|--[no-]keep-index] [-u|--include-untracked] [-a|--all] [-q|--quiet] [-m|--message <message>] [--] [<pathspec>...]::
+push [-p|--patch] [-k|--[no-]keep-index] [-u|--include-untracked] [-a|--all] [-q|--quiet] [-m|--message <message>] [--pathspec-from-file=<file> [--pathspec-file-nul]] [--] [<pathspec>...]::
 
 	Save your local modifications to a new 'stash entry' and roll them
 	back to HEAD (in the working tree and in the index).
@@ -56,38 +57,13 @@
 For quickly making a snapshot, you can omit "push".  In this mode,
 non-option arguments are not allowed to prevent a misspelled
 subcommand from making an unwanted stash entry.  The two exceptions to this
-are `stash -p` which acts as alias for `stash push -p` and pathspecs,
+are `stash -p` which acts as alias for `stash push -p` and pathspec elements,
 which are allowed after a double hyphen `--` for disambiguation.
-+
-When pathspec is given to 'git stash push', the new stash entry records the
-modified states only for the files that match the pathspec.  The index
-entries and working tree files are then rolled back to the state in
-HEAD only for these files, too, leaving files that do not match the
-pathspec intact.
-+
-If the `--keep-index` option is used, all changes already added to the
-index are left intact.
-+
-If the `--include-untracked` option is used, all untracked files are also
-stashed and then cleaned up with `git clean`, leaving the working directory
-in a very clean state. If the `--all` option is used instead then the
-ignored files are stashed and cleaned in addition to the untracked files.
-+
-With `--patch`, you can interactively select hunks from the diff
-between HEAD and the working tree to be stashed.  The stash entry is
-constructed such that its index state is the same as the index state
-of your repository, and its worktree contains only the changes you
-selected interactively.  The selected changes are then rolled back
-from your worktree. See the ``Interactive Mode'' section of
-linkgit:git-add[1] to learn how to operate the `--patch` mode.
-+
-The `--patch` option implies `--keep-index`.  You can use
-`--no-keep-index` to override this.
 
 save [-p|--patch] [-k|--[no-]keep-index] [-u|--include-untracked] [-a|--all] [-q|--quiet] [<message>]::
 
 	This option is deprecated in favour of 'git stash push'.  It
-	differs from "stash push" in that it cannot take pathspecs.
+	differs from "stash push" in that it cannot take pathspec.
 	Instead, all non-option arguments are concatenated to form the stash
 	message.
 
@@ -111,7 +87,7 @@
 
 	Show the changes recorded in the stash entry as a diff between the
 	stashed contents and the commit back when the stash entry was first
-	created. When no `<stash>` is given, it shows the latest one.
+	created.
 	By default, the command shows the diffstat, but it will accept any
 	format known to 'git diff' (e.g., `git stash show -p stash@{1}`
 	to view the second most recent entry in patch form).
@@ -128,14 +104,6 @@
 Applying the state can fail with conflicts; in this case, it is not
 removed from the stash list. You need to resolve the conflicts by hand
 and call `git stash drop` manually afterwards.
-+
-If the `--index` option is used, then tries to reinstate not only the working
-tree's changes, but also the index's ones. However, this can fail, when you
-have conflicts (which are stored in the index, where you therefore can no
-longer apply the changes as they were originally).
-+
-When no `<stash>` is given, `stash@{0}` is assumed, otherwise `<stash>` must
-be a reference of the form `stash@{<revision>}`.
 
 apply [--index] [-q|--quiet] [<stash>]::
 
@@ -149,8 +117,7 @@
 	the commit at which the `<stash>` was originally created, applies the
 	changes recorded in `<stash>` to the new working tree and index.
 	If that succeeds, and `<stash>` is a reference of the form
-	`stash@{<revision>}`, it then drops the `<stash>`. When no `<stash>`
-	is given, applies the latest one.
+	`stash@{<revision>}`, it then drops the `<stash>`.
 +
 This is useful if the branch on which you ran `git stash push` has
 changed enough that `git stash apply` fails due to conflicts. Since
@@ -166,9 +133,6 @@
 drop [-q|--quiet] [<stash>]::
 
 	Remove a single stash entry from the list of stash entries.
-	When no `<stash>` is given, it removes the latest one.
-	i.e. `stash@{0}`, otherwise `<stash>` must be a valid stash
-	log reference of the form `stash@{<revision>}`.
 
 create::
 
@@ -185,6 +149,98 @@
 	reflog.  This is intended to be useful for scripts.  It is
 	probably not the command you want to use; see "push" above.
 
+OPTIONS
+-------
+-a::
+--all::
+	This option is only valid for `push` and `save` commands.
++
+All ignored and untracked files are also stashed and then cleaned
+up with `git clean`.
+
+-u::
+--include-untracked::
+	This option is only valid for `push` and `save` commands.
++
+All untracked files are also stashed and then cleaned up with
+`git clean`.
+
+--index::
+	This option is only valid for `pop` and `apply` commands.
++
+Tries to reinstate not only the working tree's changes, but also
+the index's ones. However, this can fail, when you have conflicts
+(which are stored in the index, where you therefore can no longer
+apply the changes as they were originally).
+
+-k::
+--keep-index::
+--no-keep-index::
+	This option is only valid for `push` and `save` commands.
++
+All changes already added to the index are left intact.
+
+-p::
+--patch::
+	This option is only valid for `push` and `save` commands.
++
+Interactively select hunks from the diff between HEAD and the
+working tree to be stashed.  The stash entry is constructed such
+that its index state is the same as the index state of your
+repository, and its worktree contains only the changes you selected
+interactively.  The selected changes are then rolled back from your
+worktree. See the ``Interactive Mode'' section of linkgit:git-add[1]
+to learn how to operate the `--patch` mode.
++
+The `--patch` option implies `--keep-index`.  You can use 
+`--no-keep-index` to override this.
+
+--pathspec-from-file=<file>::
+	This option is only valid for `push` command.
++
+Pathspec is passed in `<file>` instead of commandline args. If
+`<file>` is exactly `-` then standard input is used. Pathspec
+elements are separated by LF or CR/LF. Pathspec elements can be
+quoted as explained for the configuration variable `core.quotePath`
+(see linkgit:git-config[1]). See also `--pathspec-file-nul` and
+global `--literal-pathspecs`.
+
+--pathspec-file-nul::
+	This option is only valid for `push` command.
++
+Only meaningful with `--pathspec-from-file`. Pathspec elements are
+separated with NUL character and all other characters are taken
+literally (including newlines and quotes).
+
+-q::
+--quiet::
+	This option is only valid for `apply`, `drop`, `pop`, `push`,
+	`save`, `store` commands.
++
+Quiet, suppress feedback messages.
+
+\--::
+	This option is only valid for `push` command.
++
+Separates pathspec from options for disambiguation purposes.
+
+<pathspec>...::
+	This option is only valid for `push` command.
++
+The new stash entry records the modified states only for the files
+that match the pathspec.  The index entries and working tree files
+are then rolled back to the state in HEAD only for these files,
+too, leaving files that do not match the pathspec intact.
++
+For more details, see the 'pathspec' entry in linkgit:gitglossary[7].
+
+<stash>::
+	This option is only valid for `apply`, `branch`, `drop`, `pop`,
+	`show` commands.
++
+A reference of the form `stash@{<revision>}`. When no `<stash>` is
+given, the latest stash is assumed (that is, `stash@{0}`).
+
 DISCUSSION
 ----------
 
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 5232407..218942a 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -229,7 +229,7 @@
 checked out commit for each submodule:
 +
 --------------
-git submodule foreach 'echo $path `git rev-parse HEAD`'
+git submodule foreach 'echo $sm_path `git rev-parse HEAD`'
 --------------
 
 sync [--recursive] [--] [<path>...]::
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index c7a6271..1489cb0 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -549,6 +549,22 @@
 `core.untrackedCache` configuration variable (see
 linkgit:git-config[1]).
 
+NOTES
+-----
+
+Users often try to use the assume-unchanged and skip-worktree bits
+to tell Git to ignore changes to files that are tracked.  This does not
+work as expected, since Git may still check working tree files against
+the index when performing certain operations.  In general, Git does not
+provide a way to ignore changes to tracked files, so alternate solutions
+are recommended.
+
+For example, if the file you want to change is some sort of config file,
+the repository can include a sample config file that can then be copied
+into the ignored name and modified.  The repository can even include a
+script to treat the sample file as a template, modifying and copying it
+automatically.
+
 SEE ALSO
 --------
 linkgit:git-config[1],
diff --git a/Documentation/git.txt b/Documentation/git.txt
index b1597ac..b0672bd 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -110,9 +110,23 @@
 	Do not pipe Git output into a pager.
 
 --git-dir=<path>::
-	Set the path to the repository. This can also be controlled by
-	setting the `GIT_DIR` environment variable. It can be an absolute
-	path or relative path to current working directory.
+	Set the path to the repository (".git" directory). This can also be
+	controlled by setting the `GIT_DIR` environment variable. It can be
+	an absolute path or relative path to current working directory.
++
+Specifying the location of the ".git" directory using this
+option (or `GIT_DIR` environment variable) turns off the
+repository discovery that tries to find a directory with
+".git" subdirectory (which is how the repository and the
+top-level of the working tree are discovered), and tells Git
+that you are at the top level of the working tree.  If you
+are not at the top-level directory of the working tree, you
+should tell Git where the top-level of the working tree is,
+with the `--work-tree=<path>` option (or `GIT_WORK_TREE`
+environment variable)
++
+If you just want to run git as if it was started in `<path>` then use
+`git -C <path>`.
 
 --work-tree=<path>::
 	Set the path to the working tree. It can be an absolute path
@@ -482,13 +496,36 @@
 Git Commits
 ~~~~~~~~~~~
 `GIT_AUTHOR_NAME`::
+	The human-readable name used in the author identity when creating commit or
+	tag objects, or when writing reflogs. Overrides the `user.name` and
+	`author.name` configuration settings.
+
 `GIT_AUTHOR_EMAIL`::
+	The email address used in the author identity when creating commit or
+	tag objects, or when writing reflogs. Overrides the `user.email` and
+	`author.email` configuration settings.
+
 `GIT_AUTHOR_DATE`::
+	The date used for the author identity when creating commit or tag objects, or
+	when writing reflogs. See linkgit:git-commit[1] for valid formats.
+
 `GIT_COMMITTER_NAME`::
+	The human-readable name used in the committer identity when creating commit or
+	tag objects, or when writing reflogs. Overrides the `user.name` and
+	`committer.name` configuration settings.
+
 `GIT_COMMITTER_EMAIL`::
+	The email address used in the author identity when creating commit or
+	tag objects, or when writing reflogs. Overrides the `user.email` and
+	`committer.email` configuration settings.
+
 `GIT_COMMITTER_DATE`::
-'EMAIL'::
-	see linkgit:git-commit-tree[1]
+	The date used for the committer identity when creating commit or tag objects, or
+	when writing reflogs. See linkgit:git-commit[1] for valid formats.
+
+`EMAIL`::
+	The email address used in the author and committer identities if no other
+	relevant environment variable or configuration setting has been set.
 
 Git Diffs
 ~~~~~~~~~
diff --git a/Documentation/gitcore-tutorial.txt b/Documentation/gitcore-tutorial.txt
index f880d21..c0b9525 100644
--- a/Documentation/gitcore-tutorial.txt
+++ b/Documentation/gitcore-tutorial.txt
@@ -751,7 +751,7 @@
 ================================================
 If you make the decision to start your new branch at some
 other point in the history than the current `HEAD`, you can do so by
-just telling 'git checkout' what the base of the checkout would be.
+just telling 'git switch' what the base of the checkout would be.
 In other words, if you have an earlier tag or branch, you'd just do
 
 ------------
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index ea759fd..5b9d14f 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -186,7 +186,94 @@
 --------------
 
 You can write your own custom helpers to interface with any system in
-which you keep credentials. See credential.h for details.
+which you keep credentials.
+
+Credential helpers are programs executed by Git to fetch or save
+credentials from and to long-term storage (where "long-term" is simply
+longer than a single Git process; e.g., credentials may be stored
+in-memory for a few minutes, or indefinitely on disk).
+
+Each helper is specified by a single string in the configuration
+variable `credential.helper` (and others, see linkgit:git-config[1]).
+The string is transformed by Git into a command to be executed using
+these rules:
+
+  1. If the helper string begins with "!", it is considered a shell
+     snippet, and everything after the "!" becomes the command.
+
+  2. Otherwise, if the helper string begins with an absolute path, the
+     verbatim helper string becomes the command.
+
+  3. Otherwise, the string "git credential-" is prepended to the helper
+     string, and the result becomes the command.
+
+The resulting command then has an "operation" argument appended to it
+(see below for details), and the result is executed by the shell.
+
+Here are some example specifications:
+
+----------------------------------------------------
+# run "git credential-foo"
+foo
+
+# same as above, but pass an argument to the helper
+foo --bar=baz
+
+# the arguments are parsed by the shell, so use shell
+# quoting if necessary
+foo --bar="whitespace arg"
+
+# you can also use an absolute path, which will not use the git wrapper
+/path/to/my/helper --with-arguments
+
+# or you can specify your own shell snippet
+!f() { echo "password=`cat $HOME/.secret`"; }; f
+----------------------------------------------------
+
+Generally speaking, rule (3) above is the simplest for users to specify.
+Authors of credential helpers should make an effort to assist their
+users by naming their program "git-credential-$NAME", and putting it in
+the `$PATH` or `$GIT_EXEC_PATH` during installation, which will allow a
+user to enable it with `git config credential.helper $NAME`.
+
+When a helper is executed, it will have one "operation" argument
+appended to its command line, which is one of:
+
+`get`::
+
+	Return a matching credential, if any exists.
+
+`store`::
+
+	Store the credential, if applicable to the helper.
+
+`erase`::
+
+	Remove a matching credential, if any, from the helper's storage.
+
+The details of the credential will be provided on the helper's stdin
+stream. The exact format is the same as the input/output format of the
+`git credential` plumbing command (see the section `INPUT/OUTPUT
+FORMAT` in linkgit:git-credential[1] for a detailed specification).
+
+For a `get` operation, the helper should produce a list of attributes on
+stdout in the same format (see linkgit:git-credential[1] for common
+attributes). A helper is free to produce a subset, or even no values at
+all if it has nothing useful to provide. Any provided attributes will
+overwrite those already known about by Git.  If a helper outputs a
+`quit` attribute with a value of `true` or `1`, no further helpers will
+be consulted, nor will the user be prompted (if no credential has been
+provided, the operation will then fail).
+
+For a `store` or `erase` operation, the helper's output is ignored.
+If it fails to perform the requested operation, it may complain to
+stderr to inform the user. If it does not support the requested
+operation (e.g., a read-only store), it should silently ignore the
+request.
+
+If a helper receives any other operation, it should silently ignore the
+request. This leaves room for future operations to be added (older
+helpers will just ignore the new requests).
 
 GIT
 ---
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index 50365f2..81f2a87 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -490,9 +490,16 @@
 ~~~~~~~~~~~~~~~~~~
 
 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.
+set to `.git/hooks/fsmonitor-watchman` or `.git/hooks/fsmonitor-watchmanv2`
+depending on the version of the hook to use.
+
+Version 1 takes two arguments, a version (1) and the time in elapsed
+nanoseconds since midnight, January 1, 1970.
+
+Version 2 takes two arguments, a version (2) and a token that is used
+for identifying changes since the token. For watchman this would be
+a clock id. This version must output to stdout the new token followed
+by a NUL before the list of files.
 
 The hook should output to stdout the list of all files in the working
 directory that may have changed since the requested time.  The logic
@@ -515,12 +522,61 @@
 hook to limit its search.  On error, it will fall back to verifying
 all files and folders.
 
+p4-changelist
+~~~~~~~~~~~~~
+
+This hook is invoked by `git-p4 submit`.
+
+The `p4-changelist` hook is executed after the changelist
+message has been edited by the user. It can be bypassed with the
+`--no-verify` option. It takes a single parameter, the name
+of the file that holds the proposed changelist text. Exiting
+with a non-zero status causes the command to abort.
+
+The hook is allowed to edit the changelist file and can be used
+to normalize the text into some project standard format. It can
+also be used to refuse the Submit after inspect the message file.
+
+Run `git-p4 submit --help` for details.
+
+p4-prepare-changelist
+~~~~~~~~~~~~~~~~~~~~~
+
+This hook is invoked by `git-p4 submit`.
+
+The `p4-prepare-changelist` hook is executed right after preparing
+the default changelist message and before the editor is started.
+It takes one parameter, the name of the file that contains the
+changelist text. Exiting with a non-zero status from the script
+will abort the process.
+
+The purpose of the hook is to edit the message file in place,
+and it is not supressed by the `--no-verify` option. This hook
+is called even if `--prepare-p4-only` is set.
+
+Run `git-p4 submit --help` for details.
+
+p4-post-changelist
+~~~~~~~~~~~~~~~~~~
+
+This hook is invoked by `git-p4 submit`.
+
+The `p4-post-changelist` hook is invoked after the submit has
+successfully occured in P4. It takes no parameters and is meant
+primarily for notification and cannot affect the outcome of the
+git p4 submit action.
+
+Run `git-p4 submit --help` for details.
+
 p4-pre-submit
 ~~~~~~~~~~~~~
 
 This hook is invoked by `git-p4 submit`. It takes no parameters and nothing
 from standard input. Exiting with non-zero status from this script prevent
-`git-p4 submit` from launching. Run `git-p4 submit --help` for details.
+`git-p4 submit` from launching. It can be bypassed with the `--no-verify`
+command line option. Run `git-p4 submit --help` for details.
+
+
 
 post-index-change
 ~~~~~~~~~~~~~~~~~
diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt
index 40dc4f5..ae56cca 100644
--- a/Documentation/merge-options.txt
+++ b/Documentation/merge-options.txt
@@ -157,6 +157,14 @@
 
 endif::git-pull[]
 
+--autostash::
+--no-autostash::
+	Automatically create a temporary stash entry before the operation
+	begins, and apply it after the operation ends.  This means
+	that you can run rebase on a dirty worktree.  However, use
+	with care: the final stash application after a successful
+	rebase might result in non-trivial conflicts.
+
 --allow-unrelated-histories::
 	By default, `git merge` command refuses to merge histories
 	that do not share a common ancestor.  This option can be
diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 1a7212c..a4b6f49 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -226,6 +226,7 @@
 '%GF':: show the fingerprint of the key used to sign a signed commit
 '%GP':: show the fingerprint of the primary key whose subkey was used
 	to sign a signed commit
+'%GT':: show the trust level for the key used to sign a signed commit
 '%gD':: reflog selector, e.g., `refs/stash@{1}` or `refs/stash@{2
 	minutes ago}`; the format follows the rules described for the
 	`-g` option. The portion before the `@` is the refname as
diff --git a/Documentation/technical/bundle-format.txt b/Documentation/technical/bundle-format.txt
new file mode 100644
index 0000000..0e82815
--- /dev/null
+++ b/Documentation/technical/bundle-format.txt
@@ -0,0 +1,48 @@
+= Git bundle v2 format
+
+The Git bundle format is a format that represents both refs and Git objects.
+
+== Format
+
+We will use ABNF notation to define the Git bundle format. See
+protocol-common.txt for the details.
+
+----
+bundle    = signature *prerequisite *reference LF pack
+signature = "# v2 git bundle" LF
+
+prerequisite = "-" obj-id SP comment LF
+comment      = *CHAR
+reference    = obj-id SP refname LF
+
+pack         = ... ; packfile
+----
+
+== Semantics
+
+A Git bundle consists of three parts.
+
+* "Prerequisites" lists the objects that are NOT included in the bundle and the
+  reader of the bundle MUST already have, in order to use the data in the
+  bundle. The objects stored in the bundle may refer to prerequisite objects and
+  anything reachable from them (e.g. a tree object in the bundle can reference
+  a blob that is reachable from a prerequisite) and/or expressed as a delta
+  against prerequisite objects.
+
+* "References" record the tips of the history graph, iow, what the reader of the
+  bundle CAN "git fetch" from it.
+
+* "Pack" is the pack data stream "git fetch" would send, if you fetch from a
+  repository that has the references recorded in the "References" above into a
+  repository that has references pointing at the objects listed in
+  "Prerequisites" above.
+
+In the bundle format, there can be a comment following a prerequisite obj-id.
+This is a comment and it has no specific meaning. The writer of the bundle MAY
+put any string here. The reader of the bundle MUST ignore the comment.
+
+=== Note on the shallow clone and a Git bundle
+
+Note that the prerequisites does not represent a shallow-clone boundary. The
+semantics of the prerequisites and the shallow-clone boundaries are different,
+and the Git bundle v2 format cannot represent a shallow clone repository.
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
index a4f1744..22e5116 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/technical/commit-graph-format.txt
@@ -17,6 +17,9 @@
 - The parents of the commit, stored using positional references within
   the graph file.
 
+- The Bloom filter of the commit carrying the paths that were changed between
+  the commit and its first parent.
+
 These positional references are stored as unsigned 32-bit integers
 corresponding to the array position within the list of commit OIDs. Due
 to some special constants we use to track parents, we can store at most
@@ -93,6 +96,27 @@
       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.
 
+  Bloom Filter Index (ID: {'B', 'I', 'D', 'X'}) (N * 4 bytes) [Optional]
+    * The ith entry, BIDX[i], stores the number of 8-byte word blocks in all
+      Bloom filters from commit 0 to commit i (inclusive) in lexicographic
+      order. The Bloom filter for the i-th commit spans from BIDX[i-1] to
+      BIDX[i] (plus header length), where BIDX[-1] is 0.
+    * The BIDX chunk is ignored if the BDAT chunk is not present.
+
+  Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional]
+    * It starts with header consisting of three unsigned 32-bit integers:
+      - Version of the hash algorithm being used. We currently only support
+	value 1 which implies the murmur3 hash implemented exactly as described
+	in https://en.wikipedia.org/wiki/MurmurHash#Algorithm
+      - The number of times a path is hashed and hence the number of bit positions
+	that cumulatively determine whether a file is present in the commit.
+      - The minimum number of bits 'b' per entry in the Bloom filter. If the filter
+	contains 'n' entries, then the filter size is the minimum number of 64-bit
+	words that contain n*b bits.
+    * The rest of the chunk is the concatenation of all the computed Bloom
+      filters for the commits in lexicographic order.
+    * The BDAT chunk is present iff BIDX is present.
+
   Base Graphs List (ID: {'B', 'A', 'S', 'E'}) [Optional]
       This list of H-byte hashes describe a set of B commit-graph files that
       form a commit-graph chain. The graph position for the ith commit in this
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index cab5bdd..d3a142c 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -315,10 +315,11 @@
 	    Stores two 4-byte values for every object.
 	    1: The pack-int-id for the pack storing this object.
 	    2: The offset within the pack.
-		If all offsets are less than 2^31, then the large offset chunk
+		If all offsets are less than 2^32, then the large offset chunk
 		will not exist and offsets are stored as in IDX v1.
 		If there is at least one offset value larger than 2^32-1, then
-		the large offset chunk must exist. If the large offset chunk
+		the large offset chunk must exist, and offsets larger than
+		2^31-1 must be stored in it instead. If the large offset chunk
 		exists and the 31st bit is on, then removing that bit reveals
 		the row in the large offsets containing the 8-byte offset of
 		this object.
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index 2b7f62b..616d5a6 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.25.0
+DEF_VER=v2.25.GIT
 
 LF='
 '
diff --git a/Makefile b/Makefile
index ed923a3..e9cbdf3 100644
--- a/Makefile
+++ b/Makefile
@@ -604,12 +604,12 @@
 SCRIPT_SH += git-bisect.sh
 SCRIPT_SH += git-difftool--helper.sh
 SCRIPT_SH += git-filter-branch.sh
+SCRIPT_SH += git-legacy-stash.sh
 SCRIPT_SH += git-merge-octopus.sh
 SCRIPT_SH += git-merge-one-file.sh
 SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
 SCRIPT_SH += git-quiltimport.sh
-SCRIPT_SH += git-legacy-stash.sh
 SCRIPT_SH += git-request-pull.sh
 SCRIPT_SH += git-submodule.sh
 SCRIPT_SH += git-web--browse.sh
@@ -617,8 +617,8 @@
 SCRIPT_LIB += git-mergetool--lib
 SCRIPT_LIB += git-parse-remote
 SCRIPT_LIB += git-rebase--preserve-merges
-SCRIPT_LIB += git-sh-setup
 SCRIPT_LIB += git-sh-i18n
+SCRIPT_LIB += git-sh-setup
 
 SCRIPT_PERL += git-add--interactive.perl
 SCRIPT_PERL += git-archimport.perl
@@ -681,20 +681,22 @@
 # ... and all the rest that could be moved out of bindir to gitexecdir
 PROGRAMS += $(EXTRA_PROGRAMS)
 
+PROGRAM_OBJS += bugreport.o
 PROGRAM_OBJS += credential-store.o
 PROGRAM_OBJS += daemon.o
 PROGRAM_OBJS += fast-import.o
 PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += imap-send.o
+PROGRAM_OBJS += remote-testsvn.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += shell.o
-PROGRAM_OBJS += remote-testsvn.o
 
 # Binary suffix, set to .exe for Windows builds
 X =
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
+TEST_BUILTINS_OBJS += test-bloom.o
 TEST_BUILTINS_OBJS += test-advise.o
 TEST_BUILTINS_OBJS += test-chmtime.o
 TEST_BUILTINS_OBJS += test-config.o
@@ -710,9 +712,9 @@
 TEST_BUILTINS_OBJS += test-example-decorate.o
 TEST_BUILTINS_OBJS += test-genrandom.o
 TEST_BUILTINS_OBJS += test-genzeros.o
+TEST_BUILTINS_OBJS += test-hash-speed.o
 TEST_BUILTINS_OBJS += test-hash.o
 TEST_BUILTINS_OBJS += test-hashmap.o
-TEST_BUILTINS_OBJS += test-hash-speed.o
 TEST_BUILTINS_OBJS += test-index-version.o
 TEST_BUILTINS_OBJS += test-json-writer.o
 TEST_BUILTINS_OBJS += test-lazy-init-name-hash.o
@@ -722,6 +724,7 @@
 TEST_BUILTINS_OBJS += test-oidmap.o
 TEST_BUILTINS_OBJS += test-online-cpus.o
 TEST_BUILTINS_OBJS += test-parse-options.o
+TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
 TEST_BUILTINS_OBJS += test-path-utils.o
 TEST_BUILTINS_OBJS += test-pkt-line.o
 TEST_BUILTINS_OBJS += test-prio-queue.o
@@ -737,8 +740,8 @@
 TEST_BUILTINS_OBJS += test-run-command.o
 TEST_BUILTINS_OBJS += test-scrap-cache-tree.o
 TEST_BUILTINS_OBJS += test-serve-v2.o
-TEST_BUILTINS_OBJS += test-sha1.o
 TEST_BUILTINS_OBJS += test-sha1-array.o
+TEST_BUILTINS_OBJS += test-sha1.o
 TEST_BUILTINS_OBJS += test-sha256.o
 TEST_BUILTINS_OBJS += test-sigchain.o
 TEST_BUILTINS_OBJS += test-strcmp-offset.o
@@ -748,10 +751,10 @@
 TEST_BUILTINS_OBJS += test-subprocess.o
 TEST_BUILTINS_OBJS += test-trace2.o
 TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
-TEST_BUILTINS_OBJS += test-xml-encode.o
 TEST_BUILTINS_OBJS += test-wildmatch.o
 TEST_BUILTINS_OBJS += test-windows-named-pipe.o
 TEST_BUILTINS_OBJS += test-write-cache.o
+TEST_BUILTINS_OBJS += test-xml-encode.o
 
 # Do not add more tests here unless they have extra dependencies. Add
 # them in TEST_BUILTINS_OBJS above.
@@ -788,10 +791,10 @@
 
 # what test wrappers are needed and 'install' will install, in bindir
 BINDIR_PROGRAMS_NEED_X += git
-BINDIR_PROGRAMS_NEED_X += git-upload-pack
 BINDIR_PROGRAMS_NEED_X += git-receive-pack
-BINDIR_PROGRAMS_NEED_X += git-upload-archive
 BINDIR_PROGRAMS_NEED_X += git-shell
+BINDIR_PROGRAMS_NEED_X += git-upload-archive
+BINDIR_PROGRAMS_NEED_X += git-upload-pack
 
 BINDIR_PROGRAMS_NO_X += git-cvsserver
 
@@ -815,7 +818,9 @@
 XDIFF_LIB = xdiff/lib.a
 VCSSVN_LIB = vcs-svn/lib.a
 
+GENERATED_H += config-list.h
 GENERATED_H += command-list.h
+GENERATED_H += bugreport-config-safelist.h
 
 LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentation/' 2>/dev/null || \
 	$(FIND) . \
@@ -831,15 +836,16 @@
 LIB_OBJS += alias.o
 LIB_OBJS += alloc.o
 LIB_OBJS += apply.o
-LIB_OBJS += archive.o
 LIB_OBJS += archive-tar.o
 LIB_OBJS += archive-zip.o
+LIB_OBJS += archive.o
 LIB_OBJS += argv-array.o
 LIB_OBJS += attr.o
 LIB_OBJS += base85.o
 LIB_OBJS += bisect.o
 LIB_OBJS += blame.o
 LIB_OBJS += blob.o
+LIB_OBJS += bloom.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
 LIB_OBJS += bundle.o
@@ -849,9 +855,9 @@
 LIB_OBJS += color.o
 LIB_OBJS += column.o
 LIB_OBJS += combine-diff.o
-LIB_OBJS += commit.o
 LIB_OBJS += commit-graph.o
 LIB_OBJS += commit-reach.o
+LIB_OBJS += commit.o
 LIB_OBJS += compat/obstack.o
 LIB_OBJS += compat/terminal.o
 LIB_OBJS += config.o
@@ -865,17 +871,17 @@
 LIB_OBJS += date.o
 LIB_OBJS += decorate.o
 LIB_OBJS += delta-islands.o
+LIB_OBJS += diff-delta.o
+LIB_OBJS += diff-lib.o
+LIB_OBJS += diff-no-index.o
+LIB_OBJS += diff.o
 LIB_OBJS += diffcore-break.o
 LIB_OBJS += diffcore-delta.o
 LIB_OBJS += diffcore-order.o
 LIB_OBJS += diffcore-pickaxe.o
 LIB_OBJS += diffcore-rename.o
-LIB_OBJS += diff-delta.o
-LIB_OBJS += diff-lib.o
-LIB_OBJS += diff-no-index.o
-LIB_OBJS += diff.o
-LIB_OBJS += dir.o
 LIB_OBJS += dir-iterator.o
+LIB_OBJS += dir.o
 LIB_OBJS += editor.o
 LIB_OBJS += entry.o
 LIB_OBJS += environment.o
@@ -893,7 +899,6 @@
 LIB_OBJS += graph.o
 LIB_OBJS += grep.o
 LIB_OBJS += hashmap.o
-LIB_OBJS += linear-assignment.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.o
 LIB_OBJS += ident.o
@@ -903,9 +908,10 @@
 LIB_OBJS += levenshtein.o
 LIB_OBJS += line-log.o
 LIB_OBJS += line-range.o
-LIB_OBJS += list-objects.o
-LIB_OBJS += list-objects-filter.o
+LIB_OBJS += linear-assignment.o
 LIB_OBJS += list-objects-filter-options.o
+LIB_OBJS += list-objects-filter.o
+LIB_OBJS += list-objects.o
 LIB_OBJS += ll-merge.o
 LIB_OBJS += lockfile.o
 LIB_OBJS += log-tree.o
@@ -914,31 +920,31 @@
 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
+LIB_OBJS += merge.o
 LIB_OBJS += mergesort.o
 LIB_OBJS += midx.o
 LIB_OBJS += name-hash.o
 LIB_OBJS += negotiator/default.o
 LIB_OBJS += negotiator/skipping.o
-LIB_OBJS += notes.o
 LIB_OBJS += notes-cache.o
 LIB_OBJS += notes-merge.o
 LIB_OBJS += notes-utils.o
+LIB_OBJS += notes.o
 LIB_OBJS += object.o
 LIB_OBJS += oidmap.o
 LIB_OBJS += oidset.o
-LIB_OBJS += packfile.o
-LIB_OBJS += pack-bitmap.o
 LIB_OBJS += pack-bitmap-write.o
+LIB_OBJS += pack-bitmap.o
 LIB_OBJS += pack-check.o
 LIB_OBJS += pack-objects.o
 LIB_OBJS += pack-revindex.o
 LIB_OBJS += pack-write.o
+LIB_OBJS += packfile.o
 LIB_OBJS += pager.o
-LIB_OBJS += parse-options.o
 LIB_OBJS += parse-options-cb.o
+LIB_OBJS += parse-options.o
 LIB_OBJS += patch-delta.o
 LIB_OBJS += patch-ids.o
 LIB_OBJS += path.o
@@ -955,7 +961,9 @@
 LIB_OBJS += range-diff.o
 LIB_OBJS += reachable.o
 LIB_OBJS += read-cache.o
+LIB_OBJS += rebase.o
 LIB_OBJS += rebase-interactive.o
+LIB_OBJS += ref-filter.o
 LIB_OBJS += reflog-walk.o
 LIB_OBJS += refs.o
 LIB_OBJS += refs/files-backend.o
@@ -963,12 +971,12 @@
 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 += repo-settings.o
 LIB_OBJS += repository.o
 LIB_OBJS += rerere.o
+LIB_OBJS += reset.o
 LIB_OBJS += resolve-undo.o
 LIB_OBJS += revision.o
 LIB_OBJS += run-command.o
@@ -978,8 +986,8 @@
 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-lookup.o
 LIB_OBJS += sha1-name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
@@ -989,9 +997,9 @@
 LIB_OBJS += strbuf.o
 LIB_OBJS += streaming.o
 LIB_OBJS += string-list.o
-LIB_OBJS += submodule.o
-LIB_OBJS += submodule-config.o
 LIB_OBJS += sub-process.o
+LIB_OBJS += submodule-config.o
+LIB_OBJS += submodule.o
 LIB_OBJS += symlinks.o
 LIB_OBJS += tag.o
 LIB_OBJS += tempfile.o
@@ -1010,11 +1018,11 @@
 LIB_OBJS += trace2/tr2_tgt_perf.o
 LIB_OBJS += trace2/tr2_tls.o
 LIB_OBJS += trailer.o
-LIB_OBJS += transport.o
 LIB_OBJS += transport-helper.o
+LIB_OBJS += transport.o
 LIB_OBJS += tree-diff.o
-LIB_OBJS += tree.o
 LIB_OBJS += tree-walk.o
+LIB_OBJS += tree.o
 LIB_OBJS += unpack-trees.o
 LIB_OBJS += upload-pack.o
 LIB_OBJS += url.o
@@ -1054,9 +1062,9 @@
 BUILTIN_OBJS += builtin/clean.o
 BUILTIN_OBJS += builtin/clone.o
 BUILTIN_OBJS += builtin/column.o
+BUILTIN_OBJS += builtin/commit-graph.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
@@ -1087,13 +1095,13 @@
 BUILTIN_OBJS += builtin/ls-tree.o
 BUILTIN_OBJS += builtin/mailinfo.o
 BUILTIN_OBJS += builtin/mailsplit.o
-BUILTIN_OBJS += builtin/merge.o
 BUILTIN_OBJS += builtin/merge-base.o
 BUILTIN_OBJS += builtin/merge-file.o
 BUILTIN_OBJS += builtin/merge-index.o
 BUILTIN_OBJS += builtin/merge-ours.o
 BUILTIN_OBJS += builtin/merge-recursive.o
 BUILTIN_OBJS += builtin/merge-tree.o
+BUILTIN_OBJS += builtin/merge.o
 BUILTIN_OBJS += builtin/mktag.o
 BUILTIN_OBJS += builtin/mktree.o
 BUILTIN_OBJS += builtin/multi-pack-index.o
@@ -1113,9 +1121,9 @@
 BUILTIN_OBJS += builtin/rebase.o
 BUILTIN_OBJS += builtin/receive-pack.o
 BUILTIN_OBJS += builtin/reflog.o
-BUILTIN_OBJS += builtin/remote.o
 BUILTIN_OBJS += builtin/remote-ext.o
 BUILTIN_OBJS += builtin/remote-fd.o
+BUILTIN_OBJS += builtin/remote.o
 BUILTIN_OBJS += builtin/repack.o
 BUILTIN_OBJS += builtin/replace.o
 BUILTIN_OBJS += builtin/rerere.o
@@ -1221,6 +1229,9 @@
 ifneq ($(filter leak,$(SANITIZERS)),)
 BASIC_CFLAGS += -DSUPPRESS_ANNOTATED_LEAKS
 endif
+ifneq ($(filter address,$(SANITIZERS)),)
+NO_REGEX = NeededForASAN
+endif
 endif
 
 ifndef sysconfdir
@@ -2129,7 +2140,9 @@
 
 help.sp help.s help.o: command-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: command-list.h GIT-PREFIX
+bugreport.sp bugreport.s bugreport.o: bugreport-config-safelist.h
+
+builtin/help.sp builtin/help.s builtin/help.o: config-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)"' \
@@ -2149,6 +2162,12 @@
 	ln -s $< $@ 2>/dev/null || \
 	cp $< $@
 
+config-list.h: generate-configlist.sh
+
+config-list.h:
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh \
+		>$@+ && mv $@+ $@
+
 command-list.h: generate-cmdlist.sh command-list.txt
 
 command-list.h: $(wildcard Documentation/git*.txt) Documentation/*config.txt Documentation/config/*.txt
@@ -2156,6 +2175,12 @@
 		$(patsubst %,--exclude-program %,$(EXCLUDED_PROGRAMS)) \
 		command-list.txt >$@+ && mv $@+ $@
 
+bugreport-config-safelist.h: generate-bugreport-config-safelist.sh
+
+bugreport-config-safelist.h: Documentation/config/*.txt
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-bugreport-config-safelist.sh \
+		>$@+ && mv $@+ $@
+
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
 	$(gitwebdir_SQ):$(PERL_PATH_SQ):$(SANE_TEXT_GREP):$(PAGER_ENV):\
@@ -2331,16 +2356,16 @@
 endif
 
 XDIFF_OBJS += xdiff/xdiffi.o
-XDIFF_OBJS += xdiff/xprepare.o
-XDIFF_OBJS += xdiff/xutils.o
 XDIFF_OBJS += xdiff/xemit.o
+XDIFF_OBJS += xdiff/xhistogram.o
 XDIFF_OBJS += xdiff/xmerge.o
 XDIFF_OBJS += xdiff/xpatience.o
-XDIFF_OBJS += xdiff/xhistogram.o
+XDIFF_OBJS += xdiff/xprepare.o
+XDIFF_OBJS += xdiff/xutils.o
 
+VCSSVN_OBJS += vcs-svn/fast_export.o
 VCSSVN_OBJS += vcs-svn/line_buffer.o
 VCSSVN_OBJS += vcs-svn/sliding_window.o
-VCSSVN_OBJS += vcs-svn/fast_export.o
 VCSSVN_OBJS += vcs-svn/svndiff.o
 VCSSVN_OBJS += vcs-svn/svndump.o
 
@@ -2451,6 +2476,10 @@
 git-%$X: %.o GIT-LDFLAGS $(GITLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
 
+git-bugreport$X: bugreport.o GIT-LDFLAGS $(GITLIBS)
+	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+		$(LIBS)
+
 git-imap-send$X: imap-send.o $(IMAP_SEND_BUILDDEPS) GIT-LDFLAGS $(GITLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(IMAP_SEND_LDFLAGS) $(LIBS)
@@ -2782,7 +2811,7 @@
 .PHONY: sparse $(SP_OBJ)
 sparse: $(SP_OBJ)
 
-EXCEPT_HDRS := command-list.h unicode-width.h compat/% xdiff/%
+EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
 ifndef GCRYPT_SHA256
 	EXCEPT_HDRS += sha256/gcrypt.h
 endif
@@ -2804,7 +2833,7 @@
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: command-list.h
+check: config-list.h command-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
@@ -3148,9 +3177,10 @@
 #
 ALL_COMMANDS = $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS)
 ALL_COMMANDS += git
+ALL_COMMANDS += git-citool
+ALL_COMMANDS += git-gui
 ALL_COMMANDS += gitk
 ALL_COMMANDS += gitweb
-ALL_COMMANDS += git-gui git-citool
 
 .PHONY: check-docs
 check-docs::
diff --git a/RelNotes b/RelNotes
index 091dd02..370269d 120000
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.25.0.txt
\ No newline at end of file
+Documentation/RelNotes/2.26.0.txt
\ No newline at end of file
diff --git a/add-interactive.c b/add-interactive.c
index 6a5048c..4a9bf85 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -52,6 +52,24 @@
 		diff_get_color(s->use_color, DIFF_FILE_OLD));
 	init_color(r, s, "new", s->file_new_color,
 		diff_get_color(s->use_color, DIFF_FILE_NEW));
+
+	FREE_AND_NULL(s->interactive_diff_filter);
+	git_config_get_string("interactive.difffilter",
+			      &s->interactive_diff_filter);
+
+	FREE_AND_NULL(s->interactive_diff_algorithm);
+	git_config_get_string("diff.algorithm",
+			      &s->interactive_diff_algorithm);
+
+	git_config_get_bool("interactive.singlekey", &s->use_single_key);
+}
+
+void clear_add_i_state(struct add_i_state *s)
+{
+	FREE_AND_NULL(s->interactive_diff_filter);
+	FREE_AND_NULL(s->interactive_diff_algorithm);
+	memset(s, 0, sizeof(*s));
+	s->use_color = -1;
 }
 
 /*
@@ -326,7 +344,10 @@
 				if (endp == p + sep)
 					to = from + 1;
 				else if (*endp == '-') {
-					to = strtoul(++endp, &endp, 10);
+					if (isdigit(*(++endp)))
+						to = strtoul(endp, &endp, 10);
+					else
+						to = items->items.nr;
 					/* extra characters after the range? */
 					if (endp != p + sep)
 						from = -1;
@@ -913,7 +934,7 @@
 
 	opts->prompt = N_("Patch update");
 	count = list_and_choose(s, files, opts);
-	if (count >= 0) {
+	if (count > 0) {
 		struct argv_array args = ARGV_ARRAY_INIT;
 		struct pathspec ps_selected = { 0 };
 
@@ -924,7 +945,7 @@
 		parse_pathspec(&ps_selected,
 			       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
 			       PATHSPEC_LITERAL_PATH, "", args.argv);
-		res = run_add_p(s->r, &ps_selected);
+		res = run_add_p(s->r, ADD_P_ADD, NULL, &ps_selected);
 		argv_array_clear(&args);
 		clear_pathspec(&ps_selected);
 	}
@@ -954,7 +975,7 @@
 	opts->flags = IMMEDIATE;
 	count = list_and_choose(s, files, opts);
 	opts->flags = 0;
-	if (count >= 0) {
+	if (count > 0) {
 		struct argv_array args = ARGV_ARRAY_INIT;
 
 		argv_array_pushl(&args, "git", "diff", "-p", "--cached",
@@ -1149,6 +1170,7 @@
 	strbuf_release(&print_file_item_data.worktree);
 	strbuf_release(&header);
 	prefix_item_list_clear(&commands);
+	clear_add_i_state(&s);
 
 	return res;
 }
diff --git a/add-interactive.h b/add-interactive.h
index 062dc36..693f125 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -15,13 +15,27 @@
 	char context_color[COLOR_MAXLEN];
 	char file_old_color[COLOR_MAXLEN];
 	char file_new_color[COLOR_MAXLEN];
+
+	int use_single_key;
+	char *interactive_diff_filter, *interactive_diff_algorithm;
 };
 
 void init_add_i_state(struct add_i_state *s, struct repository *r);
+void clear_add_i_state(struct add_i_state *s);
 
 struct repository;
 struct pathspec;
 int run_add_i(struct repository *r, const struct pathspec *ps);
-int run_add_p(struct repository *r, const struct pathspec *ps);
+
+enum add_p_mode {
+	ADD_P_ADD,
+	ADD_P_STASH,
+	ADD_P_RESET,
+	ADD_P_CHECKOUT,
+	ADD_P_WORKTREE,
+};
+
+int run_add_p(struct repository *r, enum add_p_mode mode,
+	      const char *revision, const struct pathspec *ps);
 
 #endif
diff --git a/add-patch.c b/add-patch.c
index 2c46fe5..d8dafa8 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -6,15 +6,218 @@
 #include "pathspec.h"
 #include "color.h"
 #include "diff.h"
+#include "compat/terminal.h"
 
 enum prompt_mode_type {
-	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK
+	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK,
+	PROMPT_MODE_MAX, /* must be last */
 };
 
-static const char *prompt_mode[] = {
-	N_("Stage mode change [y,n,a,q,d%s,?]? "),
-	N_("Stage deletion [y,n,a,q,d%s,?]? "),
-	N_("Stage this hunk [y,n,a,q,d%s,?]? ")
+struct patch_mode {
+	/*
+	 * The magic constant 4 is chosen such that all patch modes
+	 * provide enough space for three command-line arguments followed by a
+	 * trailing `NULL`.
+	 */
+	const char *diff_cmd[4], *apply_args[4], *apply_check_args[4];
+	unsigned is_reverse:1, index_only:1, apply_for_checkout:1;
+	const char *prompt_mode[PROMPT_MODE_MAX];
+	const char *edit_hunk_hint, *help_patch_text;
+};
+
+static struct patch_mode patch_mode_add = {
+	.diff_cmd = { "diff-files", NULL },
+	.apply_args = { "--cached", NULL },
+	.apply_check_args = { "--cached", NULL },
+	.prompt_mode = {
+		N_("Stage mode change [y,n,q,a,d%s,?]? "),
+		N_("Stage deletion [y,n,q,a,d%s,?]? "),
+		N_("Stage this hunk [y,n,q,a,d%s,?]? ")
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for staging."),
+	.help_patch_text =
+		N_("y - stage this hunk\n"
+		   "n - do not stage this hunk\n"
+		   "q - quit; do not stage this hunk or any of the remaining "
+			"ones\n"
+		   "a - stage this hunk and all later hunks in the file\n"
+		   "d - do not stage this hunk or any of the later hunks in "
+			"the file\n")
+};
+
+static struct patch_mode patch_mode_stash = {
+	.diff_cmd = { "diff-index", "HEAD", NULL },
+	.apply_args = { "--cached", NULL },
+	.apply_check_args = { "--cached", NULL },
+	.prompt_mode = {
+		N_("Stash mode change [y,n,q,a,d%s,?]? "),
+		N_("Stash deletion [y,n,q,a,d%s,?]? "),
+		N_("Stash this hunk [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for stashing."),
+	.help_patch_text =
+		N_("y - stash this hunk\n"
+		   "n - do not stash this hunk\n"
+		   "q - quit; do not stash this hunk or any of the remaining "
+			"ones\n"
+		   "a - stash this hunk and all later hunks in the file\n"
+		   "d - do not stash this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_reset_head = {
+	.diff_cmd = { "diff-index", "--cached", NULL },
+	.apply_args = { "-R", "--cached", NULL },
+	.apply_check_args = { "-R", "--cached", NULL },
+	.is_reverse = 1,
+	.index_only = 1,
+	.prompt_mode = {
+		N_("Unstage mode change [y,n,q,a,d%s,?]? "),
+		N_("Unstage deletion [y,n,q,a,d%s,?]? "),
+		N_("Unstage this hunk [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for unstaging."),
+	.help_patch_text =
+		N_("y - unstage this hunk\n"
+		   "n - do not unstage this hunk\n"
+		   "q - quit; do not unstage this hunk or any of the remaining "
+			"ones\n"
+		   "a - unstage this hunk and all later hunks in the file\n"
+		   "d - do not unstage this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_reset_nothead = {
+	.diff_cmd = { "diff-index", "-R", "--cached", NULL },
+	.apply_args = { "--cached", NULL },
+	.apply_check_args = { "--cached", NULL },
+	.index_only = 1,
+	.prompt_mode = {
+		N_("Apply mode change to index [y,n,q,a,d%s,?]? "),
+		N_("Apply deletion to index [y,n,q,a,d%s,?]? "),
+		N_("Apply this hunk to index [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for applying."),
+	.help_patch_text =
+		N_("y - apply this hunk to index\n"
+		   "n - do not apply this hunk to index\n"
+		   "q - quit; do not apply this hunk or any of the remaining "
+			"ones\n"
+		   "a - apply this hunk and all later hunks in the file\n"
+		   "d - do not apply this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_checkout_index = {
+	.diff_cmd = { "diff-files", NULL },
+	.apply_args = { "-R", NULL },
+	.apply_check_args = { "-R", NULL },
+	.is_reverse = 1,
+	.prompt_mode = {
+		N_("Discard mode change from worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard deletion from worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard this hunk from worktree [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for discarding."),
+	.help_patch_text =
+		N_("y - discard this hunk from worktree\n"
+		   "n - do not discard this hunk from worktree\n"
+		   "q - quit; do not discard this hunk or any of the remaining "
+			"ones\n"
+		   "a - discard this hunk and all later hunks in the file\n"
+		   "d - do not discard this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_checkout_head = {
+	.diff_cmd = { "diff-index", NULL },
+	.apply_for_checkout = 1,
+	.apply_check_args = { "-R", NULL },
+	.is_reverse = 1,
+	.prompt_mode = {
+		N_("Discard mode change from index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard deletion from index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard this hunk from index and worktree [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for discarding."),
+	.help_patch_text =
+		N_("y - discard this hunk from index and worktree\n"
+		   "n - do not discard this hunk from index and worktree\n"
+		   "q - quit; do not discard this hunk or any of the remaining "
+			"ones\n"
+		   "a - discard this hunk and all later hunks in the file\n"
+		   "d - do not discard this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_checkout_nothead = {
+	.diff_cmd = { "diff-index", "-R", NULL },
+	.apply_for_checkout = 1,
+	.apply_check_args = { NULL },
+	.prompt_mode = {
+		N_("Apply mode change to index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply deletion to index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply this hunk to index and worktree [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for applying."),
+	.help_patch_text =
+		N_("y - apply this hunk to index and worktree\n"
+		   "n - do not apply this hunk to index and worktree\n"
+		   "q - quit; do not apply this hunk or any of the remaining "
+			"ones\n"
+		   "a - apply this hunk and all later hunks in the file\n"
+		   "d - do not apply this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_worktree_head = {
+	.diff_cmd = { "diff-index", NULL },
+	.apply_args = { "-R", NULL },
+	.apply_check_args = { "-R", NULL },
+	.is_reverse = 1,
+	.prompt_mode = {
+		N_("Discard mode change from index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard deletion from index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard this hunk from index and worktree [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for discarding."),
+	.help_patch_text =
+		N_("y - discard this hunk from worktree\n"
+		   "n - do not discard this hunk from worktree\n"
+		   "q - quit; do not discard this hunk or any of the remaining "
+			"ones\n"
+		   "a - discard this hunk and all later hunks in the file\n"
+		   "d - do not discard this hunk or any of the later hunks in "
+			"the file\n"),
+};
+
+static struct patch_mode patch_mode_worktree_nothead = {
+	.diff_cmd = { "diff-index", "-R", NULL },
+	.apply_args = { NULL },
+	.apply_check_args = { NULL },
+	.prompt_mode = {
+		N_("Apply mode change to index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply deletion to index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply this hunk to index and worktree [y,n,q,a,d%s,?]? "),
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for applying."),
+	.help_patch_text =
+		N_("y - apply this hunk to worktree\n"
+		   "n - do not apply this hunk to worktree\n"
+		   "q - quit; do not apply this hunk or any of the remaining "
+			"ones\n"
+		   "a - apply this hunk and all later hunks in the file\n"
+		   "d - do not apply this hunk or any of the later hunks in "
+			"the file\n"),
 };
 
 struct hunk_header {
@@ -47,6 +250,10 @@
 		unsigned deleted:1, mode_change:1,binary:1;
 	} *file_diff;
 	size_t file_diff_nr;
+
+	/* patch mode */
+	struct patch_mode *mode;
+	const char *revision;
 };
 
 static void err(struct add_p_state *s, const char *fmt, ...)
@@ -154,6 +361,7 @@
 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 {
 	struct argv_array args = ARGV_ARRAY_INIT;
+	const char *diff_algorithm = s->s.interactive_diff_algorithm;
 	struct strbuf *plain = &s->plain, *colored = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *p, *pend, *colored_p = NULL, *colored_pend = NULL, marker = '\0';
@@ -162,9 +370,20 @@
 	struct hunk *hunk = NULL;
 	int res;
 
+	argv_array_pushv(&args, s->mode->diff_cmd);
+	if (diff_algorithm)
+		argv_array_pushf(&args, "--diff-algorithm=%s", diff_algorithm);
+	if (s->revision) {
+		struct object_id oid;
+		argv_array_push(&args,
+				/* could be on an unborn branch */
+				!strcmp("HEAD", s->revision) &&
+				get_oid("HEAD", &oid) ?
+				empty_tree_oid_hex() : s->revision);
+	}
+	color_arg_index = args.argc;
 	/* Use `--no-color` explicitly, just in case `diff.color = always`. */
-	argv_array_pushl(&args, "diff-files", "-p", "--no-color", "--", NULL);
-	color_arg_index = args.argc - 2;
+	argv_array_pushl(&args, "--no-color", "-p", "--", NULL);
 	for (i = 0; i < ps->nr; i++)
 		argv_array_push(&args, ps->items[i].original);
 
@@ -183,6 +402,7 @@
 
 	if (want_color_fd(1, -1)) {
 		struct child_process colored_cp = CHILD_PROCESS_INIT;
+		const char *diff_filter = s->s.interactive_diff_filter;
 
 		setup_child_process(s, &colored_cp, NULL);
 		xsnprintf((char *)args.argv[color_arg_index], 8, "--color");
@@ -192,6 +412,24 @@
 		argv_array_clear(&args);
 		if (res)
 			return error(_("could not parse colored diff"));
+
+		if (diff_filter) {
+			struct child_process filter_cp = CHILD_PROCESS_INIT;
+
+			setup_child_process(s, &filter_cp,
+					    diff_filter, NULL);
+			filter_cp.git_cmd = 0;
+			filter_cp.use_shell = 1;
+			strbuf_reset(&s->buf);
+			if (pipe_command(&filter_cp,
+					 colored->buf, colored->len,
+					 &s->buf, colored->len,
+					 NULL, 0) < 0)
+				return error(_("failed to run '%s'"),
+					     diff_filter);
+			strbuf_swap(colored, &s->buf);
+		}
+
 		strbuf_complete_line(colored);
 		colored_p = colored->buf;
 		colored_pend = colored_p + colored->len;
@@ -316,6 +554,9 @@
 						   colored_pend - colored_p);
 			if (colored_eol)
 				colored_p = colored_eol + 1;
+			else if (p != pend)
+				/* colored shorter than non-colored? */
+				goto mismatched_output;
 			else
 				colored_p = colored_pend;
 
@@ -340,6 +581,15 @@
 		 */
 		hunk->splittable_into++;
 
+	/* non-colored shorter than colored? */
+	if (colored_p != colored_pend) {
+mismatched_output:
+		error(_("mismatched output from interactive.diffFilter"));
+		advise(_("Your filter must maintain a one-to-one correspondence\n"
+			 "between its input and output lines."));
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -382,7 +632,10 @@
 				- header->colored_extra_start;
 		}
 
-		new_offset += delta;
+		if (s->mode->is_reverse)
+			old_offset -= delta;
+		else
+			new_offset += delta;
 
 		strbuf_addf(out, "@@ -%lu,%lu +%lu,%lu @@",
 			    old_offset, header->old_count,
@@ -805,11 +1058,10 @@
 				"(context).\n"
 				"To remove '%c' lines, delete them.\n"
 				"Lines starting with %c will be removed.\n"),
-			      '-', '+', comment_line_char);
-	strbuf_commented_addf(&s->buf,
-			      _("If the patch applies cleanly, the edited hunk "
-				"will immediately be\n"
-				"marked for staging.\n"));
+			      s->mode->is_reverse ? '+' : '-',
+			      s->mode->is_reverse ? '-' : '+',
+			      comment_line_char);
+	strbuf_commented_addf(&s->buf, "%s", _(s->mode->edit_hunk_hint));
 	/*
 	 * TRANSLATORS: 'it' refers to the patch mentioned in the previous
 	 * messages.
@@ -890,21 +1142,35 @@
 	reassemble_patch(s, file_diff, 1, &s->buf);
 
 	setup_child_process(s, &cp,
-			    "apply", "--cached", "--check", NULL);
+			    "apply", "--check", NULL);
+	argv_array_pushv(&cp.args, s->mode->apply_check_args);
 	if (pipe_command(&cp, s->buf.buf, s->buf.len, NULL, 0, NULL, 0))
 		return error(_("'git apply --cached' failed"));
 
 	return 0;
 }
 
+static int read_single_character(struct add_p_state *s)
+{
+	if (s->s.use_single_key) {
+		int res = read_key_without_echo(&s->answer);
+		printf("%s\n", res == EOF ? "" : s->answer.buf);
+		return res;
+	}
+
+	if (strbuf_getline(&s->answer, stdin) == EOF)
+		return EOF;
+	strbuf_trim_trailing_newline(&s->answer);
+	return 0;
+}
+
 static int prompt_yesno(struct add_p_state *s, const char *prompt)
 {
 	for (;;) {
 		color_fprintf(stdout, s->s.prompt_color, "%s", _(prompt));
 		fflush(stdout);
-		if (strbuf_getline(&s->answer, stdin) == EOF)
+		if (read_single_character(s) == EOF)
 			return -1;
-		strbuf_trim_trailing_newline(&s->answer);
 		switch (tolower(s->answer.buf[0])) {
 		case 'n': return 0;
 		case 'y': return 1;
@@ -957,6 +1223,57 @@
 	}
 }
 
+static int apply_for_checkout(struct add_p_state *s, struct strbuf *diff,
+			      int is_reverse)
+{
+	const char *reverse = is_reverse ? "-R" : NULL;
+	struct child_process check_index = CHILD_PROCESS_INIT;
+	struct child_process check_worktree = CHILD_PROCESS_INIT;
+	struct child_process apply_index = CHILD_PROCESS_INIT;
+	struct child_process apply_worktree = CHILD_PROCESS_INIT;
+	int applies_index, applies_worktree;
+
+	setup_child_process(s, &check_index,
+			    "apply", "--cached", "--check", reverse, NULL);
+	applies_index = !pipe_command(&check_index, diff->buf, diff->len,
+				      NULL, 0, NULL, 0);
+
+	setup_child_process(s, &check_worktree,
+			    "apply", "--check", reverse, NULL);
+	applies_worktree = !pipe_command(&check_worktree, diff->buf, diff->len,
+					 NULL, 0, NULL, 0);
+
+	if (applies_worktree && applies_index) {
+		setup_child_process(s, &apply_index,
+				    "apply", "--cached", reverse, NULL);
+		pipe_command(&apply_index, diff->buf, diff->len,
+			     NULL, 0, NULL, 0);
+
+		setup_child_process(s, &apply_worktree,
+				    "apply", reverse, NULL);
+		pipe_command(&apply_worktree, diff->buf, diff->len,
+			     NULL, 0, NULL, 0);
+
+		return 1;
+	}
+
+	if (!applies_index) {
+		err(s, _("The selected hunks do not apply to the index!"));
+		if (prompt_yesno(s, _("Apply them to the worktree "
+					  "anyway? ")) > 0) {
+			setup_child_process(s, &apply_worktree,
+					    "apply", reverse, NULL);
+			return pipe_command(&apply_worktree, diff->buf,
+					    diff->len, NULL, 0, NULL, 0);
+		}
+		err(s, _("Nothing was applied.\n"));
+	} else
+		/* As a last resort, show the diff to the user */
+		fwrite(diff->buf, diff->len, 1, stderr);
+
+	return 0;
+}
+
 #define SUMMARY_HEADER_WIDTH 20
 #define SUMMARY_LINE_WIDTH 80
 static void summarize_hunk(struct add_p_state *s, struct hunk *hunk,
@@ -1005,13 +1322,6 @@
 	return end_index;
 }
 
-static const char help_patch_text[] =
-N_("y - stage this hunk\n"
-   "n - do not stage this hunk\n"
-   "q - quit; do not stage this hunk or any of the remaining ones\n"
-   "a - stage this and all the remaining hunks\n"
-   "d - do not stage this hunk nor any of the remaining hunks\n");
-
 static const char help_patch_remainder[] =
 N_("j - leave this hunk undecided, see next undecided hunk\n"
    "J - leave this hunk undecided, see next hunk\n"
@@ -1097,11 +1407,11 @@
 			      (uintmax_t)hunk_index + 1,
 			      (uintmax_t)file_diff->hunk_nr);
 		color_fprintf(stdout, s->s.prompt_color,
-			      _(prompt_mode[prompt_mode_type]), s->buf.buf);
+			      _(s->mode->prompt_mode[prompt_mode_type]),
+			      s->buf.buf);
 		fflush(stdout);
-		if (strbuf_getline(&s->answer, stdin) == EOF)
+		if (read_single_character(s) == EOF)
 			break;
-		strbuf_trim_trailing_newline(&s->answer);
 
 		if (!s->answer.len)
 			continue;
@@ -1254,7 +1564,7 @@
 			const char *p = _(help_patch_remainder), *eol = p;
 
 			color_fprintf(stdout, s->s.help_color, "%s",
-				      _(help_patch_text));
+				      _(s->mode->help_patch_text));
 
 			/*
 			 * Show only those lines of the remainder that are
@@ -1288,10 +1598,16 @@
 		reassemble_patch(s, file_diff, 0, &s->buf);
 
 		discard_index(s->s.r->index);
-		setup_child_process(s, &cp, "apply", "--cached", NULL);
-		if (pipe_command(&cp, s->buf.buf, s->buf.len,
-				 NULL, 0, NULL, 0))
-			error(_("'git apply --cached' failed"));
+		if (s->mode->apply_for_checkout)
+			apply_for_checkout(s, &s->buf,
+					   s->mode->is_reverse);
+		else {
+			setup_child_process(s, &cp, "apply", NULL);
+			argv_array_pushv(&cp.args, s->mode->apply_args);
+			if (pipe_command(&cp, s->buf.buf, s->buf.len,
+					 NULL, 0, NULL, 0))
+				error(_("'git apply' failed"));
+		}
 		if (!repo_read_index(s->s.r))
 			repo_refresh_and_write_index(s->s.r, REFRESH_QUIET, 0,
 						     1, NULL, NULL, NULL);
@@ -1301,7 +1617,8 @@
 	return quit;
 }
 
-int run_add_p(struct repository *r, const struct pathspec *ps)
+int run_add_p(struct repository *r, enum add_p_mode mode,
+	      const char *revision, const struct pathspec *ps)
 {
 	struct add_p_state s = {
 		{ r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
@@ -1310,12 +1627,39 @@
 
 	init_add_i_state(&s.s, r);
 
+	if (mode == ADD_P_STASH)
+		s.mode = &patch_mode_stash;
+	else if (mode == ADD_P_RESET) {
+		if (!revision || !strcmp(revision, "HEAD"))
+			s.mode = &patch_mode_reset_head;
+		else
+			s.mode = &patch_mode_reset_nothead;
+	} else if (mode == ADD_P_CHECKOUT) {
+		if (!revision)
+			s.mode = &patch_mode_checkout_index;
+		else if (!strcmp(revision, "HEAD"))
+			s.mode = &patch_mode_checkout_head;
+		else
+			s.mode = &patch_mode_checkout_nothead;
+	} else if (mode == ADD_P_WORKTREE) {
+		if (!revision)
+			s.mode = &patch_mode_checkout_index;
+		else if (!strcmp(revision, "HEAD"))
+			s.mode = &patch_mode_worktree_head;
+		else
+			s.mode = &patch_mode_worktree_nothead;
+	} else
+		s.mode = &patch_mode_add;
+	s.revision = revision;
+
 	if (discard_index(r->index) < 0 || repo_read_index(r) < 0 ||
-	    repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
-					 NULL, NULL, NULL) < 0 ||
+	    (!s.mode->index_only &&
+	     repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
+					  NULL, NULL, NULL) < 0) ||
 	    parse_diff(&s, ps) < 0) {
 		strbuf_release(&s.plain);
 		strbuf_release(&s.colored);
+		clear_add_i_state(&s.s);
 		return -1;
 	}
 
@@ -1334,5 +1678,6 @@
 	strbuf_release(&s.buf);
 	strbuf_release(&s.plain);
 	strbuf_release(&s.colored);
+	clear_add_i_state(&s.s);
 	return 0;
 }
diff --git a/advice.c b/advice.c
index 56928a5..b8b6f19 100644
--- a/advice.c
+++ b/advice.c
@@ -30,6 +30,8 @@
 int advice_graft_file_deprecated = 1;
 int advice_checkout_ambiguous_remote_branch_name = 1;
 int advice_submodule_alternate_error_strategy_die = 1;
+int advice_add_ignored_file = 1;
+int advice_add_empty_pathspec = 1;
 
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
@@ -89,6 +91,8 @@
 	{ "graftFileDeprecated", &advice_graft_file_deprecated },
 	{ "checkoutAmbiguousRemoteBranchName", &advice_checkout_ambiguous_remote_branch_name },
 	{ "submoduleAlternateErrorStrategyDie", &advice_submodule_alternate_error_strategy_die },
+	{ "addIgnoredFile", &advice_add_ignored_file },
+	{ "addEmptyPathspec", &advice_add_empty_pathspec },
 
 	/* make this an alias for backward compatibility */
 	{ "pushNonFastForward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index d2ac308..5aa2fdc 100644
--- a/advice.h
+++ b/advice.h
@@ -30,6 +30,8 @@
 extern int advice_graft_file_deprecated;
 extern int advice_checkout_ambiguous_remote_branch_name;
 extern int advice_submodule_alternate_error_strategy_die;
+extern int advice_add_ignored_file;
+extern int advice_add_empty_pathspec;
 
 /**
  To add a new advice, you need to:
diff --git a/apply.c b/apply.c
index fab4432..bdc008f 100644
--- a/apply.c
+++ b/apply.c
@@ -3157,7 +3157,8 @@
 		 * See if the old one matches what the patch
 		 * applies to.
 		 */
-		hash_object_file(img->buf, img->len, blob_type, &oid);
+		hash_object_file(the_hash_algo, img->buf, img->len, blob_type,
+				 &oid);
 		if (strcmp(oid_to_hex(&oid), patch->old_oid_prefix))
 			return error(_("the patch applies to '%s' (%s), "
 				       "which does not match the "
@@ -3202,7 +3203,8 @@
 				     name);
 
 		/* verify that the result matches */
-		hash_object_file(img->buf, img->len, blob_type, &oid);
+		hash_object_file(the_hash_algo, img->buf, img->len, blob_type,
+				 &oid);
 		if (strcmp(oid_to_hex(&oid), patch->new_oid_prefix))
 			return error(_("binary patch to '%s' creates incorrect result (expecting %s, got %s)"),
 				name, patch->new_oid_prefix, oid_to_hex(&oid));
diff --git a/archive-tar.c b/archive-tar.c
index e16d3f7..5a77701 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -112,7 +112,7 @@
  * queues up writes, so that all our write(2) calls write exactly one
  * full block; pads writes to RECORDSIZE
  */
-static int stream_blocked(const struct object_id *oid)
+static int stream_blocked(struct repository *r, const struct object_id *oid)
 {
 	struct git_istream *st;
 	enum object_type type;
@@ -120,7 +120,7 @@
 	char buf[BLOCKSIZE];
 	ssize_t readlen;
 
-	st = open_istream(oid, &type, &sz, NULL);
+	st = open_istream(r, oid, &type, &sz, NULL);
 	if (!st)
 		return error(_("cannot stream blob %s"), oid_to_hex(oid));
 	for (;;) {
@@ -324,7 +324,7 @@
 		if (buffer)
 			write_blocked(buffer, size);
 		else
-			err = stream_blocked(oid);
+			err = stream_blocked(args->repo, oid);
 	}
 	free(buffer);
 	return err;
diff --git a/archive-zip.c b/archive-zip.c
index 11f5b19..e9f4262 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -345,7 +345,8 @@
 
 		if (S_ISREG(mode) && type == OBJ_BLOB && !args->convert &&
 		    size > big_file_threshold) {
-			stream = open_istream(oid, &type, &size, NULL);
+			stream = open_istream(args->repo, oid, &type, &size,
+					      NULL);
 			if (!stream)
 				return error(_("cannot stream blob %s"),
 					     oid_to_hex(oid));
diff --git a/bisect.c b/bisect.c
index e81c91d..9154f81 100644
--- a/bisect.c
+++ b/bisect.c
@@ -572,7 +572,7 @@
 {
 	float d, x = val;
 
-	if (val == 0)
+	if (!val)
 		return 0;
 
 	do {
@@ -661,11 +661,11 @@
 		mark_edges_uninteresting(revs, NULL, 0);
 }
 
-static void exit_if_skipped_commits(struct commit_list *tried,
+static enum bisect_error error_if_skipped_commits(struct commit_list *tried,
 				    const struct object_id *bad)
 {
 	if (!tried)
-		return;
+		return BISECT_OK;
 
 	printf("There are only 'skip'ped commits left to test.\n"
 	       "The first %s commit could be any of:\n", term_bad);
@@ -676,7 +676,8 @@
 	if (bad)
 		printf("%s\n", oid_to_hex(bad));
 	printf(_("We cannot bisect more!\n"));
-	exit(2);
+
+	return BISECT_ONLY_SKIPPED_LEFT;
 }
 
 static int is_expected_rev(const struct object_id *oid)
@@ -703,9 +704,10 @@
 	return res;
 }
 
-static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
+static enum bisect_error bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
 {
 	char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
+	enum bisect_error res = BISECT_OK;
 
 	memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), the_hash_algo->hexsz + 1);
 	update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
@@ -715,14 +717,24 @@
 		update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 	} else {
-		int res;
 		res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
 		if (res)
-			exit(res);
+			/*
+			 * Errors in `run_command()` itself, signaled by res < 0,
+			 * and errors in the child process, signaled by res > 0
+			 * can both be treated as regular BISECT_FAILURE (-1).
+			 */
+			return -abs(res);
 	}
 
 	argv_show_branch[1] = bisect_rev_hex;
-	return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
+	res = run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
+	/*
+	 * Errors in `run_command()` itself, signaled by res < 0,
+	 * and errors in the child process, signaled by res > 0
+	 * can both be treated as regular BISECT_FAILURE (-1).
+	 */
+	return -abs(res);
 }
 
 static struct commit *get_commit_reference(struct repository *r,
@@ -749,7 +761,7 @@
 	return rev;
 }
 
-static void handle_bad_merge_base(void)
+static enum bisect_error handle_bad_merge_base(void)
 {
 	if (is_expected_rev(current_bad_oid)) {
 		char *bad_hex = oid_to_hex(current_bad_oid);
@@ -770,14 +782,14 @@
 				"between %s and [%s].\n"),
 				bad_hex, term_bad, term_good, bad_hex, good_hex);
 		}
-		exit(3);
+		return BISECT_MERGE_BASE_CHECK;
 	}
 
 	fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
 		"git bisect cannot work properly in this case.\n"
 		"Maybe you mistook %s and %s revs?\n"),
 		term_good, term_bad, term_good, term_bad);
-	exit(1);
+	return BISECT_FAILED;
 }
 
 static void handle_skipped_merge_base(const struct object_id *mb)
@@ -799,13 +811,18 @@
  * "check_merge_bases" checks that merge bases are not "bad" (or "new").
  *
  * - If one is "bad" (or "new"), it means the user assumed something wrong
- * and we must exit with a non 0 error code.
+ * and we must return error with a non 0 error code.
  * - If one is "good" (or "old"), that's good, we have nothing to do.
  * - If one is "skipped", we can't know but we should warn.
  * - If we don't know, we should check it out and ask the user to test.
+ * - If a merge base must be tested, on success return
+ * BISECT_INTERNAL_SUCCESS_MERGE_BASE (-11) a special condition
+ * for early success, this will be converted back to 0 in
+ * check_good_are_ancestors_of_bad().
  */
-static void check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
+static enum bisect_error check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
 {
+	enum bisect_error res = BISECT_OK;
 	struct commit_list *result;
 
 	result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
@@ -813,18 +830,24 @@
 	for (; result; result = result->next) {
 		const struct object_id *mb = &result->item->object.oid;
 		if (oideq(mb, current_bad_oid)) {
-			handle_bad_merge_base();
+			res = handle_bad_merge_base();
+			break;
 		} else if (0 <= oid_array_lookup(&good_revs, mb)) {
 			continue;
 		} else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
 			handle_skipped_merge_base(mb);
 		} else {
 			printf(_("Bisecting: a merge base must be tested\n"));
-			exit(bisect_checkout(mb, no_checkout));
+			res = bisect_checkout(mb, no_checkout);
+			if (!res)
+				/* indicate early success */
+				res = BISECT_INTERNAL_SUCCESS_MERGE_BASE;
+			break;
 		}
 	}
 
 	free_commit_list(result);
+	return res;
 }
 
 static int check_ancestors(struct repository *r, int rev_nr,
@@ -850,43 +873,58 @@
  *
  * If that's not the case, we need to check the merge bases.
  * If a merge base must be tested by the user, its source code will be
- * checked out to be tested by the user and we will exit.
+ * checked out to be tested by the user and we will return.
  */
-static void check_good_are_ancestors_of_bad(struct repository *r,
+
+static enum bisect_error check_good_are_ancestors_of_bad(struct repository *r,
 					    const char *prefix,
 					    int no_checkout)
 {
-	char *filename = git_pathdup("BISECT_ANCESTORS_OK");
+	char *filename;
 	struct stat st;
 	int fd, rev_nr;
+	enum bisect_error res = BISECT_OK;
 	struct commit **rev;
 
 	if (!current_bad_oid)
-		die(_("a %s revision is needed"), term_bad);
+		return error(_("a %s revision is needed"), term_bad);
+
+	filename = git_pathdup("BISECT_ANCESTORS_OK");
 
 	/* Check if file BISECT_ANCESTORS_OK exists. */
 	if (!stat(filename, &st) && S_ISREG(st.st_mode))
 		goto done;
 
 	/* Bisecting with no good rev is ok. */
-	if (good_revs.nr == 0)
+	if (!good_revs.nr)
 		goto done;
 
 	/* Check if all good revs are ancestor of the bad rev. */
+
 	rev = get_bad_and_good_commits(r, &rev_nr);
 	if (check_ancestors(r, rev_nr, rev, prefix))
-		check_merge_bases(rev_nr, rev, no_checkout);
+		res = check_merge_bases(rev_nr, rev, no_checkout);
 	free(rev);
 
-	/* Create file BISECT_ANCESTORS_OK. */
-	fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
-	if (fd < 0)
-		warning_errno(_("could not create file '%s'"),
-			      filename);
-	else
-		close(fd);
+	if (!res) {
+		/* Create file BISECT_ANCESTORS_OK. */
+		fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+		if (fd < 0)
+			/*
+			 * BISECT_ANCESTORS_OK file is not absolutely necessary,
+			 * the bisection process will continue at the next
+			 * bisection step.
+			 * So, just signal with a warning that something
+			 * might be wrong.
+			 */
+			warning_errno(_("could not create file '%s'"),
+				filename);
+		else
+			close(fd);
+	}
  done:
 	free(filename);
+	return res;
 }
 
 /*
@@ -938,18 +976,19 @@
 }
 
 /*
- * We use the convention that exiting with an exit code 10 means that
+ * We use the convention that return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10) means
  * the bisection process finished successfully.
- * In this case the calling shell script should exit 0.
- *
+ * In this case the calling function or command should not turn a
+ * BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND return code into an error or a non zero exit code.
  * If no_checkout is non-zero, the bisection process does not
  * checkout the trial commit but instead simply updates BISECT_HEAD.
  */
-int bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
+enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
 {
 	struct rev_info revs;
 	struct commit_list *tried;
 	int reaches = 0, all = 0, nr, steps;
+	enum bisect_error res = BISECT_OK;
 	struct object_id *bisect_rev;
 	char *steps_msg;
 
@@ -957,7 +996,9 @@
 	if (read_bisect_refs())
 		die(_("reading bisect refs failed"));
 
-	check_good_are_ancestors_of_bad(r, prefix, no_checkout);
+	res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
+	if (res)
+		return res;
 
 	bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
 	revs.limited = 1;
@@ -969,33 +1010,45 @@
 
 	if (!revs.commits) {
 		/*
-		 * We should exit here only if the "bad"
+		 * We should return error here only if the "bad"
 		 * commit is also a "skip" commit.
 		 */
-		exit_if_skipped_commits(tried, NULL);
-
+		res = error_if_skipped_commits(tried, NULL);
+		if (res < 0)
+			return res;
 		printf(_("%s was both %s and %s\n"),
 		       oid_to_hex(current_bad_oid),
 		       term_good,
 		       term_bad);
-		exit(1);
+
+		return BISECT_FAILED;
 	}
 
 	if (!all) {
 		fprintf(stderr, _("No testable commit found.\n"
 			"Maybe you started with bad path parameters?\n"));
-		exit(4);
+
+		return BISECT_NO_TESTABLE_COMMIT;
 	}
 
 	bisect_rev = &revs.commits->item->object.oid;
 
 	if (oideq(bisect_rev, current_bad_oid)) {
-		exit_if_skipped_commits(tried, current_bad_oid);
+		res = error_if_skipped_commits(tried, current_bad_oid);
+		if (res)
+			return res;
 		printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
 			term_bad);
+
 		show_diff_tree(r, prefix, revs.commits->item);
-		/* This means the bisection process succeeded. */
-		exit(10);
+		/*
+		 * This means the bisection process succeeded.
+		 * Using BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10)
+		 * so that the call chain can simply check
+		 * for negative return values for early returns up
+		 * until the cmd_bisect__helper() caller.
+		 */
+		return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
 	}
 
 	nr = all - reaches - 1;
diff --git a/bisect.h b/bisect.h
index 4e69a11..8bad8d8 100644
--- a/bisect.h
+++ b/bisect.h
@@ -31,7 +31,34 @@
 	const char *header_prefix;
 };
 
-int bisect_next_all(struct repository *r,
+/*
+ * enum bisect_error represents the following return codes:
+ * BISECT_OK: success code. Internally, it means that next
+ * commit has been found (and possibly checked out) and it
+ * should be tested.
+ * BISECT_FAILED error code: default error code.
+ * BISECT_ONLY_SKIPPED_LEFT error code: only skipped
+ * commits left to be tested.
+ * BISECT_MERGE_BASE_CHECK error code: merge base check failed.
+ * BISECT_NO_TESTABLE_COMMIT error code: no testable commit found.
+ * BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND early success code:
+ * first term_bad commit found.
+ * BISECT_INTERNAL_SUCCESS_MERGE_BASE early success
+ * code: found merge base that should be tested.
+ * Early success codes BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND and
+ * BISECT_INTERNAL_SUCCESS_MERGE_BASE should be only internal codes.
+ */
+enum bisect_error {
+	BISECT_OK = 0,
+	BISECT_FAILED = -1,
+	BISECT_ONLY_SKIPPED_LEFT = -2,
+	BISECT_MERGE_BASE_CHECK = -3,
+	BISECT_NO_TESTABLE_COMMIT = -4,
+	BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND = -10,
+	BISECT_INTERNAL_SUCCESS_MERGE_BASE = -11
+};
+
+enum bisect_error bisect_next_all(struct repository *r,
 		    const char *prefix,
 		    int no_checkout);
 
diff --git a/bloom.c b/bloom.c
new file mode 100644
index 0000000..0a59d9f
--- /dev/null
+++ b/bloom.c
@@ -0,0 +1,277 @@
+#include "git-compat-util.h"
+#include "bloom.h"
+#include "commit.h"
+#include "commit-slab.h"
+#include "commit-graph.h"
+#include "object-store.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "revision.h"
+#include "hashmap.h"
+
+define_commit_slab(bloom_filter_slab, struct bloom_filter);
+
+struct bloom_filter_slab bloom_filters;
+
+struct pathmap_hash_entry {
+    struct hashmap_entry entry;
+    const char path[FLEX_ARRAY];
+};
+
+static uint32_t rotate_right(uint32_t value, int32_t count)
+{
+	uint32_t mask = 8 * sizeof(uint32_t) - 1;
+	count &= mask;
+	return ((value >> count) | (value << ((-count) & mask)));
+}
+
+/*
+ * Calculate a hash value for the given data using the given seed.
+ * Produces a uniformly distributed hash value.
+ * Not considered to be cryptographically secure.
+ * Implemented as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm
+ **/
+static uint32_t seed_murmur3(uint32_t seed, const char *data, int len)
+{
+	const uint32_t c1 = 0xcc9e2d51;
+	const uint32_t c2 = 0x1b873593;
+	const uint32_t r1 = 15;
+	const uint32_t r2 = 13;
+	const uint32_t m = 5;
+	const uint32_t n = 0xe6546b64;
+	int i;
+	uint32_t k1 = 0;
+	const char *tail;
+
+	int len4 = len / sizeof(uint32_t);
+
+	uint32_t k;
+	for (i = 0; i < len4; i++) {
+		uint32_t byte1 = (uint32_t)data[4*i];
+		uint32_t byte2 = ((uint32_t)data[4*i + 1]) << 8;
+		uint32_t byte3 = ((uint32_t)data[4*i + 2]) << 16;
+		uint32_t byte4 = ((uint32_t)data[4*i + 3]) << 24;
+		k = byte1 | byte2 | byte3 | byte4;
+		k *= c1;
+		k = rotate_right(k, r1);
+		k *= c2;
+
+		seed ^= k;
+		seed = rotate_right(seed, r2) * m + n;
+	}
+
+	tail = (data + len4 * sizeof(uint32_t));
+
+	switch (len & (sizeof(uint32_t) - 1)) {
+	case 3:
+		k1 ^= ((uint32_t)tail[2]) << 16;
+		/*-fallthrough*/
+	case 2:
+		k1 ^= ((uint32_t)tail[1]) << 8;
+		/*-fallthrough*/
+	case 1:
+		k1 ^= ((uint32_t)tail[0]) << 0;
+		k1 *= c1;
+		k1 = rotate_right(k1, r1);
+		k1 *= c2;
+		seed ^= k1;
+		break;
+	}
+
+	seed ^= (uint32_t)len;
+	seed ^= (seed >> 16);
+	seed *= 0x85ebca6b;
+	seed ^= (seed >> 13);
+	seed *= 0xc2b2ae35;
+	seed ^= (seed >> 16);
+
+	return seed;
+}
+
+static inline unsigned char get_bitmask(uint32_t pos)
+{
+	return ((unsigned char)1) << (pos & (BITS_PER_WORD - 1));
+}
+
+void load_bloom_filters(void)
+{
+	init_bloom_filter_slab(&bloom_filters);
+}
+
+void fill_bloom_key(const char *data,
+					int len,
+					struct bloom_key *key,
+					struct bloom_filter_settings *settings)
+{
+	int i;
+	const uint32_t seed0 = 0x293ae76f;
+	const uint32_t seed1 = 0x7e646e2c;
+	const uint32_t hash0 = seed_murmur3(seed0, data, len);
+	const uint32_t hash1 = seed_murmur3(seed1, data, len);
+
+	key->hashes = (uint32_t *)xcalloc(settings->num_hashes, sizeof(uint32_t));
+	for (i = 0; i < settings->num_hashes; i++)
+		key->hashes[i] = hash0 + i * hash1;
+}
+
+void add_key_to_filter(struct bloom_key *key,
+					   struct bloom_filter *filter,
+					   struct bloom_filter_settings *settings)
+{
+	int i;
+	uint64_t mod = filter->len * BITS_PER_WORD;
+
+	for (i = 0; i < settings->num_hashes; i++) {
+		uint64_t hash_mod = key->hashes[i] % mod;
+		uint64_t block_pos = hash_mod / BITS_PER_WORD;
+
+		filter->data[block_pos] |= get_bitmask(hash_mod);
+	}
+}
+
+static int load_bloom_filter_from_graph(struct commit_graph *g,
+				   struct bloom_filter *filter,
+				   struct commit *c)
+{
+	uint32_t lex_pos, start_index, end_index;
+
+	while (c->graph_pos < g->num_commits_in_base)
+		g = g->base_graph;
+
+	/* The commit graph commit 'c' lives in doesn't carry bloom filters. */
+	if (!g->chunk_bloom_indexes)
+		return 0;
+
+	lex_pos = c->graph_pos - g->num_commits_in_base;
+
+	end_index = get_be32(g->chunk_bloom_indexes + 4 * lex_pos);
+
+	if (lex_pos)
+		start_index = get_be32(g->chunk_bloom_indexes + 4 * (lex_pos - 1));
+	else
+		start_index = 0;
+
+	filter->len = end_index - start_index;
+	filter->data = (unsigned char *)(g->chunk_bloom_data +
+					sizeof(unsigned char) * start_index +
+					BLOOMDATA_CHUNK_HEADER_SIZE);
+
+	return 1;
+}
+
+struct bloom_filter *get_bloom_filter(struct repository *r,
+				      struct commit *c,
+				      int compute_if_not_present)
+{
+	struct bloom_filter *filter;
+	struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
+	int i;
+	struct diff_options diffopt;
+	int max_changes = 512;
+
+	if (!bloom_filters.slab_size)
+		return NULL;
+
+	filter = bloom_filter_slab_at(&bloom_filters, c);
+
+	if (!filter->data) {
+		load_commit_graph_info(r, c);
+		if (c->graph_pos != COMMIT_NOT_FROM_GRAPH &&
+			r->objects->commit_graph->chunk_bloom_indexes) {
+			if (load_bloom_filter_from_graph(r->objects->commit_graph, filter, c))
+				return filter;
+			else
+				return NULL;
+		}
+	}
+
+	if (filter->data || !compute_if_not_present)
+		return filter;
+
+	repo_diff_setup(r, &diffopt);
+	diffopt.flags.recursive = 1;
+	diffopt.max_changes = max_changes;
+	diff_setup_done(&diffopt);
+
+	if (c->parents)
+		diff_tree_oid(&c->parents->item->object.oid, &c->object.oid, "", &diffopt);
+	else
+		diff_tree_oid(NULL, &c->object.oid, "", &diffopt);
+	diffcore_std(&diffopt);
+
+	if (diff_queued_diff.nr <= max_changes) {
+		struct hashmap pathmap;
+		struct pathmap_hash_entry* e;
+		struct hashmap_iter iter;
+		hashmap_init(&pathmap, NULL, NULL, 0);
+
+		for (i = 0; i < diff_queued_diff.nr; i++) {
+			const char* path = diff_queued_diff.queue[i]->two->path;
+			const char* p = path;
+
+			/*
+			* Add each leading directory of the changed file, i.e. for
+			* 'dir/subdir/file' add 'dir' and 'dir/subdir' as well, so
+			* the Bloom filter could be used to speed up commands like
+			* 'git log dir/subdir', too.
+			*
+			* Note that directories are added without the trailing '/'.
+			*/
+			do {
+				char* last_slash = strrchr(p, '/');
+
+				FLEX_ALLOC_STR(e, path, path);
+				hashmap_entry_init(&e->entry, strhash(p));
+				hashmap_add(&pathmap, &e->entry);
+
+				if (!last_slash)
+					last_slash = (char*)p;
+				*last_slash = '\0';
+
+			} while (*p);
+
+			diff_free_filepair(diff_queued_diff.queue[i]);
+		}
+
+		filter->len = (hashmap_get_size(&pathmap) * settings.bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD;
+		filter->data = xcalloc(filter->len, sizeof(unsigned char));
+
+		hashmap_for_each_entry(&pathmap, &iter, e, entry) {
+			struct bloom_key key;
+			fill_bloom_key(e->path, strlen(e->path), &key, &settings);
+			add_key_to_filter(&key, filter, &settings);
+		}
+
+		hashmap_free_entries(&pathmap, struct pathmap_hash_entry, entry);
+	} else {
+		for (i = 0; i < diff_queued_diff.nr; i++)
+			diff_free_filepair(diff_queued_diff.queue[i]);
+		filter->data = NULL;
+		filter->len = 0;
+	}
+
+	free(diff_queued_diff.queue);
+	DIFF_QUEUE_CLEAR(&diff_queued_diff);
+
+	return filter;
+}
+
+int bloom_filter_contains(struct bloom_filter *filter,
+			  struct bloom_key *key,
+			  struct bloom_filter_settings *settings)
+{
+	int i;
+	uint64_t mod = filter->len * BITS_PER_WORD;
+
+	if (!mod)
+		return -1;
+
+	for (i = 0; i < settings->num_hashes; i++) {
+		uint64_t hash_mod = key->hashes[i] % mod;
+		uint64_t block_pos = hash_mod / BITS_PER_WORD;
+		if (!(filter->data[block_pos] & get_bitmask(hash_mod)))
+			return 0;
+	}
+
+	return 1;
+}
diff --git a/bloom.h b/bloom.h
new file mode 100644
index 0000000..9604723
--- /dev/null
+++ b/bloom.h
@@ -0,0 +1,58 @@
+#ifndef BLOOM_H
+#define BLOOM_H
+
+struct commit;
+struct repository;
+struct commit_graph;
+
+struct bloom_filter_settings {
+	uint32_t hash_version;
+	uint32_t num_hashes;
+	uint32_t bits_per_entry;
+};
+
+#define DEFAULT_BLOOM_FILTER_SETTINGS { 1, 7, 10 }
+#define BITS_PER_WORD 8
+#define BLOOMDATA_CHUNK_HEADER_SIZE 3*sizeof(uint32_t)
+
+/*
+ * A bloom_filter struct represents a data segment to
+ * use when testing hash values. The 'len' member
+ * dictates how many uint64_t entries are stored in
+ * 'data'.
+ */
+struct bloom_filter {
+	unsigned char *data;
+	int len;
+};
+
+/*
+ * A bloom_key represents the k hash values for a
+ * given hash input. These can be precomputed and
+ * stored in a bloom_key for re-use when testing
+ * against a bloom_filter.
+ */
+struct bloom_key {
+	uint32_t *hashes;
+};
+
+void load_bloom_filters(void);
+
+void fill_bloom_key(const char *data,
+		    int len,
+		    struct bloom_key *key,
+		    struct bloom_filter_settings *settings);
+
+void add_key_to_filter(struct bloom_key *key,
+					   struct bloom_filter *filter,
+					   struct bloom_filter_settings *settings);
+
+struct bloom_filter *get_bloom_filter(struct repository *r,
+				      struct commit *c,
+				      int compute_if_not_present);
+
+int bloom_filter_contains(struct bloom_filter *filter,
+			  struct bloom_key *key,
+			  struct bloom_filter_settings *settings);
+
+#endif
diff --git a/branch.c b/branch.c
index 5794947..bf2536c 100644
--- a/branch.c
+++ b/branch.c
@@ -344,6 +344,7 @@
 	unlink(git_path_merge_rr(r));
 	unlink(git_path_merge_msg(r));
 	unlink(git_path_merge_mode(r));
+	apply_autostash(git_path_merge_autostash(r));
 }
 
 void remove_branch_state(struct repository *r, int verbose)
diff --git a/bugreport.c b/bugreport.c
new file mode 100644
index 0000000..3770aa7
--- /dev/null
+++ b/bugreport.c
@@ -0,0 +1,418 @@
+#include "cache.h"
+#include "parse-options.h"
+#include "stdio.h"
+#include "strbuf.h"
+#include "time.h"
+#include "help.h"
+#include "compat/compiler.h"
+#include "run-command.h"
+#include "config.h"
+#include "bugreport-config-safelist.h"
+#include "khash.h"
+#include "run-command.h"
+#include "object-store.h"
+
+static void get_git_remote_https_version_info(struct strbuf *version_info)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	argv_array_push(&cp.args, "git");
+	argv_array_push(&cp.args, "remote-https");
+	argv_array_push(&cp.args, "--build-info");
+	if (capture_command(&cp, version_info, 0))
+	    strbuf_addstr(version_info, "'git-remote-https --build-info' not supported\n");
+}
+
+static void get_system_info(struct strbuf *sys_info)
+{
+	struct utsname uname_info;
+	char *shell = NULL;
+
+	/* get git version from native cmd */
+	strbuf_addstr(sys_info, "git version:\n");
+	get_version_info(sys_info, 1);
+	strbuf_complete_line(sys_info);
+
+	/* system call for other version info */
+	strbuf_addstr(sys_info, "uname -a: ");
+	if (uname(&uname_info))
+		strbuf_addf(sys_info, "uname() failed with code %d\n", errno);
+	else
+		strbuf_addf(sys_info, "%s %s %s %s\n",
+			    uname_info.sysname,
+			    uname_info.release,
+			    uname_info.version,
+			    uname_info.machine);
+
+	strbuf_addstr(sys_info, "compiler info: ");
+	get_compiler_info(sys_info);
+	strbuf_complete_line(sys_info);
+
+	shell = getenv("SHELL");
+	strbuf_addf(sys_info, "$SHELL (typically, interactive shell): %s\n",
+		    shell ? shell : "<unset>");
+
+	strbuf_addstr(sys_info, "git-remote-https --build-info:\n");
+	get_git_remote_https_version_info(sys_info);
+	strbuf_complete_line(sys_info);
+}
+
+static void get_safelisted_config(struct strbuf *config_info)
+{
+	size_t idx;
+	struct string_list_item *it = NULL;
+	struct key_value_info *kv_info = NULL;
+
+	for (idx = 0; idx < ARRAY_SIZE(bugreport_config_safelist); idx++) {
+		const struct string_list *list =
+			git_config_get_value_multi(bugreport_config_safelist[idx]);
+
+		if (!list)
+			continue;
+
+		strbuf_addf(config_info, "%s:\n", bugreport_config_safelist[idx]);
+		for_each_string_list_item(it, list) {
+			kv_info = it->util;
+			strbuf_addf(config_info, "  %s (%s)\n", it->string,
+				    kv_info ? config_scope_name(kv_info->scope)
+					    : "source unknown");
+		}
+	}
+}
+
+static void get_populated_hooks(struct strbuf *hook_info, int nongit)
+{
+	/*
+	 * Doesn't look like there is a list of all possible hooks; so below is
+	 * a transcription of `git help hooks`.
+	 */
+	const char *hooks = "applypatch-msg,"
+			    "pre-applypatch,"
+			    "post-applypatch,"
+			    "pre-commit,"
+			    "pre-merge-commit,"
+			    "prepare-commit-msg,"
+			    "commit-msg,"
+			    "post-commit,"
+			    "pre-rebase,"
+			    "post-checkout,"
+			    "post-merge,"
+			    "pre-push,"
+			    "pre-receive,"
+			    "update,"
+			    "post-receive,"
+			    "post-update,"
+			    "push-to-checkout,"
+			    "pre-auto-gc,"
+			    "post-rewrite,"
+			    "sendemail-validate,"
+			    "fsmonitor-watchman,"
+			    "p4-pre-submit,"
+			    "post-index-changex";
+	struct string_list hooks_list = STRING_LIST_INIT_DUP;
+	struct string_list_item *iter = NULL;
+
+
+	if (nongit) {
+		strbuf_addstr(hook_info,
+			"not run from a git repository - no hooks to show\n");
+		return;
+	}
+
+	string_list_split(&hooks_list, hooks, ',', -1);
+
+	for_each_string_list_item(iter, &hooks_list) {
+		if (find_hook(iter->string)) {
+			strbuf_addstr(hook_info, iter->string);
+			strbuf_complete_line(hook_info);
+		}
+	}
+}
+
+static int loose_object_cb(const struct object_id *oid, const char *path,
+			   void *data) {
+	int *loose_object_count = data;
+
+	if (loose_object_count) {
+		(*loose_object_count)++;
+		return 0;
+	}
+
+	return 1;
+}
+
+static void get_loose_object_summary(struct strbuf *obj_info, int nongit) {
+
+	int local_loose_object_count = 0, total_loose_object_count = 0;
+	int local_count_questionable = 0, total_count_questionable = 0;
+
+	if (nongit) {
+		strbuf_addstr(obj_info,
+			"not run from a git repository - no objects to show\n");
+		return;
+	}
+
+	local_count_questionable = for_each_loose_object(
+					loose_object_cb,
+					&local_loose_object_count,
+					FOR_EACH_OBJECT_LOCAL_ONLY);
+
+	total_count_questionable = for_each_loose_object(
+					loose_object_cb,
+					&total_loose_object_count,
+					0);
+
+	strbuf_addf(obj_info, "%d local loose objects%s\n",
+		    local_loose_object_count,
+		    local_count_questionable ? " (problem during count)" : "");
+
+	strbuf_addf(obj_info, "%d alternate loose objects%s\n",
+		    total_loose_object_count - local_loose_object_count,
+		    (local_count_questionable || total_count_questionable)
+			? " (problem during count)"
+			: "");
+
+	strbuf_addf(obj_info, "%d total loose objects%s\n",
+		    total_loose_object_count,
+		    total_count_questionable ? " (problem during count)" : "");
+}
+
+static void get_packed_object_summary(struct strbuf *obj_info, int nongit)
+{
+	struct packed_git *pack = NULL;
+	int pack_count = 0;
+	int object_count = 0;
+
+	if (nongit) {
+		strbuf_addstr(obj_info,
+			"not run from a git repository - no objects to show\n");
+		return;
+	}
+
+	for_each_pack(the_repository, pack) {
+		pack_count++;
+		/*
+		 * To accurately count how many objects are packed, look inside
+		 * the packfile's index.
+		 */
+		open_pack_index(pack);
+		object_count += pack->num_objects;
+	}
+
+	strbuf_addf(obj_info, "%d total packs (%d objects)\n", pack_count,
+		    object_count);
+
+}
+
+static void list_contents_of_dir_recursively(struct strbuf *contents,
+					     struct strbuf *dirpath)
+{
+	struct dirent *d;
+	DIR *dir;
+	size_t path_len;
+
+	dir = opendir(dirpath->buf);
+	if (!dir)
+		return;
+
+	strbuf_complete(dirpath, '/');
+	path_len = dirpath->len;
+
+	while ((d = readdir(dir))) {
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+
+		strbuf_addbuf(contents, dirpath);
+		strbuf_addstr(contents, d->d_name);
+		strbuf_complete_line(contents);
+
+		if (d->d_type == DT_DIR) {
+			strbuf_addstr(dirpath, d->d_name);
+			list_contents_of_dir_recursively(contents, dirpath);
+		}
+		strbuf_setlen(dirpath, path_len);
+	}
+
+	closedir(dir);
+}
+
+static void get_object_info_summary(struct strbuf *obj_info, int nongit)
+{
+	struct strbuf dirpath = STRBUF_INIT;
+
+	if (nongit) {
+		strbuf_addstr(obj_info,
+			"not run from a git repository - object info unavailable\n");
+		return;
+	}
+
+	strbuf_addstr(&dirpath, get_object_directory());
+	strbuf_complete(&dirpath, '/');
+	strbuf_addstr(&dirpath, "info/");
+
+	list_contents_of_dir_recursively(obj_info, &dirpath);
+
+	strbuf_release(&dirpath);
+}
+
+static void get_alternates_summary(struct strbuf *alternates_info, int nongit)
+{
+	struct strbuf alternates_path = STRBUF_INIT;
+	struct strbuf alternate = STRBUF_INIT;
+	FILE *file;
+	size_t exists = 0, broken = 0;
+
+	if (nongit) {
+		strbuf_addstr(alternates_info,
+			"not run from a git repository - alternates unavailable\n");
+		return;
+	}
+
+	strbuf_addstr(&alternates_path, get_object_directory());
+	strbuf_complete(&alternates_path, '/');
+	strbuf_addstr(&alternates_path, "info/alternates");
+
+	file = fopen(alternates_path.buf, "r");
+	if (!file) {
+		strbuf_addstr(alternates_info, "No alternates file found.\n");
+		strbuf_release(&alternates_path);
+		return;
+	}
+
+	while (strbuf_getline(&alternate, file) != EOF) {
+		if (!access(alternate.buf, F_OK))
+			exists++;
+		else
+			broken++;
+	}
+
+	strbuf_addf(alternates_info,
+		    "%zd alternates found (%zd working, %zd broken)\n",
+		    exists + broken,
+		    exists,
+		    broken);
+
+	fclose(file);
+	strbuf_release(&alternate);
+	strbuf_release(&alternates_path);
+}
+
+static const char * const bugreport_usage[] = {
+	N_("git bugreport [-o|--output-directory <file>] [-s|--suffix <format>]"),
+	NULL
+};
+
+static int get_bug_template(struct strbuf *template)
+{
+	const char template_text[] = N_(
+"Thank you for filling out a Git bug report!\n"
+"Please answer the following questions to help us understand your issue.\n"
+"\n"
+"What did you do before the bug happened? (Steps to reproduce your issue)\n"
+"\n"
+"What did you expect to happen? (Expected behavior)\n"
+"\n"
+"What happened instead? (Actual behavior)\n"
+"\n"
+"What's different between what you expected and what actually happened?\n"
+"\n"
+"Anything else you want to add:\n"
+"\n"
+"Please review the rest of the bug report below.\n"
+"You can delete any lines you don't wish to share.\n");
+
+	strbuf_addstr(template, template_text);
+	return 0;
+}
+
+static void get_header(struct strbuf *buf, const char *title)
+{
+	strbuf_addf(buf, "\n\n[%s]\n", title);
+}
+
+int cmd_main(int argc, const char **argv)
+{
+	struct strbuf buffer = STRBUF_INIT;
+	struct strbuf report_path = STRBUF_INIT;
+	FILE *report;
+	time_t now = time(NULL);
+	char *option_output = NULL;
+	char *option_suffix = "%F-%H%M";
+	struct stat statbuf;
+	int nongit_ok = 0;
+
+	const struct option bugreport_options[] = {
+		OPT_STRING('o', "output-directory", &option_output, N_("path"),
+			   N_("specify a destination for the bugreport file")),
+		OPT_STRING('s', "suffix", &option_suffix, N_("format"),
+			   N_("specify a strftime format suffix for the filename")),
+		OPT_END()
+	};
+
+	/* Prerequisite for hooks and config checks */
+	setup_git_directory_gently(&nongit_ok);
+
+	argc = parse_options(argc, argv, "", bugreport_options,
+			     bugreport_usage, 0);
+
+	if (option_output) {
+		strbuf_addstr(&report_path, option_output);
+		strbuf_complete(&report_path, '/');
+	}
+
+
+	strbuf_addstr(&report_path, "git-bugreport-");
+	strbuf_addftime(&report_path, option_suffix, localtime(&now), 0, 0);
+	strbuf_addstr(&report_path, ".txt");
+
+	if (!stat(report_path.buf, &statbuf))
+		die("'%s' already exists", report_path.buf);
+
+	switch (safe_create_leading_directories(report_path.buf)) {
+	case SCLD_OK:
+	case SCLD_EXISTS:
+		break;
+	default:
+		die(_("could not create leading directories for '%s'"),
+		    report_path.buf);
+	}
+
+	get_bug_template(&buffer);
+
+	get_header(&buffer, "System Info");
+	get_system_info(&buffer);
+
+	get_header(&buffer, "Safelisted Config Info");
+	get_safelisted_config(&buffer);
+
+	get_header(&buffer, "Enabled Hooks");
+	get_populated_hooks(&buffer, nongit_ok);
+
+	get_header(&buffer, "Loose Object Counts");
+	get_loose_object_summary(&buffer, nongit_ok);
+
+	get_header(&buffer, "Packed Object Summary");
+	get_packed_object_summary(&buffer, nongit_ok);
+
+	get_header(&buffer, "Object Info Summary");
+	get_object_info_summary(&buffer, nongit_ok);
+
+	get_header(&buffer, "Alternates");
+	get_alternates_summary(&buffer, nongit_ok);
+
+	report = fopen_for_writing(report_path.buf);
+
+	if (report == NULL) {
+		strbuf_release(&report_path);
+		die("couldn't open '%s' for writing", report_path.buf);
+	}
+
+	strbuf_write(&buffer, report);
+	fclose(report);
+
+	fprintf(stderr, _("Created new report at '%s'.\n"), report_path.buf);
+
+	UNLEAK(buffer);
+	UNLEAK(report_path);
+	return -launch_editor(report_path.buf, NULL, NULL);
+}
diff --git a/builtin/add.c b/builtin/add.c
index 4c38aff..18a0881 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -31,6 +31,7 @@
 static int add_renormalize;
 static int pathspec_file_nul;
 static const char *pathspec_from_file;
+static int legacy_stash_p; /* support for the scripted `git stash` */
 
 struct update_callback_data {
 	int flags;
@@ -196,12 +197,25 @@
 				    &use_builtin_add_i);
 
 	if (use_builtin_add_i == 1) {
+		enum add_p_mode mode;
+
 		if (!patch_mode)
 			return !!run_add_i(the_repository, pathspec);
-		if (strcmp(patch_mode, "--patch"))
-			die("'%s' not yet supported in the built-in add -p",
-			    patch_mode);
-		return !!run_add_p(the_repository, pathspec);
+
+		if (!strcmp(patch_mode, "--patch"))
+			mode = ADD_P_ADD;
+		else if (!strcmp(patch_mode, "--patch=stash"))
+			mode = ADD_P_STASH;
+		else if (!strcmp(patch_mode, "--patch=reset"))
+			mode = ADD_P_RESET;
+		else if (!strcmp(patch_mode, "--patch=checkout"))
+			mode = ADD_P_CHECKOUT;
+		else if (!strcmp(patch_mode, "--patch=worktree"))
+			mode = ADD_P_WORKTREE;
+		else
+			die("'%s' not supported", patch_mode);
+
+		return !!run_add_p(the_repository, mode, revision, pathspec);
 	}
 
 	argv_array_push(&argv, "add--interactive");
@@ -327,6 +341,8 @@
 		   N_("override the executable bit of the listed files")),
 	OPT_HIDDEN_BOOL(0, "warn-embedded-repo", &warn_on_embedded_repo,
 			N_("warn when adding an embedded repository")),
+	OPT_HIDDEN_BOOL(0, "legacy-stash-p", &legacy_stash_p,
+			N_("backend for `git stash -p`")),
 	OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),
 	OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),
 	OPT_END(),
@@ -390,7 +406,10 @@
 		fprintf(stderr, _(ignore_error));
 		for (i = 0; i < dir->ignored_nr; i++)
 			fprintf(stderr, "%s\n", dir->ignored[i]->name);
-		fprintf(stderr, _("Use -f if you really want to add them.\n"));
+		if (advice_add_ignored_file)
+			advise(_("Use -f if you really want to add them.\n"
+				"Turn this message off by running\n"
+				"\"git config advice.addIgnoredFile false\""));
 		exit_status = 1;
 	}
 
@@ -428,6 +447,17 @@
 			die(_("--pathspec-from-file is incompatible with --interactive/--patch"));
 		exit(interactive_add(argc - 1, argv + 1, prefix, patch_interactive));
 	}
+	if (legacy_stash_p) {
+		struct pathspec pathspec;
+
+		parse_pathspec(&pathspec, 0,
+			PATHSPEC_PREFER_FULL |
+			PATHSPEC_SYMLINK_LEADING_PATH |
+			PATHSPEC_PREFIX_ORIGIN,
+			prefix, argv);
+
+		return run_add_interactive(NULL, "--patch=stash", &pathspec);
+	}
 
 	if (edit_interactive) {
 		if (pathspec_from_file)
@@ -480,7 +510,10 @@
 
 	if (require_pathspec && pathspec.nr == 0) {
 		fprintf(stderr, _("Nothing specified, nothing added.\n"));
-		fprintf(stderr, _("Maybe you wanted to say 'git add .'?\n"));
+		if (advice_add_empty_pathspec)
+			advise( _("Maybe you wanted to say 'git add .'?\n"
+				"Turn this message off by running\n"
+				"\"git config advice.addEmptyPathspec false\""));
 		return 0;
 	}
 
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 1718df7..c1c40b5 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -52,8 +52,8 @@
 	terms->term_bad = xstrdup(bad);
 }
 
-static const char *vocab_bad = "bad|new";
-static const char *vocab_good = "good|old";
+static const char vocab_bad[] = "bad|new";
+static const char vocab_good[] = "good|old";
 
 /*
  * Check whether the string `term` belongs to the set of strings
@@ -206,31 +206,31 @@
 	struct object_id oid;
 	struct commit *commit;
 	FILE *fp = NULL;
-	int retval = 0;
+	int res = 0;
 
 	if (!strcmp(state, terms->term_bad)) {
 		strbuf_addf(&tag, "refs/bisect/%s", state);
 	} else if (one_of(state, terms->term_good, "skip", NULL)) {
 		strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
 	} else {
-		retval = error(_("Bad bisect_write argument: %s"), state);
+		res = error(_("Bad bisect_write argument: %s"), state);
 		goto finish;
 	}
 
 	if (get_oid(rev, &oid)) {
-		retval = error(_("couldn't get the oid of the rev '%s'"), rev);
+		res = error(_("couldn't get the oid of the rev '%s'"), rev);
 		goto finish;
 	}
 
 	if (update_ref(NULL, tag.buf, &oid, NULL, 0,
 		       UPDATE_REFS_MSG_ON_ERR)) {
-		retval = -1;
+		res = -1;
 		goto finish;
 	}
 
 	fp = fopen(git_path_bisect_log(), "a");
 	if (!fp) {
-		retval = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
+		res = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
 		goto finish;
 	}
 
@@ -244,7 +244,7 @@
 	if (fp)
 		fclose(fp);
 	strbuf_release(&tag);
-	return retval;
+	return res;
 }
 
 static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
@@ -291,26 +291,14 @@
 	   "You then need to give me at least one %s and %s revision.\n"
 	   "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 
-static int bisect_next_check(const struct bisect_terms *terms,
-			     const char *current_term)
+static int decide_next(const struct bisect_terms *terms,
+		       const char *current_term, int missing_good,
+		       int missing_bad)
 {
-	int missing_good = 1, missing_bad = 1, retval = 0;
-	const char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
-	const char *good_glob = xstrfmt("%s-*", terms->term_good);
-
-	if (ref_exists(bad_ref))
-		missing_bad = 0;
-
-	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
-			     (void *) &missing_good);
-
 	if (!missing_good && !missing_bad)
-		goto finish;
-
-	if (!current_term) {
-		retval = -1;
-		goto finish;
-	}
+		return 0;
+	if (!current_term)
+		return -1;
 
 	if (missing_good && !missing_bad &&
 	    !strcmp(current_term, terms->term_good)) {
@@ -321,7 +309,7 @@
 		 */
 		warning(_("bisecting only with a %s commit"), terms->term_bad);
 		if (!isatty(0))
-			goto finish;
+			return 0;
 		/*
 		 * TRANSLATORS: Make sure to include [Y] and [n] in your
 		 * translation. The program will only accept English input
@@ -329,21 +317,35 @@
 		 */
 		yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
 		if (starts_with(yesno, "N") || starts_with(yesno, "n"))
-			retval = -1;
-		goto finish;
-	}
-	if (!is_empty_or_missing_file(git_path_bisect_start())) {
-		retval = error(_(need_bad_and_good_revision_warning),
-			       vocab_bad, vocab_good, vocab_bad, vocab_good);
-	} else {
-		retval = error(_(need_bisect_start_warning),
-			       vocab_good, vocab_bad, vocab_good, vocab_bad);
+			return -1;
+		return 0;
 	}
 
-finish:
-	free((void *) good_glob);
-	free((void *) bad_ref);
-	return retval;
+	if (!is_empty_or_missing_file(git_path_bisect_start()))
+		return error(_(need_bad_and_good_revision_warning),
+			     vocab_bad, vocab_good, vocab_bad, vocab_good);
+	else
+		return error(_(need_bisect_start_warning),
+			     vocab_good, vocab_bad, vocab_good, vocab_bad);
+}
+
+static int bisect_next_check(const struct bisect_terms *terms,
+			     const char *current_term)
+{
+	int missing_good = 1, missing_bad = 1;
+	char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
+	char *good_glob = xstrfmt("%s-*", terms->term_good);
+
+	if (ref_exists(bad_ref))
+		missing_bad = 0;
+
+	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
+			     (void *) &missing_good);
+
+	free(good_glob);
+	free(bad_ref);
+
+	return decide_next(terms, current_term, missing_good, missing_bad);
 }
 
 static int get_terms(struct bisect_terms *terms)
@@ -397,7 +399,7 @@
 
 static int bisect_append_log_quoted(const char **argv)
 {
-	int retval = 0;
+	int res = 0;
 	FILE *fp = fopen(git_path_bisect_log(), "a");
 	struct strbuf orig_args = STRBUF_INIT;
 
@@ -405,25 +407,25 @@
 		return -1;
 
 	if (fprintf(fp, "git bisect start") < 1) {
-		retval = -1;
+		res = -1;
 		goto finish;
 	}
 
 	sq_quote_argv(&orig_args, argv);
 	if (fprintf(fp, "%s\n", orig_args.buf) < 1)
-		retval = -1;
+		res = -1;
 
 finish:
 	fclose(fp);
 	strbuf_release(&orig_args);
-	return retval;
+	return res;
 }
 
 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			const char **argv, int argc)
 {
 	int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
-	int flags, pathspec_pos, retval = 0;
+	int flags, pathspec_pos, res = 0;
 	struct string_list revs = STRING_LIST_INIT_DUP;
 	struct string_list states = STRING_LIST_INIT_DUP;
 	struct strbuf start_head = STRBUF_INIT;
@@ -524,7 +526,7 @@
 			argv_array_pushl(&argv, "checkout", start_head.buf,
 					 "--", NULL);
 			if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
-				retval = error(_("checking out '%s' failed."
+				res = error(_("checking out '%s' failed."
 						 " Try 'git bisect start "
 						 "<valid-branch>'."),
 					       start_head.buf);
@@ -572,12 +574,12 @@
 
 	if (no_checkout) {
 		if (get_oid(start_head.buf, &oid) < 0) {
-			retval = error(_("invalid ref: '%s'"), start_head.buf);
+			res = error(_("invalid ref: '%s'"), start_head.buf);
 			goto finish;
 		}
 		if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
 			       UPDATE_REFS_MSG_ON_ERR)) {
-			retval = -1;
+			res = -1;
 			goto finish;
 		}
 	}
@@ -589,26 +591,26 @@
 	for (i = 0; i < states.nr; i++)
 		if (bisect_write(states.items[i].string,
 				 revs.items[i].string, terms, 1)) {
-			retval = -1;
+			res = -1;
 			goto finish;
 		}
 
 	if (must_write_terms && write_terms(terms->term_bad,
 					    terms->term_good)) {
-		retval = -1;
+		res = -1;
 		goto finish;
 	}
 
-	retval = bisect_append_log_quoted(argv);
-	if (retval)
-		retval = -1;
+	res = bisect_append_log_quoted(argv);
+	if (res)
+		res = -1;
 
 finish:
 	string_list_clear(&revs, 0);
 	string_list_clear(&states, 0);
 	strbuf_release(&start_head);
 	strbuf_release(&bisect_names);
-	return retval;
+	return res;
 }
 
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
@@ -664,7 +666,8 @@
 
 	switch (cmdmode) {
 	case NEXT_ALL:
-		return bisect_next_all(the_repository, prefix, no_checkout);
+		res = bisect_next_all(the_repository, prefix, no_checkout);
+		break;
 	case WRITE_TERMS:
 		if (argc != 2)
 			return error(_("--write-terms requires two arguments"));
@@ -711,5 +714,13 @@
 		return error("BUG: unknown subcommand '%d'", cmdmode);
 	}
 	free_terms(&terms);
-	return !!res;
+
+	/*
+	 * Handle early success
+	 * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
+	 */
+	if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE)
+		res = BISECT_OK;
+
+	return abs(res);
 }
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b52c490..d677381 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -524,6 +524,8 @@
 	/* Now we are committed to check them out */
 	if (opts->checkout_worktree)
 		errs |= checkout_worktree(opts);
+	else
+		remove_marked_cache_entries(&the_index, 1);
 
 	/*
 	 * Allow updating the index when checking out from the index.
@@ -863,7 +865,7 @@
 		strbuf_addf(&msg, "checkout: moving from %s to %s",
 			old_desc ? old_desc : "(invalid)", new_branch_info->name);
 	else
-		strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
+		strbuf_insertstr(&msg, 0, reflog_msg);
 
 	if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
 		/* Nothing to do. */
@@ -1115,12 +1117,43 @@
 	}
 }
 
+static const char *parse_remote_branch(const char *arg,
+				       struct object_id *rev,
+				       int could_be_checkout_paths)
+{
+	int num_matches = 0;
+	const char *remote = unique_tracking_name(arg, rev, &num_matches);
+
+	if (remote && could_be_checkout_paths) {
+		die(_("'%s' could be both a local file and a tracking branch.\n"
+			"Please use -- (and optionally --no-guess) to disambiguate"),
+		    arg);
+	}
+
+	if (!remote && num_matches > 1) {
+	    if (advice_checkout_ambiguous_remote_branch_name) {
+		    advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
+			     "you can do so by fully qualifying the name with the --track option:\n"
+			     "\n"
+			     "    git checkout --track origin/<name>\n"
+			     "\n"
+			     "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
+			     "one remote, e.g. the 'origin' remote, consider setting\n"
+			     "checkout.defaultRemote=origin in your config."));
+	    }
+
+	    die(_("'%s' matched multiple (%d) remote tracking branches"),
+		arg, num_matches);
+	}
+
+	return remote;
+}
+
 static int parse_branchname_arg(int argc, const char **argv,
 				int dwim_new_local_branch_ok,
 				struct branch_info *new_branch_info,
 				struct checkout_opts *opts,
-				struct object_id *rev,
-				int *dwim_remotes_matched)
+				struct object_id *rev)
 {
 	const char **new_branch = &opts->new_branch;
 	int argcount = 0;
@@ -1225,13 +1258,9 @@
 			recover_with_dwim = 0;
 
 		if (recover_with_dwim) {
-			const char *remote = unique_tracking_name(arg, rev,
-								  dwim_remotes_matched);
+			const char *remote = parse_remote_branch(arg, rev,
+								 could_be_checkout_paths);
 			if (remote) {
-				if (could_be_checkout_paths)
-					die(_("'%s' could be both a local file and a tracking branch.\n"
-					      "Please use -- (and optionally --no-guess) to disambiguate"),
-					    arg);
 				*new_branch = arg;
 				arg = remote;
 				/* DWIMmed to create local branch, case (3).(b) */
@@ -1496,7 +1525,6 @@
 			 const char * const usagestr[])
 {
 	struct branch_info new_branch_info;
-	int dwim_remotes_matched = 0;
 	int parseopt_flags = 0;
 
 	memset(&new_branch_info, 0, sizeof(new_branch_info));
@@ -1604,8 +1632,7 @@
 			opts->track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts->new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, opts, &rev,
-					     &dwim_remotes_matched);
+					     &new_branch_info, opts, &rev);
 		argv += n;
 		argc -= n;
 	} else if (!opts->accept_ref && opts->from_treeish) {
@@ -1682,28 +1709,10 @@
 	}
 
 	UNLEAK(opts);
-	if (opts->patch_mode || opts->pathspec.nr) {
-		int ret = checkout_paths(opts, new_branch_info.name);
-		if (ret && dwim_remotes_matched > 1 &&
-		    advice_checkout_ambiguous_remote_branch_name)
-			advise(_("'%s' matched more than one remote tracking branch.\n"
-				 "We found %d remotes with a reference that matched. So we fell back\n"
-				 "on trying to resolve the argument as a path, but failed there too!\n"
-				 "\n"
-				 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
-				 "you can do so by fully qualifying the name with the --track option:\n"
-				 "\n"
-				 "    git checkout --track origin/<name>\n"
-				 "\n"
-				 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
-				 "one remote, e.g. the 'origin' remote, consider setting\n"
-				 "checkout.defaultRemote=origin in your config."),
-			       argv[0],
-			       dwim_remotes_matched);
-		return ret;
-	} else {
+	if (opts->patch_mode || opts->pathspec.nr)
+		return checkout_paths(opts, new_branch_info.name);
+	else
 		return checkout_branch(opts, &new_branch_info);
-	}
 }
 
 int cmd_checkout(int argc, const char **argv, const char *prefix)
diff --git a/builtin/clone.c b/builtin/clone.c
index 0fc89ae..4f6150c 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -673,7 +673,7 @@
 			       const char *msg,
 			       struct transport *transport,
 			       int check_connectivity,
-			       int check_refs_only)
+			       int check_refs_are_promisor_objects_only)
 {
 	const struct ref *rm = mapped_refs;
 
@@ -682,7 +682,8 @@
 
 		opt.transport = transport;
 		opt.progress = transport->progress;
-		opt.check_refs_only = !!check_refs_only;
+		opt.check_refs_are_promisor_objects_only =
+			!!check_refs_are_promisor_objects_only;
 
 		if (check_connected(iterate_ref_map, &rm, &opt))
 			die(_("remote did not send all necessary objects"));
@@ -1128,7 +1129,7 @@
 	if (option_required_reference.nr || option_optional_reference.nr)
 		setup_reference();
 
-	if (option_sparse_checkout && git_sparse_checkout_init(repo))
+	if (option_sparse_checkout && git_sparse_checkout_init(dir))
 		return 1;
 
 	remote = remote_get(option_origin);
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index e0c6fc4..70f1fb2 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -9,7 +9,11 @@
 
 static char const * const builtin_commit_graph_usage[] = {
 	N_("git commit-graph verify [--object-dir <objdir>] [--shallow] [--[no-]progress]"),
-	N_("git commit-graph write [--object-dir <objdir>] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] [--[no-]progress] <split options>"),
+	N_("git commit-graph write [--object-dir <objdir>] "
+	   "[--split[=<strategy>]] "
+	   "[--input=<reachable|stdin-packs|stdin-commits|append|none>] "
+	   "[--changed-paths] "
+	   "[--[no-]progress] <split options>"),
 	NULL
 };
 
@@ -19,24 +23,78 @@
 };
 
 static const char * const builtin_commit_graph_write_usage[] = {
-	N_("git commit-graph write [--object-dir <objdir>] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] [--[no-]progress] <split options>"),
+	N_("git commit-graph write [--object-dir <objdir>] "
+	   "[--split[=<strategy>]] "
+	   "[--input=<reachable|stdin-packs|stdin-commits|append|none>] "
+	   "[--changed-paths] "
+	   "[--[no-]progress] <split options>"),
 	NULL
 };
 
+enum commit_graph_input {
+	COMMIT_GRAPH_INPUT_REACHABLE     = (1 << 1),
+	COMMIT_GRAPH_INPUT_STDIN_PACKS   = (1 << 2),
+	COMMIT_GRAPH_INPUT_STDIN_COMMITS = (1 << 3),
+	COMMIT_GRAPH_INPUT_APPEND        = (1 << 4),
+	COMMIT_GRAPH_INPUT_NONE          = (1 << 5)
+};
+
 static struct opts_commit_graph {
 	const char *obj_dir;
-	int reachable;
-	int stdin_packs;
-	int stdin_commits;
-	int append;
+	enum commit_graph_input input;
 	int split;
 	int shallow;
 	int progress;
+	int enable_changed_paths;
 } opts;
 
+static struct object_directory *find_odb(struct repository *r,
+					 const char *obj_dir)
+{
+	struct object_directory *odb;
+	char *obj_dir_real = real_pathdup(obj_dir, 1);
+
+	prepare_alt_odb(r);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		if (!strcmp(obj_dir_real, real_path(odb->path)))
+			break;
+	}
+
+	free(obj_dir_real);
+
+	if (!odb)
+		die(_("could not find object directory matching %s"), obj_dir);
+	return odb;
+}
+
+static int option_parse_input(const struct option *opt, const char *arg,
+			      int unset)
+{
+	enum commit_graph_input *to = opt->value;
+	if (unset || !strcmp(arg, "packs")) {
+		*to = 0;
+		return 0;
+	}
+
+	if (!strcmp(arg, "reachable"))
+		*to |= COMMIT_GRAPH_INPUT_REACHABLE;
+	else if (!strcmp(arg, "stdin-packs"))
+		*to |= COMMIT_GRAPH_INPUT_STDIN_PACKS;
+	else if (!strcmp(arg, "stdin-commits"))
+		*to |= COMMIT_GRAPH_INPUT_STDIN_COMMITS;
+	else if (!strcmp(arg, "append"))
+		*to |= COMMIT_GRAPH_INPUT_APPEND;
+	else if (!strcmp(arg, "none"))
+		*to |= (COMMIT_GRAPH_INPUT_APPEND | COMMIT_GRAPH_INPUT_NONE);
+	else
+		die(_("unrecognized --input source, %s"), arg);
+	return 0;
+}
+
 static int graph_verify(int argc, const char **argv)
 {
 	struct commit_graph *graph = NULL;
+	struct object_directory *odb = NULL;
 	char *graph_name;
 	int open_ok;
 	int fd;
@@ -67,7 +125,8 @@
 	if (opts.progress)
 		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
-	graph_name = get_commit_graph_filename(opts.obj_dir);
+	odb = find_odb(the_repository, opts.obj_dir);
+	graph_name = get_commit_graph_filename(odb);
 	open_ok = open_commit_graph(graph_name, &fd, &st);
 	if (!open_ok && errno != ENOENT)
 		die_errno(_("Could not open commit-graph '%s'"), graph_name);
@@ -75,9 +134,9 @@
 	FREE_AND_NULL(graph_name);
 
 	if (open_ok)
-		graph = load_commit_graph_one_fd_st(fd, &st);
-	 else
-		graph = read_commit_graph_one(the_repository, opts.obj_dir);
+		graph = load_commit_graph_one_fd_st(fd, &st, odb);
+	else
+		graph = read_commit_graph_one(the_repository, odb);
 
 	/* Return failure if open_ok predicted success */
 	if (!graph)
@@ -90,10 +149,32 @@
 extern int read_replace_refs;
 static struct split_commit_graph_opts split_opts;
 
+static int write_option_parse_split(const struct option *opt, const char *arg,
+				    int unset)
+{
+	enum commit_graph_split_flags *flags = opt->value;
+
+	opts.split = 1;
+	if (!arg) {
+		*flags = COMMIT_GRAPH_SPLIT_MERGE_AUTO;
+		return 0;
+	}
+
+	if (!strcmp(arg, "merge-all"))
+		*flags = COMMIT_GRAPH_SPLIT_MERGE_REQUIRED;
+	else if (!strcmp(arg, "no-merge"))
+		*flags = COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED;
+	else
+		die(_("unrecognized --split argument, %s"), arg);
+
+	return 0;
+}
+
 static int graph_write(int argc, const char **argv)
 {
 	struct string_list *pack_indexes = NULL;
 	struct string_list *commit_hex = NULL;
+	struct object_directory *odb = NULL;
 	struct string_list lines;
 	int result = 0;
 	enum commit_graph_write_flags flags = 0;
@@ -102,17 +183,28 @@
 		OPT_STRING(0, "object-dir", &opts.obj_dir,
 			N_("dir"),
 			N_("The object directory to store the graph")),
-		OPT_BOOL(0, "reachable", &opts.reachable,
-			N_("start walk at all refs")),
-		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_CALLBACK(0, "input", &opts.input, NULL,
+			N_("include commits from this source in the graph"),
+			option_parse_input),
+		OPT_BIT(0, "reachable", &opts.input,
+			N_("start walk at all refs"),
+			COMMIT_GRAPH_INPUT_REACHABLE),
+		OPT_BIT(0, "stdin-packs", &opts.input,
+			N_("scan pack-indexes listed by stdin for commits"),
+			COMMIT_GRAPH_INPUT_STDIN_PACKS),
+		OPT_BIT(0, "stdin-commits", &opts.input,
+			N_("start walk at commits listed by stdin"),
+			COMMIT_GRAPH_INPUT_STDIN_COMMITS),
+		OPT_BIT(0, "append", &opts.input,
+			N_("include all commits already in the commit-graph file"),
+			COMMIT_GRAPH_INPUT_APPEND),
+		OPT_BOOL(0, "changed-paths", &opts.enable_changed_paths,
+			N_("enable computation for changed paths")),
 		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
-		OPT_BOOL(0, "split", &opts.split,
-			N_("allow writing an incremental commit-graph file")),
+		OPT_CALLBACK_F(0, "split", &split_opts.flags, NULL,
+			N_("allow writing an incremental commit-graph file"),
+			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
+			write_option_parse_split),
 		OPT_INTEGER(0, "max-commits", &split_opts.max_commits,
 			N_("maximum number of commits in a non-base split commit-graph")),
 		OPT_INTEGER(0, "size-multiple", &split_opts.size_multiple,
@@ -133,35 +225,43 @@
 			     builtin_commit_graph_write_options,
 			     builtin_commit_graph_write_usage, 0);
 
-	if (opts.reachable + opts.stdin_packs + opts.stdin_commits > 1)
-		die(_("use at most one of --reachable, --stdin-commits, or --stdin-packs"));
+	if ((!!(opts.input & COMMIT_GRAPH_INPUT_REACHABLE) +
+	     !!(opts.input & COMMIT_GRAPH_INPUT_STDIN_PACKS) +
+	     !!(opts.input & COMMIT_GRAPH_INPUT_STDIN_COMMITS)) > 1)
+		die(_("use at most one of --input=reachable, --input=stdin-commits, or --input=stdin-packs"));
 	if (!opts.obj_dir)
 		opts.obj_dir = get_object_directory();
-	if (opts.append)
+	if (opts.input & COMMIT_GRAPH_INPUT_APPEND)
 		flags |= COMMIT_GRAPH_WRITE_APPEND;
+	if (opts.input & COMMIT_GRAPH_INPUT_NONE)
+		flags |= COMMIT_GRAPH_WRITE_NO_INPUT;
 	if (opts.split)
 		flags |= COMMIT_GRAPH_WRITE_SPLIT;
 	if (opts.progress)
 		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
+	if (opts.enable_changed_paths ||
+	    git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
+		flags |= COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
 
 	read_replace_refs = 0;
+	odb = find_odb(the_repository, opts.obj_dir);
 
-	if (opts.reachable) {
-		if (write_commit_graph_reachable(opts.obj_dir, flags, &split_opts))
+	if (opts.input & COMMIT_GRAPH_INPUT_REACHABLE) {
+		if (write_commit_graph_reachable(odb, flags, &split_opts))
 			return 1;
 		return 0;
 	}
 
 	string_list_init(&lines, 0);
-	if (opts.stdin_packs || opts.stdin_commits) {
+	if (opts.input & (COMMIT_GRAPH_INPUT_STDIN_PACKS | COMMIT_GRAPH_INPUT_STDIN_COMMITS)) {
 		struct strbuf buf = STRBUF_INIT;
 
 		while (strbuf_getline(&buf, stdin) != EOF)
 			string_list_append(&lines, strbuf_detach(&buf, NULL));
 
-		if (opts.stdin_packs)
+		if (opts.input & COMMIT_GRAPH_INPUT_STDIN_PACKS)
 			pack_indexes = &lines;
-		if (opts.stdin_commits) {
+		if (opts.input & COMMIT_GRAPH_INPUT_STDIN_COMMITS) {
 			commit_hex = &lines;
 			flags |= COMMIT_GRAPH_WRITE_CHECK_OIDS;
 		}
@@ -169,7 +269,7 @@
 		UNLEAK(buf);
 	}
 
-	if (write_commit_graph(opts.obj_dir,
+	if (write_commit_graph(odb,
 			       pack_indexes,
 			       commit_hex,
 			       flags,
diff --git a/builtin/commit.c b/builtin/commit.c
index aa13323..e8c03d0 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -52,6 +52,20 @@
 "it empty. You can repeat your command with --allow-empty, or you can\n"
 "remove the commit entirely with \"git reset HEAD^\".\n");
 
+static const char empty_rebase_fixup_advice[] =
+N_("The fixup would make the commit empty\n"
+"If you wish to commit it anyway use:\n"
+"\n"
+"    git commit --amend --allow-empty\n"
+"    git rebase --continue\n"
+"\n"
+"To remove the commit entirely use:\n"
+"\n"
+"    git reset HEAD^\n"
+"    git rebase --continue\n"
+"\n"
+"Otherwise, please use 'git rebase --skip' to skip it\n");
+
 static const char empty_cherry_pick_advice[] =
 N_("The previous cherry-pick is now empty, possibly due to conflict resolution.\n"
 "If you wish to commit it anyway, use:\n"
@@ -59,6 +73,9 @@
 "    git commit --allow-empty\n"
 "\n");
 
+static const char empty_rebase_pick_advice[] =
+N_("Otherwise, please use 'git rebase --skip'\n");
+
 static const char empty_cherry_pick_advice_single[] =
 N_("Otherwise, please use 'git cherry-pick --skip'\n");
 
@@ -122,7 +139,6 @@
 static const char *cleanup_arg;
 
 static enum commit_whence whence;
-static int sequencer_in_use;
 static int use_editor = 1, include_status = 1;
 static int have_option_m;
 static struct strbuf message = STRBUF_INIT;
@@ -179,13 +195,14 @@
 {
 	if (file_exists(git_path_merge_head(the_repository)))
 		whence = FROM_MERGE;
-	else if (file_exists(git_path_cherry_pick_head(the_repository))) {
-		whence = FROM_CHERRY_PICK;
-		if (file_exists(git_path_seq_dir()))
-			sequencer_in_use = 1;
+	else {
+		int res = sequencer_determine_whence(the_repository, &whence,
+						     amend);
+		if (res < 0)
+			die(_("could not read sequencer state"));
+		else if (!res)
+			whence = FROM_COMMIT;
 	}
-	else
-		whence = FROM_COMMIT;
 	if (s)
 		s->whence = whence;
 }
@@ -195,7 +212,6 @@
 	wt_status_prepare(the_repository, s);
 	init_diff_ui_defaults();
 	git_config(fn, s);
-	determine_whence(s);
 	s->hints = advice_status_hints; /* must come after git_config() */
 }
 
@@ -367,7 +383,7 @@
 		die(_("index file corrupt"));
 
 	if (interactive) {
-		char *old_index_env = NULL;
+		char *old_index_env = NULL, *old_repo_index_file;
 		hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
 
 		refresh_cache_or_die(refresh_flags);
@@ -375,12 +391,16 @@
 		if (write_locked_index(&the_index, &index_lock, 0))
 			die(_("unable to create temporary index"));
 
+		old_repo_index_file = the_repository->index_file;
+		the_repository->index_file =
+			(char *)get_lock_file_path(&index_lock);
 		old_index_env = xstrdup_or_null(getenv(INDEX_ENVIRONMENT));
-		setenv(INDEX_ENVIRONMENT, get_lock_file_path(&index_lock), 1);
+		setenv(INDEX_ENVIRONMENT, the_repository->index_file, 1);
 
 		if (interactive_add(argc, argv, prefix, patch_interactive) != 0)
 			die(_("interactive add failed"));
 
+		the_repository->index_file = old_repo_index_file;
 		if (old_index_env && *old_index_env)
 			setenv(INDEX_ENVIRONMENT, old_index_env, 1);
 		else
@@ -473,8 +493,10 @@
 	if (whence != FROM_COMMIT) {
 		if (whence == FROM_MERGE)
 			die(_("cannot do a partial commit during a merge."));
-		else if (whence == FROM_CHERRY_PICK)
+		else if (is_from_cherry_pick(whence))
 			die(_("cannot do a partial commit during a cherry-pick."));
+		else if (is_from_rebase(whence))
+			die(_("cannot do a partial commit during a rebase."));
 	}
 
 	if (list_paths(&partial, !current_head ? NULL : "HEAD", &pathspec))
@@ -791,7 +813,7 @@
 	 */
 	else if (whence == FROM_MERGE)
 		hook_arg1 = "merge";
-	else if (whence == FROM_CHERRY_PICK) {
+	else if (is_from_cherry_pick(whence) || whence == FROM_REBASE_PICK) {
 		hook_arg1 = "commit";
 		hook_arg2 = "CHERRY_PICK_HEAD";
 	}
@@ -964,16 +986,23 @@
 	 */
 	if (!committable && whence != FROM_MERGE && !allow_empty &&
 	    !(amend && is_a_merge(current_head))) {
+		s->hints = advice_status_hints;
+		fprintf(stderr, "\nwhence = %d\n", whence);
 		s->display_comment_prefix = old_display_comment_prefix;
 		run_status(stdout, index_file, prefix, 0, s);
-		if (amend)
+		if (whence == FROM_REBASE_FIXUP)
+			fputs(_(empty_rebase_fixup_advice), stderr);
+		else if (amend)
 			fputs(_(empty_amend_advice), stderr);
-		else if (whence == FROM_CHERRY_PICK) {
+		else if (is_from_cherry_pick(whence) ||
+			 whence == FROM_REBASE_PICK) {
 			fputs(_(empty_cherry_pick_advice), stderr);
-			if (!sequencer_in_use)
+			if (whence == FROM_CHERRY_PICK_SINGLE)
 				fputs(_(empty_cherry_pick_advice_single), stderr);
-			else
+			else if (whence == FROM_CHERRY_PICK_MULTI)
 				fputs(_(empty_cherry_pick_advice_multi), stderr);
+			else
+				fputs(_(empty_rebase_pick_advice), stderr);
 		}
 		return 0;
 	}
@@ -1145,6 +1174,8 @@
 
 	if (s->ahead_behind_flags == AHEAD_BEHIND_UNSPECIFIED)
 		s->ahead_behind_flags = AHEAD_BEHIND_FULL;
+
+	determine_whence(s);
 }
 
 static int parse_and_validate_options(int argc, const char *argv[],
@@ -1176,8 +1207,10 @@
 	if (amend && whence != FROM_COMMIT) {
 		if (whence == FROM_MERGE)
 			die(_("You are in the middle of a merge -- cannot amend."));
-		else if (whence == FROM_CHERRY_PICK)
+		else if (is_from_cherry_pick(whence))
 			die(_("You are in the middle of a cherry-pick -- cannot amend."));
+		else if (whence == FROM_REBASE_PICK)
+			die(_("You are in the middle of a rebase -- cannot amend."));
 	}
 	if (fixup_message && squash_message)
 		die(_("Options --squash and --fixup cannot be used together"));
@@ -1199,7 +1232,8 @@
 		use_message = edit_message;
 	if (amend && !use_message && !fixup_message)
 		use_message = "HEAD";
-	if (!use_message && whence != FROM_CHERRY_PICK && renew_authorship)
+	if (!use_message && !is_from_cherry_pick(whence) &&
+	    !is_from_rebase(whence) && renew_authorship)
 		die(_("--reset-author can be used only with -C, -c or --amend."));
 	if (use_message) {
 		use_message_buffer = read_commit_message(use_message);
@@ -1208,7 +1242,8 @@
 			author_message_buffer = use_message_buffer;
 		}
 	}
-	if (whence == FROM_CHERRY_PICK && !renew_authorship) {
+	if ((is_from_cherry_pick(whence) || whence == FROM_REBASE_PICK) &&
+	    !renew_authorship) {
 		author_message = "CHERRY_PICK_HEAD";
 		author_message_buffer = read_commit_message(author_message);
 	}
@@ -1626,8 +1661,10 @@
 			reduce_heads_replace(&parents);
 	} else {
 		if (!reflog_msg)
-			reflog_msg = (whence == FROM_CHERRY_PICK)
+			reflog_msg = is_from_cherry_pick(whence)
 					? "commit (cherry-pick)"
+					: is_from_rebase(whence)
+					? "commit (rebase)"
 					: "commit";
 		commit_list_insert(current_head, &parents);
 	}
@@ -1682,13 +1719,15 @@
 	unlink(git_path_merge_mode(the_repository));
 	unlink(git_path_squash_msg(the_repository));
 
+	apply_autostash(git_path_merge_autostash(the_repository));
+
 	if (commit_index_files())
 		die(_("repository has been updated, but unable to write\n"
 		      "new_index file. Check that disk is not full and quota is\n"
 		      "not exceeded, and then \"git restore --staged :/\" to recover."));
 
 	if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
-	    write_commit_graph_reachable(get_object_directory(), 0, NULL))
+	    write_commit_graph_reachable(the_repository->objects->odb, 0, NULL))
 		return 1;
 
 	repo_rerere(the_repository, 0);
diff --git a/builtin/config.c b/builtin/config.c
index 98d65bc..ee4aef6 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -29,10 +29,11 @@
 static struct git_config_source given_config_source;
 static int actions, type;
 static char *default_value;
-static int end_null;
+static int end_nul;
 static int respect_includes_opt = -1;
 static struct config_options config_options;
 static int show_origin;
+static int show_scope;
 
 #define ACTION_GET (1<<0)
 #define ACTION_GET_ALL (1<<1)
@@ -151,10 +152,11 @@
 	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('z', "null", &end_nul, 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_BOOL(0, "show-scope", &show_scope, N_("show scope of config (worktree, local, global, system, command)")),
 	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
 	OPT_END(),
 };
@@ -178,22 +180,34 @@
 
 static void show_config_origin(struct strbuf *buf)
 {
-	const char term = end_null ? '\0' : '\t';
+	const char term = end_nul ? '\0' : '\t';
 
 	strbuf_addstr(buf, current_config_origin_type());
 	strbuf_addch(buf, ':');
-	if (end_null)
+	if (end_nul)
 		strbuf_addstr(buf, current_config_name());
 	else
 		quote_c_style(current_config_name(), buf, NULL, 0);
 	strbuf_addch(buf, term);
 }
 
+static void show_config_scope(struct strbuf *buf)
+{
+	const char term = end_nul ? '\0' : '\t';
+	const char *scope = config_scope_name(current_config_scope());
+
+	strbuf_addstr(buf, N_(scope));
+	strbuf_addch(buf, term);
+}
+
 static int show_all_config(const char *key_, const char *value_, void *cb)
 {
-	if (show_origin) {
+	if (show_origin || show_scope) {
 		struct strbuf buf = STRBUF_INIT;
-		show_config_origin(&buf);
+		if (show_scope)
+			show_config_scope(&buf);
+		if (show_origin)
+			show_config_origin(&buf);
 		/* Use fwrite as "buf" can contain \0's if "end_null" is set. */
 		fwrite(buf.buf, 1, buf.len, stdout);
 		strbuf_release(&buf);
@@ -213,6 +227,8 @@
 
 static int format_config(struct strbuf *buf, const char *key_, const char *value_)
 {
+	if (show_scope)
+		show_config_scope(buf);
 	if (show_origin)
 		show_config_origin(buf);
 	if (show_keys)
@@ -622,6 +638,7 @@
 			!strcmp(given_config_source.file, "-")) {
 		given_config_source.file = NULL;
 		given_config_source.use_stdin = 1;
+		given_config_source.scope = CONFIG_SCOPE_COMMAND;
 	}
 
 	if (use_global_config) {
@@ -637,6 +654,8 @@
 			 */
 			die(_("$HOME not set"));
 
+		given_config_source.scope = CONFIG_SCOPE_GLOBAL;
+
 		if (access_or_warn(user_config, R_OK, 0) &&
 		    xdg_config && !access_or_warn(xdg_config, R_OK, 0)) {
 			given_config_source.file = xdg_config;
@@ -646,11 +665,13 @@
 			free(xdg_config);
 		}
 	}
-	else if (use_system_config)
+	else if (use_system_config) {
 		given_config_source.file = git_etc_gitconfig();
-	else if (use_local_config)
+		given_config_source.scope = CONFIG_SCOPE_SYSTEM;
+	} else if (use_local_config) {
 		given_config_source.file = git_pathdup("config");
-	else if (use_worktree_config) {
+		given_config_source.scope = CONFIG_SCOPE_LOCAL;
+	} else if (use_worktree_config) {
 		struct worktree **worktrees = get_worktrees(0);
 		if (repository_format_worktree_config)
 			given_config_source.file = git_pathdup("config.worktree");
@@ -662,13 +683,18 @@
 			      "section in \"git help worktree\" for details"));
 		else
 			given_config_source.file = git_pathdup("config");
+		given_config_source.scope = CONFIG_SCOPE_LOCAL;
 		free_worktrees(worktrees);
 	} else if (given_config_source.file) {
 		if (!is_absolute_path(given_config_source.file) && prefix)
 			given_config_source.file =
 				prefix_filename(prefix, given_config_source.file);
+		given_config_source.scope = CONFIG_SCOPE_COMMAND;
+	} else if (given_config_source.blob) {
+		given_config_source.scope = CONFIG_SCOPE_COMMAND;
 	}
 
+
 	if (respect_includes_opt == -1)
 		config_options.respect_includes = !given_config_source.file;
 	else
@@ -678,7 +704,7 @@
 		config_options.git_dir = get_git_dir();
 	}
 
-	if (end_null) {
+	if (end_nul) {
 		term = '\0';
 		delim = '\n';
 		key_delim = '\n';
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index dbec4df..8586816 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -293,7 +293,8 @@
 		buf = read_object_file(oid, &type, &size);
 		if (!buf)
 			die("could not read blob %s", oid_to_hex(oid));
-		if (check_object_signature(oid, buf, size, type_name(type)) < 0)
+		if (check_object_signature(the_repository, oid, buf, size,
+					   type_name(type)) < 0)
 			die("oid mismatch in blob %s", oid_to_hex(oid));
 		object = parse_object_buffer(the_repository, oid, type,
 					     size, buf, &eaten);
@@ -870,8 +871,7 @@
 		printf("reset %s\nfrom %s\n\n",
 		       name, oid_to_hex(&null_oid));
 	}
-	if (starts_with(name, "refs/tags/"))
-		name += 10;
+	skip_prefix(name, "refs/tags/", &name);
 	printf("tag %s\n", name);
 	if (mark_tags) {
 		mark_next_object(&tag->object);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b4c6d92..ab7e4b1 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -906,8 +906,17 @@
 		url = xstrdup("foreign");
 
 	if (!connectivity_checked) {
+		struct check_connected_options opt = CHECK_CONNECTED_INIT;
+
+		if (filter_options.choice)
+			/*
+			 * Since a filter is specified, objects indirectly
+			 * referenced by refs are allowed to be absent.
+			 */
+			opt.check_refs_are_promisor_objects_only = 1;
+
 		rm = ref_map;
-		if (check_connected(iterate_ref_map, &rm, NULL)) {
+		if (check_connected(iterate_ref_map, &rm, &opt)) {
 			rc = error(_("%s did not send all necessary objects\n"), url);
 			goto abort;
 		}
@@ -1870,7 +1879,7 @@
 		if (progress)
 			commit_graph_flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
-		write_commit_graph_reachable(get_object_directory(),
+		write_commit_graph_reachable(the_repository->objects->odb,
 					     commit_graph_flags,
 					     NULL);
 	}
diff --git a/builtin/gc.c b/builtin/gc.c
index 3f76bf4..8e0b9cf 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -686,7 +686,7 @@
 
 	prepare_repo_settings(the_repository);
 	if (the_repository->settings.gc_write_commit_graph == 1)
-		write_commit_graph_reachable(get_object_directory(),
+		write_commit_graph_reachable(the_repository->objects->odb,
 					     !quiet && !daemonized ? COMMIT_GRAPH_WRITE_PROGRESS : 0,
 					     NULL);
 
diff --git a/builtin/grep.c b/builtin/grep.c
index 50ce8d9..99e2685 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -24,6 +24,7 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "object-store.h"
+#include "packfile.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
@@ -32,7 +33,6 @@
 
 static int recurse_submodules;
 
-#define GREP_NUM_THREADS_DEFAULT 8
 static int num_threads;
 
 static pthread_t *threads;
@@ -91,8 +91,11 @@
 
 static int skip_first_line;
 
-static void add_work(struct grep_opt *opt, const struct grep_source *gs)
+static void add_work(struct grep_opt *opt, struct grep_source *gs)
 {
+	if (opt->binary != GREP_BINARY_TEXT)
+		grep_source_load_driver(gs, opt->repo->index);
+
 	grep_lock();
 
 	while ((todo_end+1) % ARRAY_SIZE(todo) == todo_done) {
@@ -100,9 +103,6 @@
 	}
 
 	todo[todo_end].source = *gs;
-	if (opt->binary != GREP_BINARY_TEXT)
-		grep_source_load_driver(&todo[todo_end].source,
-					opt->repo->index);
 	todo[todo_end].done = 0;
 	strbuf_reset(&todo[todo_end].out);
 	todo_end = (todo_end + 1) % ARRAY_SIZE(todo);
@@ -200,12 +200,12 @@
 	int i;
 
 	pthread_mutex_init(&grep_mutex, NULL);
-	pthread_mutex_init(&grep_read_mutex, NULL);
 	pthread_mutex_init(&grep_attr_mutex, NULL);
 	pthread_cond_init(&cond_add, NULL);
 	pthread_cond_init(&cond_write, NULL);
 	pthread_cond_init(&cond_result, NULL);
 	grep_use_locks = 1;
+	enable_obj_read_lock();
 
 	for (i = 0; i < ARRAY_SIZE(todo); i++) {
 		strbuf_init(&todo[i].out, 0);
@@ -257,12 +257,12 @@
 	free(threads);
 
 	pthread_mutex_destroy(&grep_mutex);
-	pthread_mutex_destroy(&grep_read_mutex);
 	pthread_mutex_destroy(&grep_attr_mutex);
 	pthread_cond_destroy(&cond_add);
 	pthread_cond_destroy(&cond_write);
 	pthread_cond_destroy(&cond_result);
 	grep_use_locks = 0;
+	disable_obj_read_lock();
 
 	return hit;
 }
@@ -295,16 +295,6 @@
 	return st;
 }
 
-static void *lock_and_read_oid_file(const struct object_id *oid, enum object_type *type, unsigned long *size)
-{
-	void *data;
-
-	grep_read_lock();
-	data = read_object_file(oid, type, size);
-	grep_read_unlock();
-	return data;
-}
-
 static int grep_oid(struct grep_opt *opt, const struct object_id *oid,
 		     const char *filename, int tree_name_len,
 		     const char *path)
@@ -407,30 +397,28 @@
 {
 	struct repository subrepo;
 	struct repository *superproject = opt->repo;
-	const struct submodule *sub = submodule_from_path(superproject,
-							  &null_oid, path);
+	const struct submodule *sub;
 	struct grep_opt subopt;
 	int hit;
 
+	sub = submodule_from_path(superproject, &null_oid, path);
+
+	if (!is_submodule_active(superproject, path))
+		return 0;
+
+	if (repo_submodule_init(&subrepo, superproject, sub))
+		return 0;
+
 	/*
-	 * NEEDSWORK: submodules functions need to be protected because they
-	 * access the object store via config_from_gitmodules(): the latter
-	 * uses get_oid() which, for now, relies on the global the_repository
-	 * object.
+	 * NEEDSWORK: repo_read_gitmodules() might call
+	 * add_to_alternates_memory() via config_from_gitmodules(). This
+	 * operation causes a race condition with concurrent object readings
+	 * performed by the worker threads. That's why we need obj_read_lock()
+	 * here. It should be removed once it's no longer necessary to add the
+	 * subrepo's odbs to the in-memory alternates list.
 	 */
-	grep_read_lock();
-
-	if (!is_submodule_active(superproject, path)) {
-		grep_read_unlock();
-		return 0;
-	}
-
-	if (repo_submodule_init(&subrepo, superproject, sub)) {
-		grep_read_unlock();
-		return 0;
-	}
-
-	repo_read_gitmodules(&subrepo);
+	obj_read_lock();
+	repo_read_gitmodules(&subrepo, 0);
 
 	/*
 	 * NEEDSWORK: This adds the submodule's object directory to the list of
@@ -443,7 +431,7 @@
 	 * object.
 	 */
 	add_to_alternates_memory(subrepo.objects->odb->path);
-	grep_read_unlock();
+	obj_read_unlock();
 
 	memcpy(&subopt, opt, sizeof(subopt));
 	subopt.repo = &subrepo;
@@ -455,14 +443,12 @@
 		unsigned long size;
 		struct strbuf base = STRBUF_INIT;
 
+		obj_read_lock();
 		object = parse_object_or_die(oid, oid_to_hex(oid));
-
-		grep_read_lock();
+		obj_read_unlock();
 		data = read_object_with_reference(&subrepo,
 						  &object->oid, tree_type,
 						  &size, NULL);
-		grep_read_unlock();
-
 		if (!data)
 			die(_("unable to read tree (%s)"), oid_to_hex(&object->oid));
 
@@ -587,7 +573,7 @@
 			void *data;
 			unsigned long size;
 
-			data = lock_and_read_oid_file(&entry.oid, &type, &size);
+			data = read_object_file(&entry.oid, &type, &size);
 			if (!data)
 				die(_("unable to read tree (%s)"),
 				    oid_to_hex(&entry.oid));
@@ -625,12 +611,9 @@
 		struct strbuf base;
 		int hit, len;
 
-		grep_read_lock();
 		data = read_object_with_reference(opt->repo,
 						  &obj->oid, tree_type,
 						  &size, NULL);
-		grep_read_unlock();
-
 		if (!data)
 			die(_("unable to read tree (%s)"), oid_to_hex(&obj->oid));
 
@@ -659,13 +642,18 @@
 
 	for (i = 0; i < nr; i++) {
 		struct object *real_obj;
+
+		obj_read_lock();
 		real_obj = deref_tag(opt->repo, list->objects[i].item,
 				     NULL, 0);
+		obj_read_unlock();
 
 		/* load the gitmodules file for this rev */
 		if (recurse_submodules) {
 			submodule_free(opt->repo);
+			obj_read_lock();
 			gitmodules_config_oid(&real_obj->oid);
+			obj_read_unlock();
 		}
 		if (grep_object(opt, pathspec, real_obj, list->objects[i].name,
 				list->objects[i].path)) {
@@ -958,6 +946,9 @@
 			/* die the same way as if we did it at the beginning */
 			setup_git_directory();
 	}
+	/* Ignore --recurse-submodules if --no-index is given or implied */
+	if (!use_index)
+		recurse_submodules = 0;
 
 	/*
 	 * skip a -- separator; we know it cannot be
@@ -1062,7 +1053,10 @@
 	pathspec.recursive = 1;
 	pathspec.recurse_submodules = !!recurse_submodules;
 
-	if (list.nr || cached || show_in_pager) {
+	if (recurse_submodules && untracked)
+		die(_("--untracked not supported with --recurse-submodules"));
+
+	if (show_in_pager) {
 		if (num_threads > 1)
 			warning(_("invalid option combination, ignoring --threads"));
 		num_threads = 1;
@@ -1072,7 +1066,7 @@
 	} else if (num_threads < 0)
 		die(_("invalid number of threads specified (%d)"), num_threads);
 	else if (num_threads == 0)
-		num_threads = HAVE_THREADS ? GREP_NUM_THREADS_DEFAULT : 1;
+		num_threads = HAVE_THREADS ? online_cpus() : 1;
 
 	if (num_threads > 1) {
 		if (!HAVE_THREADS)
@@ -1081,6 +1075,17 @@
 		    && (opt.pre_context || opt.post_context ||
 			opt.file_break || opt.funcbody))
 			skip_first_line = 1;
+
+		/*
+		 * Pre-read gitmodules (if not read already) and force eager
+		 * initialization of packed_git to prevent racy lazy
+		 * reading/initialization once worker threads are started.
+		 */
+		if (recurse_submodules)
+			repo_read_gitmodules(the_repository, 1);
+		if (startup_info->have_repository)
+			(void)get_packed_git(the_repository);
+
 		start_threads(&opt);
 	} else {
 		/*
@@ -1115,9 +1120,6 @@
 		}
 	}
 
-	if (recurse_submodules && (!use_index || untracked))
-		die(_("option not supported with --recurse-submodules"));
-
 	if (!show_in_pager && !opt.status_only)
 		setup_pager();
 
diff --git a/builtin/help.c b/builtin/help.c
index e5590d7..1c5f2b9 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -8,6 +8,7 @@
 #include "parse-options.h"
 #include "run-command.h"
 #include "column.h"
+#include "config-list.h"
 #include "help.h"
 #include "alias.h"
 
@@ -62,6 +63,91 @@
 	NULL
 };
 
+struct slot_expansion {
+	const char *prefix;
+	const char *placeholder;
+	void (*fn)(struct string_list *list, const char *prefix);
+	int found;
+};
+
+static void list_config_help(int for_human)
+{
+	struct slot_expansion slot_expansions[] = {
+		{ "advice", "*", list_config_advices },
+		{ "color.branch", "<slot>", list_config_color_branch_slots },
+		{ "color.decorate", "<slot>", list_config_color_decorate_slots },
+		{ "color.diff", "<slot>", list_config_color_diff_slots },
+		{ "color.grep", "<slot>", list_config_color_grep_slots },
+		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
+		{ "color.remote", "<slot>", list_config_color_sideband_slots },
+		{ "color.status", "<slot>", list_config_color_status_slots },
+		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ NULL, NULL, NULL }
+	};
+	const char **p;
+	struct slot_expansion *e;
+	struct string_list keys = STRING_LIST_INIT_DUP;
+	int i;
+
+	for (p = config_name_list; *p; p++) {
+		const char *var = *p;
+		struct strbuf sb = STRBUF_INIT;
+
+		for (e = slot_expansions; e->prefix; e++) {
+
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
+			if (!strcasecmp(var, sb.buf)) {
+				e->fn(&keys, e->prefix);
+				e->found++;
+				break;
+			}
+		}
+		strbuf_release(&sb);
+		if (!e->prefix)
+			string_list_append(&keys, var);
+	}
+
+	for (e = slot_expansions; e->prefix; e++)
+		if (!e->found)
+			BUG("slot_expansion %s.%s is not used",
+			    e->prefix, e->placeholder);
+
+	string_list_sort(&keys);
+	for (i = 0; i < keys.nr; i++) {
+		const char *var = keys.items[i].string;
+		const char *wildcard, *tag, *cut;
+
+		if (for_human) {
+			puts(var);
+			continue;
+		}
+
+		wildcard = strchr(var, '*');
+		tag = strchr(var, '<');
+
+		if (!wildcard && !tag) {
+			puts(var);
+			continue;
+		}
+
+		if (wildcard && !tag)
+			cut = wildcard;
+		else if (!wildcard && tag)
+			cut = tag;
+		else
+			cut = wildcard < tag ? wildcard : tag;
+
+		/*
+		 * We may produce duplicates, but that's up to
+		 * git-completion.bash to handle
+		 */
+		printf("%.*s\n", (int)(cut - var), var);
+	}
+	string_list_clear(&keys, 0);
+}
+
 static enum help_format parse_help_format(const char *format)
 {
 	if (!strcmp(format, "man"))
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 60a5591..d967d18 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -757,7 +757,8 @@
 
 	memset(&data, 0, sizeof(data));
 	data.entry = entry;
-	data.st = open_istream(&entry->idx.oid, &type, &size, NULL);
+	data.st = open_istream(the_repository, &entry->idx.oid, &type, &size,
+			       NULL);
 	if (!data.st)
 		return -1;
 	if (size != entry->size || type != entry->type)
@@ -948,7 +949,7 @@
 	free(delta_data);
 	if (!result->data)
 		bad_object(delta_obj->idx.offset, _("failed to apply delta"));
-	hash_object_file(result->data, result->size,
+	hash_object_file(the_hash_algo, result->data, result->size,
 			 type_name(delta_obj->real_type), &delta_obj->idx.oid);
 	sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 		    &delta_obj->idx.oid);
@@ -1003,7 +1004,9 @@
 
 		if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
 					   base->obj->real_type))
-			BUG("child->real_type != OBJ_REF_DELTA");
+			die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)",
+			    (uintmax_t)child->idx.offset,
+			    oid_to_hex(&base->obj->idx.oid));
 
 		resolve_delta(child, base, result);
 		if (base->ref_first == base->ref_last && base->ofs_last == -1)
@@ -1383,8 +1386,9 @@
 		if (!base_obj->data)
 			continue;
 
-		if (check_object_signature(&d->oid, base_obj->data,
-				base_obj->size, type_name(type)))
+		if (check_object_signature(the_repository, &d->oid,
+					   base_obj->data, base_obj->size,
+					   type_name(type)))
 			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);
diff --git a/builtin/merge-base.c b/builtin/merge-base.c
index e3f8da1..6719ac1 100644
--- a/builtin/merge-base.c
+++ b/builtin/merge-base.c
@@ -114,26 +114,16 @@
 static int handle_fork_point(int argc, const char **argv)
 {
 	struct object_id oid;
-	char *refname;
 	struct commit *derived, *fork_point;
 	const char *commitname;
 
-	switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
-	case 0:
-		die("No such ref: '%s'", argv[0]);
-	case 1:
-		break; /* good */
-	default:
-		die("Ambiguous refname: '%s'", argv[0]);
-	}
-
 	commitname = (argc == 2) ? argv[1] : "HEAD";
 	if (get_oid(commitname, &oid))
 		die("Not a valid object name: '%s'", commitname);
 
 	derived = lookup_commit_reference(the_repository, &oid);
 
-	fork_point = get_fork_point(refname, derived);
+	fork_point = get_fork_point(argv[0], derived);
 
 	if (!fork_point)
 		return 1;
diff --git a/builtin/merge.c b/builtin/merge.c
index 062e911..e038bef 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -62,6 +62,7 @@
 static int option_commit = -1;
 static int option_edit = -1;
 static int allow_trivial = 1, have_message, verify_signatures;
+static int check_trust_level = 1;
 static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
 static struct strategy **use_strategies;
@@ -81,6 +82,7 @@
 static int default_to_upstream = 1;
 static int signoff;
 static const char *sign_commit;
+static int autostash;
 static int no_verify;
 
 static struct strategy all_strategy[] = {
@@ -285,6 +287,8 @@
 	OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
 	{ OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
 	  N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
+	OPT_BOOL(0, "autostash", &autostash,
+	      N_("automatically stash/stash pop before and after")),
 	OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
 	OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
 	OPT_BOOL(0, "no-verify", &no_verify, N_("bypass pre-merge-commit and commit-msg hooks")),
@@ -440,6 +444,7 @@
 		strbuf_addf(&reflog_message, "%s: %s",
 			getenv("GIT_REFLOG_ACTION"), msg);
 	}
+	apply_autostash(git_path_merge_autostash(the_repository));
 	if (squash) {
 		squash_message(head_commit, remoteheads);
 	} else {
@@ -631,6 +636,11 @@
 	} else if (!strcmp(k, "commit.gpgsign")) {
 		sign_commit = git_config_bool(k, v) ? "" : NULL;
 		return 0;
+	} else if (!strcmp(k, "gpg.mintrustlevel")) {
+		check_trust_level = 0;
+	} else if (!strcmp(k, "merge.autostash")) {
+		autostash = git_config_bool(k, v);
+		return 0;
 	}
 
 	status = fmt_merge_msg_config(k, v, cb);
@@ -1288,6 +1298,7 @@
 
 		/* Invoke 'git reset --merge' */
 		ret = cmd_reset(nargc, nargv, prefix);
+		apply_autostash(git_path_merge_autostash(the_repository));
 		goto done;
 	}
 
@@ -1397,7 +1408,8 @@
 			die(_("Can merge only exactly one commit into empty head"));
 
 		if (verify_signatures)
-			verify_merge_signature(remoteheads->item, verbosity);
+			verify_merge_signature(remoteheads->item, verbosity,
+					       check_trust_level);
 
 		remote_head_oid = &remoteheads->item->object.oid;
 		read_empty(remote_head_oid, 0);
@@ -1420,7 +1432,8 @@
 
 	if (verify_signatures) {
 		for (p = remoteheads; p; p = p->next) {
-			verify_merge_signature(p->item, verbosity);
+			verify_merge_signature(p->item, verbosity,
+					       check_trust_level);
 		}
 	}
 
@@ -1508,6 +1521,10 @@
 			goto done;
 		}
 
+		if (autostash)
+			create_autostash(the_repository,
+					 git_path_merge_autostash(the_repository),
+					 "merge");
 		if (checkout_fast_forward(the_repository,
 					  &head_commit->object.oid,
 					  &commit->object.oid,
@@ -1574,6 +1591,11 @@
 	if (fast_forward == FF_ONLY)
 		die(_("Not possible to fast-forward, aborting."));
 
+	if (autostash)
+		create_autostash(the_repository,
+				 git_path_merge_autostash(the_repository),
+				 "merge");
+
 	/* We are going to make a new commit. */
 	git_committer_info(IDENT_STRICT);
 
diff --git a/builtin/mktag.c b/builtin/mktag.c
index 6fb7dc8..4982d3a 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -29,8 +29,11 @@
 	const struct object_id *repl = lookup_replace_object(the_repository, oid);
 
 	if (buffer) {
-		if (type == type_from_string(expected_type))
-			ret = check_object_signature(repl, buffer, size, expected_type);
+		if (type == type_from_string(expected_type)) {
+			ret = check_object_signature(the_repository, repl,
+						     buffer, size,
+						     expected_type);
+		}
 		free(buffer);
 	}
 	return ret;
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 6b9e8c8..a9dcd25 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -16,15 +16,15 @@
  */
 #define CUTOFF_DATE_SLOP 86400
 
-typedef struct rev_name {
-	const char *tip_name;
+struct rev_name {
+	char *tip_name;
 	timestamp_t taggerdate;
 	int generation;
 	int distance;
 	int from_tag;
-} rev_name;
+};
 
-define_commit_slab(commit_rev_name, struct rev_name *);
+define_commit_slab(commit_rev_name, struct rev_name);
 
 static timestamp_t cutoff = TIME_MAX;
 static struct commit_rev_name rev_names;
@@ -32,16 +32,16 @@
 /* How many generations are maximally preferred over _one_ merge traversal? */
 #define MERGE_TRAVERSAL_WEIGHT 65535
 
-static struct rev_name *get_commit_rev_name(struct commit *commit)
+static int is_valid_rev_name(const struct rev_name *name)
 {
-	struct rev_name **slot = commit_rev_name_peek(&rev_names, commit);
-
-	return slot ? *slot : NULL;
+	return name && (name->generation || name->tip_name);
 }
 
-static void set_commit_rev_name(struct commit *commit, struct rev_name *name)
+static struct rev_name *get_commit_rev_name(const struct commit *commit)
 {
-	*commit_rev_name_at(&rev_names, commit) = name;
+	struct rev_name *name = commit_rev_name_peek(&rev_names, commit);
+
+	return is_valid_rev_name(name) ? name : NULL;
 }
 
 static int is_better_name(struct rev_name *name,
@@ -81,28 +81,54 @@
 }
 
 static struct rev_name *create_or_update_name(struct commit *commit,
-					      const char *tip_name,
 					      timestamp_t taggerdate,
 					      int generation, int distance,
 					      int from_tag)
 {
-	struct rev_name *name = get_commit_rev_name(commit);
+	struct rev_name *name = commit_rev_name_at(&rev_names, commit);
 
-	if (name == NULL) {
-		name = xmalloc(sizeof(*name));
-		set_commit_rev_name(commit, name);
-		goto copy_data;
-	} else if (is_better_name(name, taggerdate, distance, from_tag)) {
-copy_data:
-		name->tip_name = tip_name;
-		name->taggerdate = taggerdate;
-		name->generation = generation;
-		name->distance = distance;
-		name->from_tag = from_tag;
+	if (is_valid_rev_name(name)) {
+		if (!is_better_name(name, taggerdate, distance, from_tag))
+			return NULL;
 
-		return name;
-	} else
-		return NULL;
+		/*
+		 * This string might still be shared with ancestors
+		 * (generation > 0).  We can release it here regardless,
+		 * because the new name that has just won will be better
+		 * for them as well, so name_rev() will replace these
+		 * stale pointers when it processes the parents.
+		 */
+		if (!name->generation)
+			free(name->tip_name);
+	}
+
+	name->taggerdate = taggerdate;
+	name->generation = generation;
+	name->distance = distance;
+	name->from_tag = from_tag;
+
+	return name;
+}
+
+static char *get_parent_name(const struct rev_name *name, int parent_number)
+{
+	struct strbuf sb = STRBUF_INIT;
+	size_t len;
+
+	strip_suffix(name->tip_name, "^0", &len);
+	if (name->generation > 0) {
+		strbuf_grow(&sb, len +
+			    1 + decimal_width(name->generation) +
+			    1 + decimal_width(parent_number));
+		strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
+			    name->generation, parent_number);
+	} else {
+		strbuf_grow(&sb, len +
+			    1 + decimal_width(parent_number));
+		strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
+			    parent_number);
+	}
+	return strbuf_detach(&sb, NULL);
 }
 
 static void name_rev(struct commit *start_commit,
@@ -113,20 +139,20 @@
 	struct commit *commit;
 	struct commit **parents_to_queue = NULL;
 	size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
-	char *to_free = NULL;
+	struct rev_name *start_name;
 
 	parse_commit(start_commit);
 	if (start_commit->date < cutoff)
 		return;
 
-	if (deref)
-		tip_name = to_free = xstrfmt("%s^0", tip_name);
-
-	if (!create_or_update_name(start_commit, tip_name, taggerdate, 0, 0,
-				   from_tag)) {
-		free(to_free);
+	start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
+					   from_tag);
+	if (!start_name)
 		return;
-	}
+	if (deref)
+		start_name->tip_name = xstrfmt("%s^0", tip_name);
+	else
+		start_name->tip_name = xstrdup(tip_name);
 
 	memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
 	prio_queue_put(&queue, start_commit);
@@ -142,7 +168,7 @@
 				parents;
 				parents = parents->next, parent_number++) {
 			struct commit *parent = parents->item;
-			const char *new_name;
+			struct rev_name *parent_name;
 			int generation, distance;
 
 			parse_commit(parent);
@@ -150,30 +176,23 @@
 				continue;
 
 			if (parent_number > 1) {
-				size_t len;
-
-				strip_suffix(name->tip_name, "^0", &len);
-				if (name->generation > 0)
-					new_name = xstrfmt("%.*s~%d^%d",
-							   (int)len,
-							   name->tip_name,
-							   name->generation,
-							   parent_number);
-				else
-					new_name = xstrfmt("%.*s^%d", (int)len,
-							   name->tip_name,
-							   parent_number);
 				generation = 0;
 				distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
 			} else {
-				new_name = name->tip_name;
 				generation = name->generation + 1;
 				distance = name->distance + 1;
 			}
 
-			if (create_or_update_name(parent, new_name, taggerdate,
-						  generation, distance,
-						  from_tag)) {
+			parent_name = create_or_update_name(parent, taggerdate,
+							    generation,
+							    distance, from_tag);
+			if (parent_name) {
+				if (parent_number > 1)
+					parent_name->tip_name =
+						get_parent_name(name,
+								parent_number);
+				else
+					parent_name->tip_name = name->tip_name;
 				ALLOC_GROW(parents_to_queue,
 					   parents_to_queue_nr + 1,
 					   parents_to_queue_alloc);
@@ -228,6 +247,10 @@
 	struct tip_table_entry {
 		struct object_id oid;
 		const char *refname;
+		struct commit *commit;
+		timestamp_t taggerdate;
+		unsigned int from_tag:1;
+		unsigned int deref:1;
 	} *table;
 	int nr;
 	int alloc;
@@ -235,13 +258,18 @@
 } tip_table;
 
 static void add_to_tip_table(const struct object_id *oid, const char *refname,
-			     int shorten_unambiguous)
+			     int shorten_unambiguous, struct commit *commit,
+			     timestamp_t taggerdate, int from_tag, int deref)
 {
 	refname = name_ref_abbrev(refname, shorten_unambiguous);
 
 	ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
 	oidcpy(&tip_table.table[tip_table.nr].oid, oid);
 	tip_table.table[tip_table.nr].refname = xstrdup(refname);
+	tip_table.table[tip_table.nr].commit = commit;
+	tip_table.table[tip_table.nr].taggerdate = taggerdate;
+	tip_table.table[tip_table.nr].from_tag = from_tag;
+	tip_table.table[tip_table.nr].deref = deref;
 	tip_table.nr++;
 	tip_table.sorted = 0;
 }
@@ -252,12 +280,30 @@
 	return oidcmp(&a->oid, &b->oid);
 }
 
+static int cmp_by_tag_and_age(const void *a_, const void *b_)
+{
+	const struct tip_table_entry *a = a_, *b = b_;
+	int cmp;
+
+	/* Prefer tags. */
+	cmp = b->from_tag - a->from_tag;
+	if (cmp)
+		return cmp;
+
+	/* Older is better. */
+	if (a->taggerdate < b->taggerdate)
+		return -1;
+	return a->taggerdate != b->taggerdate;
+}
+
 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
 {
 	struct object *o = parse_object(the_repository, oid);
 	struct name_ref_data *data = cb_data;
 	int can_abbreviate_output = data->tags_only && data->name_only;
 	int deref = 0;
+	int from_tag = 0;
+	struct commit *commit = NULL;
 	timestamp_t taggerdate = TIME_MAX;
 
 	if (data->tags_only && !starts_with(path, "refs/tags/"))
@@ -306,8 +352,6 @@
 			return 0;
 	}
 
-	add_to_tip_table(oid, path, can_abbreviate_output);
-
 	while (o && o->type == OBJ_TAG) {
 		struct tag *t = (struct tag *) o;
 		if (!t->tagged)
@@ -317,17 +361,35 @@
 		taggerdate = t->date;
 	}
 	if (o && o->type == OBJ_COMMIT) {
-		struct commit *commit = (struct commit *)o;
-		int from_tag = starts_with(path, "refs/tags/");
-
+		commit = (struct commit *)o;
+		from_tag = starts_with(path, "refs/tags/");
 		if (taggerdate == TIME_MAX)
 			taggerdate = commit->date;
-		path = name_ref_abbrev(path, can_abbreviate_output);
-		name_rev(commit, xstrdup(path), taggerdate, from_tag, deref);
 	}
+
+	add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
+			 from_tag, deref);
 	return 0;
 }
 
+static void name_tips(void)
+{
+	int i;
+
+	/*
+	 * Try to set better names first, so that worse ones spread
+	 * less.
+	 */
+	QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
+	for (i = 0; i < tip_table.nr; i++) {
+		struct tip_table_entry *e = &tip_table.table[i];
+		if (e->commit) {
+			name_rev(e->commit, e->refname, e->taggerdate,
+				 e->from_tag, e->deref);
+		}
+	}
+}
+
 static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
 {
 	struct tip_table_entry *table = table_;
@@ -357,11 +419,11 @@
 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 {
 	struct rev_name *n;
-	struct commit *c;
+	const struct commit *c;
 
 	if (o->type != OBJ_COMMIT)
 		return get_exact_ref_match(o);
-	c = (struct commit *) o;
+	c = (const struct commit *) o;
 	n = get_commit_rev_name(c);
 	if (!n)
 		return NULL;
@@ -540,6 +602,7 @@
 			cutoff = TIME_MIN;
 	}
 	for_each_ref(name_ref, &data);
+	name_tips();
 
 	if (transform_stdin) {
 		char buffer[2048];
diff --git a/builtin/notes.c b/builtin/notes.c
index 95456f3..35e468e 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -622,7 +622,7 @@
 
 		strbuf_grow(&d.buf, size + 1);
 		if (d.buf.len && prev_buf && size)
-			strbuf_insert(&d.buf, 0, "\n", 1);
+			strbuf_insertstr(&d.buf, 0, "\n");
 		if (prev_buf && size)
 			strbuf_insert(&d.buf, 0, prev_buf, size);
 		free(prev_buf);
@@ -745,7 +745,7 @@
 	memset(&pretty_ctx, 0, sizeof(pretty_ctx));
 	format_commit_message(partial, "%s", &msg, &pretty_ctx);
 	strbuf_trim(&msg);
-	strbuf_insert(&msg, 0, "notes: ", 7);
+	strbuf_insertstr(&msg, 0, "notes: ");
 	update_ref(msg.buf, o->local_ref, &oid,
 		   is_null_oid(&parent_oid) ? NULL : &parent_oid,
 		   0, UPDATE_REFS_DIE_ON_ERR);
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 393c20a..c4c57e0 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -92,10 +92,11 @@
 
 static struct packed_git *reuse_packfile;
 static uint32_t reuse_packfile_objects;
-static off_t reuse_packfile_offset;
+static struct bitmap *reuse_packfile_bitmap;
 
 static int use_bitmap_index_default = 1;
 static int use_bitmap_index = -1;
+static int allow_pack_reuse = 1;
 static enum {
 	WRITE_BITMAP_FALSE = 0,
 	WRITE_BITMAP_QUIET,
@@ -275,12 +276,12 @@
 		off_t len)
 {
 	unsigned char *in;
-	unsigned long avail;
+	size_t avail;
 
 	while (len) {
 		in = use_pack(p, w_curs, offset, &avail);
 		if (avail > len)
-			avail = (unsigned long)len;
+			avail = xsize_t(len);
 		hashwrite(f, in, avail);
 		offset += avail;
 		len -= avail;
@@ -303,7 +304,8 @@
 	if (!usable_delta) {
 		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)
+		    (st = open_istream(the_repository, &entry->idx.oid, &type,
+				       &size, NULL)) != NULL)
 			buf = NULL;
 		else {
 			buf = read_object_file(&entry->idx.oid, &type, &size);
@@ -784,57 +786,185 @@
 	return wo;
 }
 
-static off_t write_reused_pack(struct hashfile *f)
+
+/*
+ * A reused set of objects. All objects in a chunk have the same
+ * relative position in the original packfile and the generated
+ * packfile.
+ */
+
+static struct reused_chunk {
+	/* The offset of the first object of this chunk in the original
+	 * packfile. */
+	off_t original;
+	/* The offset of the first object of this chunk in the generated
+	 * packfile minus "original". */
+	off_t difference;
+} *reused_chunks;
+static int reused_chunks_nr;
+static int reused_chunks_alloc;
+
+static void record_reused_object(off_t where, off_t offset)
 {
-	unsigned char buffer[8192];
-	off_t to_write, total;
-	int fd;
+	if (reused_chunks_nr && reused_chunks[reused_chunks_nr-1].difference == offset)
+		return;
 
-	if (!is_pack_valid(reuse_packfile))
-		die(_("packfile is invalid: %s"), reuse_packfile->pack_name);
+	ALLOC_GROW(reused_chunks, reused_chunks_nr + 1,
+		   reused_chunks_alloc);
+	reused_chunks[reused_chunks_nr].original = where;
+	reused_chunks[reused_chunks_nr].difference = offset;
+	reused_chunks_nr++;
+}
 
-	fd = git_open(reuse_packfile->pack_name);
-	if (fd < 0)
-		die_errno(_("unable to open packfile for reuse: %s"),
-			  reuse_packfile->pack_name);
-
-	if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
-		die_errno(_("unable to seek in reused packfile"));
-
-	if (reuse_packfile_offset < 0)
-		reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
-
-	total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
-
-	while (to_write) {
-		int read_pack = xread(fd, buffer, sizeof(buffer));
-
-		if (read_pack <= 0)
-			die_errno(_("unable to read from reused packfile"));
-
-		if (read_pack > to_write)
-			read_pack = to_write;
-
-		hashwrite(f, buffer, read_pack);
-		to_write -= read_pack;
-
-		/*
-		 * We don't know the actual number of objects written,
-		 * only how many bytes written, how many bytes total, and
-		 * how many objects total. So we can fake it by pretending all
-		 * objects we are writing are the same size. This gives us a
-		 * smooth progress meter, and at the end it matches the true
-		 * answer.
-		 */
-		written = reuse_packfile_objects *
-				(((double)(total - to_write)) / total);
-		display_progress(progress_state, written);
+/*
+ * Binary search to find the chunk that "where" is in. Note
+ * that we're not looking for an exact match, just the first
+ * chunk that contains it (which implicitly ends at the start
+ * of the next chunk.
+ */
+static off_t find_reused_offset(off_t where)
+{
+	int lo = 0, hi = reused_chunks_nr;
+	while (lo < hi) {
+		int mi = lo + ((hi - lo) / 2);
+		if (where == reused_chunks[mi].original)
+			return reused_chunks[mi].difference;
+		if (where < reused_chunks[mi].original)
+			hi = mi;
+		else
+			lo = mi + 1;
 	}
 
-	close(fd);
-	written = reuse_packfile_objects;
-	display_progress(progress_state, written);
-	return reuse_packfile_offset - sizeof(struct pack_header);
+	/*
+	 * The first chunk starts at zero, so we can't have gone below
+	 * there.
+	 */
+	assert(lo);
+	return reused_chunks[lo-1].difference;
+}
+
+static void write_reused_pack_one(size_t pos, struct hashfile *out,
+				  struct pack_window **w_curs)
+{
+	off_t offset, next, cur;
+	enum object_type type;
+	unsigned long size;
+
+	offset = reuse_packfile->revindex[pos].offset;
+	next = reuse_packfile->revindex[pos + 1].offset;
+
+	record_reused_object(offset, offset - hashfile_total(out));
+
+	cur = offset;
+	type = unpack_object_header(reuse_packfile, w_curs, &cur, &size);
+	assert(type >= 0);
+
+	if (type == OBJ_OFS_DELTA) {
+		off_t base_offset;
+		off_t fixup;
+
+		unsigned char header[MAX_PACK_OBJECT_HEADER];
+		unsigned len;
+
+		base_offset = get_delta_base(reuse_packfile, w_curs, &cur, type, offset);
+		assert(base_offset != 0);
+
+		/* Convert to REF_DELTA if we must... */
+		if (!allow_ofs_delta) {
+			int base_pos = find_revindex_position(reuse_packfile, base_offset);
+			const unsigned char *base_sha1 =
+				nth_packed_object_sha1(reuse_packfile,
+						       reuse_packfile->revindex[base_pos].nr);
+
+			len = encode_in_pack_object_header(header, sizeof(header),
+							   OBJ_REF_DELTA, size);
+			hashwrite(out, header, len);
+			hashwrite(out, base_sha1, 20);
+			copy_pack_data(out, reuse_packfile, w_curs, cur, next - cur);
+			return;
+		}
+
+		/* Otherwise see if we need to rewrite the offset... */
+		fixup = find_reused_offset(offset) -
+			find_reused_offset(base_offset);
+		if (fixup) {
+			unsigned char ofs_header[10];
+			unsigned i, ofs_len;
+			off_t ofs = offset - base_offset - fixup;
+
+			len = encode_in_pack_object_header(header, sizeof(header),
+							   OBJ_OFS_DELTA, size);
+
+			i = sizeof(ofs_header) - 1;
+			ofs_header[i] = ofs & 127;
+			while (ofs >>= 7)
+				ofs_header[--i] = 128 | (--ofs & 127);
+
+			ofs_len = sizeof(ofs_header) - i;
+
+			hashwrite(out, header, len);
+			hashwrite(out, ofs_header + sizeof(ofs_header) - ofs_len, ofs_len);
+			copy_pack_data(out, reuse_packfile, w_curs, cur, next - cur);
+			return;
+		}
+
+		/* ...otherwise we have no fixup, and can write it verbatim */
+	}
+
+	copy_pack_data(out, reuse_packfile, w_curs, offset, next - offset);
+}
+
+static size_t write_reused_pack_verbatim(struct hashfile *out,
+					 struct pack_window **w_curs)
+{
+	size_t pos = 0;
+
+	while (pos < reuse_packfile_bitmap->word_alloc &&
+			reuse_packfile_bitmap->words[pos] == (eword_t)~0)
+		pos++;
+
+	if (pos) {
+		off_t to_write;
+
+		written = (pos * BITS_IN_EWORD);
+		to_write = reuse_packfile->revindex[written].offset
+			- sizeof(struct pack_header);
+
+		/* We're recording one chunk, not one object. */
+		record_reused_object(sizeof(struct pack_header), 0);
+		hashflush(out);
+		copy_pack_data(out, reuse_packfile, w_curs,
+			sizeof(struct pack_header), to_write);
+
+		display_progress(progress_state, written);
+	}
+	return pos;
+}
+
+static void write_reused_pack(struct hashfile *f)
+{
+	size_t i = 0;
+	uint32_t offset;
+	struct pack_window *w_curs = NULL;
+
+	if (allow_ofs_delta)
+		i = write_reused_pack_verbatim(f, &w_curs);
+
+	for (; i < reuse_packfile_bitmap->word_alloc; ++i) {
+		eword_t word = reuse_packfile_bitmap->words[i];
+		size_t pos = (i * BITS_IN_EWORD);
+
+		for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
+			if ((word >> offset) == 0)
+				break;
+
+			offset += ewah_bit_ctz64(word >> offset);
+			write_reused_pack_one(pos + offset, f, &w_curs);
+			display_progress(progress_state, ++written);
+		}
+	}
+
+	unuse_pack(&w_curs);
 }
 
 static const char no_split_warning[] = N_(
@@ -867,11 +997,9 @@
 		offset = write_pack_header(f, nr_remaining);
 
 		if (reuse_packfile) {
-			off_t packfile_size;
 			assert(pack_to_stdout);
-
-			packfile_size = write_reused_pack(f);
-			offset += packfile_size;
+			write_reused_pack(f);
+			offset = hashfile_total(f);
 		}
 
 		nr_written = 0;
@@ -1000,6 +1128,10 @@
 {
 	struct object_entry *entry;
 
+	if (reuse_packfile_bitmap &&
+	    bitmap_walk_contains(bitmap_git, reuse_packfile_bitmap, oid))
+		return 1;
+
 	entry = packlist_find(&to_pack, oid);
 	if (!entry)
 		return 0;
@@ -1536,8 +1668,8 @@
 		struct pack_window *w_curs = NULL;
 		const unsigned char *base_ref = NULL;
 		struct object_entry *base_entry;
-		unsigned long used, used_0;
-		unsigned long avail;
+		size_t used, used_0;
+		size_t avail;
 		off_t ofs;
 		unsigned char *buf, c;
 		enum object_type type;
@@ -1992,7 +2124,8 @@
 	struct pack_window *w_curs;
 	unsigned char *buf;
 	enum object_type type;
-	unsigned long used, avail, size;
+	unsigned long used, size;
+	size_t avail;
 
 	if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
 		packing_data_lock(&to_pack);
@@ -2552,6 +2685,13 @@
 	free(p);
 }
 
+static int obj_is_packed(const struct object_id *oid)
+{
+	return packlist_find(&to_pack, oid) ||
+		(reuse_packfile_bitmap &&
+		 bitmap_walk_contains(bitmap_git, reuse_packfile_bitmap, oid));
+}
+
 static void add_tag_chain(const struct object_id *oid)
 {
 	struct tag *tag;
@@ -2563,7 +2703,7 @@
 	 * it was included via bitmaps, we would not have parsed it
 	 * previously).
 	 */
-	if (packlist_find(&to_pack, oid))
+	if (obj_is_packed(oid))
 		return;
 
 	tag = lookup_tag(the_repository, oid);
@@ -2587,7 +2727,7 @@
 
 	if (starts_with(path, "refs/tags/") && /* is a tag? */
 	    !peel_ref(path, &peeled)    && /* peelable? */
-	    packlist_find(&to_pack, &peeled))      /* object packed? */
+	    obj_is_packed(&peeled)) /* object packed? */
 		add_tag_chain(oid);
 	return 0;
 }
@@ -2655,6 +2795,7 @@
 
 	if (nr_deltas && n > 1) {
 		unsigned nr_done = 0;
+
 		if (progress)
 			progress_state = start_progress(_("Compressing objects"),
 							nr_deltas);
@@ -2699,6 +2840,10 @@
 		use_bitmap_index_default = git_config_bool(k, v);
 		return 0;
 	}
+	if (!strcmp(k, "pack.allowpackreuse")) {
+		allow_pack_reuse = git_config_bool(k, v);
+		return 0;
+	}
 	if (!strcmp(k, "pack.threads")) {
 		delta_search_threads = git_config_int(k, v);
 		if (delta_search_threads < 0)
@@ -3030,8 +3175,8 @@
  */
 static int pack_options_allow_reuse(void)
 {
-	return pack_to_stdout &&
-	       allow_ofs_delta &&
+	return allow_pack_reuse &&
+	       pack_to_stdout &&
 	       !ignore_packed_keep_on_disk &&
 	       !ignore_packed_keep_in_core &&
 	       (!local || !have_non_local_packs) &&
@@ -3040,7 +3185,7 @@
 
 static int get_object_list_from_bitmap(struct rev_info *revs)
 {
-	if (!(bitmap_git = prepare_bitmap_walk(revs)))
+	if (!(bitmap_git = prepare_bitmap_walk(revs, &filter_options)))
 		return -1;
 
 	if (pack_options_allow_reuse() &&
@@ -3048,13 +3193,14 @@
 			bitmap_git,
 			&reuse_packfile,
 			&reuse_packfile_objects,
-			&reuse_packfile_offset)) {
+			&reuse_packfile_bitmap)) {
 		assert(reuse_packfile_objects);
 		nr_result += reuse_packfile_objects;
 		display_progress(progress_state, nr_result);
 	}
 
-	traverse_bitmap_commit_list(bitmap_git, &add_object_entry_from_bitmap);
+	traverse_bitmap_commit_list(bitmap_git, revs,
+				    &add_object_entry_from_bitmap);
 	return 0;
 }
 
@@ -3418,7 +3564,6 @@
 	if (filter_options.choice) {
 		if (!pack_to_stdout)
 			die(_("cannot use --filter without --stdout"));
-		use_bitmap_index = 0;
 	}
 
 	/*
@@ -3509,7 +3654,9 @@
 	if (progress)
 		fprintf_ln(stderr,
 			   _("Total %"PRIu32" (delta %"PRIu32"),"
-			     " reused %"PRIu32" (delta %"PRIu32")"),
-			   written, written_delta, reused, reused_delta);
+			     " reused %"PRIu32" (delta %"PRIu32"),"
+			     " pack-reused %"PRIu32),
+			   written, written_delta, reused, reused_delta,
+			   reuse_packfile_objects);
 	return 0;
 }
diff --git a/builtin/pull.c b/builtin/pull.c
index d25ff13..9beb484 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -15,6 +15,7 @@
 #include "sha1-array.h"
 #include "remote.h"
 #include "dir.h"
+#include "rebase.h"
 #include "refs.h"
 #include "refspec.h"
 #include "revision.h"
@@ -26,15 +27,6 @@
 #include "commit-reach.h"
 #include "sequencer.h"
 
-enum rebase_type {
-	REBASE_INVALID = -1,
-	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
@@ -45,22 +37,9 @@
 static enum rebase_type parse_config_rebase(const char *key, const char *value,
 		int fatal)
 {
-	int v = git_parse_maybe_bool(value);
-
-	if (!v)
-		return REBASE_FALSE;
-	else if (v > 0)
-		return REBASE_TRUE;
-	else if (!strcmp(value, "preserve") || !strcmp(value, "p"))
-		return REBASE_PRESERVE;
-	else if (!strcmp(value, "merges") || !strcmp(value, "m"))
-		return REBASE_MERGES;
-	else if (!strcmp(value, "interactive") || !strcmp(value, "i"))
-		return REBASE_INTERACTIVE;
-	/*
-	 * Please update _git_config() in git-completion.bash when you
-	 * add new rebase modes.
-	 */
+	enum rebase_type v = rebase_parse_value(value);
+	if (v != REBASE_INVALID)
+		return v;
 
 	if (fatal)
 		die(_("Invalid value for %s: %s"), key, value);
@@ -107,6 +86,7 @@
 static char *opt_verify_signatures;
 static int opt_autostash = -1;
 static int config_autostash;
+static int check_trust_level = 1;
 static struct argv_array opt_strategies = ARGV_ARRAY_INIT;
 static struct argv_array opt_strategy_opts = ARGV_ARRAY_INIT;
 static char *opt_gpg_sign;
@@ -183,7 +163,7 @@
 		N_("verify that the named commit has a valid GPG signature"),
 		PARSE_OPT_NOARG),
 	OPT_BOOL(0, "autostash", &opt_autostash,
-		N_("automatically stash/stash pop before and after rebase")),
+		N_("automatically stash/stash pop before and after")),
 	OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
 		N_("merge strategy to use"),
 		0),
@@ -355,6 +335,8 @@
  */
 static int git_pull_config(const char *var, const char *value, void *cb)
 {
+	int status;
+
 	if (!strcmp(var, "rebase.autostash")) {
 		config_autostash = git_config_bool(var, value);
 		return 0;
@@ -362,7 +344,14 @@
 		recurse_submodules = git_config_bool(var, value) ?
 			RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 		return 0;
+	} else if (!strcmp(var, "gpg.mintrustlevel")) {
+		check_trust_level = 0;
 	}
+
+	status = git_gpg_config(var, value, cb);
+	if (status)
+		return status;
+
 	return git_default_config(var, value, cb);
 }
 
@@ -587,7 +576,8 @@
 			die(_("unable to access commit %s"),
 			    oid_to_hex(merge_head));
 
-		verify_merge_signature(commit, opt_verbosity);
+		verify_merge_signature(commit, opt_verbosity,
+				       check_trust_level);
 	}
 
 	/*
@@ -671,6 +661,10 @@
 	argv_array_pushv(&args, opt_strategy_opts.argv);
 	if (opt_gpg_sign)
 		argv_array_push(&args, opt_gpg_sign);
+	if (opt_autostash == 0)
+		argv_array_push(&args, "--no-autostash");
+	else if (opt_autostash == 1)
+		argv_array_push(&args, "--autostash");
 	if (opt_allow_unrelated_histories > 0)
 		argv_array_push(&args, "--allow-unrelated-histories");
 
@@ -918,9 +912,6 @@
 	if (get_oid("HEAD", &orig_head))
 		oidclr(&orig_head);
 
-	if (!opt_rebase && opt_autostash != -1)
-		die(_("--[no-]autostash option is only valid with --rebase."));
-
 	autostash = config_autostash;
 	if (opt_rebase) {
 		if (opt_autostash != -1)
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 8081741..3ff96e5 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -27,6 +27,9 @@
 #include "branch.h"
 #include "sequencer.h"
 #include "rebase-interactive.h"
+#include "reset.h"
+
+#define DEFAULT_REFLOG_ACTION "rebase"
 
 static char const * const builtin_rebase_usage[] = {
 	N_("git rebase [-i] [options] [--exec <cmd>] "
@@ -44,14 +47,22 @@
 
 enum rebase_type {
 	REBASE_UNSPECIFIED = -1,
-	REBASE_AM,
+	REBASE_APPLY,
 	REBASE_MERGE,
-	REBASE_INTERACTIVE,
 	REBASE_PRESERVE_MERGES
 };
 
+enum empty_type {
+	EMPTY_UNSPECIFIED = -1,
+	EMPTY_DROP,
+	EMPTY_KEEP,
+	EMPTY_ASK
+};
+
 struct rebase_options {
 	enum rebase_type type;
+	enum empty_type empty;
+	const char *default_backend;
 	const char *state_dir;
 	struct commit *upstream;
 	const char *upstream_name;
@@ -77,7 +88,6 @@
 	const char *action;
 	int signoff;
 	int allow_rerere_autoupdate;
-	int keep_empty;
 	int autosquash;
 	char *gpg_sign_opt;
 	int autostash;
@@ -92,6 +102,8 @@
 
 #define REBASE_OPTIONS_INIT {			  	\
 		.type = REBASE_UNSPECIFIED,	  	\
+		.empty = EMPTY_UNSPECIFIED,	  	\
+		.default_backend = "merge",	  	\
 		.flags = REBASE_NO_QUIET, 		\
 		.git_am_opts = ARGV_ARRAY_INIT,		\
 		.git_format_patch_opt = STRBUF_INIT	\
@@ -110,6 +122,9 @@
 		replay.allow_rerere_auto = opts->allow_rerere_autoupdate;
 	replay.allow_empty = 1;
 	replay.allow_empty_message = opts->allow_empty_message;
+	replay.drop_redundant_commits = (opts->empty == EMPTY_DROP);
+	replay.keep_redundant_commits = (opts->empty == EMPTY_KEEP);
+	replay.quiet = !(opts->flags & REBASE_NO_QUIET);
 	replay.verbose = opts->flags & REBASE_VERBOSE;
 	replay.reschedule_failed_exec = opts->reschedule_failed_exec;
 	replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
@@ -246,21 +261,17 @@
 }
 
 static int get_revision_ranges(struct commit *upstream, struct commit *onto,
-			       const char **head_hash,
+			       struct object_id *orig_head, const char **head_hash,
 			       char **revisions, char **shortrevisions)
 {
 	struct commit *base_rev = upstream ? upstream : onto;
 	const char *shorthead;
-	struct object_id orig_head;
 
-	if (get_oid("HEAD", &orig_head))
-		return error(_("no HEAD?"));
-
-	*head_hash = find_unique_abbrev(&orig_head, GIT_MAX_HEXSZ);
+	*head_hash = find_unique_abbrev(orig_head, GIT_MAX_HEXSZ);
 	*revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid),
 						   *head_hash);
 
-	shorthead = find_unique_abbrev(&orig_head, DEFAULT_ABBREV);
+	shorthead = find_unique_abbrev(orig_head, DEFAULT_ABBREV);
 
 	if (upstream) {
 		const char *shortrev;
@@ -314,12 +325,8 @@
 	struct replay_opts replay = get_replay_opts(opts);
 	struct string_list commands = STRING_LIST_INIT_DUP;
 
-	if (prepare_branch_to_be_rebased(the_repository, &replay,
-					 opts->switch_to))
-		return -1;
-
-	if (get_revision_ranges(opts->upstream, opts->onto, &head_hash,
-				&revisions, &shortrevisions))
+	if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_head,
+				&head_hash, &revisions, &shortrevisions))
 		return -1;
 
 	if (init_basic_state(&replay,
@@ -337,8 +344,8 @@
 
 	argv_array_pushl(&make_script_args, "", revisions, NULL);
 	if (opts->restrict_revision)
-		argv_array_push(&make_script_args,
-				oid_to_hex(&opts->restrict_revision->object.oid));
+		argv_array_pushf(&make_script_args, "^%s",
+				 oid_to_hex(&opts->restrict_revision->object.oid));
 
 	ret = sequencer_make_script(the_repository, &todo_list.buf,
 				    make_script_args.argc, make_script_args.argv,
@@ -367,7 +374,7 @@
 	return ret;
 }
 
-static int run_rebase_interactive(struct rebase_options *opts,
+static int run_sequencer_rebase(struct rebase_options *opts,
 				  enum action command)
 {
 	unsigned flags = 0;
@@ -375,7 +382,6 @@
 
 	git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
 
-	flags |= opts->keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
 	flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
 	flags |= opts->rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
 	flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
@@ -439,6 +445,21 @@
 	return ret;
 }
 
+static int parse_opt_keep_empty(const struct option *opt, const char *arg,
+				int unset)
+{
+	struct rebase_options *opts = opt->value;
+
+	BUG_ON_OPT_ARG(arg);
+
+	/*
+	 * If we ever want to remap --keep-empty to --empty=keep, insert:
+	 * 	opts->empty = unset ? EMPTY_UNSPECIFIED : EMPTY_KEEP;
+	 */
+	opts->type = REBASE_MERGE;
+	return 0;
+}
+
 static const char * const builtin_rebase_interactive_usage[] = {
 	N_("git rebase--interactive [<options>]"),
 	NULL
@@ -452,9 +473,13 @@
 	struct option options[] = {
 		OPT_NEGBIT(0, "ff", &opts.flags, N_("allow fast-forward"),
 			   REBASE_FORCE),
-		OPT_BOOL(0, "keep-empty", &opts.keep_empty, N_("keep empty commits")),
-		OPT_BOOL(0, "allow-empty-message", &opts.allow_empty_message,
-			 N_("allow commits with empty messages")),
+		{ OPTION_CALLBACK, 'k', "keep-empty", &options, NULL,
+			N_("(DEPRECATED) keep empty commits"),
+			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
+			parse_opt_keep_empty },
+		OPT_BOOL_F(0, "allow-empty-message", &opts.allow_empty_message,
+			   N_("allow commits with empty messages"),
+			   PARSE_OPT_HIDDEN),
 		OPT_BOOL(0, "rebase-merges", &opts.rebase_merges, N_("rebase merge commits")),
 		OPT_BOOL(0, "rebase-cousins", &opts.rebase_cousins,
 			 N_("keep original branch points of cousins")),
@@ -524,28 +549,26 @@
 		warning(_("--[no-]rebase-cousins has no effect without "
 			  "--rebase-merges"));
 
-	return !!run_rebase_interactive(&opts, command);
+	return !!run_sequencer_rebase(&opts, command);
 }
 
-static int is_interactive(struct rebase_options *opts)
+static int is_merge(struct rebase_options *opts)
 {
-	return opts->type == REBASE_INTERACTIVE ||
+	return opts->type == REBASE_MERGE ||
 		opts->type == REBASE_PRESERVE_MERGES;
 }
 
-static void imply_interactive(struct rebase_options *opts, const char *option)
+static void imply_merge(struct rebase_options *opts, const char *option)
 {
 	switch (opts->type) {
-	case REBASE_AM:
+	case REBASE_APPLY:
 		die(_("%s requires an interactive rebase"), option);
 		break;
-	case REBASE_INTERACTIVE:
+	case REBASE_MERGE:
 	case REBASE_PRESERVE_MERGES:
 		break;
-	case REBASE_MERGE:
-		/* we now implement --merge via --interactive */
 	default:
-		opts->type = REBASE_INTERACTIVE; /* implied */
+		opts->type = REBASE_MERGE; /* implied */
 		break;
 	}
 }
@@ -566,15 +589,6 @@
 	return path.buf;
 }
 
-/* Read one file, then strip line endings */
-static int read_one(const char *path, struct strbuf *buf)
-{
-	if (strbuf_read_file(buf, path, 0) < 0)
-		return error_errno(_("could not read '%s'"), path);
-	strbuf_trim_trailing_newline(buf);
-	return 0;
-}
-
 /* Initialize the rebase options from the state directory. */
 static int read_basic_state(struct rebase_options *opts)
 {
@@ -582,8 +596,8 @@
 	struct strbuf buf = STRBUF_INIT;
 	struct object_id oid;
 
-	if (read_one(state_dir_path("head-name", opts), &head_name) ||
-	    read_one(state_dir_path("onto", opts), &buf))
+	if (!read_oneliner(&head_name, state_dir_path("head-name", opts), 0, 1) ||
+	    !read_oneliner(&buf, state_dir_path("onto", opts), 0, 1))
 		return -1;
 	opts->head_name = starts_with(head_name.buf, "refs/") ?
 		xstrdup(head_name.buf) : NULL;
@@ -599,9 +613,9 @@
 	 */
 	strbuf_reset(&buf);
 	if (file_exists(state_dir_path("orig-head", opts))) {
-		if (read_one(state_dir_path("orig-head", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("orig-head", opts), 0, 1))
 			return -1;
-	} else if (read_one(state_dir_path("head", opts), &buf))
+	} else if (!read_oneliner(&buf, state_dir_path("head", opts), 0, 1))
 		return -1;
 	if (get_oid(buf.buf, &opts->orig_head))
 		return error(_("invalid orig-head: '%s'"), buf.buf);
@@ -621,8 +635,7 @@
 
 	if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 		strbuf_reset(&buf);
-		if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
-			    &buf))
+		if (!read_oneliner(&buf, state_dir_path("allow_rerere_autoupdate", opts), 0, 1))
 			return -1;
 		if (!strcmp(buf.buf, "--rerere-autoupdate"))
 			opts->allow_rerere_autoupdate = RERERE_AUTOUPDATE;
@@ -635,8 +648,7 @@
 
 	if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 		strbuf_reset(&buf);
-		if (read_one(state_dir_path("gpg_sign_opt", opts),
-			    &buf))
+		if (!read_oneliner(&buf, state_dir_path("gpg_sign_opt", opts), 0, 1))
 			return -1;
 		free(opts->gpg_sign_opt);
 		opts->gpg_sign_opt = xstrdup(buf.buf);
@@ -644,7 +656,7 @@
 
 	if (file_exists(state_dir_path("strategy", opts))) {
 		strbuf_reset(&buf);
-		if (read_one(state_dir_path("strategy", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("strategy", opts), 0, 1))
 			return -1;
 		free(opts->strategy);
 		opts->strategy = xstrdup(buf.buf);
@@ -652,7 +664,7 @@
 
 	if (file_exists(state_dir_path("strategy_opts", opts))) {
 		strbuf_reset(&buf);
-		if (read_one(state_dir_path("strategy_opts", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("strategy_opts", opts), 0, 1))
 			return -1;
 		free(opts->strategy_opts);
 		opts->strategy_opts = xstrdup(buf.buf);
@@ -671,8 +683,8 @@
 		   opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
 	write_file(state_dir_path("orig-head", opts), "%s",
 		   oid_to_hex(&opts->orig_head));
-	write_file(state_dir_path("quiet", opts), "%s",
-		   opts->flags & REBASE_NO_QUIET ? "" : "t");
+	if (!(opts->flags & REBASE_NO_QUIET))
+		write_file(state_dir_path("quiet", opts), "%s", "");
 	if (opts->flags & REBASE_VERBOSE)
 		write_file(state_dir_path("verbose", opts), "%s", "");
 	if (opts->strategy)
@@ -695,51 +707,6 @@
 	return 0;
 }
 
-static int apply_autostash(struct rebase_options *opts)
-{
-	const char *path = state_dir_path("autostash", opts);
-	struct strbuf autostash = STRBUF_INIT;
-	struct child_process stash_apply = CHILD_PROCESS_INIT;
-
-	if (!file_exists(path))
-		return 0;
-
-	if (read_one(path, &autostash))
-		return error(_("Could not read '%s'"), path);
-	/* Ensure that the hash is not mistaken for a number */
-	strbuf_addstr(&autostash, "^0");
-	argv_array_pushl(&stash_apply.args,
-			 "stash", "apply", autostash.buf, NULL);
-	stash_apply.git_cmd = 1;
-	stash_apply.no_stderr = stash_apply.no_stdout =
-		stash_apply.no_stdin = 1;
-	if (!run_command(&stash_apply))
-		printf(_("Applied autostash.\n"));
-	else {
-		struct argv_array args = ARGV_ARRAY_INIT;
-		int res = 0;
-
-		argv_array_pushl(&args,
-				 "stash", "store", "-m", "autostash", "-q",
-				 autostash.buf, NULL);
-		if (run_command_v_opt(args.argv, RUN_GIT_CMD))
-			res = error(_("Cannot store %s"), autostash.buf);
-		argv_array_clear(&args);
-		strbuf_release(&autostash);
-		if (res)
-			return res;
-
-		fprintf(stderr,
-			_("Applying autostash resulted in conflicts.\n"
-			  "Your changes are safe in the stash.\n"
-			  "You can run \"git stash pop\" or \"git stash drop\" "
-			  "at any time.\n"));
-	}
-
-	strbuf_release(&autostash);
-	return 0;
-}
-
 static int finish_rebase(struct rebase_options *opts)
 {
 	struct strbuf dir = STRBUF_INIT;
@@ -747,14 +714,14 @@
 	int ret = 0;
 
 	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
-	apply_autostash(opts);
+	apply_autostash(state_dir_path("autostash", opts));
 	close_object_store(the_repository->objects);
 	/*
 	 * We ignore errors in 'gc --auto', since the
 	 * user should see them.
 	 */
 	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
-	if (opts->type == REBASE_INTERACTIVE) {
+	if (opts->type == REBASE_MERGE) {
 		struct replay_opts replay = REPLAY_OPTS_INIT;
 
 		replay.action = REPLAY_INTERACTIVE_REBASE;
@@ -792,143 +759,6 @@
 	}
 }
 
-#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
-
-#define RESET_HEAD_DETACH (1<<0)
-#define RESET_HEAD_HARD (1<<1)
-#define RESET_HEAD_RUN_POST_CHECKOUT_HOOK (1<<2)
-#define RESET_HEAD_REFS_ONLY (1<<3)
-#define RESET_ORIG_HEAD (1<<4)
-
-static int reset_head(struct object_id *oid, const char *action,
-		      const char *switch_to_branch, unsigned flags,
-		      const char *reflog_orig_head, const char *reflog_head)
-{
-	unsigned detach_head = flags & RESET_HEAD_DETACH;
-	unsigned reset_hard = flags & RESET_HEAD_HARD;
-	unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
-	unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
-	unsigned update_orig_head = flags & RESET_ORIG_HEAD;
-	struct object_id head_oid;
-	struct tree_desc desc[2] = { { NULL }, { NULL } };
-	struct lock_file lock = LOCK_INIT;
-	struct unpack_trees_options unpack_tree_opts;
-	struct tree *tree;
-	const char *reflog_action;
-	struct strbuf msg = STRBUF_INIT;
-	size_t prefix_len;
-	struct object_id *orig = NULL, oid_orig,
-		*old_orig = NULL, oid_old_orig;
-	int ret = 0, nr = 0;
-
-	if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
-		BUG("Not a fully qualified branch: '%s'", switch_to_branch);
-
-	if (!refs_only && hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
-		ret = -1;
-		goto leave_reset_head;
-	}
-
-	if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
-		ret = error(_("could not determine HEAD revision"));
-		goto leave_reset_head;
-	}
-
-	if (!oid)
-		oid = &head_oid;
-
-	if (refs_only)
-		goto reset_head_refs;
-
-	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
-	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
-	unpack_tree_opts.head_idx = 1;
-	unpack_tree_opts.src_index = the_repository->index;
-	unpack_tree_opts.dst_index = the_repository->index;
-	unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
-	unpack_tree_opts.update = 1;
-	unpack_tree_opts.merge = 1;
-	if (!detach_head)
-		unpack_tree_opts.reset = 1;
-
-	if (repo_read_index_unmerged(the_repository) < 0) {
-		ret = error(_("could not read index"));
-		goto leave_reset_head;
-	}
-
-	if (!reset_hard && !fill_tree_descriptor(the_repository, &desc[nr++], &head_oid)) {
-		ret = error(_("failed to find tree of %s"),
-			    oid_to_hex(&head_oid));
-		goto leave_reset_head;
-	}
-
-	if (!fill_tree_descriptor(the_repository, &desc[nr++], oid)) {
-		ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
-		goto leave_reset_head;
-	}
-
-	if (unpack_trees(nr, desc, &unpack_tree_opts)) {
-		ret = -1;
-		goto leave_reset_head;
-	}
-
-	tree = parse_tree_indirect(oid);
-	prime_cache_tree(the_repository, the_repository->index, tree);
-
-	if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
-		ret = error(_("could not write index"));
-		goto leave_reset_head;
-	}
-
-reset_head_refs:
-	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
-	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
-	prefix_len = msg.len;
-
-	if (update_orig_head) {
-		if (!get_oid("ORIG_HEAD", &oid_old_orig))
-			old_orig = &oid_old_orig;
-		if (!get_oid("HEAD", &oid_orig)) {
-			orig = &oid_orig;
-			if (!reflog_orig_head) {
-				strbuf_addstr(&msg, "updating ORIG_HEAD");
-				reflog_orig_head = msg.buf;
-			}
-			update_ref(reflog_orig_head, "ORIG_HEAD", orig,
-				   old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
-		} else if (old_orig)
-			delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
-	}
-
-	if (!reflog_head) {
-		strbuf_setlen(&msg, prefix_len);
-		strbuf_addstr(&msg, "updating HEAD");
-		reflog_head = msg.buf;
-	}
-	if (!switch_to_branch)
-		ret = update_ref(reflog_head, "HEAD", oid, orig,
-				 detach_head ? REF_NO_DEREF : 0,
-				 UPDATE_REFS_MSG_ON_ERR);
-	else {
-		ret = update_ref(reflog_head, switch_to_branch, oid,
-				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
-		if (!ret)
-			ret = create_symref("HEAD", switch_to_branch,
-					    reflog_head);
-	}
-	if (run_hook)
-		run_hook_le(NULL, "post-checkout",
-			    oid_to_hex(orig ? orig : &null_oid),
-			    oid_to_hex(oid), "1", NULL);
-
-leave_reset_head:
-	strbuf_release(&msg);
-	rollback_lock_file(&lock);
-	while (nr)
-		free((void *)desc[--nr].buffer);
-	return ret;
-}
-
 static int move_to_original_branch(struct rebase_options *opts)
 {
 	struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
@@ -944,8 +774,10 @@
 		    opts->head_name, oid_to_hex(&opts->onto->object.oid));
 	strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 		    opts->head_name);
-	ret = reset_head(NULL, "", opts->head_name, RESET_HEAD_REFS_ONLY,
-			 orig_head_reflog.buf, head_reflog.buf);
+	ret = reset_head(the_repository, NULL, "", opts->head_name,
+			 RESET_HEAD_REFS_ONLY,
+			 orig_head_reflog.buf, head_reflog.buf,
+			 DEFAULT_REFLOG_ACTION);
 
 	strbuf_release(&orig_head_reflog);
 	strbuf_release(&head_reflog);
@@ -1033,8 +865,9 @@
 		free(rebased_patches);
 		argv_array_clear(&am.args);
 
-		reset_head(&opts->orig_head, "checkout", opts->head_name, 0,
-			   "HEAD", NULL);
+		reset_head(the_repository, &opts->orig_head, "checkout",
+			   opts->head_name, 0,
+			   "HEAD", NULL, DEFAULT_REFLOG_ACTION);
 		error(_("\ngit encountered an error while preparing the "
 			"patches to replay\n"
 			"these revisions:\n"
@@ -1087,8 +920,8 @@
 	int status;
 	const char *backend, *backend_func;
 
-	if (opts->type == REBASE_INTERACTIVE) {
-		/* Run builtin interactive rebase */
+	if (opts->type == REBASE_MERGE) {
+		/* Run sequencer-based rebase */
 		setenv("GIT_CHERRY_PICK_HELP", resolvemsg, 1);
 		if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 			setenv("GIT_SEQUENCE_EDITOR", ":", 1);
@@ -1101,11 +934,11 @@
 			opts->gpg_sign_opt = tmp;
 		}
 
-		status = run_rebase_interactive(opts, action);
+		status = run_sequencer_rebase(opts, action);
 		goto finished_rebase;
 	}
 
-	if (opts->type == REBASE_AM) {
+	if (opts->type == REBASE_APPLY) {
 		status = run_am(opts);
 		goto finished_rebase;
 	}
@@ -1125,8 +958,6 @@
 	add_var(&script_snippet, "revisions", opts->revisions);
 	add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 		oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
-	add_var(&script_snippet, "GIT_QUIET",
-		opts->flags & REBASE_NO_QUIET ? "" : "t");
 	sq_quote_argv_pretty(&buf, opts->git_am_opts.argv);
 	add_var(&script_snippet, "git_am_opt", buf.buf);
 	strbuf_release(&buf);
@@ -1144,7 +975,6 @@
 		opts->allow_rerere_autoupdate ?
 			opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
 			"--rerere-autoupdate" : "--no-rerere-autoupdate" : "");
-	add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 	add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 	add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 	add_var(&script_snippet, "cmd", opts->cmd);
@@ -1162,7 +992,7 @@
 	add_var(&script_snippet, "git_format_patch_opt",
 		opts->git_format_patch_opt.buf);
 
-	if (is_interactive(opts) &&
+	if (is_merge(opts) &&
 	    !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 		strbuf_addstr(&script_snippet,
 			      "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
@@ -1187,15 +1017,15 @@
 finished_rebase:
 	if (opts->dont_finish_rebase)
 		; /* do nothing */
-	else if (opts->type == REBASE_INTERACTIVE)
-		; /* interactive rebase cleans up after itself */
+	else if (opts->type == REBASE_MERGE)
+		; /* merge backend cleans up after itself */
 	else if (status == 0) {
 		if (!file_exists(state_dir_path("stopped-sha", opts)))
 			finish_rebase(opts);
 	} else if (status == 2) {
 		struct strbuf dir = STRBUF_INIT;
 
-		apply_autostash(opts);
+		apply_autostash(state_dir_path("autostash", opts));
 		strbuf_addstr(&dir, opts->state_dir);
 		remove_dir_recursively(&dir, 0);
 		strbuf_release(&dir);
@@ -1246,6 +1076,10 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "rebase.backend")) {
+		return git_config_string(&opts->default_backend, var, value);
+	}
+
 	return git_default_config(var, value, data);
 }
 
@@ -1309,6 +1143,18 @@
 	return res && is_linear_history(onto, head);
 }
 
+static int parse_opt_am(const struct option *opt, const char *arg, int unset)
+{
+	struct rebase_options *opts = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	opts->type = REBASE_APPLY;
+
+	return 0;
+}
+
 /* -i followed by -m is still -i */
 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 {
@@ -1317,7 +1163,7 @@
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
 
-	if (!is_interactive(opts))
+	if (!is_merge(opts))
 		opts->type = REBASE_MERGE;
 
 	return 0;
@@ -1332,12 +1178,35 @@
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
 
-	opts->type = REBASE_INTERACTIVE;
+	opts->type = REBASE_MERGE;
 	opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 
 	return 0;
 }
 
+static enum empty_type parse_empty_value(const char *value)
+{
+	if (!strcasecmp(value, "drop"))
+		return EMPTY_DROP;
+	else if (!strcasecmp(value, "keep"))
+		return EMPTY_KEEP;
+	else if (!strcasecmp(value, "ask"))
+		return EMPTY_ASK;
+
+	die(_("unrecognized empty type '%s'; valid values are \"drop\", \"keep\", and \"ask\"."), value);
+}
+
+static int parse_opt_empty(const struct option *opt, const char *arg, int unset)
+{
+	struct rebase_options *options = opt->value;
+	enum empty_type value = parse_empty_value(arg);
+
+	BUG_ON_OPT_NEG(unset);
+
+	options->empty = value;
+	return 0;
+}
+
 static void NORETURN error_on_missing_default_upstream(void)
 {
 	struct branch *current_branch = branch_get(NULL);
@@ -1373,14 +1242,14 @@
 	const char *env;
 	struct strbuf buf = STRBUF_INIT;
 
-	if (!is_interactive(options))
+	if (!is_merge(options))
 		return;
 
 	env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 	if (env && strcmp("rebase", env))
 		return; /* only override it if it is "rebase" */
 
-	strbuf_addf(&buf, "rebase -i (%s)", options->action);
+	strbuf_addf(&buf, "rebase (%s)", options->action);
 	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
 	strbuf_release(&buf);
 }
@@ -1397,7 +1266,6 @@
 	return 0;
 }
 
-
 int cmd_rebase(int argc, const char **argv, const char *prefix)
 {
 	struct rebase_options options = REBASE_OPTIONS_INIT;
@@ -1418,6 +1286,7 @@
 	struct object_id squash_onto;
 	char *squash_onto_name = NULL;
 	int reschedule_failed_exec = -1;
+	int allow_preemptive_ff = 1;
 	struct option builtin_rebase_options[] = {
 		OPT_STRING(0, "onto", &options.onto_name,
 			   N_("revision"),
@@ -1428,7 +1297,7 @@
 			 N_("allow pre-rebase hook to run")),
 		OPT_NEGBIT('q', "quiet", &options.flags,
 			   N_("be quiet. implies --no-stat"),
-			   REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
+			   REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 		OPT_BIT('v', "verbose", &options.flags,
 			N_("display a diffstat of what changed upstream"),
 			REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
@@ -1469,6 +1338,10 @@
 		OPT_CMDMODE(0, "show-current-patch", &action,
 			    N_("show the patch file being applied or merged"),
 			    ACTION_SHOW_CURRENT_PATCH),
+		{ OPTION_CALLBACK, 0, "apply", &options, NULL,
+			N_("use apply strategies to rebase"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
+			parse_opt_am },
 		{ OPTION_CALLBACK, 'm', "merge", &options, NULL,
 			N_("use merging strategies to rebase"),
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
@@ -1482,8 +1355,13 @@
 				 "ignoring them"),
 			      REBASE_PRESERVE_MERGES, PARSE_OPT_HIDDEN),
 		OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
-		OPT_BOOL('k', "keep-empty", &options.keep_empty,
-			 N_("preserve empty commits during rebase")),
+		OPT_CALLBACK_F(0, "empty", &options, N_("{drop,keep,ask}"),
+			       N_("how to handle commits that become empty"),
+			       PARSE_OPT_NONEG, parse_opt_empty),
+		{ OPTION_CALLBACK, 'k', "keep-empty", &options, NULL,
+			N_("(DEPRECATED) keep empty commits"),
+			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
+			parse_opt_keep_empty },
 		OPT_BOOL(0, "autosquash", &options.autosquash,
 			 N_("move commits that begin with "
 			    "squash!/fixup! under -i")),
@@ -1495,9 +1373,10 @@
 		OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 				N_("add exec lines after each commit of the "
 				   "editable list")),
-		OPT_BOOL(0, "allow-empty-message",
-			 &options.allow_empty_message,
-			 N_("allow rebasing commits with empty messages")),
+		OPT_BOOL_F(0, "allow-empty-message",
+			   &options.allow_empty_message,
+			   N_("allow rebasing commits with empty messages"),
+			   PARSE_OPT_HIDDEN),
 		{OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 			N_("mode"),
 			N_("try to rebase merges instead of skipping them"),
@@ -1537,7 +1416,7 @@
 		die(_("It looks like 'git am' is in progress. Cannot rebase."));
 
 	if (is_directory(apply_dir())) {
-		options.type = REBASE_AM;
+		options.type = REBASE_APPLY;
 		options.state_dir = apply_dir();
 	} else if (is_directory(merge_dir())) {
 		strbuf_reset(&buf);
@@ -1549,7 +1428,7 @@
 			strbuf_reset(&buf);
 			strbuf_addf(&buf, "%s/interactive", merge_dir());
 			if(file_exists(buf.buf)) {
-				options.type = REBASE_INTERACTIVE;
+				options.type = REBASE_MERGE;
 				options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 			} else
 				options.type = REBASE_MERGE;
@@ -1589,12 +1468,12 @@
 		die(_("No rebase in progress?"));
 	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
 
-	if (action == ACTION_EDIT_TODO && !is_interactive(&options))
+	if (action == ACTION_EDIT_TODO && !is_merge(&options))
 		die(_("The --edit-todo action can only be used during "
 		      "interactive rebase."));
 
 	if (trace2_is_enabled()) {
-		if (is_interactive(&options))
+		if (is_merge(&options))
 			trace2_cmd_mode("interactive");
 		else if (exec.nr)
 			trace2_cmd_mode("interactive-exec");
@@ -1642,8 +1521,8 @@
 		rerere_clear(the_repository, &merge_rr);
 		string_list_clear(&merge_rr, 1);
 
-		if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
-			       NULL, NULL) < 0)
+		if (reset_head(the_repository, NULL, "reset", NULL, RESET_HEAD_HARD,
+			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
 			die(_("could not discard worktree changes"));
 		remove_branch_state(the_repository, 0);
 		if (read_basic_state(&options))
@@ -1660,9 +1539,9 @@
 
 		if (read_basic_state(&options))
 			exit(1);
-		if (reset_head(&options.orig_head, "reset",
+		if (reset_head(the_repository, &options.orig_head, "reset",
 			       options.head_name, RESET_HEAD_HARD,
-			       NULL, NULL) < 0)
+			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
 			die(_("could not move back to %s"),
 			    oid_to_hex(&options.orig_head));
 		remove_branch_state(the_repository, 0);
@@ -1670,7 +1549,7 @@
 		goto cleanup;
 	}
 	case ACTION_QUIT: {
-		if (options.type == REBASE_INTERACTIVE) {
+		if (options.type == REBASE_MERGE) {
 			struct replay_opts replay = REPLAY_OPTS_INIT;
 
 			replay.action = REPLAY_INTERACTIVE_REBASE;
@@ -1719,13 +1598,20 @@
 		    state_dir_base, cmd_live_rebase, buf.buf);
 	}
 
+	if ((options.flags & REBASE_INTERACTIVE_EXPLICIT) ||
+	    (action != ACTION_NONE) ||
+	    (exec.nr > 0) ||
+	    options.autosquash) {
+		allow_preemptive_ff = 0;
+	}
+
 	for (i = 0; i < options.git_am_opts.argc; i++) {
 		const char *option = options.git_am_opts.argv[i], *p;
 		if (!strcmp(option, "--committer-date-is-author-date") ||
 		    !strcmp(option, "--ignore-date") ||
 		    !strcmp(option, "--whitespace=fix") ||
 		    !strcmp(option, "--whitespace=strip"))
-			options.flags |= REBASE_FORCE;
+			allow_preemptive_ff = 0;
 		else if (skip_prefix(option, "-C", &p)) {
 			while (*p)
 				if (!isdigit(*(p++)))
@@ -1745,8 +1631,8 @@
 	if (!(options.flags & REBASE_NO_QUIET))
 		argv_array_push(&options.git_am_opts, "-q");
 
-	if (options.keep_empty)
-		imply_interactive(&options, "--keep-empty");
+	if (options.empty != EMPTY_UNSPECIFIED)
+		imply_merge(&options, "--empty");
 
 	if (gpg_sign) {
 		free(options.gpg_sign_opt);
@@ -1756,7 +1642,7 @@
 	if (exec.nr) {
 		int i;
 
-		imply_interactive(&options, "--exec");
+		imply_merge(&options, "--exec");
 
 		strbuf_reset(&buf);
 		for (i = 0; i < exec.nr; i++)
@@ -1772,7 +1658,7 @@
 		else if (strcmp("no-rebase-cousins", rebase_merges))
 			die(_("Unknown mode: %s"), rebase_merges);
 		options.rebase_merges = 1;
-		imply_interactive(&options, "--rebase-merges");
+		imply_merge(&options, "--rebase-merges");
 	}
 
 	if (strategy_options.nr) {
@@ -1791,10 +1677,9 @@
 	if (options.strategy) {
 		options.strategy = xstrdup(options.strategy);
 		switch (options.type) {
-		case REBASE_AM:
+		case REBASE_APPLY:
 			die(_("--strategy requires --merge or --interactive"));
 		case REBASE_MERGE:
-		case REBASE_INTERACTIVE:
 		case REBASE_PRESERVE_MERGES:
 			/* compatible */
 			break;
@@ -1807,47 +1692,65 @@
 	}
 
 	if (options.type == REBASE_MERGE)
-		imply_interactive(&options, "--merge");
+		imply_merge(&options, "--merge");
 
 	if (options.root && !options.onto_name)
-		imply_interactive(&options, "--root without --onto");
+		imply_merge(&options, "--root without --onto");
 
 	if (isatty(2) && options.flags & REBASE_NO_QUIET)
 		strbuf_addstr(&options.git_format_patch_opt, " --progress");
 
-	switch (options.type) {
-	case REBASE_MERGE:
-	case REBASE_INTERACTIVE:
-	case REBASE_PRESERVE_MERGES:
-		options.state_dir = merge_dir();
-		break;
-	case REBASE_AM:
-		options.state_dir = apply_dir();
-		break;
-	default:
-		/* the default rebase backend is `--am` */
-		options.type = REBASE_AM;
-		options.state_dir = apply_dir();
-		break;
-	}
-
-	if (reschedule_failed_exec > 0 && !is_interactive(&options))
-		die(_("--reschedule-failed-exec requires "
-		      "--exec or --interactive"));
-	if (reschedule_failed_exec >= 0)
-		options.reschedule_failed_exec = reschedule_failed_exec;
-
-	if (options.git_am_opts.argc) {
-		/* all am options except -q are compatible only with --am */
+	if (options.git_am_opts.argc || options.type == REBASE_APPLY) {
+		/* all am options except -q are compatible only with --apply */
 		for (i = options.git_am_opts.argc - 1; i >= 0; i--)
 			if (strcmp(options.git_am_opts.argv[i], "-q"))
 				break;
 
-		if (is_interactive(&options) && i >= 0)
-			die(_("cannot combine am options with either "
-			      "interactive or merge options"));
+		if (i >= 0) {
+			if (is_merge(&options))
+				die(_("cannot combine apply options with "
+				      "merge options"));
+			else
+				options.type = REBASE_APPLY;
+		}
 	}
 
+	if (options.type == REBASE_UNSPECIFIED) {
+		if (!strcmp(options.default_backend, "merge"))
+			imply_merge(&options, "--merge");
+		else if (!strcmp(options.default_backend, "apply"))
+			options.type = REBASE_APPLY;
+		else
+			die(_("Unknown rebase backend: %s"),
+			    options.default_backend);
+	}
+
+	switch (options.type) {
+	case REBASE_MERGE:
+	case REBASE_PRESERVE_MERGES:
+		options.state_dir = merge_dir();
+		break;
+	case REBASE_APPLY:
+		options.state_dir = apply_dir();
+		break;
+	default:
+		BUG("options.type was just set above; should be unreachable.");
+	}
+
+	if (options.empty == EMPTY_UNSPECIFIED) {
+		if (options.flags & REBASE_INTERACTIVE_EXPLICIT)
+			options.empty = EMPTY_ASK;
+		else if (exec.nr > 0)
+			options.empty = EMPTY_KEEP;
+		else
+			options.empty = EMPTY_DROP;
+	}
+	if (reschedule_failed_exec > 0 && !is_merge(&options))
+		die(_("--reschedule-failed-exec requires "
+		      "--exec or --interactive"));
+	if (reschedule_failed_exec >= 0)
+		options.reschedule_failed_exec = reschedule_failed_exec;
+
 	if (options.signoff) {
 		if (options.type == REBASE_PRESERVE_MERGES)
 			die("cannot combine '--signoff' with "
@@ -1994,49 +1897,8 @@
 		die(_("could not read index"));
 
 	if (options.autostash) {
-		struct lock_file lock_file = LOCK_INIT;
-		int fd;
-
-		fd = hold_locked_index(&lock_file, 0);
-		refresh_cache(REFRESH_QUIET);
-		if (0 <= fd)
-			repo_update_index_if_able(the_repository, &lock_file);
-		rollback_lock_file(&lock_file);
-
-		if (has_unstaged_changes(the_repository, 1) ||
-		    has_uncommitted_changes(the_repository, 1)) {
-			const char *autostash =
-				state_dir_path("autostash", &options);
-			struct child_process stash = CHILD_PROCESS_INIT;
-			struct object_id oid;
-
-			argv_array_pushl(&stash.args,
-					 "stash", "create", "autostash", NULL);
-			stash.git_cmd = 1;
-			stash.no_stdin = 1;
-			strbuf_reset(&buf);
-			if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
-				die(_("Cannot autostash"));
-			strbuf_trim_trailing_newline(&buf);
-			if (get_oid(buf.buf, &oid))
-				die(_("Unexpected stash response: '%s'"),
-				    buf.buf);
-			strbuf_reset(&buf);
-			strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
-
-			if (safe_create_leading_directories_const(autostash))
-				die(_("Could not create directory for '%s'"),
-				    options.state_dir);
-			write_file(autostash, "%s", oid_to_hex(&oid));
-			printf(_("Created autostash: %s\n"), buf.buf);
-			if (reset_head(NULL, "reset --hard",
-				       NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
-				die(_("could not reset --hard"));
-
-			if (discard_index(the_repository->index) < 0 ||
-				repo_read_index(the_repository) < 0)
-				die(_("could not read index"));
-		}
+		create_autostash(the_repository, state_dir_path("autostash", &options),
+				 DEFAULT_REFLOG_ACTION);
 	}
 
 	if (require_clean_work_tree(the_repository, "rebase",
@@ -2053,12 +1915,14 @@
 	/*
 	 * Check if we are already based on onto with linear history,
 	 * in which case we could fast-forward without replacing the commits
-	 * with new commits recreated by replaying their changes. This
-	 * optimization must not be done if this is an interactive rebase.
+	 * with new commits recreated by replaying their changes.
+	 *
+	 * Note that can_fast_forward() initializes merge_base, so we have to
+	 * call it before checking allow_preemptive_ff.
 	 */
 	if (can_fast_forward(options.onto, options.upstream, options.restrict_revision,
 		    &options.orig_head, &merge_base) &&
-	    !is_interactive(&options)) {
+	    allow_preemptive_ff) {
 		int flag;
 
 		if (!(options.flags & REBASE_FORCE)) {
@@ -2076,10 +1940,11 @@
 				strbuf_addf(&buf, "%s: checkout %s",
 					    getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
 					    options.switch_to);
-				if (reset_head(&oid, "checkout",
+				if (reset_head(the_repository, &oid, "checkout",
 					       options.head_name,
 					       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
-					       NULL, buf.buf) < 0) {
+					       NULL, buf.buf,
+					       DEFAULT_REFLOG_ACTION) < 0) {
 					ret = !!error(_("could not switch to "
 							"%s"),
 						      options.switch_to);
@@ -2141,7 +2006,7 @@
 		diff_flush(&opts);
 	}
 
-	if (is_interactive(&options))
+	if (is_merge(&options))
 		goto run_rebase;
 
 	/* Detach HEAD and reset the tree */
@@ -2151,10 +2016,10 @@
 
 	strbuf_addf(&msg, "%s: checkout %s",
 		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
-	if (reset_head(&options.onto->object.oid, "checkout", NULL,
+	if (reset_head(the_repository, &options.onto->object.oid, "checkout", NULL,
 		       RESET_HEAD_DETACH | RESET_ORIG_HEAD |
 		       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
-		       NULL, msg.buf))
+		       NULL, msg.buf, DEFAULT_REFLOG_ACTION))
 		die(_("Could not detach HEAD"));
 	strbuf_release(&msg);
 
@@ -2169,8 +2034,9 @@
 		strbuf_addf(&msg, "rebase finished: %s onto %s",
 			options.head_name ? options.head_name : "detached HEAD",
 			oid_to_hex(&options.onto->object.oid));
-		reset_head(NULL, "Fast-forwarded", options.head_name,
-			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf);
+		reset_head(the_repository, NULL, "Fast-forwarded", options.head_name,
+			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
+			   DEFAULT_REFLOG_ACTION);
 		strbuf_release(&msg);
 		ret = !!finish_rebase(&options);
 		goto cleanup;
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 4d34309..81dfd56 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -560,15 +560,16 @@
 
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
+
 		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 			flags |= EXPIRE_REFLOGS_DRY_RUN;
-		else if (starts_with(arg, "--expire=")) {
-			if (parse_expiry_date(arg + 9, &cb.cmd.expire_total))
+		else if (skip_prefix(arg, "--expire=", &arg)) {
+			if (parse_expiry_date(arg, &cb.cmd.expire_total))
 				die(_("'%s' is not a valid timestamp"), arg);
 			explicit_expiry |= EXPIRE_TOTAL;
 		}
-		else if (starts_with(arg, "--expire-unreachable=")) {
-			if (parse_expiry_date(arg + 21, &cb.cmd.expire_unreachable))
+		else if (skip_prefix(arg, "--expire-unreachable=", &arg)) {
+			if (parse_expiry_date(arg, &cb.cmd.expire_unreachable))
 				die(_("'%s' is not a valid timestamp"), arg);
 			explicit_expiry |= EXPIRE_UNREACH;
 		}
diff --git a/builtin/remote.c b/builtin/remote.c
index 96bbe82..555d4c8 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -6,6 +6,7 @@
 #include "string-list.h"
 #include "strbuf.h"
 #include "run-command.h"
+#include "rebase.h"
 #include "refs.h"
 #include "refspec.h"
 #include "object-store.h"
@@ -248,9 +249,8 @@
 struct branch_info {
 	char *remote_name;
 	struct string_list merge;
-	enum {
-		NO_REBASE, NORMAL_REBASE, INTERACTIVE_REBASE, REBASE_MERGES
-	} rebase;
+	enum rebase_type rebase;
+	char *push_remote_name;
 };
 
 static struct string_list branch_list = STRING_LIST_INIT_NODUP;
@@ -264,59 +264,69 @@
 
 static int config_read_branches(const char *key, const char *value, void *cb)
 {
-	if (starts_with(key, "branch.")) {
-		const char *orig_key = key;
-		char *name;
-		struct string_list_item *item;
-		struct branch_info *info;
-		enum { REMOTE, MERGE, REBASE } type;
-		size_t key_len;
+	const char *orig_key = key;
+	char *name;
+	struct string_list_item *item;
+	struct branch_info *info;
+	enum { REMOTE, MERGE, REBASE, PUSH_REMOTE } type;
+	size_t key_len;
 
-		key += 7;
-		if (strip_suffix(key, ".remote", &key_len)) {
-			name = xmemdupz(key, key_len);
-			type = REMOTE;
-		} else if (strip_suffix(key, ".merge", &key_len)) {
-			name = xmemdupz(key, key_len);
-			type = MERGE;
-		} else if (strip_suffix(key, ".rebase", &key_len)) {
-			name = xmemdupz(key, key_len);
-			type = REBASE;
-		} else
-			return 0;
+	if (!starts_with(key, "branch."))
+		return 0;
 
-		item = string_list_insert(&branch_list, name);
+	key += strlen("branch.");
+	if (strip_suffix(key, ".remote", &key_len))
+		type = REMOTE;
+	else if (strip_suffix(key, ".merge", &key_len))
+		type = MERGE;
+	else if (strip_suffix(key, ".rebase", &key_len))
+		type = REBASE;
+	else if (strip_suffix(key, ".pushremote", &key_len))
+		type = PUSH_REMOTE;
+	else
+		return 0;
+	name = xmemdupz(key, key_len);
 
-		if (!item->util)
-			item->util = xcalloc(1, sizeof(struct branch_info));
-		info = item->util;
-		if (type == REMOTE) {
-			if (info->remote_name)
-				warning(_("more than one %s"), orig_key);
-			info->remote_name = xstrdup(value);
-		} else if (type == MERGE) {
-			char *space = strchr(value, ' ');
-			value = abbrev_branch(value);
-			while (space) {
-				char *merge;
-				merge = xstrndup(value, space - value);
-				string_list_append(&info->merge, merge);
-				value = abbrev_branch(space + 1);
-				space = strchr(value, ' ');
-			}
-			string_list_append(&info->merge, xstrdup(value));
-		} else {
-			int v = git_parse_maybe_bool(value);
-			if (v >= 0)
-				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;
+	item = string_list_insert(&branch_list, name);
+
+	if (!item->util)
+		item->util = xcalloc(1, sizeof(struct branch_info));
+	info = item->util;
+	switch (type) {
+	case REMOTE:
+		if (info->remote_name)
+			warning(_("more than one %s"), orig_key);
+		info->remote_name = xstrdup(value);
+		break;
+	case MERGE: {
+		char *space = strchr(value, ' ');
+		value = abbrev_branch(value);
+		while (space) {
+			char *merge;
+			merge = xstrndup(value, space - value);
+			string_list_append(&info->merge, merge);
+			value = abbrev_branch(space + 1);
+			space = strchr(value, ' ');
 		}
+		string_list_append(&info->merge, xstrdup(value));
+		break;
 	}
+	case REBASE:
+		/*
+		 * Consider invalid values as false and check the
+		 * truth value with >= REBASE_TRUE.
+		 */
+		info->rebase = rebase_parse_value(value);
+		break;
+	case PUSH_REMOTE:
+		if (info->push_remote_name)
+			warning(_("more than one %s"), orig_key);
+		info->push_remote_name = xstrdup(value);
+		break;
+	default:
+		BUG("unexpected type=%d", type);
+	}
+
 	return 0;
 }
 
@@ -605,6 +615,56 @@
 	return 0;
 }
 
+struct push_default_info
+{
+	const char *old_name;
+	enum config_scope scope;
+	struct strbuf origin;
+	int linenr;
+};
+
+static int config_read_push_default(const char *key, const char *value,
+	void *cb)
+{
+	struct push_default_info* info = cb;
+	if (strcmp(key, "remote.pushdefault") ||
+	    !value || strcmp(value, info->old_name))
+		return 0;
+
+	info->scope = current_config_scope();
+	strbuf_reset(&info->origin);
+	strbuf_addstr(&info->origin, current_config_name());
+	info->linenr = current_config_line();
+
+	return 0;
+}
+
+static void handle_push_default(const char* old_name, const char* new_name)
+{
+	struct push_default_info push_default = {
+		old_name, CONFIG_SCOPE_UNKNOWN, STRBUF_INIT, -1 };
+	git_config(config_read_push_default, &push_default);
+	if (push_default.scope >= CONFIG_SCOPE_COMMAND)
+		; /* pass */
+	else if (push_default.scope >= CONFIG_SCOPE_LOCAL) {
+		int result = git_config_set_gently("remote.pushDefault",
+						   new_name);
+		if (new_name && result && result != CONFIG_NOTHING_SET)
+			die(_("could not set '%s'"), "remote.pushDefault");
+		else if (!new_name && result && result != CONFIG_NOTHING_SET)
+			die(_("could not unset '%s'"), "remote.pushDefault");
+	} else if (push_default.scope >= CONFIG_SCOPE_SYSTEM) {
+		/* warn */
+		warning(_("The %s configuration remote.pushDefault in:\n"
+			  "\t%s:%d\n"
+			  "now names the non-existent remote '%s'"),
+			config_scope_name(push_default.scope),
+			push_default.origin.buf, push_default.linenr,
+			old_name);
+	}
+}
+
+
 static int mv(int argc, const char **argv)
 {
 	struct option options[] = {
@@ -680,6 +740,11 @@
 			strbuf_addf(&buf, "branch.%s.remote", item->string);
 			git_config_set(buf.buf, rename.new_name);
 		}
+		if (info->push_remote_name && !strcmp(info->push_remote_name, rename.old_name)) {
+			strbuf_reset(&buf);
+			strbuf_addf(&buf, "branch.%s.pushremote", item->string);
+			git_config_set(buf.buf, rename.new_name);
+		}
 	}
 
 	if (!refspec_updated)
@@ -735,6 +800,9 @@
 			die(_("creating '%s' failed"), buf.buf);
 	}
 	string_list_clear(&remote_branches, 1);
+
+	handle_push_default(rename.old_name, rename.new_name);
+
 	return 0;
 }
 
@@ -781,6 +849,13 @@
 					die(_("could not unset '%s'"), buf.buf);
 			}
 		}
+		if (info->push_remote_name && !strcmp(info->push_remote_name, remote->name)) {
+			strbuf_reset(&buf);
+			strbuf_addf(&buf, "branch.%s.pushremote", item->string);
+			result = git_config_set_gently(buf.buf, NULL);
+			if (result && result != CONFIG_NOTHING_SET)
+				die(_("could not unset '%s'"), buf.buf);
+		}
 	}
 
 	/*
@@ -813,6 +888,8 @@
 		strbuf_addf(&buf, "remote.%s", remote->name);
 		if (git_config_rename_section(buf.buf, NULL) < 1)
 			return error(_("Could not remove config section '%s'"), buf.buf);
+
+		handle_push_default(remote->name, NULL);
 	}
 
 	return result;
@@ -943,7 +1020,7 @@
 		return 0;
 	if ((n = strlen(branch_item->string)) > show_info->width)
 		show_info->width = n;
-	if (branch_info->rebase)
+	if (branch_info->rebase >= REBASE_TRUE)
 		show_info->any_rebase = 1;
 
 	item = string_list_insert(show_info->list, branch_item->string);
@@ -960,16 +1037,16 @@
 	int width = show_info->width + 4;
 	int i;
 
-	if (branch_info->rebase && branch_info->merge.nr > 1) {
+	if (branch_info->rebase >= REBASE_TRUE && branch_info->merge.nr > 1) {
 		error(_("invalid branch.%s.merge; cannot rebase onto > 1 branch"),
 			item->string);
 		return 0;
 	}
 
 	printf("    %-*s ", show_info->width, item->string);
-	if (branch_info->rebase) {
+	if (branch_info->rebase >= REBASE_TRUE) {
 		const char *msg;
-		if (branch_info->rebase == INTERACTIVE_REBASE)
+		if (branch_info->rebase == REBASE_INTERACTIVE)
 			msg = _("rebases interactively onto remote %s");
 		else if (branch_info->rebase == REBASE_MERGES)
 			msg = _("rebases interactively (with merges) onto "
diff --git a/builtin/replace.c b/builtin/replace.c
index bd92dc6..b36d17a 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -409,7 +409,8 @@
 	struct tag *tag;
 	int i;
 
-	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
+	hash_object_file(the_hash_algo, extra->value, extra->len,
+			 type_name(OBJ_TAG), &tag_oid);
 	tag = lookup_tag(the_repository, &tag_oid);
 	if (!tag)
 		return error(_("bad mergetag in commit '%s'"), ref);
diff --git a/builtin/reset.c b/builtin/reset.c
index 18228c3..ef5b5ec 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -164,6 +164,7 @@
 	opt.format_callback_data = &intent_to_add;
 	opt.flags.override_submodule_config = 1;
 	opt.repo = the_repository;
+	opt.ita_invisible_in_index = 1;
 
 	if (do_diff_cache(tree_oid, &opt))
 		return 1;
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index e28d62e..35e14ad 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -253,11 +253,19 @@
 static void show_object(struct object *obj, const char *name, void *cb_data)
 {
 	struct rev_list_info *info = cb_data;
+	struct rev_info *revs = info->revs;
+
 	if (finish_object(obj, name, cb_data))
 		return;
 	display_progress(progress, ++progress_counter);
 	if (info->flags & REV_LIST_QUIET)
 		return;
+
+	if (revs->count) {
+		revs->count_right++;
+		return;
+	}
+
 	if (arg_show_object_names)
 		show_object_with_name(stdout, obj, name);
 	else
@@ -364,6 +372,79 @@
 	return 0;
 }
 
+static int try_bitmap_count(struct rev_info *revs,
+			    struct list_objects_filter_options *filter)
+{
+	uint32_t commit_count = 0,
+		 tag_count = 0,
+		 tree_count = 0,
+		 blob_count = 0;
+	int max_count;
+	struct bitmap_index *bitmap_git;
+
+	/* This function only handles counting, not general traversal. */
+	if (!revs->count)
+		return -1;
+
+	/*
+	 * A bitmap result can't know left/right, etc, because we don't
+	 * actually traverse.
+	 */
+	if (revs->left_right || revs->cherry_mark)
+		return -1;
+
+	/*
+	 * If we're counting reachable objects, we can't handle a max count of
+	 * commits to traverse, since we don't know which objects go with which
+	 * commit.
+	 */
+	if (revs->max_count >= 0 &&
+	    (revs->tag_objects || revs->tree_objects || revs->blob_objects))
+		return -1;
+
+	/*
+	 * This must be saved before doing any walking, since the revision
+	 * machinery will count it down to zero while traversing.
+	 */
+	max_count = revs->max_count;
+
+	bitmap_git = prepare_bitmap_walk(revs, filter);
+	if (!bitmap_git)
+		return -1;
+
+	count_bitmap_commit_list(bitmap_git, &commit_count,
+				 revs->tree_objects ? &tree_count : NULL,
+				 revs->blob_objects ? &blob_count : NULL,
+				 revs->tag_objects ? &tag_count : NULL);
+	if (max_count >= 0 && max_count < commit_count)
+		commit_count = max_count;
+
+	printf("%d\n", commit_count + tree_count + blob_count + tag_count);
+	free_bitmap_index(bitmap_git);
+	return 0;
+}
+
+static int try_bitmap_traversal(struct rev_info *revs,
+				struct list_objects_filter_options *filter)
+{
+	struct bitmap_index *bitmap_git;
+
+	/*
+	 * We can't use a bitmap result with a traversal limit, since the set
+	 * of commits we'd get would be essentially random.
+	 */
+	if (revs->max_count >= 0)
+		return -1;
+
+	bitmap_git = prepare_bitmap_walk(revs, filter);
+	if (!bitmap_git)
+		return -1;
+
+	traverse_bitmap_commit_list(bitmap_git, revs, &show_object_fast);
+	free_bitmap_index(bitmap_git);
+	return 0;
+}
+
 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info revs;
@@ -521,8 +602,10 @@
 	if (revs.show_notes)
 		die(_("rev-list does not support display of notes"));
 
-	if (filter_options.choice && use_bitmap_index)
-		die(_("cannot combine --use-bitmap-index with object filtering"));
+	if (revs.count &&
+	    (revs.tag_objects || revs.tree_objects || revs.blob_objects) &&
+	    (revs.left_right || revs.cherry_mark))
+		die(_("marked counting is incompatible with --objects"));
 
 	save_commit_buffer = (revs.verbose_header ||
 			      revs.grep_filter.pattern_list ||
@@ -533,28 +616,11 @@
 	if (show_progress)
 		progress = start_delayed_progress(show_progress, 0);
 
-	if (use_bitmap_index && !revs.prune) {
-		if (revs.count && !revs.left_right && !revs.cherry_mark) {
-			uint32_t commit_count;
-			int max_count = revs.max_count;
-			struct bitmap_index *bitmap_git;
-			if ((bitmap_git = prepare_bitmap_walk(&revs))) {
-				count_bitmap_commit_list(bitmap_git, &commit_count, NULL, NULL, NULL);
-				if (max_count >= 0 && max_count < commit_count)
-					commit_count = max_count;
-				printf("%d\n", commit_count);
-				free_bitmap_index(bitmap_git);
-				return 0;
-			}
-		} else if (revs.max_count < 0 &&
-			   revs.tag_objects && revs.tree_objects && revs.blob_objects) {
-			struct bitmap_index *bitmap_git;
-			if ((bitmap_git = prepare_bitmap_walk(&revs))) {
-				traverse_bitmap_commit_list(bitmap_git, &show_object_fast);
-				free_bitmap_index(bitmap_git);
-				return 0;
-			}
-		}
+	if (use_bitmap_index) {
+		if (!try_bitmap_count(&revs, &filter_options))
+			return 0;
+		if (!try_bitmap_traversal(&revs, &filter_options))
+			return 0;
 	}
 
 	if (prepare_revision_walk(&revs))
diff --git a/builtin/rm.c b/builtin/rm.c
index 19ce95a..4858631 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -235,7 +235,8 @@
 }
 
 static int show_only = 0, force = 0, index_only = 0, recursive = 0, quiet = 0;
-static int ignore_unmatch = 0;
+static int ignore_unmatch = 0, pathspec_file_nul;
+static char *pathspec_from_file;
 
 static struct option builtin_rm_options[] = {
 	OPT__DRY_RUN(&show_only, N_("dry run")),
@@ -245,6 +246,8 @@
 	OPT_BOOL('r', NULL,             &recursive,  N_("allow recursive removal")),
 	OPT_BOOL( 0 , "ignore-unmatch", &ignore_unmatch,
 				N_("exit with a zero status even if nothing matched")),
+	OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),
+	OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),
 	OPT_END(),
 };
 
@@ -259,8 +262,24 @@
 
 	argc = parse_options(argc, argv, prefix, builtin_rm_options,
 			     builtin_rm_usage, 0);
-	if (!argc)
-		usage_with_options(builtin_rm_usage, builtin_rm_options);
+
+	parse_pathspec(&pathspec, 0,
+		       PATHSPEC_PREFER_CWD,
+		       prefix, argv);
+
+	if (pathspec_from_file) {
+		if (pathspec.nr)
+			die(_("--pathspec-from-file is incompatible with pathspec arguments"));
+
+		parse_pathspec_file(&pathspec, 0,
+				    PATHSPEC_PREFER_CWD,
+				    prefix, pathspec_from_file, pathspec_file_nul);
+	} else if (pathspec_file_nul) {
+		die(_("--pathspec-file-nul requires --pathspec-from-file"));
+	}
+
+	if (!pathspec.nr)
+		die(_("No pathspec was given. Which files should I remove?"));
 
 	if (!index_only)
 		setup_work_tree();
@@ -270,9 +289,6 @@
 	if (read_cache() < 0)
 		die(_("index file corrupt"));
 
-	parse_pathspec(&pathspec, 0,
-		       PATHSPEC_PREFER_CWD,
-		       prefix, argv);
 	refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, &pathspec, NULL, NULL);
 
 	seen = xcalloc(pathspec.nr, 1);
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index b3bed89..740da4b 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -13,11 +13,12 @@
 #include "resolve-undo.h"
 #include "unpack-trees.h"
 #include "wt-status.h"
+#include "quote.h"
 
 static const char *empty_base = "";
 
 static char const * const builtin_sparse_checkout_usage[] = {
-	N_("git sparse-checkout (init|list|set|disable) <options>"),
+	N_("git sparse-checkout (init|list|set|add|disable) <options>"),
 	NULL
 };
 
@@ -77,8 +78,10 @@
 
 		string_list_sort(&sl);
 
-		for (i = 0; i < sl.nr; i++)
-			printf("%s\n", sl.items[i].string);
+		for (i = 0; i < sl.nr; i++) {
+			quote_c_style(sl.items[i].string, NULL, stdout, 0);
+			printf("\n");
+		}
 
 		return 0;
 	}
@@ -140,6 +143,22 @@
 	return result;
 }
 
+static char *escaped_pattern(char *pattern)
+{
+	char *p = pattern;
+	struct strbuf final = STRBUF_INIT;
+
+	while (*p) {
+		if (is_glob_special(*p))
+			strbuf_addch(&final, '\\');
+
+		strbuf_addch(&final, *p);
+		p++;
+	}
+
+	return strbuf_detach(&final, NULL);
+}
+
 static void write_cone_to_file(FILE *fp, struct pattern_list *pl)
 {
 	int i;
@@ -164,10 +183,11 @@
 	fprintf(fp, "/*\n!/*/\n");
 
 	for (i = 0; i < sl.nr; i++) {
-		char *pattern = sl.items[i].string;
+		char *pattern = escaped_pattern(sl.items[i].string);
 
 		if (strlen(pattern))
 			fprintf(fp, "%s/\n!%s/*/\n", pattern, pattern);
+		free(pattern);
 	}
 
 	string_list_clear(&sl, 0);
@@ -185,8 +205,9 @@
 	string_list_remove_duplicates(&sl, 0);
 
 	for (i = 0; i < sl.nr; i++) {
-		char *pattern = sl.items[i].string;
+		char *pattern = escaped_pattern(sl.items[i].string);
 		fprintf(fp, "%s/\n", pattern);
+		free(pattern);
 	}
 }
 
@@ -199,6 +220,10 @@
 	int result;
 
 	sparse_filename = get_sparse_checkout_filename();
+
+	if (safe_create_leading_directories(sparse_filename))
+		die(_("failed to create directory for sparse-checkout file"));
+
 	fd = hold_lock_file_for_update(&lk, sparse_filename,
 				      LOCK_DIE_ON_ERROR);
 
@@ -369,17 +394,20 @@
 
 	strbuf_trim_trailing_dir_sep(line);
 
+	if (strbuf_normalize_path(line))
+		die(_("could not normalize path %s"), line->buf);
+
 	if (!line->len)
 		return;
 
 	if (line->buf[0] != '/')
-		strbuf_insert(line, 0, "/", 1);
+		strbuf_insertstr(line, 0, "/");
 
 	insert_recursive_pattern(pl, line);
 }
 
 static char const * const builtin_sparse_checkout_set_usage[] = {
-	N_("git sparse-checkout set (--stdin | <patterns>)"),
+	N_("git sparse-checkout (set|add) (--stdin | <patterns>)"),
 	NULL
 };
 
@@ -387,45 +415,38 @@
 	int use_stdin;
 } set_opts;
 
-static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
+static void add_patterns_from_input(struct pattern_list *pl,
+				    int argc, const char **argv)
 {
 	int i;
-	struct pattern_list pl;
-	int result;
-	int changed_config = 0;
-
-	static struct option builtin_sparse_checkout_set_options[] = {
-		OPT_BOOL(0, "stdin", &set_opts.use_stdin,
-			 N_("read patterns from standard in")),
-		OPT_END(),
-	};
-
-	repo_read_index(the_repository);
-	require_clean_work_tree(the_repository,
-				N_("set sparse-checkout patterns"), NULL, 1, 0);
-
-	memset(&pl, 0, sizeof(pl));
-
-	argc = parse_options(argc, argv, prefix,
-			     builtin_sparse_checkout_set_options,
-			     builtin_sparse_checkout_set_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
-
 	if (core_sparse_checkout_cone) {
 		struct strbuf line = STRBUF_INIT;
 
-		hashmap_init(&pl.recursive_hashmap, pl_hashmap_cmp, NULL, 0);
-		hashmap_init(&pl.parent_hashmap, pl_hashmap_cmp, NULL, 0);
-		pl.use_cone_patterns = 1;
+		hashmap_init(&pl->recursive_hashmap, pl_hashmap_cmp, NULL, 0);
+		hashmap_init(&pl->parent_hashmap, pl_hashmap_cmp, NULL, 0);
+		pl->use_cone_patterns = 1;
 
 		if (set_opts.use_stdin) {
-			while (!strbuf_getline(&line, stdin))
-				strbuf_to_cone_pattern(&line, &pl);
+			struct strbuf unquoted = STRBUF_INIT;
+			while (!strbuf_getline(&line, stdin)) {
+				if (line.buf[0] == '"') {
+					strbuf_reset(&unquoted);
+					if (unquote_c_style(&unquoted, line.buf, NULL))
+						die(_("unable to unquote C-style string '%s'"),
+						line.buf);
+
+					strbuf_swap(&unquoted, &line);
+				}
+
+				strbuf_to_cone_pattern(&line, pl);
+			}
+
+			strbuf_release(&unquoted);
 		} else {
 			for (i = 0; i < argc; i++) {
 				strbuf_setlen(&line, 0);
 				strbuf_addstr(&line, argv[i]);
-				strbuf_to_cone_pattern(&line, &pl);
+				strbuf_to_cone_pattern(&line, pl);
 			}
 		}
 	} else {
@@ -435,13 +456,84 @@
 			while (!strbuf_getline(&line, stdin)) {
 				size_t len;
 				char *buf = strbuf_detach(&line, &len);
-				add_pattern(buf, empty_base, 0, &pl, 0);
+				add_pattern(buf, empty_base, 0, pl, 0);
 			}
 		} else {
 			for (i = 0; i < argc; i++)
-				add_pattern(argv[i], empty_base, 0, &pl, 0);
+				add_pattern(argv[i], empty_base, 0, pl, 0);
 		}
 	}
+}
+
+enum modify_type {
+	REPLACE,
+	ADD,
+};
+
+static void add_patterns_cone_mode(int argc, const char **argv,
+				   struct pattern_list *pl)
+{
+	struct strbuf buffer = STRBUF_INIT;
+	struct pattern_entry *pe;
+	struct hashmap_iter iter;
+	struct pattern_list existing;
+	char *sparse_filename = get_sparse_checkout_filename();
+
+	add_patterns_from_input(pl, argc, argv);
+
+	memset(&existing, 0, sizeof(existing));
+	existing.use_cone_patterns = core_sparse_checkout_cone;
+
+	if (add_patterns_from_file_to_list(sparse_filename, "", 0,
+					   &existing, NULL))
+		die(_("unable to load existing sparse-checkout patterns"));
+	free(sparse_filename);
+
+	hashmap_for_each_entry(&existing.recursive_hashmap, &iter, pe, ent) {
+		if (!hashmap_contains_parent(&pl->recursive_hashmap,
+					pe->pattern, &buffer) ||
+		    !hashmap_contains_parent(&pl->parent_hashmap,
+					pe->pattern, &buffer)) {
+			strbuf_reset(&buffer);
+			strbuf_addstr(&buffer, pe->pattern);
+			insert_recursive_pattern(pl, &buffer);
+		}
+	}
+
+	clear_pattern_list(&existing);
+	strbuf_release(&buffer);
+}
+
+static void add_patterns_literal(int argc, const char **argv,
+				 struct pattern_list *pl)
+{
+	char *sparse_filename = get_sparse_checkout_filename();
+	if (add_patterns_from_file_to_list(sparse_filename, "", 0,
+					   pl, NULL))
+		die(_("unable to load existing sparse-checkout patterns"));
+	free(sparse_filename);
+	add_patterns_from_input(pl, argc, argv);
+}
+
+static int modify_pattern_list(int argc, const char **argv, enum modify_type m)
+{
+	int result;
+	int changed_config = 0;
+	struct pattern_list pl;
+	memset(&pl, 0, sizeof(pl));
+
+	switch (m) {
+	case ADD:
+		if (core_sparse_checkout_cone)
+			add_patterns_cone_mode(argc, argv, &pl);
+		else
+			add_patterns_literal(argc, argv, &pl);
+		break;
+
+	case REPLACE:
+		add_patterns_from_input(&pl, argc, argv);
+		break;
+	}
 
 	if (!core_apply_sparse_checkout) {
 		set_config(MODE_ALL_PATTERNS);
@@ -458,6 +550,27 @@
 	return result;
 }
 
+static int sparse_checkout_set(int argc, const char **argv, const char *prefix,
+			       enum modify_type m)
+{
+	static struct option builtin_sparse_checkout_set_options[] = {
+		OPT_BOOL(0, "stdin", &set_opts.use_stdin,
+			 N_("read patterns from standard in")),
+		OPT_END(),
+	};
+
+	repo_read_index(the_repository);
+	require_clean_work_tree(the_repository,
+				N_("set sparse-checkout patterns"), NULL, 1, 0);
+
+	argc = parse_options(argc, argv, prefix,
+			     builtin_sparse_checkout_set_options,
+			     builtin_sparse_checkout_set_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+
+	return modify_pattern_list(argc, argv, m);
+}
+
 static int sparse_checkout_disable(int argc, const char **argv)
 {
 	struct pattern_list pl;
@@ -506,7 +619,9 @@
 		if (!strcmp(argv[0], "init"))
 			return sparse_checkout_init(argc, argv);
 		if (!strcmp(argv[0], "set"))
-			return sparse_checkout_set(argc, argv, prefix);
+			return sparse_checkout_set(argc, argv, prefix, REPLACE);
+		if (!strcmp(argv[0], "add"))
+			return sparse_checkout_set(argc, argv, prefix, ADD);
 		if (!strcmp(argv[0], "disable"))
 			return sparse_checkout_disable(argc, argv);
 	}
diff --git a/builtin/stash.c b/builtin/stash.c
index 4ad3adf..78af6ce 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -27,6 +27,7 @@
 	N_("git stash clear"),
 	N_("git stash [push [-p|--patch] [-k|--[no-]keep-index] [-q|--quiet]\n"
 	   "          [-u|--include-untracked] [-a|--all] [-m|--message <message>]\n"
+	   "          [--pathspec-from-file=<file> [--pathspec-file-nul]]\n"
 	   "          [--] [<pathspec>...]]"),
 	N_("git stash save [-p|--patch] [-k|--[no-]keep-index] [-q|--quiet]\n"
 	   "          [-u|--include-untracked] [-a|--all] [<message>]"),
@@ -998,9 +999,9 @@
 {
 	int ret = 0;
 	struct child_process cp_read_tree = CHILD_PROCESS_INIT;
-	struct child_process cp_add_i = CHILD_PROCESS_INIT;
 	struct child_process cp_diff_tree = CHILD_PROCESS_INIT;
 	struct index_state istate = { NULL };
+	char *old_index_env = NULL, *old_repo_index_file;
 
 	remove_path(stash_index_path.buf);
 
@@ -1014,16 +1015,19 @@
 	}
 
 	/* Find out what the user wants. */
-	cp_add_i.git_cmd = 1;
-	argv_array_pushl(&cp_add_i.args, "add--interactive", "--patch=stash",
-			 "--", NULL);
-	add_pathspecs(&cp_add_i.args, ps);
-	argv_array_pushf(&cp_add_i.env_array, "GIT_INDEX_FILE=%s",
-			 stash_index_path.buf);
-	if (run_command(&cp_add_i)) {
-		ret = -1;
-		goto done;
-	}
+	old_repo_index_file = the_repository->index_file;
+	the_repository->index_file = stash_index_path.buf;
+	old_index_env = xstrdup_or_null(getenv(INDEX_ENVIRONMENT));
+	setenv(INDEX_ENVIRONMENT, the_repository->index_file, 1);
+
+	ret = run_add_interactive(NULL, "--patch=stash", ps);
+
+	the_repository->index_file = old_repo_index_file;
+	if (old_index_env && *old_index_env)
+		setenv(INDEX_ENVIRONMENT, old_index_env, 1);
+	else
+		unsetenv(INDEX_ENVIRONMENT);
+	FREE_AND_NULL(old_index_env);
 
 	/* State of the working tree. */
 	if (write_index_as_tree(&info->w_tree, &istate, stash_index_path.buf, 0,
@@ -1448,13 +1452,17 @@
 	return ret;
 }
 
-static int push_stash(int argc, const char **argv, const char *prefix)
+static int push_stash(int argc, const char **argv, const char *prefix,
+		      int push_assumed)
 {
+	int force_assume = 0;
 	int keep_index = -1;
 	int patch_mode = 0;
 	int include_untracked = 0;
 	int quiet = 0;
+	int pathspec_file_nul = 0;
 	const char *stash_msg = NULL;
+	const char *pathspec_from_file = NULL;
 	struct pathspec ps;
 	struct option options[] = {
 		OPT_BOOL('k', "keep-index", &keep_index,
@@ -1468,16 +1476,45 @@
 			    N_("include ignore files"), 2),
 		OPT_STRING('m', "message", &stash_msg, N_("message"),
 			   N_("stash message")),
+		OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),
+		OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),
 		OPT_END()
 	};
 
-	if (argc)
+	if (argc) {
+		force_assume = !strcmp(argv[0], "-p");
 		argc = parse_options(argc, argv, prefix, options,
 				     git_stash_push_usage,
-				     0);
+				     PARSE_OPT_KEEP_DASHDASH);
+	}
+
+	if (argc) {
+		if (!strcmp(argv[0], "--")) {
+			argc--;
+			argv++;
+		} else if (push_assumed && !force_assume) {
+			die("subcommand wasn't specified; 'push' can't be assumed due to unexpected token '%s'",
+			    argv[0]);
+		}
+	}
 
 	parse_pathspec(&ps, 0, PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
 		       prefix, argv);
+
+	if (pathspec_from_file) {
+		if (patch_mode)
+			die(_("--pathspec-from-file is incompatible with --patch"));
+
+		if (ps.nr)
+			die(_("--pathspec-from-file is incompatible with pathspec arguments"));
+
+		parse_pathspec_file(&ps, 0,
+				    PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
+				    prefix, pathspec_from_file, pathspec_file_nul);
+	} else if (pathspec_file_nul) {
+		die(_("--pathspec-file-nul requires --pathspec-from-file"));
+	}
+
 	return do_push_stash(&ps, stash_msg, quiet, keep_index, patch_mode,
 			     include_untracked);
 }
@@ -1547,7 +1584,6 @@
 
 int cmd_stash(int argc, const char **argv, const char *prefix)
 {
-	int i = -1;
 	pid_t pid = getpid();
 	const char *index_file;
 	struct argv_array args = ARGV_ARRAY_INIT;
@@ -1580,7 +1616,7 @@
 		    (uintmax_t)pid);
 
 	if (!argc)
-		return !!push_stash(0, NULL, prefix);
+		return !!push_stash(0, NULL, prefix, 0);
 	else if (!strcmp(argv[0], "apply"))
 		return !!apply_stash(argc, argv, prefix);
 	else if (!strcmp(argv[0], "clear"))
@@ -1600,45 +1636,15 @@
 	else if (!strcmp(argv[0], "create"))
 		return !!create_stash(argc, argv, prefix);
 	else if (!strcmp(argv[0], "push"))
-		return !!push_stash(argc, argv, prefix);
+		return !!push_stash(argc, argv, prefix, 0);
 	else if (!strcmp(argv[0], "save"))
 		return !!save_stash(argc, argv, prefix);
 	else if (*argv[0] != '-')
 		usage_msg_opt(xstrfmt(_("unknown subcommand: %s"), argv[0]),
 			      git_stash_usage, options);
 
-	if (strcmp(argv[0], "-p")) {
-		while (++i < argc && strcmp(argv[i], "--")) {
-			/*
-			 * `akpqu` is a string which contains all short options,
-			 * except `-m` which is verified separately.
-			 */
-			if ((strlen(argv[i]) == 2) && *argv[i] == '-' &&
-			    strchr("akpqu", argv[i][1]))
-				continue;
-
-			if (!strcmp(argv[i], "--all") ||
-			    !strcmp(argv[i], "--keep-index") ||
-			    !strcmp(argv[i], "--no-keep-index") ||
-			    !strcmp(argv[i], "--patch") ||
-			    !strcmp(argv[i], "--quiet") ||
-			    !strcmp(argv[i], "--include-untracked"))
-				continue;
-
-			/*
-			 * `-m` and `--message=` are verified separately because
-			 * they need to be immediately followed by a string
-			 * (i.e.`-m"foobar"` or `--message="foobar"`).
-			 */
-			if (starts_with(argv[i], "-m") ||
-			    starts_with(argv[i], "--message="))
-				continue;
-
-			usage_with_options(git_stash_usage, options);
-		}
-	}
-
+	/* Assume 'stash push' */
 	argv_array_push(&args, "push");
 	argv_array_pushv(&args, argv);
-	return !!push_stash(args.argc, args.argv, prefix);
+	return !!push_stash(args.argc, args.argv, prefix, 1);
 }
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c72931e..b6e4c79 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -782,6 +782,8 @@
 	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
 	struct rev_info rev;
 	int diff_files_result;
+	struct strbuf buf = STRBUF_INIT;
+	const char *git_dir;
 
 	if (!submodule_from_path(the_repository, &null_oid, path))
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
@@ -794,10 +796,18 @@
 		goto cleanup;
 	}
 
-	if (!is_submodule_active(the_repository, path)) {
+	strbuf_addf(&buf, "%s/.git", path);
+	git_dir = read_gitfile(buf.buf);
+	if (!git_dir)
+		git_dir = buf.buf;
+
+	if (!is_submodule_active(the_repository, path) ||
+	    !is_git_directory(git_dir)) {
 		print_status(flags, '-', path, ce_oid, displaypath);
+		strbuf_release(&buf);
 		goto cleanup;
 	}
+	strbuf_release(&buf);
 
 	argv_array_pushl(&diff_files_args, "diff-files",
 			 "--ignore-submodules=dirty", "--quiet", "--",
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 9100964..dd4a75e 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -265,7 +265,8 @@
 	} else {
 		struct object *obj;
 		int eaten;
-		hash_object_file(buf, size, type_name(type), &obj_list[nr].oid);
+		hash_object_file(the_hash_algo, buf, size, type_name(type),
+				 &obj_list[nr].oid);
 		added_object(nr, type, buf, size);
 		obj = parse_object_buffer(the_repository, &obj_list[nr].oid,
 					  type, size, buf,
diff --git a/cache-tree.c b/cache-tree.c
index 1bd1b23..a537a80 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -407,13 +407,15 @@
 
 	if (repair) {
 		struct object_id oid;
-		hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
+		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
+				 tree_type, &oid);
 		if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 			oidcpy(&it->oid, &oid);
 		else
 			to_invalidate = 1;
 	} else if (dryrun) {
-		hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
+		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
+				 tree_type, &it->oid);
 	} else if (write_object_file(buffer.buf, buffer.len, tree_type,
 				     &it->oid)) {
 		strbuf_release(&buffer);
@@ -826,9 +828,10 @@
 			i++;
 		}
 		strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
-		strbuf_add(&tree_buf, oid->hash, the_hash_algo->rawsz);
+		strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 	}
-	hash_object_file(tree_buf.buf, tree_buf.len, tree_type, &new_oid);
+	hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, tree_type,
+			 &new_oid);
 	if (!oideq(&new_oid, &it->oid))
 		BUG("cache-tree for path %.*s does not match. "
 		    "Expected %s got %s", len, path->buf,
diff --git a/cache.h b/cache.h
index cbfaead..b3fcb60 100644
--- a/cache.h
+++ b/cache.h
@@ -21,10 +21,10 @@
 #include <zlib.h>
 typedef struct git_zstream {
 	z_stream z;
-	unsigned long avail_in;
-	unsigned long avail_out;
-	unsigned long total_in;
-	unsigned long total_out;
+	size_t avail_in;
+	size_t avail_out;
+	size_t total_in;
+	size_t total_out;
 	unsigned char *next_in;
 	unsigned char *next_out;
 } git_zstream;
@@ -41,7 +41,7 @@
 int git_deflate_abort(git_zstream *);
 int git_deflate_end_gently(git_zstream *);
 int git_deflate(git_zstream *, int flush);
-unsigned long git_deflate_bound(git_zstream *, unsigned long);
+size_t git_deflate_bound(git_zstream *, size_t);
 
 #if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
 #define DTYPE(de)	((de)->d_type)
@@ -324,7 +324,7 @@
 	struct hashmap dir_hash;
 	struct object_id oid;
 	struct untracked_cache *untracked;
-	uint64_t fsmonitor_last_update;
+	char *fsmonitor_last_update;
 	struct ewah_bitmap *fsmonitor_dirty;
 	struct mem_pool *ce_mem_pool;
 	struct progress *progress;
@@ -1363,7 +1363,8 @@
 int unpack_loose_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
 int parse_loose_header(const char *hdr, unsigned long *sizep);
 
-int check_object_signature(const struct object_id *oid, void *buf, unsigned long size, const char *type);
+int check_object_signature(struct repository *r, const struct object_id *oid,
+			   void *buf, unsigned long size, const char *type);
 
 int finalize_object_file(const char *tmpfile, const char *filename);
 
diff --git a/ci/lib.sh b/ci/lib.sh
index a90d0dc..c3a8cd2 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -162,6 +162,9 @@
 	if [ "$jobname" = linux-gcc ]
 	then
 		export CC=gcc-8
+		MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=$(which python3)"
+	else
+		MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=$(which python2)"
 	fi
 
 	export GIT_TEST_HTTPD=true
@@ -182,6 +185,9 @@
 	if [ "$jobname" = osx-gcc ]
 	then
 		export CC=gcc-9
+		MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=$(which python3)"
+	else
+		MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=$(which python2)"
 	fi
 
 	# t9810 occasionally fails on Travis CI OS X
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index ff0ef7f..17e25aa 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -19,7 +19,9 @@
 	export GIT_TEST_OE_SIZE=10
 	export GIT_TEST_OE_DELTA_SIZE=5
 	export GIT_TEST_COMMIT_GRAPH=1
+	export GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=1
 	export GIT_TEST_MULTI_PACK_INDEX=1
+	export GIT_TEST_ADD_I_USE_BUILTIN=1
 	make test
 	;;
 linux-gcc-4.8)
diff --git a/ci/test-documentation.sh b/ci/test-documentation.sh
index b3e76ef..de41888 100755
--- a/ci/test-documentation.sh
+++ b/ci/test-documentation.sh
@@ -7,6 +7,7 @@
 
 filter_log () {
 	sed -e '/^GIT_VERSION = /d' \
+	    -e "/constant Gem::ConfigMap is deprecated/d" \
 	    -e '/^    \* new asciidoc flags$/d' \
 	    -e '/stripped namespace before processing/d' \
 	    -e '/Attributed.*IDs for element/d' \
diff --git a/color.c b/color.c
index ebb222e..64f52a4 100644
--- a/color.c
+++ b/color.c
@@ -24,6 +24,14 @@
 	GIT_COLOR_RESET,
 };
 
+enum {
+	COLOR_BACKGROUND_OFFSET = 10,
+	COLOR_FOREGROUND_ANSI = 30,
+	COLOR_FOREGROUND_RGB = 38,
+	COLOR_FOREGROUND_256 = 38,
+	COLOR_FOREGROUND_BRIGHT_ANSI = 90,
+};
+
 /* Ignore the RESET at the end when giving the size */
 const int column_colors_ansi_max = ARRAY_SIZE(column_colors_ansi) - 1;
 
@@ -61,15 +69,38 @@
 	return 0;
 }
 
-static int parse_color(struct color *out, const char *name, int len)
+/*
+ * If an ANSI color is recognized in "name", fill "out" and return 0.
+ * Otherwise, leave out unchanged and return -1.
+ */
+static int parse_ansi_color(struct color *out, const char *name, int len)
 {
 	/* Positions in array must match ANSI color codes */
 	static const char * const color_names[] = {
 		"black", "red", "green", "yellow",
 		"blue", "magenta", "cyan", "white"
 	};
-	char *end;
 	int i;
+	int color_offset = COLOR_FOREGROUND_ANSI;
+
+	if (strncasecmp(name, "bright", 6) == 0) {
+		color_offset = COLOR_FOREGROUND_BRIGHT_ANSI;
+		name += 6;
+		len -= 6;
+	}
+	for (i = 0; i < ARRAY_SIZE(color_names); i++) {
+		if (match_word(name, len, color_names[i])) {
+			out->type = COLOR_ANSI;
+			out->value = i + color_offset;
+			return 0;
+		}
+	}
+	return -1;
+}
+
+static int parse_color(struct color *out, const char *name, int len)
+{
+	char *end;
 	long val;
 
 	/* First try the special word "normal"... */
@@ -89,12 +120,8 @@
 	}
 
 	/* Then pick from our human-readable color names... */
-	for (i = 0; i < ARRAY_SIZE(color_names); i++) {
-		if (match_word(name, len, color_names[i])) {
-			out->type = COLOR_ANSI;
-			out->value = i;
-			return 0;
-		}
+	if (parse_ansi_color(out, name, len) == 0) {
+		return 0;
 	}
 
 	/* And finally try a literal 256-color-mode number */
@@ -109,10 +136,15 @@
 		else if (val < 0) {
 			out->type = COLOR_NORMAL;
 			return 0;
-		/* Rewrite low numbers as more-portable standard colors. */
+		/* Rewrite 0-7 as more-portable standard colors. */
 		} else if (val < 8) {
 			out->type = COLOR_ANSI;
-			out->value = val;
+			out->value = val + COLOR_FOREGROUND_ANSI;
+			return 0;
+		/* Rewrite 8-15 as more-portable aixterm colors. */
+		} else if (val < 16) {
+			out->type = COLOR_ANSI;
+			out->value = val - 8 + COLOR_FOREGROUND_BRIGHT_ANSI;
 			return 0;
 		} else if (val < 256) {
 			out->type = COLOR_256;
@@ -166,23 +198,26 @@
  * already have the ANSI escape code in it. "out" should have enough
  * space in it to fit any color.
  */
-static char *color_output(char *out, int len, const struct color *c, char type)
+static char *color_output(char *out, int len, const struct color *c, int background)
 {
+	int offset = 0;
+
+	if (background)
+		offset = COLOR_BACKGROUND_OFFSET;
 	switch (c->type) {
 	case COLOR_UNSPECIFIED:
 	case COLOR_NORMAL:
 		break;
 	case COLOR_ANSI:
-		if (len < 2)
-			BUG("color parsing ran out of space");
-		*out++ = type;
-		*out++ = '0' + c->value;
+		out += xsnprintf(out, len, "%d", c->value + offset);
 		break;
 	case COLOR_256:
-		out += xsnprintf(out, len, "%c8;5;%d", type, c->value);
+		out += xsnprintf(out, len, "%d;5;%d", COLOR_FOREGROUND_256 + offset,
+				 c->value);
 		break;
 	case COLOR_RGB:
-		out += xsnprintf(out, len, "%c8;2;%d;%d;%d", type,
+		out += xsnprintf(out, len, "%d;2;%d;%d;%d",
+				 COLOR_FOREGROUND_RGB + offset,
 				 c->red, c->green, c->blue);
 		break;
 	}
@@ -279,14 +314,12 @@
 		if (!color_empty(&fg)) {
 			if (sep++)
 				OUT(';');
-			/* foreground colors are all in the 3x range */
-			dst = color_output(dst, end - dst, &fg, '3');
+			dst = color_output(dst, end - dst, &fg, 0);
 		}
 		if (!color_empty(&bg)) {
 			if (sep++)
 				OUT(';');
-			/* background colors are all in the 4x range */
-			dst = color_output(dst, end - dst, &bg, '4');
+			dst = color_output(dst, end - dst, &bg, 1);
 		}
 		OUT('m');
 	}
diff --git a/command-list.txt b/command-list.txt
index 2087894..185e5e3 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -54,6 +54,7 @@
 git-bisect                              mainporcelain           info
 git-blame                               ancillaryinterrogators          complete
 git-branch                              mainporcelain           history
+git-bugreport                           ancillaryinterrogators
 git-bundle                              mainporcelain
 git-cat-file                            plumbinginterrogators
 git-check-attr                          purehelpers
diff --git a/commit-graph.c b/commit-graph.c
index b205e65..b1e2a92 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -16,13 +16,18 @@
 #include "hashmap.h"
 #include "replace-object.h"
 #include "progress.h"
+#include "bloom.h"
+#include "commit-slab.h"
 
 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
+#define GRAPH_CHUNKID_BLOOMINDEXES 0x42494458 /* "BIDX" */
+#define GRAPH_CHUNKID_BLOOMDATA 0x42444154 /* "BDAT" */
 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
+#define MAX_NUM_CHUNKS 7
 
 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
 
@@ -44,30 +49,63 @@
 /* Remember to update object flag allocation in object.h */
 #define REACHABLE       (1u<<15)
 
-char *get_commit_graph_filename(const char *obj_dir)
+/* Keep track of the order in which commits are added to our list. */
+define_commit_slab(commit_pos, int);
+static struct commit_pos commit_pos = COMMIT_SLAB_INIT(1, commit_pos);
+
+static void set_commit_pos(struct repository *r, const struct object_id *oid)
 {
-	char *filename = xstrfmt("%s/info/commit-graph", obj_dir);
-	char *normalized = xmalloc(strlen(filename) + 1);
-	normalize_path_copy(normalized, filename);
-	free(filename);
-	return normalized;
+	static int32_t max_pos;
+	struct commit *commit = lookup_commit(r, oid);
+
+	if (!commit)
+		return; /* should never happen, but be lenient */
+
+	*commit_pos_at(&commit_pos, commit) = max_pos++;
 }
 
-static char *get_split_graph_filename(const char *obj_dir,
+static int commit_pos_cmp(const void *va, const void *vb)
+{
+	const struct commit *a = *(const struct commit **)va;
+	const struct commit *b = *(const struct commit **)vb;
+	return commit_pos_at(&commit_pos, a) -
+	       commit_pos_at(&commit_pos, b);
+}
+
+static int commit_gen_cmp(const void *va, const void *vb)
+{
+	const struct commit *a = *(const struct commit **)va;
+	const struct commit *b = *(const struct commit **)vb;
+
+	/* lower generation commits first */
+	if (a->generation < b->generation)
+		return -1;
+	else if (a->generation > b->generation)
+		return 1;
+
+	/* use date as a heuristic when generations are equal */
+	if (a->date < b->date)
+		return -1;
+	else if (a->date > b->date)
+		return 1;
+	return 0;
+}
+
+char *get_commit_graph_filename(struct object_directory *odb)
+{
+	return xstrfmt("%s/info/commit-graph", odb->path);
+}
+
+static char *get_split_graph_filename(struct object_directory *odb,
 				      const char *oid_hex)
 {
-	char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph",
-				 obj_dir,
-				 oid_hex);
-	char *normalized = xmalloc(strlen(filename) + 1);
-	normalize_path_copy(normalized, filename);
-	free(filename);
-	return normalized;
+	return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
+		       oid_hex);
 }
 
-static char *get_chain_filename(const char *obj_dir)
+static char *get_chain_filename(struct object_directory *odb)
 {
-	return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir);
+	return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
 }
 
 static uint8_t oid_version(void)
@@ -117,7 +155,8 @@
 	return 1;
 }
 
-struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
+struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
+						 struct object_directory *odb)
 {
 	void *graph_map;
 	size_t graph_size;
@@ -133,7 +172,9 @@
 	graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	ret = parse_commit_graph(graph_map, fd, graph_size);
 
-	if (!ret) {
+	if (ret)
+		ret->odb = odb;
+	else {
 		munmap(graph_map, graph_size);
 		close(fd);
 	}
@@ -280,6 +321,32 @@
 				chunk_repeated = 1;
 			else
 				graph->chunk_base_graphs = data + chunk_offset;
+			break;
+
+		case GRAPH_CHUNKID_BLOOMINDEXES:
+			if (graph->chunk_bloom_indexes)
+				chunk_repeated = 1;
+			else
+				graph->chunk_bloom_indexes = data + chunk_offset;
+			break;
+
+		case GRAPH_CHUNKID_BLOOMDATA:
+			if (graph->chunk_bloom_data)
+				chunk_repeated = 1;
+			else {
+				uint32_t hash_version;
+				graph->chunk_bloom_data = data + chunk_offset;
+				hash_version = get_be32(data + chunk_offset);
+
+				if (hash_version != 1)
+					break;
+
+				graph->bloom_filter_settings = xmalloc(sizeof(struct bloom_filter_settings));
+				graph->bloom_filter_settings->hash_version = hash_version;
+				graph->bloom_filter_settings->num_hashes = get_be32(data + chunk_offset + 4);
+				graph->bloom_filter_settings->bits_per_entry = get_be32(data + chunk_offset + 8);
+			}
+			break;
 		}
 
 		if (chunk_repeated) {
@@ -298,6 +365,17 @@
 		last_chunk_offset = chunk_offset;
 	}
 
+	/* We need both the bloom chunks to exist together. Else ignore the data */
+	if ((graph->chunk_bloom_indexes && !graph->chunk_bloom_data)
+		 || (!graph->chunk_bloom_indexes && graph->chunk_bloom_data)) {
+		graph->chunk_bloom_indexes = NULL;
+		graph->chunk_bloom_data = NULL;
+		graph->bloom_filter_settings = NULL;
+	}
+
+	if (graph->chunk_bloom_indexes && graph->chunk_bloom_data)
+		load_bloom_filters();
+
 	hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 
 	if (verify_commit_graph_lite(graph)) {
@@ -308,7 +386,8 @@
 	return graph;
 }
 
-static struct commit_graph *load_commit_graph_one(const char *graph_file)
+static struct commit_graph *load_commit_graph_one(const char *graph_file,
+						  struct object_directory *odb)
 {
 
 	struct stat st;
@@ -319,7 +398,7 @@
 	if (!open_ok)
 		return NULL;
 
-	g = load_commit_graph_one_fd_st(fd, &st);
+	g = load_commit_graph_one_fd_st(fd, &st, odb);
 
 	if (g)
 		g->filename = xstrdup(graph_file);
@@ -327,15 +406,13 @@
 	return g;
 }
 
-static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir)
+static struct commit_graph *load_commit_graph_v1(struct repository *r,
+						 struct object_directory *odb)
 {
-	char *graph_name = get_commit_graph_filename(obj_dir);
-	struct commit_graph *g = load_commit_graph_one(graph_name);
+	char *graph_name = get_commit_graph_filename(odb);
+	struct commit_graph *g = load_commit_graph_one(graph_name, odb);
 	free(graph_name);
 
-	if (g)
-		g->obj_dir = obj_dir;
-
 	return g;
 }
 
@@ -372,14 +449,15 @@
 	return 1;
 }
 
-static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir)
+static struct commit_graph *load_commit_graph_chain(struct repository *r,
+						    struct object_directory *odb)
 {
 	struct commit_graph *graph_chain = NULL;
 	struct strbuf line = STRBUF_INIT;
 	struct stat st;
 	struct object_id *oids;
 	int i = 0, valid = 1, count;
-	char *chain_name = get_chain_filename(obj_dir);
+	char *chain_name = get_chain_filename(odb);
 	FILE *fp;
 	int stat_res;
 
@@ -412,14 +490,12 @@
 
 		valid = 0;
 		for (odb = r->objects->odb; odb; odb = odb->next) {
-			char *graph_name = get_split_graph_filename(odb->path, line.buf);
-			struct commit_graph *g = load_commit_graph_one(graph_name);
+			char *graph_name = get_split_graph_filename(odb, line.buf);
+			struct commit_graph *g = load_commit_graph_one(graph_name, odb);
 
 			free(graph_name);
 
 			if (g) {
-				g->obj_dir = odb->path;
-
 				if (add_graph_to_chain(g, graph_chain, oids, i)) {
 					graph_chain = g;
 					valid = 1;
@@ -442,23 +518,25 @@
 	return graph_chain;
 }
 
-struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir)
+struct commit_graph *read_commit_graph_one(struct repository *r,
+					   struct object_directory *odb)
 {
-	struct commit_graph *g = load_commit_graph_v1(r, obj_dir);
+	struct commit_graph *g = load_commit_graph_v1(r, odb);
 
 	if (!g)
-		g = load_commit_graph_chain(r, obj_dir);
+		g = load_commit_graph_chain(r, odb);
 
 	return g;
 }
 
-static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
+static void prepare_commit_graph_one(struct repository *r,
+				     struct object_directory *odb)
 {
 
 	if (r->objects->commit_graph)
 		return;
 
-	r->objects->commit_graph = read_commit_graph_one(r, obj_dir);
+	r->objects->commit_graph = read_commit_graph_one(r, odb);
 }
 
 /*
@@ -505,7 +583,7 @@
 	for (odb = r->objects->odb;
 	     !r->objects->commit_graph && odb;
 	     odb = odb->next)
-		prepare_commit_graph_one(r, odb->path);
+		prepare_commit_graph_one(r, odb);
 	return !!r->objects->commit_graph;
 }
 
@@ -772,7 +850,7 @@
 
 struct write_commit_graph_context {
 	struct repository *r;
-	char *obj_dir;
+	struct object_directory *odb;
 	char *graph_name;
 	struct packed_oid_list oids;
 	struct packed_commit_list commits;
@@ -794,9 +872,13 @@
 	unsigned append:1,
 		 report_progress:1,
 		 split:1,
-		 check_oids:1;
+		 check_oids:1,
+		 no_input:1,
+		 changed_paths:1,
+		 order_by_pack:1;
 
 	const struct split_commit_graph_opts *split_opts;
+	uint32_t total_bloom_filter_data_size;
 };
 
 static void write_graph_chunk_fanout(struct hashfile *f,
@@ -992,6 +1074,59 @@
 	}
 }
 
+static void write_graph_chunk_bloom_indexes(struct hashfile *f,
+					    struct write_commit_graph_context *ctx)
+{
+	struct commit **list = ctx->commits.list;
+	struct commit **last = ctx->commits.list + ctx->commits.nr;
+	uint32_t cur_pos = 0;
+	struct progress *progress = NULL;
+	int i = 0;
+
+	if (ctx->report_progress)
+		progress = start_delayed_progress(
+			_("Writing changed paths Bloom filters index"),
+			ctx->commits.nr);
+
+	while (list < last) {
+		struct bloom_filter *filter = get_bloom_filter(ctx->r, *list, 0);
+		cur_pos += filter->len;
+		display_progress(progress, ++i);
+		hashwrite_be32(f, cur_pos);
+		list++;
+	}
+
+	stop_progress(&progress);
+}
+
+static void write_graph_chunk_bloom_data(struct hashfile *f,
+					 struct write_commit_graph_context *ctx,
+					 struct bloom_filter_settings *settings)
+{
+	struct commit **list = ctx->commits.list;
+	struct commit **last = ctx->commits.list + ctx->commits.nr;
+	struct progress *progress = NULL;
+	int i = 0;
+
+	if (ctx->report_progress)
+		progress = start_delayed_progress(
+			_("Writing changed paths Bloom filters data"),
+			ctx->commits.nr);
+
+	hashwrite_be32(f, settings->hash_version);
+	hashwrite_be32(f, settings->num_hashes);
+	hashwrite_be32(f, settings->bits_per_entry);
+
+	while (list < last) {
+		struct bloom_filter *filter = get_bloom_filter(ctx->r, *list, 0);
+		display_progress(progress, ++i);
+		hashwrite(f, filter->data, filter->len * sizeof(unsigned char));
+		list++;
+	}
+
+	stop_progress(&progress);
+}
+
 static int oid_compare(const void *_a, const void *_b)
 {
 	const struct object_id *a = (const struct object_id *)_a;
@@ -1023,6 +1158,8 @@
 	oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
 	ctx->oids.nr++;
 
+	set_commit_pos(ctx->r, oid);
+
 	return 0;
 }
 
@@ -1139,6 +1276,38 @@
 	stop_progress(&ctx->progress);
 }
 
+static void compute_bloom_filters(struct write_commit_graph_context *ctx)
+{
+	int i;
+	struct progress *progress = NULL;
+	struct commit **sorted_by_pos;
+
+	load_bloom_filters();
+
+	if (ctx->report_progress)
+		progress = start_delayed_progress(
+			_("Computing changed paths Bloom filters"),
+			ctx->commits.nr);
+
+	ALLOC_ARRAY(sorted_by_pos, ctx->commits.nr);
+	COPY_ARRAY(sorted_by_pos, ctx->commits.list, ctx->commits.nr);
+
+	if (ctx->order_by_pack)
+		QSORT(sorted_by_pos, ctx->commits.nr, commit_pos_cmp);
+	else
+		QSORT(sorted_by_pos, ctx->commits.nr, commit_gen_cmp);
+
+	for (i = 0; i < ctx->commits.nr; i++) {
+		struct commit *c = sorted_by_pos[i];
+		struct bloom_filter *filter = get_bloom_filter(ctx->r, c, 1);
+		ctx->total_bloom_filter_data_size += sizeof(unsigned char) * filter->len;
+		display_progress(progress, i + 1);
+	}
+
+	free(sorted_by_pos);
+	stop_progress(&progress);
+}
+
 static int add_ref_to_list(const char *refname,
 			   const struct object_id *oid,
 			   int flags, void *cb_data)
@@ -1149,7 +1318,7 @@
 	return 0;
 }
 
-int write_commit_graph_reachable(const char *obj_dir,
+int write_commit_graph_reachable(struct object_directory *odb,
 				 enum commit_graph_write_flags flags,
 				 const struct split_commit_graph_opts *split_opts)
 {
@@ -1157,7 +1326,7 @@
 	int result;
 
 	for_each_ref(add_ref_to_list, &list);
-	result = write_commit_graph(obj_dir, NULL, &list,
+	result = write_commit_graph(odb, NULL, &list,
 				    flags, split_opts);
 
 	string_list_clear(&list, 0);
@@ -1172,7 +1341,7 @@
 	struct strbuf packname = STRBUF_INIT;
 	int dirlen;
 
-	strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
+	strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
 	dirlen = packname.len;
 	if (ctx->report_progress) {
 		strbuf_addf(&progress_title,
@@ -1356,22 +1525,23 @@
 	int fd;
 	struct hashfile *f;
 	struct lock_file lk = LOCK_INIT;
-	uint32_t chunk_ids[6];
-	uint64_t chunk_offsets[6];
+	uint32_t chunk_ids[MAX_NUM_CHUNKS + 1];
+	uint64_t chunk_offsets[MAX_NUM_CHUNKS + 1];
 	const unsigned hashsz = the_hash_algo->rawsz;
 	struct strbuf progress_title = STRBUF_INIT;
 	int num_chunks = 3;
 	struct object_id file_hash;
+	struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
 
 	if (ctx->split) {
 		struct strbuf tmp_file = STRBUF_INIT;
 
 		strbuf_addf(&tmp_file,
 			    "%s/info/commit-graphs/tmp_graph_XXXXXX",
-			    ctx->obj_dir);
+			    ctx->odb->path);
 		ctx->graph_name = strbuf_detach(&tmp_file, NULL);
 	} else {
-		ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
+		ctx->graph_name = get_commit_graph_filename(ctx->odb);
 	}
 
 	if (safe_create_leading_directories(ctx->graph_name)) {
@@ -1382,7 +1552,7 @@
 	}
 
 	if (ctx->split) {
-		char *lock_name = get_chain_filename(ctx->obj_dir);
+		char *lock_name = get_chain_filename(ctx->odb);
 
 		hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
 
@@ -1406,6 +1576,12 @@
 		chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
 		num_chunks++;
 	}
+	if (ctx->changed_paths) {
+		chunk_ids[num_chunks] = GRAPH_CHUNKID_BLOOMINDEXES;
+		num_chunks++;
+		chunk_ids[num_chunks] = GRAPH_CHUNKID_BLOOMDATA;
+		num_chunks++;
+	}
 	if (ctx->num_commit_graphs_after > 1) {
 		chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
 		num_chunks++;
@@ -1424,6 +1600,15 @@
 						4 * ctx->num_extra_edges;
 		num_chunks++;
 	}
+	if (ctx->changed_paths) {
+		chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
+						sizeof(uint32_t) * ctx->commits.nr;
+		num_chunks++;
+
+		chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
+						sizeof(uint32_t) * 3 + ctx->total_bloom_filter_data_size;
+		num_chunks++;
+	}
 	if (ctx->num_commit_graphs_after > 1) {
 		chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
 						hashsz * (ctx->num_commit_graphs_after - 1);
@@ -1461,6 +1646,10 @@
 	write_graph_chunk_data(f, hashsz, ctx);
 	if (ctx->num_extra_edges)
 		write_graph_chunk_extra_edges(f, ctx);
+	if (ctx->changed_paths) {
+		write_graph_chunk_bloom_indexes(f, ctx);
+		write_graph_chunk_bloom_data(f, ctx, &bloom_settings);
+	}
 	if (ctx->num_commit_graphs_after > 1 &&
 	    write_graph_chunk_base(f, ctx)) {
 		return -1;
@@ -1470,7 +1659,7 @@
 
 	if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
 		char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
-		char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
+		char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
 
 		free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
 		free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
@@ -1506,12 +1695,12 @@
 				}
 			}
 		} else {
-			char *graph_name = get_commit_graph_filename(ctx->obj_dir);
+			char *graph_name = get_commit_graph_filename(ctx->odb);
 			unlink(graph_name);
 		}
 
 		ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
-		final_graph_name = get_split_graph_filename(ctx->obj_dir,
+		final_graph_name = get_split_graph_filename(ctx->odb,
 					ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
 
@@ -1539,36 +1728,42 @@
 
 	int max_commits = 0;
 	int size_mult = 2;
+	enum commit_graph_split_flags flags = COMMIT_GRAPH_SPLIT_MERGE_AUTO;
 
 	if (ctx->split_opts) {
 		max_commits = ctx->split_opts->max_commits;
 
 		if (ctx->split_opts->size_multiple)
 			size_mult = ctx->split_opts->size_multiple;
+
+		flags = ctx->split_opts->flags;
 	}
 
 	g = ctx->r->objects->commit_graph;
 	num_commits = ctx->commits.nr;
 	ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
 
-	while (g && (g->num_commits <= size_mult * num_commits ||
-		    (max_commits && num_commits > max_commits))) {
-		if (strcmp(g->obj_dir, ctx->obj_dir))
-			break;
+	if (flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED) {
+		while (g && (g->num_commits <= size_mult * num_commits ||
+			    (max_commits && num_commits > max_commits) ||
+			    (flags == COMMIT_GRAPH_SPLIT_MERGE_REQUIRED))) {
+			if (g->odb != ctx->odb)
+				break;
 
-		num_commits += g->num_commits;
-		g = g->base_graph;
+			num_commits += g->num_commits;
+			g = g->base_graph;
 
-		ctx->num_commit_graphs_after--;
+			ctx->num_commit_graphs_after--;
+		}
 	}
 
 	ctx->new_base_graph = g;
 
 	if (ctx->num_commit_graphs_after == 2) {
-		char *old_graph_name = get_commit_graph_filename(g->obj_dir);
+		char *old_graph_name = get_commit_graph_filename(g->odb);
 
 		if (!strcmp(g->filename, old_graph_name) &&
-		    strcmp(g->obj_dir, ctx->obj_dir)) {
+		    g->odb != ctx->odb) {
 			ctx->num_commit_graphs_after = 1;
 			ctx->new_base_graph = NULL;
 		}
@@ -1719,13 +1914,13 @@
 	if (ctx->split_opts && ctx->split_opts->expire_time)
 		expire_time -= ctx->split_opts->expire_time;
 	if (!ctx->split) {
-		char *chain_file_name = get_chain_filename(ctx->obj_dir);
+		char *chain_file_name = get_chain_filename(ctx->odb);
 		unlink(chain_file_name);
 		free(chain_file_name);
 		ctx->num_commit_graphs_after = 0;
 	}
 
-	strbuf_addstr(&path, ctx->obj_dir);
+	strbuf_addstr(&path, ctx->odb->path);
 	strbuf_addstr(&path, "/info/commit-graphs");
 	dir = opendir(path.buf);
 
@@ -1764,7 +1959,7 @@
 	strbuf_release(&path);
 }
 
-int write_commit_graph(const char *obj_dir,
+int write_commit_graph(struct object_directory *odb,
 		       struct string_list *pack_indexes,
 		       struct string_list *commit_hex,
 		       enum commit_graph_write_flags flags,
@@ -1772,7 +1967,6 @@
 {
 	struct write_commit_graph_context *ctx;
 	uint32_t i, count_distinct = 0;
-	size_t len;
 	int res = 0;
 
 	if (!commit_graph_compatible(the_repository))
@@ -1780,19 +1974,15 @@
 
 	ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
 	ctx->r = the_repository;
-
-	/* normalize object dir with no trailing slash */
-	ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
-	normalize_path_copy(ctx->obj_dir, obj_dir);
-	len = strlen(ctx->obj_dir);
-	if (len && ctx->obj_dir[len - 1] == '/')
-		ctx->obj_dir[len - 1] = 0;
-
+	ctx->odb = odb;
 	ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
 	ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
 	ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
 	ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
 	ctx->split_opts = split_opts;
+	ctx->no_input = flags & COMMIT_GRAPH_WRITE_NO_INPUT ? 1 : 0;
+	ctx->changed_paths = flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS ? 1 : 0;
+	ctx->total_bloom_filter_data_size = 0;
 
 	if (ctx->split) {
 		struct commit_graph *g;
@@ -1824,7 +2014,7 @@
 		ctx->oids.alloc = split_opts->max_commits;
 
 	if (ctx->append) {
-		prepare_commit_graph_one(ctx->r, ctx->obj_dir);
+		prepare_commit_graph_one(ctx->r, ctx->odb);
 		if (ctx->r->objects->commit_graph)
 			ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
 	}
@@ -1842,6 +2032,7 @@
 	}
 
 	if (pack_indexes) {
+		ctx->order_by_pack = 1;
 		if ((res = fill_oids_from_packs(ctx, pack_indexes)))
 			goto cleanup;
 	}
@@ -1851,8 +2042,10 @@
 			goto cleanup;
 	}
 
-	if (!pack_indexes && !commit_hex)
+	if (!ctx->no_input && !pack_indexes && !commit_hex) {
+		ctx->order_by_pack = 1;
 		fill_oids_from_all_packs(ctx);
+	}
 
 	close_reachable(ctx);
 
@@ -1875,7 +2068,7 @@
 		goto cleanup;
 	}
 
-	if (!ctx->commits.nr)
+	if (!ctx->commits.nr && (!ctx->split_opts || ctx->split_opts->flags != COMMIT_GRAPH_SPLIT_MERGE_REQUIRED))
 		goto cleanup;
 
 	if (ctx->split) {
@@ -1887,6 +2080,9 @@
 
 	compute_generation_numbers(ctx);
 
+	if (ctx->changed_paths)
+		compute_bloom_filters(ctx);
+
 	res = write_commit_graph_file(ctx);
 
 	if (ctx->split)
@@ -1898,7 +2094,6 @@
 	free(ctx->graph_name);
 	free(ctx->commits.list);
 	free(ctx->oids.list);
-	free(ctx->obj_dir);
 
 	if (ctx->commit_graph_filenames_after) {
 		for (i = 0; i < ctx->num_commit_graphs_after; i++) {
@@ -2112,6 +2307,7 @@
 		g->data = NULL;
 		close(g->graph_fd);
 	}
+	free(g->bloom_filter_settings);
 	free(g->filename);
 	free(g);
 }
diff --git a/commit-graph.h b/commit-graph.h
index 7f5c933..8f5f62d 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -5,13 +5,16 @@
 #include "repository.h"
 #include "string-list.h"
 #include "cache.h"
+#include "object-store.h"
 
 #define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH"
 #define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD"
+#define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS"
 
 struct commit;
+struct bloom_filter_settings;
 
-char *get_commit_graph_filename(const char *obj_dir);
+char *get_commit_graph_filename(struct object_directory *odb);
 int open_commit_graph(const char *graph_file, int *fd, struct stat *st);
 
 /*
@@ -48,7 +51,7 @@
 	uint32_t num_commits;
 	struct object_id oid;
 	char *filename;
-	const char *obj_dir;
+	struct object_directory *odb;
 
 	uint32_t num_commits_in_base;
 	struct commit_graph *base_graph;
@@ -58,10 +61,16 @@
 	const unsigned char *chunk_commit_data;
 	const unsigned char *chunk_extra_edges;
 	const unsigned char *chunk_base_graphs;
+	const unsigned char *chunk_bloom_indexes;
+	const unsigned char *chunk_bloom_data;
+
+	struct bloom_filter_settings *bloom_filter_settings;
 };
 
-struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st);
-struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir);
+struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
+						 struct object_directory *odb);
+struct commit_graph *read_commit_graph_one(struct repository *r,
+					   struct object_directory *odb);
 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 					size_t graph_size);
 
@@ -76,13 +85,22 @@
 	COMMIT_GRAPH_WRITE_PROGRESS   = (1 << 1),
 	COMMIT_GRAPH_WRITE_SPLIT      = (1 << 2),
 	/* Make sure that each OID in the input is a valid commit OID. */
-	COMMIT_GRAPH_WRITE_CHECK_OIDS = (1 << 3)
+	COMMIT_GRAPH_WRITE_CHECK_OIDS = (1 << 3),
+	COMMIT_GRAPH_WRITE_NO_INPUT   = (1 << 4),
+	COMMIT_GRAPH_WRITE_BLOOM_FILTERS = (1 << 5),
+};
+
+enum commit_graph_split_flags {
+	COMMIT_GRAPH_SPLIT_MERGE_AUTO       = 0,
+	COMMIT_GRAPH_SPLIT_MERGE_REQUIRED   = 1,
+	COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED = 2
 };
 
 struct split_commit_graph_opts {
 	int size_multiple;
 	int max_commits;
 	timestamp_t expire_time;
+	enum commit_graph_split_flags flags;
 };
 
 /*
@@ -91,10 +109,10 @@
  * is not compatible with the commit-graph feature, then the
  * methods will return 0 without writing a commit-graph.
  */
-int write_commit_graph_reachable(const char *obj_dir,
+int write_commit_graph_reachable(struct object_directory *odb,
 				 enum commit_graph_write_flags flags,
 				 const struct split_commit_graph_opts *split_opts);
-int write_commit_graph(const char *obj_dir,
+int write_commit_graph(struct object_directory *odb,
 		       struct string_list *pack_indexes,
 		       struct string_list *commit_hex,
 		       enum commit_graph_write_flags flags,
diff --git a/commit.c b/commit.c
index 434ec03..d6cbdd6 100644
--- a/commit.c
+++ b/commit.c
@@ -927,12 +927,22 @@
 	struct commit_list *bases;
 	int i;
 	struct commit *ret = NULL;
+	char *full_refname;
+
+	switch (dwim_ref(refname, strlen(refname), &oid, &full_refname)) {
+	case 0:
+		die("No such ref: '%s'", refname);
+	case 1:
+		break; /* good */
+	default:
+		die("Ambiguous refname: '%s'", refname);
+	}
 
 	memset(&revs, 0, sizeof(revs));
 	revs.initial = 1;
-	for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
+	for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
 
-	if (!revs.nr && !get_oid(refname, &oid))
+	if (!revs.nr)
 		add_one_commit(&oid, &revs);
 
 	for (i = 0; i < revs.nr; i++)
@@ -958,6 +968,7 @@
 
 cleanup_return:
 	free_commit_list(bases);
+	free(full_refname);
 	return ret;
 }
 
@@ -993,7 +1004,7 @@
 			strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 			inspos += gpg_sig_header_len;
 		}
-		strbuf_insert(buf, inspos++, " ", 1);
+		strbuf_insertstr(buf, inspos++, " ");
 		strbuf_insert(buf, inspos, bol, len);
 		inspos += len;
 		copypos += len;
@@ -1136,21 +1147,23 @@
 	return ret;
 }
 
-void verify_merge_signature(struct commit *commit, int verbosity)
+void verify_merge_signature(struct commit *commit, int verbosity,
+			    int check_trust)
 {
 	char hex[GIT_MAX_HEXSZ + 1];
 	struct signature_check signature_check;
+	int ret;
 	memset(&signature_check, 0, sizeof(signature_check));
 
-	check_commit_signature(commit, &signature_check);
+	ret = check_commit_signature(commit, &signature_check);
 
 	find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
 	switch (signature_check.result) {
 	case 'G':
+		if (ret || (check_trust && signature_check.trust_level < TRUST_MARGINAL))
+			die(_("Commit %s has an untrusted GPG signature, "
+			      "allegedly by %s."), hex, signature_check.signer);
 		break;
-	case 'U':
-		die(_("Commit %s has an untrusted GPG signature, "
-		      "allegedly by %s."), hex, signature_check.signer);
 	case 'B':
 		die(_("Commit %s has a bad GPG signature "
 		      "allegedly by %s."), hex, signature_check.signer);
diff --git a/commit.h b/commit.h
index 221cdaa..008a0fa 100644
--- a/commit.h
+++ b/commit.h
@@ -383,8 +383,18 @@
  * Verify a single commit with check_commit_signature() and die() if it is not
  * a good signature. This isn't really suitable for general use, but is a
  * helper to implement consistent logic for pull/merge --verify-signatures.
+ *
+ * The check_trust parameter is meant for backward-compatibility.  The GPG
+ * interface verifies key trust with a default trust level that is below the
+ * default trust level for merge operations.  Its value should be non-zero if
+ * the user hasn't set a minimum trust level explicitly in their configuration.
+ *
+ * If the user has set a minimum trust level, then that value should be obeyed
+ * and check_trust should be zero, even if the configured trust level is below
+ * the default trust level for merges.
  */
-void verify_merge_signature(struct commit *commit, int verbose);
+void verify_merge_signature(struct commit *commit, int verbose,
+			    int check_trust);
 
 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused);
 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused);
diff --git a/compat/compiler.h b/compat/compiler.h
new file mode 100644
index 0000000..bda5098
--- /dev/null
+++ b/compat/compiler.h
@@ -0,0 +1,24 @@
+#ifndef COMPILER_H
+#define COMPILER_H
+
+#include "git-compat-util.h"
+#include "strbuf.h"
+
+#ifdef __GLIBC__
+#include <gnu/libc-version.h>
+
+static inline void get_compiler_info(struct strbuf *info)
+{
+	strbuf_addf(info, "glibc: %s", gnu_get_libc_version());
+}
+
+#else
+
+static inline void get_compiler_info(struct strbuf *info)
+{
+	strbuf_addstr(info, "get_compiler_info() not implemented");
+}
+
+#endif
+
+#endif /* COMPILER_H */
diff --git a/compat/mingw.c b/compat/mingw.c
index 402c1ad..b523014 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -13,6 +13,19 @@
 
 static const int delay[] = { 0, 1, 10, 20, 40 };
 
+void open_in_gdb(void)
+{
+	static struct child_process cp = CHILD_PROCESS_INIT;
+	extern char *_pgmptr;
+
+	argv_array_pushl(&cp.args, "mintty", "gdb", NULL);
+	argv_array_pushf(&cp.args, "--pid=%d", getpid());
+	cp.clean_on_exit = 1;
+	if (start_command(&cp) < 0)
+		die_errno("Could not start gdb");
+	sleep(1);
+}
+
 int err_win_to_posix(DWORD winerr)
 {
 	int error = ENOSYS;
diff --git a/compat/mingw.h b/compat/mingw.h
index 714bc1d..e6fe810 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -599,6 +599,16 @@
 int main(int argc, const char **argv);
 
 /*
+ * For debugging: if a problem occurs, say, in a Git process that is spawned
+ * from another Git process which in turn is spawned from yet another Git
+ * process, it can be quite daunting to figure out what is going on.
+ *
+ * Call this function to open a new MinTTY (this assumes you are in Git for
+ * Windows' SDK) with a GDB that attaches to the current process right away.
+ */
+extern void open_in_gdb(void);
+
+/*
  * Used by Pthread API implementation for Windows
  */
 int err_win_to_posix(DWORD winerr);
diff --git a/compat/obstack.h b/compat/obstack.h
index 01e7c81..f90a46d 100644
--- a/compat/obstack.h
+++ b/compat/obstack.h
@@ -135,8 +135,10 @@
    alignment relative to 0.  */
 
 #define __PTR_ALIGN(B, P, A)						    \
-  __BPTR_ALIGN (sizeof (PTR_INT_TYPE) < sizeof (void *) ? (B) : (char *) 0, \
-		P, A)
+  (sizeof (PTR_INT_TYPE) < sizeof(void *) ?                                 \
+   __BPTR_ALIGN((B), (P), (A)) :                                            \
+   (void *)__BPTR_ALIGN((PTR_INT_TYPE)(void *)0, (PTR_INT_TYPE)(P), (A))            \
+  )
 
 #include <string.h>
 
diff --git a/compat/regex/regex.h b/compat/regex/regex.h
index 08a2609..2d34128 100644
--- a/compat/regex/regex.h
+++ b/compat/regex/regex.h
@@ -41,6 +41,11 @@
 extern "C" {
 #endif
 
+#define regcomp git_regcomp
+#define regexec git_regexec
+#define regerror git_regerror
+#define regfree git_regfree
+
 /* The following two types have to be signed and unsigned integer type
    wide enough to hold a value of a pointer.  For most ANSI compilers
    ptrdiff_t and size_t should be likely OK.  Still size of these two
diff --git a/compat/terminal.c b/compat/terminal.c
index fa13ee6..35bca03 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -2,6 +2,9 @@
 #include "compat/terminal.h"
 #include "sigchain.h"
 #include "strbuf.h"
+#include "run-command.h"
+#include "string-list.h"
+#include "hashmap.h"
 
 #if defined(HAVE_DEV_TTY) || defined(GIT_WINDOWS_NATIVE)
 
@@ -32,7 +35,7 @@
 	term_fd = -1;
 }
 
-static int disable_echo(void)
+static int disable_bits(tcflag_t bits)
 {
 	struct termios t;
 
@@ -43,7 +46,7 @@
 	old_term = t;
 	sigchain_push_common(restore_term_on_signal);
 
-	t.c_lflag &= ~ECHO;
+	t.c_lflag &= ~bits;
 	if (!tcsetattr(term_fd, TCSAFLUSH, &t))
 		return 0;
 
@@ -53,17 +56,44 @@
 	return -1;
 }
 
+static int disable_echo(void)
+{
+	return disable_bits(ECHO);
+}
+
+static int enable_non_canonical(void)
+{
+	return disable_bits(ICANON | ECHO);
+}
+
 #elif defined(GIT_WINDOWS_NATIVE)
 
 #define INPUT_PATH "CONIN$"
 #define OUTPUT_PATH "CONOUT$"
 #define FORCE_TEXT "t"
 
+static int use_stty = 1;
+static struct string_list stty_restore = STRING_LIST_INIT_DUP;
 static HANDLE hconin = INVALID_HANDLE_VALUE;
 static DWORD cmode;
 
 static void restore_term(void)
 {
+	if (use_stty) {
+		int i;
+		struct child_process cp = CHILD_PROCESS_INIT;
+
+		if (stty_restore.nr == 0)
+			return;
+
+		argv_array_push(&cp.args, "stty");
+		for (i = 0; i < stty_restore.nr; i++)
+			argv_array_push(&cp.args, stty_restore.items[i].string);
+		run_command(&cp);
+		string_list_clear(&stty_restore, 0);
+		return;
+	}
+
 	if (hconin == INVALID_HANDLE_VALUE)
 		return;
 
@@ -72,8 +102,39 @@
 	hconin = INVALID_HANDLE_VALUE;
 }
 
-static int disable_echo(void)
+static int disable_bits(DWORD bits)
 {
+	if (use_stty) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+
+		argv_array_push(&cp.args, "stty");
+
+		if (bits & ENABLE_LINE_INPUT) {
+			string_list_append(&stty_restore, "icanon");
+			argv_array_push(&cp.args, "-icanon");
+		}
+
+		if (bits & ENABLE_ECHO_INPUT) {
+			string_list_append(&stty_restore, "echo");
+			argv_array_push(&cp.args, "-echo");
+		}
+
+		if (bits & ENABLE_PROCESSED_INPUT) {
+			string_list_append(&stty_restore, "-ignbrk");
+			string_list_append(&stty_restore, "intr");
+			string_list_append(&stty_restore, "^c");
+			argv_array_push(&cp.args, "ignbrk");
+			argv_array_push(&cp.args, "intr");
+			argv_array_push(&cp.args, "");
+		}
+
+		if (run_command(&cp) == 0)
+			return 0;
+
+		/* `stty` could not be executed; access the Console directly */
+		use_stty = 0;
+	}
+
 	hconin = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE,
 	    FILE_SHARE_READ, NULL, OPEN_EXISTING,
 	    FILE_ATTRIBUTE_NORMAL, NULL);
@@ -82,7 +143,7 @@
 
 	GetConsoleMode(hconin, &cmode);
 	sigchain_push_common(restore_term_on_signal);
-	if (!SetConsoleMode(hconin, cmode & (~ENABLE_ECHO_INPUT))) {
+	if (!SetConsoleMode(hconin, cmode & ~bits)) {
 		CloseHandle(hconin);
 		hconin = INVALID_HANDLE_VALUE;
 		return -1;
@@ -91,6 +152,47 @@
 	return 0;
 }
 
+static int disable_echo(void)
+{
+	return disable_bits(ENABLE_ECHO_INPUT);
+}
+
+static int enable_non_canonical(void)
+{
+	return disable_bits(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT);
+}
+
+/*
+ * Override `getchar()`, as the default implementation does not use
+ * `ReadFile()`.
+ *
+ * This poses a problem when we want to see whether the standard
+ * input has more characters, as the default of Git for Windows is to start the
+ * Bash in a MinTTY, which uses a named pipe to emulate a pty, in which case
+ * our `poll()` emulation calls `PeekNamedPipe()`, which seems to require
+ * `ReadFile()` to be called first to work properly (it only reports 0
+ * available bytes, otherwise).
+ *
+ * So let's just override `getchar()` with a version backed by `ReadFile()` and
+ * go our merry ways from here.
+ */
+static int mingw_getchar(void)
+{
+	DWORD read = 0;
+	unsigned char ch;
+
+	if (!ReadFile(GetStdHandle(STD_INPUT_HANDLE), &ch, 1, &read, NULL))
+		return EOF;
+
+	if (!read) {
+		error("Unexpected 0 read");
+		return EOF;
+	}
+
+	return ch;
+}
+#define getchar mingw_getchar
+
 #endif
 
 #ifndef FORCE_TEXT
@@ -137,6 +239,126 @@
 	return buf.buf;
 }
 
+/*
+ * The `is_known_escape_sequence()` function returns 1 if the passed string
+ * corresponds to an Escape sequence that the terminal capabilities contains.
+ *
+ * To avoid depending on ncurses or other platform-specific libraries, we rely
+ * on the presence of the `infocmp` executable to do the job for us (failing
+ * silently if the program is not available or refused to run).
+ */
+struct escape_sequence_entry {
+	struct hashmap_entry entry;
+	char sequence[FLEX_ARRAY];
+};
+
+static int sequence_entry_cmp(const void *hashmap_cmp_fn_data,
+			      const struct escape_sequence_entry *e1,
+			      const struct escape_sequence_entry *e2,
+			      const void *keydata)
+{
+	return strcmp(e1->sequence, keydata ? keydata : e2->sequence);
+}
+
+static int is_known_escape_sequence(const char *sequence)
+{
+	static struct hashmap sequences;
+	static int initialized;
+
+	if (!initialized) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		struct strbuf buf = STRBUF_INIT;
+		char *p, *eol;
+
+		hashmap_init(&sequences, (hashmap_cmp_fn)sequence_entry_cmp,
+			     NULL, 0);
+
+		argv_array_pushl(&cp.args, "infocmp", "-L", "-1", NULL);
+		if (pipe_command(&cp, NULL, 0, &buf, 0, NULL, 0))
+			strbuf_setlen(&buf, 0);
+
+		for (eol = p = buf.buf; *p; p = eol + 1) {
+			p = strchr(p, '=');
+			if (!p)
+				break;
+			p++;
+			eol = strchrnul(p, '\n');
+
+			if (starts_with(p, "\\E")) {
+				char *comma = memchr(p, ',', eol - p);
+				struct escape_sequence_entry *e;
+
+				p[0] = '^';
+				p[1] = '[';
+				FLEX_ALLOC_MEM(e, sequence, p, comma - p);
+				hashmap_entry_init(&e->entry,
+						   strhash(e->sequence));
+				hashmap_add(&sequences, &e->entry);
+			}
+			if (!*eol)
+				break;
+		}
+		initialized = 1;
+	}
+
+	return !!hashmap_get_from_hash(&sequences, strhash(sequence), sequence);
+}
+
+int read_key_without_echo(struct strbuf *buf)
+{
+	static int warning_displayed;
+	int ch;
+
+	if (warning_displayed || enable_non_canonical() < 0) {
+		if (!warning_displayed) {
+			warning("reading single keystrokes not supported on "
+				"this platform; reading line instead");
+			warning_displayed = 1;
+		}
+
+		return strbuf_getline(buf, stdin);
+	}
+
+	strbuf_reset(buf);
+	ch = getchar();
+	if (ch == EOF) {
+		restore_term();
+		return EOF;
+	}
+	strbuf_addch(buf, ch);
+
+	if (ch == '\033' /* ESC */) {
+		/*
+		 * We are most likely looking at an Escape sequence. Let's try
+		 * to read more bytes, waiting at most half a second, assuming
+		 * that the sequence is complete if we did not receive any byte
+		 * within that time.
+		 *
+		 * Start by replacing the Escape byte with ^[ */
+		strbuf_splice(buf, buf->len - 1, 1, "^[", 2);
+
+		/*
+		 * Query the terminal capabilities once about all the Escape
+		 * sequences it knows about, so that we can avoid waiting for
+		 * half a second when we know that the sequence is complete.
+		 */
+		while (!is_known_escape_sequence(buf->buf)) {
+			struct pollfd pfd = { .fd = 0, .events = POLLIN };
+
+			if (poll(&pfd, 1, 500) < 1)
+				break;
+
+			ch = getchar();
+			if (ch == EOF)
+				return 0;
+			strbuf_addch(buf, ch);
+		}
+	}
+
+	restore_term();
+	return 0;
+}
+
 #else
 
 char *git_terminal_prompt(const char *prompt, int echo)
@@ -144,4 +366,23 @@
 	return getpass(prompt);
 }
 
+int read_key_without_echo(struct strbuf *buf)
+{
+	static int warning_displayed;
+	const char *res;
+
+	if (!warning_displayed) {
+		warning("reading single keystrokes not supported on this "
+			"platform; reading line instead");
+		warning_displayed = 1;
+	}
+
+	res = getpass("");
+	strbuf_reset(buf);
+	if (!res)
+		return EOF;
+	strbuf_addstr(buf, res);
+	return 0;
+}
+
 #endif
diff --git a/compat/terminal.h b/compat/terminal.h
index 97db7cd..a9d52b8 100644
--- a/compat/terminal.h
+++ b/compat/terminal.h
@@ -3,4 +3,7 @@
 
 char *git_terminal_prompt(const char *prompt, int echo);
 
+/* Read a single keystroke, without echoing it to the terminal */
+int read_key_without_echo(struct strbuf *buf);
+
 #endif /* COMPAT_TERMINAL_H */
diff --git a/compat/vcbuild/scripts/clink.pl b/compat/vcbuild/scripts/clink.pl
index ec95a3b..d9f71b7 100755
--- a/compat/vcbuild/scripts/clink.pl
+++ b/compat/vcbuild/scripts/clink.pl
@@ -45,9 +45,9 @@
 	} elsif ("$arg" eq "-liconv") {
 		push(@args, "libiconv.lib");
 	} elsif ("$arg" eq "-lcrypto") {
-		push(@args, "libeay32.lib");
+		push(@args, "libcrypto.lib");
 	} elsif ("$arg" eq "-lssl") {
-		push(@args, "ssleay32.lib");
+		push(@args, "libssl.lib");
 	} elsif ("$arg" eq "-lcurl") {
 		my $lib = "";
 		# Newer vcpkg definitions call this libcurl_imp.lib; Do we
diff --git a/config.c b/config.c
index d75f88c..d17d2bd 100644
--- a/config.c
+++ b/config.c
@@ -204,7 +204,7 @@
 		strbuf_splice(pat, 0, 1, path.buf, slash - path.buf);
 		prefix = slash - path.buf + 1 /* slash */;
 	} else if (!is_absolute_path(pat->buf))
-		strbuf_insert(pat, 0, "**/", 3);
+		strbuf_insertstr(pat, 0, "**/");
 
 	add_trailing_starstar_for_dir(pat);
 
@@ -1702,6 +1702,7 @@
 	char *xdg_config = xdg_config_home("config");
 	char *user_config = expand_user_path("~/.gitconfig", 0);
 	char *repo_config;
+	enum config_scope prev_parsing_scope = current_parsing_scope;
 
 	if (opts->commondir)
 		repo_config = mkpathdup("%s/config", opts->commondir);
@@ -1724,15 +1725,12 @@
 	if (user_config && !access_or_die(user_config, R_OK, ACCESS_EACCES_OK))
 		ret += git_config_from_file(fn, user_config, data);
 
-	current_parsing_scope = CONFIG_SCOPE_REPO;
+	current_parsing_scope = CONFIG_SCOPE_LOCAL;
 	if (!opts->ignore_repo && repo_config &&
 	    !access_or_die(repo_config, R_OK, 0))
 		ret += git_config_from_file(fn, repo_config, data);
 
-	/*
-	 * Note: this should have a new scope, CONFIG_SCOPE_WORKTREE.
-	 * But let's not complicate things before it's actually needed.
-	 */
+	current_parsing_scope = CONFIG_SCOPE_WORKTREE;
 	if (!opts->ignore_worktree && repository_format_worktree_config) {
 		char *path = git_pathdup("config.worktree");
 		if (!access_or_die(path, R_OK, 0))
@@ -1740,11 +1738,11 @@
 		free(path);
 	}
 
-	current_parsing_scope = CONFIG_SCOPE_CMDLINE;
+	current_parsing_scope = CONFIG_SCOPE_COMMAND;
 	if (!opts->ignore_cmdline && git_config_from_parameters(fn, data) < 0)
 		die(_("unable to parse command-line config"));
 
-	current_parsing_scope = CONFIG_SCOPE_UNKNOWN;
+	current_parsing_scope = prev_parsing_scope;
 	free(xdg_config);
 	free(user_config);
 	free(repo_config);
@@ -1765,6 +1763,9 @@
 		data = &inc;
 	}
 
+	if (config_source)
+		current_parsing_scope = config_source->scope;
+
 	/*
 	 * If we have a specific filename, use it. Otherwise, follow the
 	 * regular lookup sequence.
@@ -3297,6 +3298,26 @@
 	}
 }
 
+const char *config_scope_name(enum config_scope scope)
+{
+	switch (scope) {
+	case CONFIG_SCOPE_SYSTEM:
+		return "system";
+	case CONFIG_SCOPE_GLOBAL:
+		return "global";
+	case CONFIG_SCOPE_LOCAL:
+		return "local";
+	case CONFIG_SCOPE_WORKTREE:
+		return "worktree";
+	case CONFIG_SCOPE_COMMAND:
+		return "command";
+	case CONFIG_SCOPE_SUBMODULE:
+		return "submodule";
+	default:
+		return "unknown";
+	}
+}
+
 const char *current_config_name(void)
 {
 	const char *name;
@@ -3317,6 +3338,14 @@
 		return current_parsing_scope;
 }
 
+int current_config_line(void)
+{
+	if (current_config_kvi)
+		return current_config_kvi->linenr;
+	else
+		return cf->linenr;
+}
+
 int lookup_config(const char **mapping, int nr_mapping, const char *var)
 {
 	int i;
diff --git a/config.h b/config.h
index 91fd4c5..9b3773f 100644
--- a/config.h
+++ b/config.h
@@ -35,10 +35,22 @@
 
 #define CONFIG_REGEX_NONE ((void *)1)
 
+enum config_scope {
+	CONFIG_SCOPE_UNKNOWN = 0,
+	CONFIG_SCOPE_SYSTEM,
+	CONFIG_SCOPE_GLOBAL,
+	CONFIG_SCOPE_LOCAL,
+	CONFIG_SCOPE_WORKTREE,
+	CONFIG_SCOPE_COMMAND,
+	CONFIG_SCOPE_SUBMODULE,
+};
+const char *config_scope_name(enum config_scope scope);
+
 struct git_config_source {
 	unsigned int use_stdin:1;
 	const char *file;
 	const char *blob;
+	enum config_scope scope;
 };
 
 enum config_origin_type {
@@ -294,17 +306,10 @@
 
 int git_config_parse_parameter(const char *, config_fn_t fn, void *data);
 
-enum config_scope {
-	CONFIG_SCOPE_UNKNOWN = 0,
-	CONFIG_SCOPE_SYSTEM,
-	CONFIG_SCOPE_GLOBAL,
-	CONFIG_SCOPE_REPO,
-	CONFIG_SCOPE_CMDLINE,
-};
-
 enum config_scope current_config_scope(void);
 const char *current_config_origin_type(void);
 const char *current_config_name(void);
+int current_config_line(void);
 
 /**
  * Include Directives
diff --git a/connected.c b/connected.c
index c337f5f..7e9bd1b 100644
--- a/connected.c
+++ b/connected.c
@@ -52,19 +52,28 @@
 		strbuf_release(&idx_file);
 	}
 
-	if (opt->check_refs_only) {
+	if (opt->check_refs_are_promisor_objects_only) {
 		/*
 		 * For partial clones, we don't want to have to do a regular
 		 * connectivity check because we have to enumerate and exclude
 		 * all promisor objects (slow), and then the connectivity check
 		 * itself becomes a no-op because in a partial clone every
 		 * object is a promisor object. Instead, just make sure we
-		 * received the objects pointed to by each wanted ref.
+		 * received, in a promisor packfile, the objects pointed to by
+		 * each wanted ref.
 		 */
 		do {
-			if (!repo_has_object_file_with_flags(the_repository, &oid,
-							     OBJECT_INFO_SKIP_FETCH_OBJECT))
-				return 1;
+			struct packed_git *p;
+
+			for (p = get_all_packs(the_repository); p; p = p->next) {
+				if (!p->pack_promisor)
+					continue;
+				if (find_pack_entry_one(oid.hash, p))
+					goto promisor_pack_found;
+			}
+			return 1;
+promisor_pack_found:
+			;
 		} while (!fn(cb_data, &oid));
 		return 0;
 	}
diff --git a/connected.h b/connected.h
index ce2e7d8..eba5c26 100644
--- a/connected.h
+++ b/connected.h
@@ -48,12 +48,13 @@
 	unsigned is_deepening_fetch : 1;
 
 	/*
-	 * If non-zero, only check the top-level objects referenced by the
-	 * wanted refs (passed in as cb_data). This is useful for partial
-	 * clones, where enumerating and excluding all promisor objects is very
-	 * slow and the commit-walk itself becomes a no-op.
+	 * If non-zero, only check that the top-level objects referenced by the
+	 * wanted refs (passed in as cb_data) are promisor objects. This is
+	 * useful for partial clones, where enumerating and excluding all
+	 * promisor objects is very slow and the commit-walk itself becomes a
+	 * no-op.
 	 */
-	unsigned check_refs_only : 1;
+	unsigned check_refs_are_promisor_objects_only : 1;
 };
 
 #define CHECK_CONNECTED_INIT { 0 }
diff --git a/contrib/buildsystems/engine.pl b/contrib/buildsystems/engine.pl
index fba8a3f..0709785 100755
--- a/contrib/buildsystems/engine.pl
+++ b/contrib/buildsystems/engine.pl
@@ -343,9 +343,9 @@
         } elsif ("$part" eq "-lz") {
             push(@libs, "zlib.lib");
         } elsif ("$part" eq "-lcrypto") {
-            push(@libs, "libeay32.lib");
+            push(@libs, "libcrypto.lib");
         } elsif ("$part" eq "-lssl") {
-            push(@libs, "ssleay32.lib");
+            push(@libs, "libssl.lib");
         } elsif ("$part" eq "-lcurl") {
             push(@libs, "libcurl.lib");
         } elsif ("$part" eq "-lexpat") {
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index e4d9ff4..1aac5a5 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1069,15 +1069,32 @@
 	done
 }
 
-# __git_find_on_cmdline requires 1 argument
+# Check whether one of the given words is present on the command line,
+# and print the first word found.
+#
+# Usage: __git_find_on_cmdline [<option>]... "<wordlist>"
+# --show-idx: Optionally show the index of the found word in the $words array.
 __git_find_on_cmdline ()
 {
-	local word subcommand c=1
+	local word c=1 show_idx
+
+	while test $# -gt 1; do
+		case "$1" in
+		--show-idx)	show_idx=y ;;
+		*)		return 1 ;;
+		esac
+		shift
+	done
+	local wordlist="$1"
+
 	while [ $c -lt $cword ]; do
-		word="${words[c]}"
-		for subcommand in $1; do
-			if [ "$subcommand" = "$word" ]; then
-				echo "$subcommand"
+		for word in $wordlist; do
+			if [ "$word" = "${words[c]}" ]; then
+				if [ -n "$show_idx" ]; then
+					echo "$c $word"
+				else
+					echo "$word"
+				fi
 				return
 			fi
 		done
@@ -2718,6 +2735,27 @@
 	__git_complete_revlist
 }
 
+_git_sparse_checkout ()
+{
+	local subcommands="list init set disable"
+	local subcommand="$(__git_find_on_cmdline "$subcommands")"
+	if [ -z "$subcommand" ]; then
+		__gitcomp "$subcommands"
+		return
+	fi
+
+	case "$subcommand,$cur" in
+	init,--*)
+		__gitcomp "--cone"
+		;;
+	set,--*)
+		__gitcomp "--stdin"
+		;;
+	*)
+		;;
+	esac
+}
+
 _git_stash ()
 {
 	local save_opts='--all --keep-index --no-keep-index --quiet --patch --include-untracked'
@@ -2969,33 +3007,83 @@
 	_git_log
 }
 
+__git_complete_worktree_paths ()
+{
+	local IFS=$'\n'
+	__gitcomp_nl "$(git worktree list --porcelain |
+		# Skip the first entry: it's the path of the main worktree,
+		# which can't be moved, removed, locked, etc.
+		sed -n -e '2,$ s/^worktree //p')"
+}
+
 _git_worktree ()
 {
 	local subcommands="add list lock move prune remove unlock"
-	local subcommand="$(__git_find_on_cmdline "$subcommands")"
-	if [ -z "$subcommand" ]; then
+	local subcommand subcommand_idx
+
+	subcommand="$(__git_find_on_cmdline --show-idx "$subcommands")"
+	subcommand_idx="${subcommand% *}"
+	subcommand="${subcommand#* }"
+
+	case "$subcommand,$cur" in
+	,*)
 		__gitcomp "$subcommands"
-	else
-		case "$subcommand,$cur" in
-		add,--*)
-			__gitcomp_builtin worktree_add
+		;;
+	*,--*)
+		__gitcomp_builtin worktree_$subcommand
+		;;
+	add,*)	# usage: git worktree add [<options>] <path> [<commit-ish>]
+		# Here we are not completing an --option, it's either the
+		# path or a ref.
+		case "$prev" in
+		-b|-B)	# Complete refs for branch to be created/reseted.
+			__git_complete_refs
 			;;
-		list,--*)
-			__gitcomp_builtin worktree_list
+		-*)	# The previous word is an -o|--option without an
+			# unstuck argument: have to complete the path for
+			# the new worktree, so don't list anything, but let
+			# Bash fall back to filename completion.
 			;;
-		lock,--*)
-			__gitcomp_builtin worktree_lock
-			;;
-		prune,--*)
-			__gitcomp_builtin worktree_prune
-			;;
-		remove,--*)
-			__gitcomp "--force"
-			;;
-		*)
+		*)	# The previous word is not an --option, so it must
+			# be either the 'add' subcommand, the unstuck
+			# argument of an option (e.g. branch for -b|-B), or
+			# the path for the new worktree.
+			if [ $cword -eq $((subcommand_idx+1)) ]; then
+				# Right after the 'add' subcommand: have to
+				# complete the path, so fall back to Bash
+				# filename completion.
+				:
+			else
+				case "${words[cword-2]}" in
+				-b|-B)	# After '-b <branch>': have to
+					# complete the path, so fall back
+					# to Bash filename completion.
+					;;
+				*)	# After the path: have to complete
+					# the ref to be checked out.
+					__git_complete_refs
+					;;
+				esac
+			fi
 			;;
 		esac
-	fi
+		;;
+	lock,*|remove,*|unlock,*)
+		__git_complete_worktree_paths
+		;;
+	move,*)
+		if [ $cword -eq $((subcommand_idx+1)) ]; then
+			# The first parameter must be an existing working
+			# tree to be moved.
+			__git_complete_worktree_paths
+		else
+			# The second parameter is the destination: it could
+			# be any path, so don't list anything, but let Bash
+			# fall back to filename completion.
+			:
+		fi
+		;;
+	esac
 }
 
 __git_complete_common () {
diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index 1d510cd..014cd7c 100644
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -429,11 +429,7 @@
 		__git_eread "$g/rebase-merge/head-name" b
 		__git_eread "$g/rebase-merge/msgnum" step
 		__git_eread "$g/rebase-merge/end" total
-		if [ -f "$g/rebase-merge/interactive" ]; then
-			r="|REBASE-i"
-		else
-			r="|REBASE-m"
-		fi
+		r="|REBASE"
 	else
 		if [ -d "$g/rebase-apply" ]; then
 			__git_eread "$g/rebase-apply/next" step
diff --git a/contrib/credential/netrc/.gitignore b/contrib/credential/netrc/.gitignore
new file mode 100644
index 0000000..d41cdde
--- /dev/null
+++ b/contrib/credential/netrc/.gitignore
@@ -0,0 +1 @@
+git-credential-netrc
diff --git a/contrib/credential/netrc/Makefile b/contrib/credential/netrc/Makefile
index 6174e3b..c284fb8 100644
--- a/contrib/credential/netrc/Makefile
+++ b/contrib/credential/netrc/Makefile
@@ -1,8 +1,30 @@
 # The default target of this Makefile is...
 all::
 
-test:
+SCRIPT_PERL = git-credential-netrc.perl
+GIT_ROOT_DIR = ../../..
+HERE = contrib/credential/netrc
+
+SCRIPT_PERL_FULL = $(patsubst %,$(HERE)/%,$(SCRIPT_PERL))
+
+all:: build
+
+build:
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
+                build-perl-script
+
+install: build
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
+                install-perl-script
+
+clean:
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
+                clean-perl-script
+
+test: build
 	./t-git-credential-netrc.sh
 
-testverbose:
+testverbose: build
 	./t-git-credential-netrc.sh -d -v
+
+.PHONY: all build install clean test testverbose
diff --git a/contrib/credential/netrc/git-credential-netrc b/contrib/credential/netrc/git-credential-netrc.perl
similarity index 98%
rename from contrib/credential/netrc/git-credential-netrc
rename to contrib/credential/netrc/git-credential-netrc.perl
index ebfc123..bc57cc6 100755
--- a/contrib/credential/netrc/git-credential-netrc
+++ b/contrib/credential/netrc/git-credential-netrc.perl
@@ -423,7 +423,7 @@
 	# load settings from git config
 	my $options = shift;
 	# set from command argument, gpg.program option, or default to gpg
-	$options->{'gpg'} //= Git->repository()->config('gpg.program')
+	$options->{'gpg'} //= Git::config('gpg.program')
 	                  // 'gpg';
 	log_verbose("using $options{'gpg'} for GPG operations");
 }
diff --git a/convert.c b/convert.c
index 797e0bd..5ead3ce 100644
--- a/convert.c
+++ b/convert.c
@@ -1146,7 +1146,7 @@
 	/* are we "faking" in place editing ? */
 	if (src == buf->buf)
 		to_free = strbuf_detach(buf, NULL);
-	hash_object_file(src, len, "blob", &oid);
+	hash_object_file(the_hash_algo, src, len, "blob", &oid);
 
 	strbuf_grow(buf, len + cnt * (the_hash_algo->hexsz + 3));
 	for (;;) {
@@ -1940,7 +1940,7 @@
  * the contents cannot be filtered without reading the whole thing
  * in-core.
  *
- * Note that you would be crazy to set CRLF, smuge/clean or ident to a
+ * Note that you would be crazy to set CRLF, smudge/clean or ident to a
  * large binary blob you would want us not to slurp into the memory!
  */
 struct stream_filter *get_stream_filter(const struct index_state *istate,
diff --git a/credential.h b/credential.h
index 5772d50..a5a3ee9 100644
--- a/credential.h
+++ b/credential.h
@@ -90,96 +90,6 @@
  * return status;
  * }
  * -----------------------------------------------------------------------
- *
- * Credential Helpers
- * ------------------
- *
- * Credential helpers are programs executed by Git to fetch or save
- * credentials from and to long-term storage (where "long-term" is simply
- * longer than a single Git process; e.g., credentials may be stored
- * in-memory for a few minutes, or indefinitely on disk).
- *
- * Each helper is specified by a single string in the configuration
- * variable `credential.helper` (and others, see Documentation/git-config.txt).
- * The string is transformed by Git into a command to be executed using
- * these rules:
- *
- *   1. If the helper string begins with "!", it is considered a shell
- *      snippet, and everything after the "!" becomes the command.
- *
- *   2. Otherwise, if the helper string begins with an absolute path, the
- *      verbatim helper string becomes the command.
- *
- *   3. Otherwise, the string "git credential-" is prepended to the helper
- *      string, and the result becomes the command.
- *
- * The resulting command then has an "operation" argument appended to it
- * (see below for details), and the result is executed by the shell.
- *
- * Here are some example specifications:
- *
- * ----------------------------------------------------
- * # run "git credential-foo"
- * foo
- *
- * # same as above, but pass an argument to the helper
- * foo --bar=baz
- *
- * # the arguments are parsed by the shell, so use shell
- * # quoting if necessary
- * foo --bar="whitespace arg"
- *
- * # you can also use an absolute path, which will not use the git wrapper
- * /path/to/my/helper --with-arguments
- *
- * # or you can specify your own shell snippet
- * !f() { echo "password=`cat $HOME/.secret`"; }; f
- * ----------------------------------------------------
- *
- * Generally speaking, rule (3) above is the simplest for users to specify.
- * Authors of credential helpers should make an effort to assist their
- * users by naming their program "git-credential-$NAME", and putting it in
- * the $PATH or $GIT_EXEC_PATH during installation, which will allow a user
- * to enable it with `git config credential.helper $NAME`.
- *
- * When a helper is executed, it will have one "operation" argument
- * appended to its command line, which is one of:
- *
- * `get`::
- *
- * 	Return a matching credential, if any exists.
- *
- * `store`::
- *
- * 	Store the credential, if applicable to the helper.
- *
- * `erase`::
- *
- * 	Remove a matching credential, if any, from the helper's storage.
- *
- * The details of the credential will be provided on the helper's stdin
- * stream. The exact format is the same as the input/output format of the
- * `git credential` plumbing command (see the section `INPUT/OUTPUT
- * FORMAT` in Documentation/git-credential.txt for a detailed specification).
- *
- * For a `get` operation, the helper should produce a list of attributes
- * on stdout in the same format. A helper is free to produce a subset, or
- * even no values at all if it has nothing useful to provide. Any provided
- * attributes will overwrite those already known about by Git.  If a helper
- * outputs a `quit` attribute with a value of `true` or `1`, no further
- * helpers will be consulted, nor will the user be prompted (if no
- * credential has been provided, the operation will then fail).
- *
- * For a `store` or `erase` operation, the helper's output is ignored.
- * If it fails to perform the requested operation, it may complain to
- * stderr to inform the user. If it does not support the requested
- * operation (e.g., a read-only store), it should silently ignore the
- * request.
- *
- * If a helper receives any other operation, it should silently ignore the
- * request. This leaves room for future operations to be added (older
- * helpers will just ignore the new requests).
- *
  */
 
 
diff --git a/csum-file.h b/csum-file.h
index a98b1ee..f9cbd31 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -42,6 +42,15 @@
 void crc32_begin(struct hashfile *);
 uint32_t crc32_end(struct hashfile *);
 
+/*
+ * Returns the total number of bytes fed to the hashfile so far (including ones
+ * that have not been written out to the descriptor yet).
+ */
+static inline off_t hashfile_total(struct hashfile *f)
+{
+	return f->total + f->offset;
+}
+
 static inline void hashwrite_u8(struct hashfile *f, uint8_t data)
 {
 	hashwrite(f, &data, sizeof(data));
diff --git a/diff.c b/diff.c
index 8e2914c..f2cfbf2 100644
--- a/diff.c
+++ b/diff.c
@@ -414,14 +414,6 @@
 		return 0;
 	}
 
-	if (!strcmp(var, "diff.wserrorhighlight")) {
-		int val = parse_ws_error_highlight(value);
-		if (val < 0)
-			return -1;
-		ws_error_highlight_default = val;
-		return 0;
-	}
-
 	if (git_color_config(var, value, cb) < 0)
 		return -1;
 
@@ -450,6 +442,14 @@
 		return color_parse(value, diff_colors[slot]);
 	}
 
+	if (!strcmp(var, "diff.wserrorhighlight")) {
+		int val = parse_ws_error_highlight(value);
+		if (val < 0)
+			return -1;
+		ws_error_highlight_default = val;
+		return 0;
+	}
+
 	/* like GNU diff's --suppress-blank-empty option  */
 	if (!strcmp(var, "diff.suppressblankempty") ||
 			/* for backwards compatibility */
@@ -4024,7 +4024,7 @@
 				return 0;
 			}
 		}
-		s->data = read_object_file(&s->oid, &type, &s->size);
+		s->data = repo_read_object_file(r, &s->oid, &type, &s->size);
 		if (!s->data)
 			die("unable to read %s", oid_to_hex(&s->oid));
 		s->should_free = 1;
diff --git a/diff.h b/diff.h
index 6febe7e..9443dc1 100644
--- a/diff.h
+++ b/diff.h
@@ -285,6 +285,11 @@
 	/* Number of hexdigits to abbreviate raw format output to. */
 	int abbrev;
 
+	/* If non-zero, then stop computing after this many changes. */
+	int max_changes;
+	/* For internal use only. */
+	int num_changes;
+
 	int ita_invisible_in_index;
 /* white-space error highlighting */
 #define WSEH_NEW (1<<12)
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 531d7ad..e189f40 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -263,8 +263,8 @@
 	if (!filespec->oid_valid) {
 		if (diff_populate_filespec(r, filespec, 0))
 			return 0;
-		hash_object_file(filespec->data, filespec->size, "blob",
-				 &filespec->oid);
+		hash_object_file(r->hash_algo, filespec->data, filespec->size,
+				 "blob", &filespec->oid);
 	}
 	return oidhash(&filespec->oid);
 }
diff --git a/dir.c b/dir.c
index 7d25522..137fe37 100644
--- a/dir.c
+++ b/dir.c
@@ -41,7 +41,8 @@
 	int nr_files;
 	int nr_dirs;
 
-	struct dirent *de;
+	const char *d_name;
+	int d_type;
 	const char *file;
 	struct untracked_cache_dir *ucd;
 };
@@ -50,8 +51,8 @@
 	struct index_state *istate, const char *path, int len,
 	struct untracked_cache_dir *untracked,
 	int check_only, int stop_at_first_file, const struct pathspec *pathspec);
-static int get_dtype(struct dirent *de, struct index_state *istate,
-		     const char *path, int len);
+static int resolve_dtype(int dtype, struct index_state *istate,
+			 const char *path, int len);
 
 int count_slashes(const char *s)
 {
@@ -635,11 +636,42 @@
 	return strncmp(ee1->pattern, ee2->pattern, min_len);
 }
 
+static char *dup_and_filter_pattern(const char *pattern)
+{
+	char *set, *read;
+	size_t count  = 0;
+	char *result = xstrdup(pattern);
+
+	set = result;
+	read = result;
+
+	while (*read) {
+		/* skip escape characters (once) */
+		if (*read == '\\')
+			read++;
+
+		*set = *read;
+
+		set++;
+		read++;
+		count++;
+	}
+	*set = 0;
+
+	if (count > 2 &&
+	    *(set - 1) == '*' &&
+	    *(set - 2) == '/')
+		*(set - 2) = 0;
+
+	return result;
+}
+
 static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern *given)
 {
 	struct pattern_entry *translated;
 	char *truncated;
 	char *data = NULL;
+	const char *prev, *cur, *next;
 
 	if (!pl->use_cone_patterns)
 		return;
@@ -656,17 +688,57 @@
 		return;
 	}
 
+	if (given->patternlen <= 2 ||
+	    *given->pattern == '*' ||
+	    strstr(given->pattern, "**")) {
+		/* Not a cone pattern. */
+		warning(_("unrecognized pattern: '%s'"), given->pattern);
+		goto clear_hashmaps;
+	}
+
+	prev = given->pattern;
+	cur = given->pattern + 1;
+	next = given->pattern + 2;
+
+	while (*cur) {
+		/* Watch for glob characters '*', '\', '[', '?' */
+		if (!is_glob_special(*cur))
+			goto increment;
+
+		/* But only if *prev != '\\' */
+		if (*prev == '\\')
+			goto increment;
+
+		/* But allow the initial '\' */
+		if (*cur == '\\' &&
+		    is_glob_special(*next))
+			goto increment;
+
+		/* But a trailing '/' then '*' is fine */
+		if (*prev == '/' &&
+		    *cur == '*' &&
+		    *next == 0)
+			goto increment;
+
+		/* Not a cone pattern. */
+		warning(_("unrecognized pattern: '%s'"), given->pattern);
+		goto clear_hashmaps;
+
+	increment:
+		prev++;
+		cur++;
+		next++;
+	}
+
 	if (given->patternlen > 2 &&
 	    !strcmp(given->pattern + given->patternlen - 2, "/*")) {
 		if (!(given->flags & PATTERN_FLAG_NEGATIVE)) {
 			/* Not a cone pattern. */
-			pl->use_cone_patterns = 0;
 			warning(_("unrecognized pattern: '%s'"), given->pattern);
 			goto clear_hashmaps;
 		}
 
-		truncated = xstrdup(given->pattern);
-		truncated[given->patternlen - 2] = 0;
+		truncated = dup_and_filter_pattern(given->pattern);
 
 		translated = xmalloc(sizeof(struct pattern_entry));
 		translated->pattern = truncated;
@@ -700,7 +772,7 @@
 
 	translated = xmalloc(sizeof(struct pattern_entry));
 
-	translated->pattern = xstrdup(given->pattern);
+	translated->pattern = dup_and_filter_pattern(given->pattern);
 	translated->patternlen = given->patternlen;
 	hashmap_entry_init(&translated->ent,
 			   ignore_case ?
@@ -1002,8 +1074,8 @@
 				oidcpy(&oid_stat->oid,
 				       &istate->cache[pos]->oid);
 			else
-				hash_object_file(buf, size, "blob",
-						 &oid_stat->oid);
+				hash_object_file(the_hash_algo, buf, size,
+						 "blob", &oid_stat->oid);
 			fill_stat_data(&oid_stat->stat, &st);
 			oid_stat->valid = 1;
 		}
@@ -1215,8 +1287,7 @@
 		int prefix = pattern->nowildcardlen;
 
 		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR) {
-			if (*dtype == DT_UNKNOWN)
-				*dtype = get_dtype(NULL, istate, pathname, pathlen);
+			*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
 			if (*dtype != DT_DIR)
 				continue;
 		}
@@ -1656,36 +1727,41 @@
 static enum path_treatment treat_directory(struct dir_struct *dir,
 	struct index_state *istate,
 	struct untracked_cache_dir *untracked,
-	const char *dirname, int len, int baselen, int exclude,
+	const char *dirname, int len, int baselen, int excluded,
 	const struct pathspec *pathspec)
 {
-	int nested_repo = 0;
-
+	/*
+	 * WARNING: From this function, you can return path_recurse or you
+	 *          can call read_directory_recursive() (or neither), but
+	 *          you CAN'T DO BOTH.
+	 */
+	enum path_treatment state;
+	int nested_repo = 0, old_ignored_nr, stop_early;
 	/* The "len-1" is to strip the final '/' */
-	switch (directory_exists_in_index(istate, dirname, len-1)) {
-	case index_directory:
+	enum exist_status status = directory_exists_in_index(istate, dirname, len-1);
+
+	if (status == index_directory)
 		return path_recurse;
-
-	case index_gitdir:
+	if (status == index_gitdir)
 		return path_none;
+	if (status != index_nonexistent)
+		BUG("Unhandled value for directory_exists_in_index: %d\n", status);
 
-	case index_nonexistent:
-		if ((dir->flags & DIR_SKIP_NESTED_GIT) ||
-		    !(dir->flags & DIR_NO_GITLINKS)) {
-			struct strbuf sb = STRBUF_INIT;
-			strbuf_addstr(&sb, dirname);
-			nested_repo = is_nonbare_repository_dir(&sb);
-			strbuf_release(&sb);
-		}
-		if (nested_repo)
-			return ((dir->flags & DIR_SKIP_NESTED_GIT) ? path_none :
-				(exclude ? path_excluded : path_untracked));
+	if ((dir->flags & DIR_SKIP_NESTED_GIT) ||
+		!(dir->flags & DIR_NO_GITLINKS)) {
+		struct strbuf sb = STRBUF_INIT;
+		strbuf_addstr(&sb, dirname);
+		nested_repo = is_nonbare_repository_dir(&sb);
+		strbuf_release(&sb);
+	}
+	if (nested_repo)
+		return ((dir->flags & DIR_SKIP_NESTED_GIT) ? path_none :
+			(excluded ? path_excluded : path_untracked));
 
-		if (dir->flags & DIR_SHOW_OTHER_DIRECTORIES)
-			break;
-		if (exclude &&
-			(dir->flags & DIR_SHOW_IGNORED_TOO) &&
-			(dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING)) {
+	if (!(dir->flags & DIR_SHOW_OTHER_DIRECTORIES)) {
+		if (excluded &&
+		    (dir->flags & DIR_SHOW_IGNORED_TOO) &&
+		    (dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING)) {
 
 			/*
 			 * This is an excluded directory and we are
@@ -1712,18 +1788,101 @@
 
 	/* This is the "show_other_directories" case */
 
-	if (!(dir->flags & DIR_HIDE_EMPTY_DIRECTORIES))
-		return exclude ? path_excluded : path_untracked;
-
-	untracked = lookup_untracked(dir->untracked, untracked,
-				     dirname + baselen, len - baselen);
+	/*
+	 * We only need to recurse into untracked/ignored directories if
+	 * either of the following bits is set:
+	 *   - DIR_SHOW_IGNORED_TOO (because then we need to determine if
+	 *                           there are ignored directories below)
+	 *   - DIR_HIDE_EMPTY_DIRECTORIES (because we have to determine if
+	 *                                 the directory is empty)
+	 */
+	if (!(dir->flags & (DIR_SHOW_IGNORED_TOO | DIR_HIDE_EMPTY_DIRECTORIES)))
+		return excluded ? path_excluded : path_untracked;
 
 	/*
-	 * If this is an excluded directory, then we only need to check if
-	 * the directory contains any files.
+	 * If we only want to determine if dirname is empty, then we can
+	 * stop at the first file we find underneath that directory rather
+	 * than continuing to recurse beyond it.  If DIR_SHOW_IGNORED_TOO
+	 * is set, then we want MORE than just determining if dirname is
+	 * empty.
 	 */
-	return read_directory_recursive(dir, istate, dirname, len,
-					untracked, 1, exclude, pathspec);
+	stop_early = ((dir->flags & DIR_HIDE_EMPTY_DIRECTORIES) &&
+		      !(dir->flags & DIR_SHOW_IGNORED_TOO));
+
+	/*
+	 * If /every/ file within an untracked directory is ignored, then
+	 * we want to treat the directory as ignored (for e.g. status
+	 * --porcelain), without listing the individual ignored files
+	 * underneath.  To do so, we'll save the current ignored_nr, and
+	 * pop all the ones added after it if it turns out the entire
+	 * directory is ignored.
+	 */
+	old_ignored_nr = dir->ignored_nr;
+
+	/* Actually recurse into dirname now, we'll fixup the state later. */
+	untracked = lookup_untracked(dir->untracked, untracked,
+				     dirname + baselen, len - baselen);
+	state = read_directory_recursive(dir, istate, dirname, len, untracked,
+					 stop_early, stop_early, pathspec);
+
+	/* There are a variety of reasons we may need to fixup the state... */
+	if (state == path_excluded) {
+		int i;
+
+		/*
+		 * When stop_early is set, read_directory_recursive() will
+		 * never return path_untracked regardless of whether
+		 * underlying paths were untracked or ignored (because
+		 * returning early means it excluded some paths, or
+		 * something like that -- see commit 5aaa7fd39aaf ("Improve
+		 * performance of git status --ignored", 2017-09-18)).
+		 * However, we're not really concerned with the status of
+		 * files under the directory, we just wanted to know
+		 * whether the directory was empty (state == path_none) or
+		 * not (state == path_excluded), and if not, we'd return
+		 * our original status based on whether the untracked
+		 * directory matched an exclusion pattern.
+		 */
+		if (stop_early)
+			state = excluded ? path_excluded : path_untracked;
+
+		else {
+			/*
+			 * When
+			 *     !stop_early && state == path_excluded
+			 * then all paths under dirname were ignored.  For
+			 * this case, git status --porcelain wants to just
+			 * list the directory itself as ignored and not
+			 * list the individual paths underneath.  Remove
+			 * the individual paths underneath.
+			 */
+			for (i = old_ignored_nr + 1; i<dir->ignored_nr; ++i)
+				free(dir->ignored[i]);
+			dir->ignored_nr = old_ignored_nr;
+		}
+	}
+
+	/*
+	 * If there is nothing under the current directory and we are not
+	 * hiding empty directories, then we need to report on the
+	 * untracked or ignored status of the directory itself.
+	 */
+	if (state == path_none && !(dir->flags & DIR_HIDE_EMPTY_DIRECTORIES))
+		state = excluded ? path_excluded : path_untracked;
+
+	/*
+	 * We can recurse into untracked directories that don't match any
+	 * of the given pathspecs when some file underneath the directory
+	 * might match one of the pathspecs.  If so, we should make sure
+	 * to note that the directory itself did not match.
+	 */
+	if (pathspec &&
+	    !match_pathspec(istate, pathspec, dirname, len,
+			    0 /* prefix */, NULL,
+			    0 /* do NOT special case dirs */))
+		state = path_none;
+
+	return state;
 }
 
 /*
@@ -1842,10 +2001,9 @@
 	return DT_UNKNOWN;
 }
 
-static int get_dtype(struct dirent *de, struct index_state *istate,
-		     const char *path, int len)
+static int resolve_dtype(int dtype, struct index_state *istate,
+			 const char *path, int len)
 {
-	int dtype = de ? DTYPE(de) : DT_UNKNOWN;
 	struct stat st;
 
 	if (dtype != DT_UNKNOWN)
@@ -1864,86 +2022,6 @@
 	return dtype;
 }
 
-static enum path_treatment treat_one_path(struct dir_struct *dir,
-					  struct untracked_cache_dir *untracked,
-					  struct index_state *istate,
-					  struct strbuf *path,
-					  int baselen,
-					  const struct pathspec *pathspec,
-					  int dtype, struct dirent *de)
-{
-	int exclude;
-	int has_path_in_index = !!index_file_exists(istate, path->buf, path->len, ignore_case);
-	enum path_treatment path_treatment;
-
-	if (dtype == DT_UNKNOWN)
-		dtype = get_dtype(de, istate, path->buf, path->len);
-
-	/* Always exclude indexed files */
-	if (dtype != DT_DIR && has_path_in_index)
-		return path_none;
-
-	/*
-	 * When we are looking at a directory P in the working tree,
-	 * there are three cases:
-	 *
-	 * (1) P exists in the index.  Everything inside the directory P in
-	 * the working tree needs to go when P is checked out from the
-	 * index.
-	 *
-	 * (2) P does not exist in the index, but there is P/Q in the index.
-	 * We know P will stay a directory when we check out the contents
-	 * of the index, but we do not know yet if there is a directory
-	 * P/Q in the working tree to be killed, so we need to recurse.
-	 *
-	 * (3) P does not exist in the index, and there is no P/Q in the index
-	 * to require P to be a directory, either.  Only in this case, we
-	 * know that everything inside P will not be killed without
-	 * recursing.
-	 */
-	if ((dir->flags & DIR_COLLECT_KILLED_ONLY) &&
-	    (dtype == DT_DIR) &&
-	    !has_path_in_index &&
-	    (directory_exists_in_index(istate, path->buf, path->len) == index_nonexistent))
-		return path_none;
-
-	exclude = is_excluded(dir, istate, path->buf, &dtype);
-
-	/*
-	 * Excluded? If we don't explicitly want to show
-	 * ignored files, ignore it
-	 */
-	if (exclude && !(dir->flags & (DIR_SHOW_IGNORED|DIR_SHOW_IGNORED_TOO)))
-		return path_excluded;
-
-	switch (dtype) {
-	default:
-		return path_none;
-	case DT_DIR:
-		strbuf_addch(path, '/');
-		path_treatment = treat_directory(dir, istate, untracked,
-						 path->buf, path->len,
-						 baselen, exclude, pathspec);
-		/*
-		 * If 1) we only want to return directories that
-		 * match an exclude pattern and 2) this directory does
-		 * not match an exclude pattern but all of its
-		 * contents are excluded, then indicate that we should
-		 * recurse into this directory (instead of marking the
-		 * directory itself as an ignored path).
-		 */
-		if (!exclude &&
-		    path_treatment == path_excluded &&
-		    (dir->flags & DIR_SHOW_IGNORED_TOO) &&
-		    (dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING))
-			return path_recurse;
-		return path_treatment;
-	case DT_REG:
-	case DT_LNK:
-		return exclude ? path_excluded : path_untracked;
-	}
-}
-
 static enum path_treatment treat_path_fast(struct dir_struct *dir,
 					   struct untracked_cache_dir *untracked,
 					   struct cached_dir *cdir,
@@ -1952,6 +2030,11 @@
 					   int baselen,
 					   const struct pathspec *pathspec)
 {
+	/*
+	 * WARNING: From this function, you can return path_recurse or you
+	 *          can call read_directory_recursive() (or neither), but
+	 *          you CAN'T DO BOTH.
+	 */
 	strbuf_setlen(path, baselen);
 	if (!cdir->ucd) {
 		strbuf_addstr(path, cdir->file);
@@ -1985,21 +2068,86 @@
 				      int baselen,
 				      const struct pathspec *pathspec)
 {
-	int dtype;
-	struct dirent *de = cdir->de;
+	int has_path_in_index, dtype, excluded;
+	enum path_treatment path_treatment;
 
-	if (!de)
+	if (!cdir->d_name)
 		return treat_path_fast(dir, untracked, cdir, istate, path,
 				       baselen, pathspec);
-	if (is_dot_or_dotdot(de->d_name) || !fspathcmp(de->d_name, ".git"))
+	if (is_dot_or_dotdot(cdir->d_name) || !fspathcmp(cdir->d_name, ".git"))
 		return path_none;
 	strbuf_setlen(path, baselen);
-	strbuf_addstr(path, de->d_name);
+	strbuf_addstr(path, cdir->d_name);
 	if (simplify_away(path->buf, path->len, pathspec))
 		return path_none;
 
-	dtype = DTYPE(de);
-	return treat_one_path(dir, untracked, istate, path, baselen, pathspec, dtype, de);
+	dtype = resolve_dtype(cdir->d_type, istate, path->buf, path->len);
+
+	/* Always exclude indexed files */
+	has_path_in_index = !!index_file_exists(istate, path->buf, path->len,
+						ignore_case);
+	if (dtype != DT_DIR && has_path_in_index)
+		return path_none;
+
+	/*
+	 * When we are looking at a directory P in the working tree,
+	 * there are three cases:
+	 *
+	 * (1) P exists in the index.  Everything inside the directory P in
+	 * the working tree needs to go when P is checked out from the
+	 * index.
+	 *
+	 * (2) P does not exist in the index, but there is P/Q in the index.
+	 * We know P will stay a directory when we check out the contents
+	 * of the index, but we do not know yet if there is a directory
+	 * P/Q in the working tree to be killed, so we need to recurse.
+	 *
+	 * (3) P does not exist in the index, and there is no P/Q in the index
+	 * to require P to be a directory, either.  Only in this case, we
+	 * know that everything inside P will not be killed without
+	 * recursing.
+	 */
+	if ((dir->flags & DIR_COLLECT_KILLED_ONLY) &&
+	    (dtype == DT_DIR) &&
+	    !has_path_in_index &&
+	    (directory_exists_in_index(istate, path->buf, path->len) == index_nonexistent))
+		return path_none;
+
+	excluded = is_excluded(dir, istate, path->buf, &dtype);
+
+	/*
+	 * Excluded? If we don't explicitly want to show
+	 * ignored files, ignore it
+	 */
+	if (excluded && !(dir->flags & (DIR_SHOW_IGNORED|DIR_SHOW_IGNORED_TOO)))
+		return path_excluded;
+
+	switch (dtype) {
+	default:
+		return path_none;
+	case DT_DIR:
+		strbuf_addch(path, '/');
+		path_treatment = treat_directory(dir, istate, untracked,
+						 path->buf, path->len,
+						 baselen, excluded, pathspec);
+		/*
+		 * If 1) we only want to return directories that
+		 * match an exclude pattern and 2) this directory does
+		 * not match an exclude pattern but all of its
+		 * contents are excluded, then indicate that we should
+		 * recurse into this directory (instead of marking the
+		 * directory itself as an ignored path).
+		 */
+		if (!excluded &&
+		    path_treatment == path_excluded &&
+		    (dir->flags & DIR_SHOW_IGNORED_TOO) &&
+		    (dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING))
+			return path_recurse;
+		return path_treatment;
+	case DT_REG:
+	case DT_LNK:
+		return excluded ? path_excluded : path_untracked;
+	}
 }
 
 static void add_untracked(struct untracked_cache_dir *dir, const char *name)
@@ -2087,10 +2235,17 @@
 
 static int read_cached_dir(struct cached_dir *cdir)
 {
+	struct dirent *de;
+
 	if (cdir->fdir) {
-		cdir->de = readdir(cdir->fdir);
-		if (!cdir->de)
+		de = readdir(cdir->fdir);
+		if (!de) {
+			cdir->d_name = NULL;
+			cdir->d_type = DT_UNKNOWN;
 			return -1;
+		}
+		cdir->d_name = de->d_name;
+		cdir->d_type = DTYPE(de);
 		return 0;
 	}
 	while (cdir->nr_dirs < cdir->untracked->dirs_nr) {
@@ -2185,14 +2340,10 @@
 	int stop_at_first_file, const struct pathspec *pathspec)
 {
 	/*
-	 * WARNING WARNING WARNING:
-	 *
-	 * Any updates to the traversal logic here may need corresponding
-	 * updates in treat_leading_path().  See the commit message for the
-	 * commit adding this warning as well as the commit preceding it
-	 * for details.
+	 * WARNING: Do NOT recurse unless path_recurse is returned from
+	 *          treat_path().  Recursing on any other return value
+	 *          can result in exponential slowdown.
 	 */
-
 	struct cached_dir cdir;
 	enum path_treatment state, subdir_state, dir_state = path_none;
 	struct strbuf path = STRBUF_INIT;
@@ -2214,13 +2365,7 @@
 			dir_state = state;
 
 		/* recurse into subdir if instructed by treat_path */
-		if ((state == path_recurse) ||
-			((state == path_untracked) &&
-			 (get_dtype(cdir.de, istate, path.buf, path.len) == DT_DIR) &&
-			 ((dir->flags & DIR_SHOW_IGNORED_TOO) ||
-			  (pathspec &&
-			   do_match_pathspec(istate, pathspec, path.buf, path.len,
-					     baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC)))) {
+		if (state == path_recurse) {
 			struct untracked_cache_dir *ud;
 			ud = lookup_untracked(dir->untracked, untracked,
 					      path.buf + baselen,
@@ -2268,7 +2413,7 @@
 					add_untracked(untracked, path.buf + baselen);
 				break;
 			}
-			/* skip the dir_add_* part */
+			/* skip the add_path_to_appropriate_result_list() */
 			continue;
 		}
 
@@ -2304,20 +2449,11 @@
 			      const char *path, int len,
 			      const struct pathspec *pathspec)
 {
-	/*
-	 * WARNING WARNING WARNING:
-	 *
-	 * Any updates to the traversal logic here may need corresponding
-	 * updates in treat_leading_path().  See the commit message for the
-	 * commit adding this warning as well as the commit preceding it
-	 * for details.
-	 */
-
 	struct strbuf sb = STRBUF_INIT;
+	struct strbuf subdir = STRBUF_INIT;
 	int prevlen, baselen;
 	const char *cp;
 	struct cached_dir cdir;
-	struct dirent *de;
 	enum path_treatment state = path_none;
 
 	/*
@@ -2342,22 +2478,8 @@
 	if (!len)
 		return 1;
 
-	/*
-	 * We need a manufactured dirent with sufficient space to store a
-	 * leading directory component of path in its d_name.  Here, we
-	 * assume that the dirent's d_name is either declared as
-	 *    char d_name[BIG_ENOUGH]
-	 * or that it is declared at the end of the struct as
-	 *    char d_name[]
-	 * For either case, padding with len+1 bytes at the end will ensure
-	 * sufficient storage space.
-	 */
-	de = xcalloc(1, st_add3(sizeof(struct dirent), len, 1));
 	memset(&cdir, 0, sizeof(cdir));
-	cdir.de = de;
-#if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
-	de->d_type = DT_DIR;
-#endif
+	cdir.d_type = DT_DIR;
 	baselen = 0;
 	prevlen = 0;
 	while (1) {
@@ -2374,21 +2496,10 @@
 			break;
 		strbuf_reset(&sb);
 		strbuf_add(&sb, path, prevlen);
-		memcpy(de->d_name, path+prevlen, baselen-prevlen);
-		de->d_name[baselen-prevlen] = '\0';
-		state = treat_path(dir, NULL, &cdir, istate, &sb, prevlen,
-				    pathspec);
-		if (state == path_untracked &&
-		    get_dtype(cdir.de, istate, sb.buf, sb.len) == DT_DIR &&
-		    (dir->flags & DIR_SHOW_IGNORED_TOO ||
-		     do_match_pathspec(istate, pathspec, sb.buf, sb.len,
-				       baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC)) {
-			add_path_to_appropriate_result_list(dir, NULL, &cdir,
-							    istate,
-							    &sb, baselen,
-							    pathspec, state);
-			state = path_recurse;
-		}
+		strbuf_reset(&subdir);
+		strbuf_add(&subdir, path+prevlen, baselen-prevlen);
+		cdir.d_name = subdir.buf;
+		state = treat_path(dir, NULL, &cdir, istate, &sb, prevlen, pathspec);
 
 		if (state != path_recurse)
 			break; /* do not recurse into it */
@@ -2399,7 +2510,7 @@
 					    &sb, baselen, pathspec,
 					    state);
 
-	free(de);
+	strbuf_release(&subdir);
 	strbuf_release(&sb);
 	return state == path_recurse;
 }
diff --git a/ewah/bitmap.c b/ewah/bitmap.c
index 52f1178..d8cec58 100644
--- a/ewah/bitmap.c
+++ b/ewah/bitmap.c
@@ -22,21 +22,26 @@
 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
 
-struct bitmap *bitmap_new(void)
+struct bitmap *bitmap_word_alloc(size_t word_alloc)
 {
 	struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
-	bitmap->words = xcalloc(32, sizeof(eword_t));
-	bitmap->word_alloc = 32;
+	bitmap->words = xcalloc(word_alloc, sizeof(eword_t));
+	bitmap->word_alloc = word_alloc;
 	return bitmap;
 }
 
+struct bitmap *bitmap_new(void)
+{
+	return bitmap_word_alloc(32);
+}
+
 void bitmap_set(struct bitmap *self, size_t pos)
 {
 	size_t block = EWAH_BLOCK(pos);
 
 	if (block >= self->word_alloc) {
 		size_t old_size = self->word_alloc;
-		self->word_alloc = block * 2;
+		self->word_alloc = block ? block * 2 : 1;
 		REALLOC_ARRAY(self->words, self->word_alloc);
 		memset(self->words + old_size, 0x0,
 			(self->word_alloc - old_size) * sizeof(eword_t));
@@ -45,6 +50,14 @@
 	self->words[block] |= EWAH_MASK(pos);
 }
 
+void bitmap_unset(struct bitmap *self, size_t pos)
+{
+	size_t block = EWAH_BLOCK(pos);
+
+	if (block < self->word_alloc)
+		self->words[block] &= ~EWAH_MASK(pos);
+}
+
 int bitmap_get(struct bitmap *self, size_t pos)
 {
 	size_t block = EWAH_BLOCK(pos);
diff --git a/ewah/ewok.h b/ewah/ewok.h
index 84b2a29..011852b 100644
--- a/ewah/ewok.h
+++ b/ewah/ewok.h
@@ -172,7 +172,9 @@
 };
 
 struct bitmap *bitmap_new(void);
+struct bitmap *bitmap_word_alloc(size_t word_alloc);
 void bitmap_set(struct bitmap *self, size_t pos);
+void bitmap_unset(struct bitmap *self, size_t pos);
 int bitmap_get(struct bitmap *self, size_t pos);
 void bitmap_reset(struct bitmap *self);
 void bitmap_free(struct bitmap *self);
diff --git a/fsmonitor.c b/fsmonitor.c
index 868cca0..932bd90 100644
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@ -6,8 +6,10 @@
 #include "run-command.h"
 #include "strbuf.h"
 
-#define INDEX_EXTENSION_VERSION	(1)
-#define HOOK_INTERFACE_VERSION	(1)
+#define INDEX_EXTENSION_VERSION1	(1)
+#define INDEX_EXTENSION_VERSION2	(2)
+#define HOOK_INTERFACE_VERSION1		(1)
+#define HOOK_INTERFACE_VERSION2		(2)
 
 struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
 
@@ -24,6 +26,22 @@
 	ce->ce_flags &= ~CE_FSMONITOR_VALID;
 }
 
+static int fsmonitor_hook_version(void)
+{
+	int hook_version;
+
+	if (git_config_get_int("core.fsmonitorhookversion", &hook_version))
+		return -1;
+
+	if (hook_version == HOOK_INTERFACE_VERSION1 ||
+	    hook_version == HOOK_INTERFACE_VERSION2)
+		return hook_version;
+
+	warning("Invalid hook version '%i' in core.fsmonitorhookversion. "
+		"Must be 1 or 2.", hook_version);
+	return -1;
+}
+
 int read_fsmonitor_extension(struct index_state *istate, const void *data,
 	unsigned long sz)
 {
@@ -32,17 +50,26 @@
 	uint32_t ewah_size;
 	struct ewah_bitmap *fsmonitor_dirty;
 	int ret;
+	uint64_t timestamp;
+	struct strbuf last_update = STRBUF_INIT;
 
-	if (sz < sizeof(uint32_t) + sizeof(uint64_t) + sizeof(uint32_t))
+	if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
 		return error("corrupt fsmonitor extension (too short)");
 
 	hdr_version = get_be32(index);
 	index += sizeof(uint32_t);
-	if (hdr_version != INDEX_EXTENSION_VERSION)
+	if (hdr_version == INDEX_EXTENSION_VERSION1) {
+		timestamp = get_be64(index);
+		strbuf_addf(&last_update, "%"PRIu64"", timestamp);
+		index += sizeof(uint64_t);
+	} else if (hdr_version == INDEX_EXTENSION_VERSION2) {
+		strbuf_addstr(&last_update, index);
+		index += last_update.len + 1;
+	} else {
 		return error("bad fsmonitor version %d", hdr_version);
+	}
 
-	istate->fsmonitor_last_update = get_be64(index);
-	index += sizeof(uint64_t);
+	istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
 
 	ewah_size = get_be32(index);
 	index += sizeof(uint32_t);
@@ -79,7 +106,6 @@
 void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
 {
 	uint32_t hdr_version;
-	uint64_t tm;
 	uint32_t ewah_start;
 	uint32_t ewah_size = 0;
 	int fixup = 0;
@@ -89,11 +115,12 @@
 		BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
 		    (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
 
-	put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
+	put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
 	strbuf_add(sb, &hdr_version, sizeof(uint32_t));
 
-	put_be64(&tm, istate->fsmonitor_last_update);
-	strbuf_add(sb, &tm, sizeof(uint64_t));
+	strbuf_addstr(sb, istate->fsmonitor_last_update);
+	strbuf_addch(sb, 0); /* Want to keep a NUL */
+
 	fixup = sb->len;
 	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
 
@@ -110,9 +137,9 @@
 }
 
 /*
- * Call the query-fsmonitor hook passing the time of the last saved results.
+ * Call the query-fsmonitor hook passing the last update token of the saved results.
  */
-static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
+static int query_fsmonitor(int version, const char *last_update, struct strbuf *query_result)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 
@@ -121,7 +148,7 @@
 
 	argv_array_push(&cp.args, core_fsmonitor);
 	argv_array_pushf(&cp.args, "%d", version);
-	argv_array_pushf(&cp.args, "%" PRIuMAX, (uintmax_t)last_update);
+	argv_array_pushf(&cp.args, "%s", last_update);
 	cp.use_shell = 1;
 	cp.dir = get_git_work_tree();
 
@@ -148,14 +175,18 @@
 void refresh_fsmonitor(struct index_state *istate)
 {
 	struct strbuf query_result = STRBUF_INIT;
-	int query_success = 0;
-	size_t bol; /* beginning of line */
+	int query_success = 0, hook_version = -1;
+	size_t bol = 0; /* beginning of line */
 	uint64_t last_update;
+	struct strbuf last_update_token = STRBUF_INIT;
 	char *buf;
 	unsigned int i;
 
 	if (!core_fsmonitor || istate->fsmonitor_has_run_once)
 		return;
+
+	hook_version = fsmonitor_hook_version();
+
 	istate->fsmonitor_has_run_once = 1;
 
 	trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
@@ -164,26 +195,60 @@
 	 * should be inclusive to ensure we don't miss potential changes.
 	 */
 	last_update = getnanotime();
+	if (hook_version == HOOK_INTERFACE_VERSION1)
+		strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
 
 	/*
-	 * If we have a last update time, call query_fsmonitor for the set of
-	 * changes since that time, else assume everything is possibly dirty
+	 * If we have a last update token, call query_fsmonitor for the set of
+	 * changes since that token, else assume everything is possibly dirty
 	 * and check it all.
 	 */
 	if (istate->fsmonitor_last_update) {
-		query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION,
-			istate->fsmonitor_last_update, &query_result);
+		if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) {
+			query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
+				istate->fsmonitor_last_update, &query_result);
+
+			if (query_success) {
+				if (hook_version < 0)
+					hook_version = HOOK_INTERFACE_VERSION2;
+
+				/*
+				 * First entry will be the last update token
+				 * Need to use a char * variable because static
+				 * analysis was suggesting to use strbuf_addbuf
+				 * but we don't want to copy the entire strbuf
+				 * only the the chars up to the first NUL
+				 */
+				buf = query_result.buf;
+				strbuf_addstr(&last_update_token, buf);
+				if (!last_update_token.len) {
+					warning("Empty last update token.");
+					query_success = 0;
+				} else {
+					bol = last_update_token.len + 1;
+				}
+			} else if (hook_version < 0) {
+				hook_version = HOOK_INTERFACE_VERSION1;
+				if (!last_update_token.len)
+					strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
+			}
+		}
+
+		if (hook_version == HOOK_INTERFACE_VERSION1) {
+			query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
+				istate->fsmonitor_last_update, &query_result);
+		}
+
 		trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
 		trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
 			core_fsmonitor, query_success ? "success" : "failure");
 	}
 
 	/* a fsmonitor process can return '/' to indicate all entries are invalid */
-	if (query_success && query_result.buf[0] != '/') {
+	if (query_success && query_result.buf[bol] != '/') {
 		/* Mark all entries returned by the monitor as dirty */
 		buf = query_result.buf;
-		bol = 0;
-		for (i = 0; i < query_result.len; i++) {
+		for (i = bol; i < query_result.len; i++) {
 			if (buf[i] != '\0')
 				continue;
 			fsmonitor_refresh_callback(istate, buf + bol);
@@ -217,18 +282,21 @@
 	}
 	strbuf_release(&query_result);
 
-	/* Now that we've updated istate, save the last_update time */
-	istate->fsmonitor_last_update = last_update;
+	/* Now that we've updated istate, save the last_update_token */
+	FREE_AND_NULL(istate->fsmonitor_last_update);
+	istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
 }
 
 void add_fsmonitor(struct index_state *istate)
 {
 	unsigned int i;
+	struct strbuf last_update = STRBUF_INIT;
 
 	if (!istate->fsmonitor_last_update) {
 		trace_printf_key(&trace_fsmonitor, "add fsmonitor");
 		istate->cache_changed |= FSMONITOR_CHANGED;
-		istate->fsmonitor_last_update = getnanotime();
+		strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
+		istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
 
 		/* reset the fsmonitor state */
 		for (i = 0; i < istate->cache_nr; i++)
@@ -250,7 +318,7 @@
 	if (istate->fsmonitor_last_update) {
 		trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
 		istate->cache_changed |= FSMONITOR_CHANGED;
-		istate->fsmonitor_last_update = 0;
+		FREE_AND_NULL(istate->fsmonitor_last_update);
 	}
 }
 
diff --git a/generate-bugreport-config-safelist.sh b/generate-bugreport-config-safelist.sh
new file mode 100755
index 0000000..2794a8a
--- /dev/null
+++ b/generate-bugreport-config-safelist.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+cat <<EOF
+/* Automatically generated by bugreport-generate-config-safelist.sh */
+
+
+static const char *bugreport_config_safelist[] = {
+EOF
+
+# cat all regular files in Documentation/config
+find Documentation/config -type f -exec cat {} \; |
+# print the command name which matches the annotate-bugreport macro
+sed -n 's/^\([^[:blank:]]*\)[[:blank:]]\{1,\}annotate:bugreport\[include\].* ::$/  "\1",/p' \
+	| sort
+
+cat <<EOF
+};
+EOF
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 71158f7..45fecf8 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -76,23 +76,6 @@
 	echo "};"
 }
 
-print_config_list () {
-	cat <<EOF
-static const char *config_name_list[] = {
-EOF
-	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt |
-	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
-	sort |
-	while read line
-	do
-		echo "	\"$line\","
-	done
-	cat <<EOF
-	NULL,
-};
-EOF
-}
-
 exclude_programs=
 while test "--exclude-program" = "$1"
 do
@@ -113,5 +96,3 @@
 define_category_names "$1"
 echo
 print_command_list "$1"
-echo
-print_config_list
diff --git a/generate-configlist.sh b/generate-configlist.sh
new file mode 100755
index 0000000..8692fe5
--- /dev/null
+++ b/generate-configlist.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+echo "/* Automatically generated by generate-configlist.sh */"
+echo
+
+print_config_list () {
+	cat <<EOF
+static const char *config_name_list[] = {
+EOF
+	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt |
+	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
+	sort |
+	sed 's/^.*$/	"&",/'
+	cat <<EOF
+	NULL,
+};
+EOF
+}
+
+echo
+print_config_list
diff --git a/git-legacy-stash.sh b/git-legacy-stash.sh
index 53fa574..4d4ebb4 100755
--- a/git-legacy-stash.sh
+++ b/git-legacy-stash.sh
@@ -207,7 +207,7 @@
 
 		# find out what the user wants
 		GIT_INDEX_FILE="$TMP-index" \
-			git add--interactive --patch=stash -- "$@" &&
+			git add --legacy-stash-p -- "$@" &&
 
 		# state of the working tree
 		w_tree=$(GIT_INDEX_FILE="$TMP-index" git write-tree) ||
diff --git a/git-p4.py b/git-p4.py
index 40d9e7c..b8b2a16 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -7,13 +7,21 @@
 #            2007 Trolltech ASA
 # License: MIT <http://www.opensource.org/licenses/mit-license.php>
 #
+# pylint: disable=invalid-name,missing-docstring,too-many-arguments,broad-except
+# pylint: disable=no-self-use,wrong-import-position,consider-iterating-dictionary
+# pylint: disable=wrong-import-order,unused-import,too-few-public-methods
+# pylint: disable=too-many-lines,ungrouped-imports,fixme,too-many-locals
+# pylint: disable=line-too-long,bad-whitespace,superfluous-parens
+# pylint: disable=too-many-statements,too-many-instance-attributes
+# pylint: disable=too-many-branches,too-many-nested-blocks
+#
 import sys
-if sys.hexversion < 0x02040000:
-    # The limiter is the subprocess module
-    sys.stderr.write("git-p4: requires Python 2.4 or later.\n")
+if sys.version_info.major < 3 and sys.version_info.minor < 7:
+    sys.stderr.write("git-p4: requires Python 2.7 or later.\n")
     sys.exit(1)
 import os
 import optparse
+import functools
 import marshal
 import subprocess
 import tempfile
@@ -26,37 +34,17 @@
 import zlib
 import ctypes
 import errno
+import glob
 
+# On python2.7 where raw_input() and input() are both availble,
+# we want raw_input's semantics, but aliased to input for python3
+# compatibility
 # support basestring in python3
 try:
-    unicode = unicode
-except NameError:
-    # 'unicode' is undefined, must be Python 3
-    str = str
-    unicode = str
-    bytes = bytes
-    basestring = (str,bytes)
-else:
-    # 'unicode' exists, must be Python 2
-    str = str
-    unicode = unicode
-    bytes = str
-    basestring = basestring
-
-try:
-    from subprocess import CalledProcessError
-except ImportError:
-    # from python2.7:subprocess.py
-    # Exception classes used by this module.
-    class CalledProcessError(Exception):
-        """This exception is raised when a process run by check_call() returns
-        a non-zero exit status.  The exit status will be stored in the
-        returncode attribute."""
-        def __init__(self, returncode, cmd):
-            self.returncode = returncode
-            self.cmd = cmd
-        def __str__(self):
-            return "Command '%s' returned non-zero exit status %d" % (self.cmd, self.returncode)
+    if raw_input and input:
+        input = raw_input
+except:
+    pass
 
 verbose = False
 
@@ -105,7 +93,7 @@
         # Provide a way to not pass this option by setting git-p4.retries to 0
         real_cmd += ["-r", str(retries)]
 
-    if isinstance(cmd,basestring):
+    if not isinstance(cmd, list):
         real_cmd = ' '.join(real_cmd) + ' ' + cmd
     else:
         real_cmd += cmd
@@ -161,6 +149,9 @@
         return st.f_bavail * st.f_frsize
 
 def die(msg):
+    """ Terminate execution. Make sure that any running child processes have been wait()ed for before
+        calling this.
+    """
     if verbose:
         raise Exception(msg)
     else:
@@ -175,18 +166,118 @@
     """
     choices = set(m.group(1) for m in re.finditer(r"\[(.)\]", prompt_text))
     while True:
-        response = raw_input(prompt_text).strip().lower()
+        sys.stderr.flush()
+        sys.stdout.write(prompt_text)
+        sys.stdout.flush()
+        response=sys.stdin.readline().strip().lower()
         if not response:
             continue
         response = response[0]
         if response in choices:
             return response
 
+# We need different encoding/decoding strategies for text data being passed
+# around in pipes depending on python version
+if bytes is not str:
+    # For python3, always encode and decode as appropriate
+    def decode_text_stream(s):
+        return s.decode() if isinstance(s, bytes) else s
+    def encode_text_stream(s):
+        return s.encode() if isinstance(s, str) else s
+else:
+    # For python2.7, pass read strings as-is, but also allow writing unicode
+    def decode_text_stream(s):
+        return s
+    def encode_text_stream(s):
+        return s.encode('utf_8') if isinstance(s, unicode) else s
+
+def decode_path(path):
+    """Decode a given string (bytes or otherwise) using configured path encoding options
+    """
+    encoding = gitConfig('git-p4.pathEncoding') or 'utf_8'
+    if bytes is not str:
+        return path.decode(encoding, errors='replace') if isinstance(path, bytes) else path
+    else:
+        try:
+            path.decode('ascii')
+        except:
+            path = path.decode(encoding, errors='replace')
+            if verbose:
+                print('Path with non-ASCII characters detected. Used {} to decode: {}'.format(encoding, path))
+        return path
+
+def run_git_hook(cmd, param=[]):
+    """Execute a hook if the hook exists."""
+    if verbose:
+        sys.stderr.write("Looking for hook: %s\n" % cmd)
+        sys.stderr.flush()
+
+    hooks_path = gitConfig("core.hooksPath")
+    if len(hooks_path) <= 0:
+        hooks_path = os.path.join(os.environ["GIT_DIR"], "hooks")
+
+    if not isinstance(param, list):
+        param=[param]
+
+    # resolve hook file name, OS depdenent
+    hook_file = os.path.join(hooks_path, cmd)
+    if platform.system() == 'Windows':
+        if not os.path.isfile(hook_file):
+            # look for the file with an extension
+            files = glob.glob(hook_file + ".*")
+            if not files:
+                return True
+            files.sort()
+            hook_file = files.pop()
+            while hook_file.upper().endswith(".SAMPLE"):
+                # The file is a sample hook. We don't want it
+                if len(files) > 0:
+                    hook_file = files.pop()
+                else:
+                    return True
+
+    if not os.path.isfile(hook_file) or not os.access(hook_file, os.X_OK):
+        return True
+
+    return run_hook_command(hook_file, param) == 0
+
+def run_hook_command(cmd, param):
+    """Executes a git hook command
+       cmd = the command line file to be executed. This can be
+       a file that is run by OS association.
+
+       param = a list of parameters to pass to the cmd command
+
+       On windows, the extension is checked to see if it should
+       be run with the Git for Windows Bash shell.  If there
+       is no file extension, the file is deemed a bash shell
+       and will be handed off to sh.exe. Otherwise, Windows
+       will be called with the shell to handle the file assocation.
+
+       For non Windows operating systems, the file is called
+       as an executable.
+    """
+    cli = [cmd] + param
+    use_shell = False
+    if platform.system() == 'Windows':
+        (root,ext) = os.path.splitext(cmd)
+        if ext == "":
+            exe_path = os.environ.get("EXEPATH")
+            if exe_path is None:
+                exe_path = ""
+            else:
+                exe_path = os.path.join(exe_path, "bin")
+            cli = [os.path.join(exe_path, "SH.EXE")] + cli
+        else:
+            use_shell = True
+    return subprocess.call(cli, shell=use_shell)
+
+
 def write_pipe(c, stdin):
     if verbose:
         sys.stderr.write('Writing pipe: %s\n' % str(c))
 
-    expand = isinstance(c,basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdin=subprocess.PIPE, shell=expand)
     pipe = p.stdin
     val = pipe.write(stdin)
@@ -198,6 +289,8 @@
 
 def p4_write_pipe(c, stdin):
     real_cmd = p4_build_cmd(c)
+    if bytes is not str and isinstance(stdin, str):
+        stdin = encode_text_stream(stdin)
     return write_pipe(real_cmd, stdin)
 
 def read_pipe_full(c):
@@ -208,15 +301,17 @@
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
-    expand = isinstance(c,basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=expand)
     (out, err) = p.communicate()
-    return (p.returncode, out, err)
+    return (p.returncode, out, decode_text_stream(err))
 
-def read_pipe(c, ignore_error=False):
+def read_pipe(c, ignore_error=False, raw=False):
     """ Read output from  command. Returns the output text on
         success. On failure, terminates execution, unless
         ignore_error is True, when it returns an empty string.
+
+        If raw is True, do not attempt to decode output text.
     """
     (retcode, out, err) = read_pipe_full(c)
     if retcode != 0:
@@ -224,6 +319,8 @@
             out = ""
         else:
             die('Command failed: %s\nError: %s' % (str(c), err))
+    if not raw:
+        out = decode_text_stream(out)
     return out
 
 def read_pipe_text(c):
@@ -234,23 +331,22 @@
     if retcode != 0:
         return None
     else:
-        return out.rstrip()
+        return decode_text_stream(out).rstrip()
 
-def p4_read_pipe(c, ignore_error=False):
+def p4_read_pipe(c, ignore_error=False, raw=False):
     real_cmd = p4_build_cmd(c)
-    return read_pipe(real_cmd, ignore_error)
+    return read_pipe(real_cmd, ignore_error, raw=raw)
 
 def read_pipe_lines(c):
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
-    expand = isinstance(c, basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, shell=expand)
     pipe = p.stdout
-    val = pipe.readlines()
+    val = [decode_text_stream(line) for line in pipe.readlines()]
     if pipe.close() or p.wait():
         die('Command failed: %s' % str(c))
-
     return val
 
 def p4_read_pipe_lines(c):
@@ -278,6 +374,7 @@
     cmd = p4_build_cmd(["move", "-k", "@from", "@to"])
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     (out, err) = p.communicate()
+    err = decode_text_stream(err)
     # return code will be 1 in either case
     if err.find("Invalid option") >= 0:
         return False
@@ -287,7 +384,7 @@
     return True
 
 def system(cmd, ignore_error=False):
-    expand = isinstance(cmd,basestring)
+    expand = not isinstance(cmd, list)
     if verbose:
         sys.stderr.write("executing %s\n" % str(cmd))
     retcode = subprocess.call(cmd, shell=expand)
@@ -299,7 +396,7 @@
 def p4_system(cmd):
     """Specifically invoke p4 as the system command. """
     real_cmd = p4_build_cmd(cmd)
-    expand = isinstance(real_cmd, basestring)
+    expand = not isinstance(real_cmd, list)
     retcode = subprocess.call(real_cmd, shell=expand)
     if retcode:
         raise CalledProcessError(retcode, real_cmd)
@@ -537,7 +634,7 @@
 # Return the set of all p4 labels
 def getP4Labels(depotPaths):
     labels = set()
-    if isinstance(depotPaths,basestring):
+    if not isinstance(depotPaths, list):
         depotPaths = [depotPaths]
 
     for l in p4CmdList(["labels"] + ["%s..." % p for p in depotPaths]):
@@ -554,12 +651,7 @@
         gitTags.add(tag)
     return gitTags
 
-def diffTreePattern():
-    # This is a simple generator for the diff tree regex pattern. This could be
-    # a class variable if this and parseDiffTreeEntry were a part of a class.
-    pattern = re.compile(':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
-    while True:
-        yield pattern
+_diff_tree_pattern = None
 
 def parseDiffTreeEntry(entry):
     """Parses a single diff tree entry into its component elements.
@@ -580,7 +672,11 @@
 
     If the pattern is not matched, None is returned."""
 
-    match = diffTreePattern().next().match(entry)
+    global _diff_tree_pattern
+    if not _diff_tree_pattern:
+        _diff_tree_pattern = re.compile(':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
+
+    match = _diff_tree_pattern.match(entry)
     if match:
         return {
             'src_mode': match.group(1),
@@ -618,13 +714,21 @@
         super(P4RequestSizeException, self).__init__(exit_code, p4_result)
         self.limit = limit
 
+class P4CommandException(P4Exception):
+    """ Something went wrong calling p4 which means we have to give up """
+    def __init__(self, msg):
+        self.msg = msg
+
+    def __str__(self):
+        return self.msg
+
 def isModeExecChanged(src_mode, dst_mode):
     return isModeExec(src_mode) != isModeExec(dst_mode)
 
 def p4CmdList(cmd, stdin=None, stdin_mode='w+b', cb=None, skip_info=False,
         errors_as_exceptions=False):
 
-    if isinstance(cmd,basestring):
+    if not isinstance(cmd, list):
         cmd = "-G " + cmd
         expand = True
     else:
@@ -641,11 +745,12 @@
     stdin_file = None
     if stdin is not None:
         stdin_file = tempfile.TemporaryFile(prefix='p4-stdin', mode=stdin_mode)
-        if isinstance(stdin,basestring):
+        if not isinstance(stdin, list):
             stdin_file.write(stdin)
         else:
             for i in stdin:
-                stdin_file.write(i + '\n')
+                stdin_file.write(encode_text_stream(i))
+                stdin_file.write(b'\n')
         stdin_file.flush()
         stdin_file.seek(0)
 
@@ -658,6 +763,20 @@
     try:
         while True:
             entry = marshal.load(p4.stdout)
+            if bytes is not str:
+                # Decode unmarshalled dict to use str keys and values, except for:
+                #   - `data` which may contain arbitrary binary data
+                #   - `depotFile[0-9]*`, `path`, or `clientFile` which may contain non-UTF8 encoded text
+                decoded_entry = {}
+                for key, value in entry.items():
+                    key = key.decode()
+                    if isinstance(value, bytes) and not (key in ('data', 'path', 'clientFile') or key.startswith('depotFile')):
+                        value = value.decode()
+                    decoded_entry[key] = value
+                # Parse out data if it's an error response
+                if decoded_entry.get('code') == 'error' and 'data' in decoded_entry:
+                    decoded_entry['data'] = decoded_entry['data'].decode()
+                entry = decoded_entry
             if skip_info:
                 if 'code' in entry and entry['code'] == 'info':
                     continue
@@ -708,7 +827,8 @@
         if "depotFile" in entry:
             # Search for the base client side depot path, as long as it starts with the branch's P4 path.
             # The base path always ends with "/...".
-            if entry["depotFile"].find(depotPath) == 0 and entry["depotFile"][-4:] == "/...":
+            entry_path = decode_path(entry['depotFile'])
+            if entry_path.find(depotPath) == 0 and entry_path[-4:] == "/...":
                 output = entry
                 break
         elif "data" in entry:
@@ -723,11 +843,11 @@
         return ""
     clientPath = ""
     if "path" in output:
-        clientPath = output.get("path")
+        clientPath = decode_path(output['path'])
     elif "data" in output:
         data = output.get("data")
-        lastSpace = data.rfind(" ")
-        clientPath = data[lastSpace + 1:]
+        lastSpace = data.rfind(b" ")
+        clientPath = decode_path(data[lastSpace + 1:])
 
     if clientPath.endswith("..."):
         clientPath = clientPath[:-3]
@@ -875,6 +995,7 @@
     cmd = [ "git", "rev-parse", "--symbolic", "--verify", branch ]
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     out, _ = p.communicate()
+    out = decode_text_stream(out)
     if p.returncode:
         return False
     # expect exactly one line of output: the branch name
@@ -1152,7 +1273,7 @@
         assert False, "Method 'pushFile' required in " + self.__class__.__name__
 
     def hasLargeFileExtension(self, relPath):
-        return reduce(
+        return functools.reduce(
             lambda a, b: a or b,
             [relPath.endswith('.' + e) for e in gitConfigList('git-p4.largeFileExtensions')],
             False
@@ -1259,7 +1380,7 @@
             ['git', 'lfs', 'pointer', '--file=' + contentFile],
             stdout=subprocess.PIPE
         )
-        pointerFile = pointerProcess.stdout.read()
+        pointerFile = decode_text_stream(pointerProcess.stdout.read())
         if pointerProcess.wait():
             os.remove(contentFile)
             die('git-lfs pointer command failed. Did you install the extension?')
@@ -1395,14 +1516,14 @@
         for (key, val) in self.users.items():
             s += "%s\t%s\n" % (key.expandtabs(1), val.expandtabs(1))
 
-        open(self.getUserCacheFilename(), "wb").write(s)
+        open(self.getUserCacheFilename(), 'w').write(s)
         self.userMapFromPerforceServer = True
 
     def loadUserMapFromCache(self):
         self.users = {}
         self.userMapFromPerforceServer = False
         try:
-            cache = open(self.getUserCacheFilename(), "rb")
+            cache = open(self.getUserCacheFilename(), 'r')
             lines = cache.readlines()
             cache.close()
             for line in lines:
@@ -1517,13 +1638,39 @@
                                      "work from a local git branch that is not master"),
                 optparse.make_option("--disable-p4sync", dest="disable_p4sync", action="store_true",
                                      help="Skip Perforce sync of p4/master after submit or shelve"),
+                optparse.make_option("--no-verify", dest="no_verify", action="store_true",
+                                     help="Bypass p4-pre-submit and p4-changelist hooks"),
         ]
         self.description = """Submit changes from git to the perforce depot.\n
-    The `p4-pre-submit` hook is executed if it exists and is executable.
-    The hook takes no parameters and nothing from standard input. Exiting with
-    non-zero status from this script prevents `git-p4 submit` from launching.
+    The `p4-pre-submit` hook is executed if it exists and is executable. It
+    can be bypassed with the `--no-verify` command line option. The hook takes
+    no parameters and nothing from standard input. Exiting with a non-zero status
+    from this script prevents `git-p4 submit` from launching.
 
-    One usage scenario is to run unit tests in the hook."""
+    One usage scenario is to run unit tests in the hook.
+
+    The `p4-prepare-changelist` hook is executed right after preparing the default
+    changelist message and before the editor is started. It takes one parameter,
+    the name of the file that contains the changelist text. Exiting with a non-zero
+    status from the script will abort the process.
+
+    The purpose of the hook is to edit the message file in place, and it is not
+    supressed by the `--no-verify` option. This hook is called even if
+    `--prepare-p4-only` is set.
+
+    The `p4-changelist` hook is executed after the changelist message has been
+    edited by the user. It can be bypassed with the `--no-verify` option. It
+    takes a single parameter, the name of the file that holds the proposed
+    changelist text. Exiting with a non-zero status causes the command to abort.
+
+    The hook is allowed to edit the changelist file and can be used to normalize
+    the text into some project standard format. It can also be used to refuse the
+    Submit after inspect the message file.
+
+    The `p4-post-changelist` hook is invoked after the submit has successfully
+    occured in P4. It takes no parameters and is meant primarily for notification
+    and cannot affect the outcome of the git p4 submit action.
+    """
 
         self.usage += " [name of git branch to submit into perforce depot]"
         self.origin = ""
@@ -1541,6 +1688,7 @@
         self.exportLabels = False
         self.p4HasMoveCommand = p4_has_move_command()
         self.branch = None
+        self.no_verify = False
 
         if gitConfig('git-p4.largeFileSystem'):
             die("Large file system not supported for git-p4 submit command. Please remove it from config.")
@@ -1679,7 +1827,8 @@
         c = changes[0]
         if c['User'] == newUser: return   # nothing to do
         c['User'] = newUser
-        input = marshal.dumps(c)
+        # p4 does not understand format version 3 and above
+        input = marshal.dumps(c, 2)
 
         result = p4CmdList("change -f -i", stdin=input)
         for r in result:
@@ -1743,7 +1892,7 @@
                 break
         if not change_entry:
             die('Failed to decode output of p4 change -o')
-        for key, value in change_entry.iteritems():
+        for key, value in change_entry.items():
             if key.startswith('File'):
                 if 'depot-paths' in settings:
                     if not [p for p in settings['depot-paths']
@@ -1927,6 +2076,9 @@
         applyPatchCmd = patchcmd + "--check --apply -"
         patch_succeeded = True
 
+        if verbose:
+            print("TryPatch: %s" % tryPatchCmd)
+
         if os.system(tryPatchCmd) != 0:
             fixed_rcs_keywords = False
             patch_succeeded = False
@@ -1966,6 +2118,7 @@
                 print("Retrying the patch with RCS keywords cleaned up")
                 if os.system(tryPatchCmd) == 0:
                     patch_succeeded = True
+                    print("Patch succeesed this time with RCS keywords cleaned")
 
         if not patch_succeeded:
             for f in editedFiles:
@@ -2023,58 +2176,76 @@
         tmpFile = os.fdopen(handle, "w+b")
         if self.isWindows:
             submitTemplate = submitTemplate.replace("\n", "\r\n")
-        tmpFile.write(submitTemplate)
+        tmpFile.write(encode_text_stream(submitTemplate))
         tmpFile.close()
 
-        if self.prepare_p4_only:
-            #
-            # Leave the p4 tree prepared, and the submit template around
-            # and let the user decide what to do next
-            #
-            print()
-            print("P4 workspace prepared for submission.")
-            print("To submit or revert, go to client workspace")
-            print("  " + self.clientPath)
-            print()
-            print("To submit, use \"p4 submit\" to write a new description,")
-            print("or \"p4 submit -i <%s\" to use the one prepared by" \
-                  " \"git p4\"." % fileName)
-            print("You can delete the file \"%s\" when finished." % fileName)
-
-            if self.preserveUser and p4User and not self.p4UserIsMe(p4User):
-                print("To preserve change ownership by user %s, you must\n" \
-                      "do \"p4 change -f <change>\" after submitting and\n" \
-                      "edit the User field.")
-            if pureRenameCopy:
-                print("After submitting, renamed files must be re-synced.")
-                print("Invoke \"p4 sync -f\" on each of these files:")
-                for f in pureRenameCopy:
-                    print("  " + f)
-
-            print()
-            print("To revert the changes, use \"p4 revert ...\", and delete")
-            print("the submit template file \"%s\"" % fileName)
-            if filesToAdd:
-                print("Since the commit adds new files, they must be deleted:")
-                for f in filesToAdd:
-                    print("  " + f)
-            print()
-            return True
-
-        #
-        # Let the user edit the change description, then submit it.
-        #
         submitted = False
 
         try:
+            # Allow the hook to edit the changelist text before presenting it
+            # to the user.
+            if not run_git_hook("p4-prepare-changelist", [fileName]):
+                return False
+
+            if self.prepare_p4_only:
+                #
+                # Leave the p4 tree prepared, and the submit template around
+                # and let the user decide what to do next
+                #
+                submitted = True
+                print("")
+                print("P4 workspace prepared for submission.")
+                print("To submit or revert, go to client workspace")
+                print("  " + self.clientPath)
+                print("")
+                print("To submit, use \"p4 submit\" to write a new description,")
+                print("or \"p4 submit -i <%s\" to use the one prepared by" \
+                      " \"git p4\"." % fileName)
+                print("You can delete the file \"%s\" when finished." % fileName)
+
+                if self.preserveUser and p4User and not self.p4UserIsMe(p4User):
+                    print("To preserve change ownership by user %s, you must\n" \
+                          "do \"p4 change -f <change>\" after submitting and\n" \
+                          "edit the User field.")
+                if pureRenameCopy:
+                    print("After submitting, renamed files must be re-synced.")
+                    print("Invoke \"p4 sync -f\" on each of these files:")
+                    for f in pureRenameCopy:
+                        print("  " + f)
+
+                print("")
+                print("To revert the changes, use \"p4 revert ...\", and delete")
+                print("the submit template file \"%s\"" % fileName)
+                if filesToAdd:
+                    print("Since the commit adds new files, they must be deleted:")
+                    for f in filesToAdd:
+                        print("  " + f)
+                print("")
+                sys.stdout.flush()
+                return True
+
             if self.edit_template(fileName):
+                if not self.no_verify:
+                    if not run_git_hook("p4-changelist", [fileName]):
+                        print("The p4-changelist hook failed.")
+                        sys.stdout.flush()
+                        return False
+
                 # read the edited message and submit
                 tmpFile = open(fileName, "rb")
-                message = tmpFile.read()
+                message = decode_text_stream(tmpFile.read())
                 tmpFile.close()
                 if self.isWindows:
                     message = message.replace("\r\n", "\n")
-                submitTemplate = message[:message.index(separatorLine)]
+                if message.find(separatorLine) != -1:
+                    submitTemplate = message[:message.index(separatorLine)]
+                else:
+                    submitTemplate = message
+
+                if len(submitTemplate.strip()) == 0:
+                    print("Changelist is empty, aborting this changelist.")
+                    sys.stdout.flush()
+                    return False
 
                 if update_shelve:
                     p4_write_pipe(['shelve', '-r', '-i'], submitTemplate)
@@ -2097,20 +2268,23 @@
 
                 submitted = True
 
+                run_git_hook("p4-post-changelist")
         finally:
-            # skip this patch
+            # Revert changes if we skip this patch
             if not submitted or self.shelve:
                 if self.shelve:
                     print ("Reverting shelved files.")
                 else:
                     print ("Submission cancelled, undoing p4 changes.")
+                sys.stdout.flush()
                 for f in editedFiles | filesToDelete:
                     p4_revert(f)
                 for f in filesToAdd:
                     p4_revert(f)
                     os.remove(f)
 
-        os.remove(fileName)
+            if not self.prepare_p4_only:
+                os.remove(fileName)
         return submitted
 
     # Export git tags as p4 labels. Create a p4 label and then tag
@@ -2334,13 +2508,17 @@
             sys.exit("number of commits (%d) must match number of shelved changelist (%d)" %
                      (len(commits), num_shelves))
 
-        hooks_path = gitConfig("core.hooksPath")
-        if len(hooks_path) <= 0:
-            hooks_path = os.path.join(os.environ.get("GIT_DIR", ".git"), "hooks")
-
-        hook_file = os.path.join(hooks_path, "p4-pre-submit")
-        if os.path.isfile(hook_file) and os.access(hook_file, os.X_OK) and subprocess.call([hook_file]) != 0:
-            sys.exit(1)
+        if not self.no_verify:
+            try:
+                if not run_git_hook("p4-pre-submit"):
+                    print("\nThe p4-pre-submit hook failed, aborting the submit.\n\nYou can skip " \
+                        "this pre-submission check by adding\nthe command line option '--no-verify', " \
+                        "however,\nthis will also skip the p4-changelist hook as well.")
+                    sys.exit(1)
+            except Exception as e:
+                print("\nThe p4-pre-submit hook failed, aborting the submit.\n\nThe hook failed "\
+                    "with the error '{0}'".format(e.message) )
+                sys.exit(1)
 
         #
         # Apply the commits, one at a time.  On failure, ask if should
@@ -2490,7 +2668,7 @@
 
     def convert_client_path(self, clientFile):
         # chop off //client/ part to make it relative
-        if not clientFile.startswith(self.client_prefix):
+        if not decode_path(clientFile).startswith(self.client_prefix):
             die("No prefix '%s' on clientFile '%s'" %
                 (self.client_prefix, clientFile))
         return clientFile[len(self.client_prefix):]
@@ -2499,7 +2677,7 @@
         """ Caching file paths by "p4 where" batch query """
 
         # List depot file paths exclude that already cached
-        fileArgs = [f['path'] for f in files if f['path'] not in self.client_spec_path_cache]
+        fileArgs = [f['path'] for f in files if decode_path(f['path']) not in self.client_spec_path_cache]
 
         if len(fileArgs) == 0:
             return  # All files in cache
@@ -2514,16 +2692,18 @@
             if "unmap" in res:
                 # it will list all of them, but only one not unmap-ped
                 continue
+            depot_path = decode_path(res['depotFile'])
             if gitConfigBool("core.ignorecase"):
-                res['depotFile'] = res['depotFile'].lower()
-            self.client_spec_path_cache[res['depotFile']] = self.convert_client_path(res["clientFile"])
+                depot_path = depot_path.lower()
+            self.client_spec_path_cache[depot_path] = self.convert_client_path(res["clientFile"])
 
         # not found files or unmap files set to ""
         for depotFile in fileArgs:
+            depotFile = decode_path(depotFile)
             if gitConfigBool("core.ignorecase"):
                 depotFile = depotFile.lower()
             if depotFile not in self.client_spec_path_cache:
-                self.client_spec_path_cache[depotFile] = ""
+                self.client_spec_path_cache[depotFile] = b''
 
     def map_in_client(self, depot_path):
         """Return the relative location in the client where this
@@ -2628,6 +2808,7 @@
     def checkpoint(self):
         self.gitStream.write("checkpoint\n\n")
         self.gitStream.write("progress checkpoint\n\n")
+        self.gitStream.flush()
         out = self.gitOutput.readline()
         if self.verbose:
             print("checkpoint finished: " + out)
@@ -2641,7 +2822,7 @@
             elif path.lower() == p.lower():
                 return False
         for p in self.depotPaths:
-            if p4PathStartsWith(path, p):
+            if p4PathStartsWith(path, decode_path(p)):
                 return True
         return False
 
@@ -2650,7 +2831,7 @@
         fnum = 0
         while "depotFile%s" % fnum in commit:
             path =  commit["depotFile%s" % fnum]
-            found = self.isPathWanted(path)
+            found = self.isPathWanted(decode_path(path))
             if not found:
                 fnum = fnum + 1
                 continue
@@ -2684,7 +2865,7 @@
         if self.useClientSpec:
             # branch detection moves files up a level (the branch name)
             # from what client spec interpretation gives
-            path = self.clientSpecDirs.map_in_client(path)
+            path = decode_path(self.clientSpecDirs.map_in_client(path))
             if self.detectBranches:
                 for b in self.knownBranches:
                     if p4PathStartsWith(path, b + "/"):
@@ -2718,14 +2899,15 @@
         branches = {}
         fnum = 0
         while "depotFile%s" % fnum in commit:
-            path =  commit["depotFile%s" % fnum]
+            raw_path = commit["depotFile%s" % fnum]
+            path = decode_path(raw_path)
             found = self.isPathWanted(path)
             if not found:
                 fnum = fnum + 1
                 continue
 
             file = {}
-            file["path"] = path
+            file["path"] = raw_path
             file["rev"] = commit["rev%s" % fnum]
             file["action"] = commit["action%s" % fnum]
             file["type"] = commit["type%s" % fnum]
@@ -2734,7 +2916,7 @@
             # start with the full relative path where this file would
             # go in a p4 client
             if self.useClientSpec:
-                relPath = self.clientSpecDirs.map_in_client(path)
+                relPath = decode_path(self.clientSpecDirs.map_in_client(path))
             else:
                 relPath = self.stripRepoPath(path, self.depotPaths)
 
@@ -2750,7 +2932,7 @@
         return branches
 
     def writeToGitStream(self, gitMode, relPath, contents):
-        self.gitStream.write('M %s inline %s\n' % (gitMode, relPath))
+        self.gitStream.write(encode_text_stream(u'M {} inline {}\n'.format(gitMode, relPath)))
         self.gitStream.write('data %d\n' % sum(len(d) for d in contents))
         for d in contents:
             self.gitStream.write(d)
@@ -2772,14 +2954,15 @@
     # - helper for streamP4Files
 
     def streamOneP4File(self, file, contents):
-        relPath = self.stripRepoPath(file['depotFile'], self.branchPrefixes)
-        relPath = self.encodeWithUTF8(relPath)
+        file_path = file['depotFile']
+        relPath = self.stripRepoPath(decode_path(file_path), self.branchPrefixes)
+
         if verbose:
             if 'fileSize' in self.stream_file:
                 size = int(self.stream_file['fileSize'])
             else:
                 size = 0 # deleted files don't get a fileSize apparently
-            sys.stdout.write('\r%s --> %s (%i MB)\n' % (file['depotFile'], relPath, size/1024/1024))
+            sys.stdout.write('\r%s --> %s (%i MB)\n' % (file_path, relPath, size/1024/1024))
             sys.stdout.flush()
 
         (type_base, type_mods) = split_p4_type(file["type"])
@@ -2791,13 +2974,13 @@
             git_mode = "120000"
             # p4 print on a symlink sometimes contains "target\n";
             # if it does, remove the newline
-            data = ''.join(contents)
+            data = ''.join(decode_text_stream(c) for c in contents)
             if not data:
                 # Some version of p4 allowed creating a symlink that pointed
                 # to nothing.  This causes p4 errors when checking out such
                 # a change, and errors here too.  Work around it by ignoring
                 # the bad symlink; hopefully a future change fixes it.
-                print("\nIgnoring empty symlink in %s" % file['depotFile'])
+                print("\nIgnoring empty symlink in %s" % file_path)
                 return
             elif data[-1] == '\n':
                 contents = [data[:-1]]
@@ -2816,7 +2999,7 @@
             # just the native "NT" type.
             #
             try:
-                text = p4_read_pipe(['print', '-q', '-o', '-', '%s@%s' % (file['depotFile'], file['change'])])
+                text = p4_read_pipe(['print', '-q', '-o', '-', '%s@%s' % (decode_path(file['depotFile']), file['change'])], raw=True)
             except Exception as e:
                 if 'Translation of file content failed' in str(e):
                     type_base = 'binary'
@@ -2824,7 +3007,7 @@
                     raise e
             else:
                 if p4_version_string().find('/NT') >= 0:
-                    text = text.replace('\r\n', '\n')
+                    text = text.replace(b'\r\n', b'\n')
                 contents = [ text ]
 
         if type_base == "apple":
@@ -2845,7 +3028,7 @@
         pattern = p4_keywords_regexp_for_type(type_base, type_mods)
         if pattern:
             regexp = re.compile(pattern, re.VERBOSE)
-            text = ''.join(contents)
+            text = ''.join(decode_text_stream(c) for c in contents)
             text = regexp.sub(r'$\1$', text)
             contents = [ text ]
 
@@ -2855,12 +3038,11 @@
         self.writeToGitStream(git_mode, relPath, contents)
 
     def streamOneP4Deletion(self, file):
-        relPath = self.stripRepoPath(file['path'], self.branchPrefixes)
-        relPath = self.encodeWithUTF8(relPath)
+        relPath = self.stripRepoPath(decode_path(file['path']), self.branchPrefixes)
         if verbose:
             sys.stdout.write("delete %s\n" % relPath)
             sys.stdout.flush()
-        self.gitStream.write("D %s\n" % relPath)
+        self.gitStream.write(encode_text_stream(u'D {}\n'.format(relPath)))
 
         if self.largeFileSystem and self.largeFileSystem.isLargeFile(relPath):
             self.largeFileSystem.removeLargeFile(relPath)
@@ -2960,9 +3142,9 @@
                 if 'shelved_cl' in f:
                     # Handle shelved CLs using the "p4 print file@=N" syntax to print
                     # the contents
-                    fileArg = '%s@=%d' % (f['path'], f['shelved_cl'])
+                    fileArg = f['path'] + encode_text_stream('@={}'.format(f['shelved_cl']))
                 else:
-                    fileArg = '%s#%s' % (f['path'], f['rev'])
+                    fileArg = f['path'] + encode_text_stream('#{}'.format(f['rev']))
 
                 fileArgs.append(fileArg)
 
@@ -3043,8 +3225,8 @@
         if self.clientSpecDirs:
             self.clientSpecDirs.update_client_spec_path_cache(files)
 
-        files = [f for f in files
-            if self.inClientSpec(f['path']) and self.hasBranchPrefix(f['path'])]
+        files = [f for (f, path) in ((f, decode_path(f['path'])) for f in files)
+            if self.inClientSpec(path) and self.hasBranchPrefix(path)]
 
         if gitConfigBool('git-p4.keepEmptyCommits'):
             allow_empty = True
@@ -3539,6 +3721,74 @@
             print("IO error details: {}".format(err))
             print(self.gitError.read())
 
+
+    def importRevisions(self, args, branch_arg_given):
+        changes = []
+
+        if len(self.changesFile) > 0:
+            with open(self.changesFile) as f:
+                output = f.readlines()
+            changeSet = set()
+            for line in output:
+                changeSet.add(int(line))
+
+            for change in changeSet:
+                changes.append(change)
+
+            changes.sort()
+        else:
+            # catch "git p4 sync" with no new branches, in a repo that
+            # does not have any existing p4 branches
+            if len(args) == 0:
+                if not self.p4BranchesInGit:
+                    raise P4CommandException("No remote p4 branches.  Perhaps you never did \"git p4 clone\" in here.")
+
+                # The default branch is master, unless --branch is used to
+                # specify something else.  Make sure it exists, or complain
+                # nicely about how to use --branch.
+                if not self.detectBranches:
+                    if not branch_exists(self.branch):
+                        if branch_arg_given:
+                            raise P4CommandException("Error: branch %s does not exist." % self.branch)
+                        else:
+                            raise P4CommandException("Error: no branch %s; perhaps specify one with --branch." %
+                                self.branch)
+
+            if self.verbose:
+                print("Getting p4 changes for %s...%s" % (', '.join(self.depotPaths),
+                                                          self.changeRange))
+            changes = p4ChangesForPaths(self.depotPaths, self.changeRange, self.changes_block_size)
+
+            if len(self.maxChanges) > 0:
+                changes = changes[:min(int(self.maxChanges), len(changes))]
+
+        if len(changes) == 0:
+            if not self.silent:
+                print("No changes to import!")
+        else:
+            if not self.silent and not self.detectBranches:
+                print("Import destination: %s" % self.branch)
+
+            self.updatedBranches = set()
+
+            if not self.detectBranches:
+                if args:
+                    # start a new branch
+                    self.initialParent = ""
+                else:
+                    # build on a previous revision
+                    self.initialParent = parseRevision(self.branch)
+
+            self.importChanges(changes)
+
+            if not self.silent:
+                print("")
+                if len(self.updatedBranches) > 0:
+                    sys.stdout.write("Updated branches: ")
+                    for b in self.updatedBranches:
+                        sys.stdout.write("%s " % b)
+                    sys.stdout.write("\n")
+
     def openStreams(self):
         self.importProcess = subprocess.Popen(["git", "fast-import"],
                                               stdin=subprocess.PIPE,
@@ -3548,12 +3798,24 @@
         self.gitStream = self.importProcess.stdin
         self.gitError = self.importProcess.stderr
 
+        if bytes is not str:
+            # Wrap gitStream.write() so that it can be called using `str` arguments
+            def make_encoded_write(write):
+                def encoded_write(s):
+                    return write(s.encode() if isinstance(s, str) else s)
+                return encoded_write
+
+            self.gitStream.write = make_encoded_write(self.gitStream.write)
+
     def closeStreams(self):
+        if self.gitStream is None:
+            return
         self.gitStream.close()
         if self.importProcess.wait() != 0:
             die("fast-import failed: %s" % self.gitError.read())
         self.gitOutput.close()
         self.gitError.close()
+        self.gitStream = None
 
     def run(self, args):
         if self.importIntoRemotes:
@@ -3737,87 +3999,36 @@
                     b = b[len(self.projectName):]
                 self.createdBranches.add(b)
 
+        p4_check_access()
+
         self.openStreams()
 
-        if revision:
-            self.importHeadRevision(revision)
-        else:
-            changes = []
+        err = None
 
-            if len(self.changesFile) > 0:
-                output = open(self.changesFile).readlines()
-                changeSet = set()
-                for line in output:
-                    changeSet.add(int(line))
-
-                for change in changeSet:
-                    changes.append(change)
-
-                changes.sort()
+        try:
+            if revision:
+                self.importHeadRevision(revision)
             else:
-                # catch "git p4 sync" with no new branches, in a repo that
-                # does not have any existing p4 branches
-                if len(args) == 0:
-                    if not self.p4BranchesInGit:
-                        die("No remote p4 branches.  Perhaps you never did \"git p4 clone\" in here.")
+                self.importRevisions(args, branch_arg_given)
 
-                    # The default branch is master, unless --branch is used to
-                    # specify something else.  Make sure it exists, or complain
-                    # nicely about how to use --branch.
-                    if not self.detectBranches:
-                        if not branch_exists(self.branch):
-                            if branch_arg_given:
-                                die("Error: branch %s does not exist." % self.branch)
-                            else:
-                                die("Error: no branch %s; perhaps specify one with --branch." %
-                                    self.branch)
+            if gitConfigBool("git-p4.importLabels"):
+                self.importLabels = True
 
-                if self.verbose:
-                    print("Getting p4 changes for %s...%s" % (', '.join(self.depotPaths),
-                                                              self.changeRange))
-                changes = p4ChangesForPaths(self.depotPaths, self.changeRange, self.changes_block_size)
+            if self.importLabels:
+                p4Labels = getP4Labels(self.depotPaths)
+                gitTags = getGitTags()
 
-                if len(self.maxChanges) > 0:
-                    changes = changes[:min(int(self.maxChanges), len(changes))]
+                missingP4Labels = p4Labels - gitTags
+                self.importP4Labels(self.gitStream, missingP4Labels)
 
-            if len(changes) == 0:
-                if not self.silent:
-                    print("No changes to import!")
-            else:
-                if not self.silent and not self.detectBranches:
-                    print("Import destination: %s" % self.branch)
+        except P4CommandException as e:
+            err = e
 
-                self.updatedBranches = set()
+        finally:
+            self.closeStreams()
 
-                if not self.detectBranches:
-                    if args:
-                        # start a new branch
-                        self.initialParent = ""
-                    else:
-                        # build on a previous revision
-                        self.initialParent = parseRevision(self.branch)
-
-                self.importChanges(changes)
-
-                if not self.silent:
-                    print("")
-                    if len(self.updatedBranches) > 0:
-                        sys.stdout.write("Updated branches: ")
-                        for b in self.updatedBranches:
-                            sys.stdout.write("%s " % b)
-                        sys.stdout.write("\n")
-
-        if gitConfigBool("git-p4.importLabels"):
-            self.importLabels = True
-
-        if self.importLabels:
-            p4Labels = getP4Labels(self.depotPaths)
-            gitTags = getGitTags()
-
-            missingP4Labels = p4Labels - gitTags
-            self.importP4Labels(self.gitStream, missingP4Labels)
-
-        self.closeStreams()
+        if err:
+            die(str(err))
 
         # Cleanup temporary branches created during import
         if self.tempBranches != []:
@@ -4121,7 +4332,6 @@
     "unshelve" : P4Unshelve,
 }
 
-
 def main():
     if len(sys.argv[1:]) == 0:
         printUsage(commands.keys())
diff --git a/git-submodule.sh b/git-submodule.sh
index aaa1809..afcb4c0 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -241,13 +241,15 @@
 	    die "$(eval_gettext "'\$sm_path' does not have a commit checked out")"
 	fi
 
-	if test -z "$force" &&
-		! git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" > /dev/null 2>&1
+	if test -z "$force"
 	then
-		eval_gettextln "The following path is ignored by one of your .gitignore files:
-\$sm_path
-Use -f if you really want to add it." >&2
-		exit 1
+	    dryerr=$(git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" 2>&1 >/dev/null)
+	    res=$?
+	    if test $res -ne 0
+	    then
+		 echo >&2 "$dryerr"
+		 exit $res
+	    fi
 	fi
 
 	if test -n "$custom_name"
diff --git a/gpg-interface.c b/gpg-interface.c
index 5134ce2..2d538bc 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -7,6 +7,8 @@
 #include "tempfile.h"
 
 static char *configured_signing_key;
+static enum signature_trust_level configured_min_trust_level = TRUST_UNDEFINED;
+
 struct gpg_format {
 	const char *name;
 	const char *program;
@@ -85,6 +87,8 @@
 #define GPG_STATUS_UID		(1<<2)
 /* The status includes key fingerprints */
 #define GPG_STATUS_FINGERPRINT	(1<<3)
+/* The status includes trust level */
+#define GPG_STATUS_TRUST_LEVEL	(1<<4)
 
 /* Short-hand for standard exclusive *SIG status with keyid & UID */
 #define GPG_STATUS_STDSIG	(GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
@@ -96,13 +100,23 @@
 } sigcheck_gpg_status[] = {
 	{ 'G', "GOODSIG ", GPG_STATUS_STDSIG },
 	{ 'B', "BADSIG ", GPG_STATUS_STDSIG },
-	{ 'U', "TRUST_NEVER", 0 },
-	{ 'U', "TRUST_UNDEFINED", 0 },
 	{ 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
 	{ 'X', "EXPSIG ", GPG_STATUS_STDSIG },
 	{ 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
 	{ 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
 	{ 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT },
+	{ 0, "TRUST_", GPG_STATUS_TRUST_LEVEL },
+};
+
+static struct {
+	const char *key;
+	enum signature_trust_level value;
+} sigcheck_gpg_trust_level[] = {
+	{ "UNDEFINED", TRUST_UNDEFINED },
+	{ "NEVER", TRUST_NEVER },
+	{ "MARGINAL", TRUST_MARGINAL },
+	{ "FULLY", TRUST_FULLY },
+	{ "ULTIMATE", TRUST_ULTIMATE },
 };
 
 static void replace_cstring(char **field, const char *line, const char *next)
@@ -115,6 +129,20 @@
 		*field = NULL;
 }
 
+static int parse_gpg_trust_level(const char *level,
+				 enum signature_trust_level *res)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_trust_level); i++) {
+		if (!strcmp(sigcheck_gpg_trust_level[i].key, level)) {
+			*res = sigcheck_gpg_trust_level[i].value;
+			return 0;
+		}
+	}
+	return 1;
+}
+
 static void parse_gpg_output(struct signature_check *sigc)
 {
 	const char *buf = sigc->gpg_status;
@@ -136,9 +164,18 @@
 		/* Iterate over all search strings */
 		for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
 			if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
+				/*
+				 * GOODSIG, BADSIG etc. can occur only once for
+				 * each signature.  Therefore, if we had more
+				 * than one then we're dealing with multiple
+				 * signatures.  We don't support them
+				 * currently, and they're rather hard to
+				 * create, so something is likely fishy and we
+				 * should reject them altogether.
+				 */
 				if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
 					if (seen_exclusive_status++)
-						goto found_duplicate_status;
+						goto error;
 				}
 
 				if (sigcheck_gpg_status[i].result)
@@ -154,6 +191,25 @@
 						replace_cstring(&sigc->signer, line, next);
 					}
 				}
+
+				/* Do we have trust level? */
+				if (sigcheck_gpg_status[i].flags & GPG_STATUS_TRUST_LEVEL) {
+					/*
+					 * GPG v1 and v2 differs in how the
+					 * TRUST_ lines are written.  Some
+					 * trust lines contain no additional
+					 * space-separated information for v1.
+					 */
+					size_t trust_size = strcspn(line, " \n");
+					char *trust = xmemdupz(line, trust_size);
+
+					if (parse_gpg_trust_level(trust, &sigc->trust_level)) {
+						free(trust);
+						goto error;
+					}
+					free(trust);
+				}
+
 				/* Do we have fingerprint? */
 				if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {
 					const char *limit;
@@ -191,14 +247,7 @@
 	}
 	return;
 
-found_duplicate_status:
-	/*
-	 * GOODSIG, BADSIG etc. can occur only once for each signature.
-	 * Therefore, if we had more than one then we're dealing with multiple
-	 * signatures.  We don't support them currently, and they're rather
-	 * hard to create, so something is likely fishy and we should reject
-	 * them altogether.
-	 */
+error:
 	sigc->result = 'E';
 	/* Clear partial data to avoid confusion */
 	FREE_AND_NULL(sigc->primary_key_fingerprint);
@@ -264,6 +313,7 @@
 	int status;
 
 	sigc->result = 'N';
+	sigc->trust_level = -1;
 
 	status = verify_signed_buffer(payload, plen, signature, slen,
 				      &gpg_output, &gpg_status);
@@ -273,7 +323,8 @@
 	sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
 	sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
 	parse_gpg_output(sigc);
-	status |= sigc->result != 'G' && sigc->result != 'U';
+	status |= sigc->result != 'G';
+	status |= sigc->trust_level < configured_min_trust_level;
 
  out:
 	strbuf_release(&gpg_status);
@@ -320,6 +371,8 @@
 {
 	struct gpg_format *fmt = NULL;
 	char *fmtname = NULL;
+	char *trust;
+	int ret;
 
 	if (!strcmp(var, "user.signingkey")) {
 		if (!value)
@@ -339,6 +392,20 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "gpg.mintrustlevel")) {
+		if (!value)
+			return config_error_nonbool(var);
+
+		trust = xstrdup_toupper(value);
+		ret = parse_gpg_trust_level(trust, &configured_min_trust_level);
+		free(trust);
+
+		if (ret)
+			return error("unsupported value for %s: %s", var,
+				     value);
+		return 0;
+	}
+
 	if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
 		fmtname = "openpgp";
 
diff --git a/gpg-interface.h b/gpg-interface.h
index 93cc3af..f4e9b4f 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -7,6 +7,14 @@
 #define GPG_VERIFY_RAW			2
 #define GPG_VERIFY_OMIT_STATUS	4
 
+enum signature_trust_level {
+	TRUST_UNDEFINED,
+	TRUST_NEVER,
+	TRUST_MARGINAL,
+	TRUST_FULLY,
+	TRUST_ULTIMATE,
+};
+
 struct signature_check {
 	char *payload;
 	char *gpg_output;
@@ -16,7 +24,6 @@
 	 * possible "result":
 	 * 0 (not checked)
 	 * N (checked but no further result)
-	 * U (untrusted good)
 	 * G (good)
 	 * B (bad)
 	 */
@@ -25,6 +32,7 @@
 	char *key;
 	char *fingerprint;
 	char *primary_key_fingerprint;
+	enum signature_trust_level trust_level;
 };
 
 void signature_check_clear(struct signature_check *sigc);
diff --git a/graph.c b/graph.c
index aaf9706..4fb25ad 100644
--- a/graph.c
+++ b/graph.c
@@ -1233,8 +1233,14 @@
 			 * prevent any other edges from moving
 			 * horizontally.
 			 */
-			if (horizontal_edge == -1)
-				horizontal_edge = i;
+			if (horizontal_edge == -1) {
+				int j;
+				horizontal_edge_target = target;
+				horizontal_edge = i - 1;
+
+				for (j = (target * 2) + 3; j < (i - 2); j += 2)
+					graph->mapping[j] = target;
+			}
 		}
 	}
 
diff --git a/grep.c b/grep.c
index 0552b12..13232a9 100644
--- a/grep.c
+++ b/grep.c
@@ -1540,11 +1540,6 @@
 		pthread_mutex_unlock(&grep_attr_mutex);
 }
 
-/*
- * Same as git_attr_mutex, but protecting the thread-unsafe object db access.
- */
-pthread_mutex_t grep_read_mutex;
-
 static int match_funcname(struct grep_opt *opt, struct grep_source *gs, char *bol, char *eol)
 {
 	xdemitconf_t *xecfg = opt->priv;
@@ -1741,13 +1736,20 @@
 	}
 
 	/*
-	 * fill_textconv is not remotely thread-safe; it may load objects
-	 * behind the scenes, and it modifies the global diff tempfile
-	 * structure.
+	 * fill_textconv is not remotely thread-safe; it modifies the global
+	 * diff tempfile structure, writes to the_repo's odb and might
+	 * internally call thread-unsafe functions such as the
+	 * prepare_packed_git() lazy-initializator. Because of the last two, we
+	 * must ensure mutual exclusion between this call and the object reading
+	 * API, thus we use obj_read_lock() here.
+	 *
+	 * TODO: allowing text conversion to run in parallel with object
+	 * reading operations might increase performance in the multithreaded
+	 * non-worktreee git-grep with --textconv.
 	 */
-	grep_read_lock();
+	obj_read_lock();
 	size = fill_textconv(r, driver, df, &buf);
-	grep_read_unlock();
+	obj_read_unlock();
 	free_filespec(df);
 
 	/*
@@ -1813,10 +1815,15 @@
 		grep_source_load_driver(gs, opt->repo->index);
 		/*
 		 * We might set up the shared textconv cache data here, which
-		 * is not thread-safe.
+		 * is not thread-safe. Also, get_oid_with_context() and
+		 * parse_object() might be internally called. As they are not
+		 * currenty thread-safe and might be racy with object reading,
+		 * obj_read_lock() must be called.
 		 */
 		grep_attr_lock();
+		obj_read_lock();
 		textconv = userdiff_get_textconv(opt->repo, gs->driver);
+		obj_read_unlock();
 		grep_attr_unlock();
 	}
 
@@ -2116,10 +2123,7 @@
 {
 	enum object_type type;
 
-	grep_read_lock();
 	gs->buf = read_object_file(gs->identifier, &type, &gs->size);
-	grep_read_unlock();
-
 	if (!gs->buf)
 		return error(_("'%s': unable to read %s"),
 			     gs->name,
diff --git a/grep.h b/grep.h
index 811fd27..9115db8 100644
--- a/grep.h
+++ b/grep.h
@@ -220,18 +220,5 @@
  */
 extern int grep_use_locks;
 extern pthread_mutex_t grep_attr_mutex;
-extern pthread_mutex_t grep_read_mutex;
-
-static inline void grep_read_lock(void)
-{
-	if (grep_use_locks)
-		pthread_mutex_lock(&grep_read_mutex);
-}
-
-static inline void grep_read_unlock(void)
-{
-	if (grep_use_locks)
-		pthread_mutex_unlock(&grep_read_mutex);
-}
 
 #endif
diff --git a/help.c b/help.c
index cf67624..44cee69 100644
--- a/help.c
+++ b/help.c
@@ -407,91 +407,6 @@
 	putchar('\n');
 }
 
-struct slot_expansion {
-	const char *prefix;
-	const char *placeholder;
-	void (*fn)(struct string_list *list, const char *prefix);
-	int found;
-};
-
-void list_config_help(int for_human)
-{
-	struct slot_expansion slot_expansions[] = {
-		{ "advice", "*", list_config_advices },
-		{ "color.branch", "<slot>", list_config_color_branch_slots },
-		{ "color.decorate", "<slot>", list_config_color_decorate_slots },
-		{ "color.diff", "<slot>", list_config_color_diff_slots },
-		{ "color.grep", "<slot>", list_config_color_grep_slots },
-		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
-		{ "color.remote", "<slot>", list_config_color_sideband_slots },
-		{ "color.status", "<slot>", list_config_color_status_slots },
-		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
-		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
-		{ NULL, NULL, NULL }
-	};
-	const char **p;
-	struct slot_expansion *e;
-	struct string_list keys = STRING_LIST_INIT_DUP;
-	int i;
-
-	for (p = config_name_list; *p; p++) {
-		const char *var = *p;
-		struct strbuf sb = STRBUF_INIT;
-
-		for (e = slot_expansions; e->prefix; e++) {
-
-			strbuf_reset(&sb);
-			strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
-			if (!strcasecmp(var, sb.buf)) {
-				e->fn(&keys, e->prefix);
-				e->found++;
-				break;
-			}
-		}
-		strbuf_release(&sb);
-		if (!e->prefix)
-			string_list_append(&keys, var);
-	}
-
-	for (e = slot_expansions; e->prefix; e++)
-		if (!e->found)
-			BUG("slot_expansion %s.%s is not used",
-			    e->prefix, e->placeholder);
-
-	string_list_sort(&keys);
-	for (i = 0; i < keys.nr; i++) {
-		const char *var = keys.items[i].string;
-		const char *wildcard, *tag, *cut;
-
-		if (for_human) {
-			puts(var);
-			continue;
-		}
-
-		wildcard = strchr(var, '*');
-		tag = strchr(var, '<');
-
-		if (!wildcard && !tag) {
-			puts(var);
-			continue;
-		}
-
-		if (wildcard && !tag)
-			cut = wildcard;
-		else if (!wildcard && tag)
-			cut = tag;
-		else
-			cut = wildcard < tag ? wildcard : tag;
-
-		/*
-		 * We may produce duplicates, but that's up to
-		 * git-completion.bash to handle
-		 */
-		printf("%.*s\n", (int)(cut - var), var);
-	}
-	string_list_clear(&keys, 0);
-}
-
 static int get_alias(const char *var, const char *value, void *data)
 {
 	struct string_list *list = data;
@@ -707,8 +622,33 @@
 	exit(1);
 }
 
+void get_version_info(struct strbuf *buf, int show_build_options)
+{
+	/*
+	 * The format of this string should be kept stable for compatibility
+	 * with external projects that rely on the output of "git version".
+	 *
+	 * Always show the version, even if other options are given.
+	 */
+	strbuf_addf(buf, "git version %s\n", git_version_string);
+
+	if (show_build_options) {
+		strbuf_addf(buf, "cpu: %s\n", GIT_HOST_CPU);
+		if (git_built_from_commit_string[0])
+			strbuf_addf(buf, "built from commit: %s\n",
+			       git_built_from_commit_string);
+		else
+			strbuf_addstr(buf, "no commit associated with this build\n");
+		strbuf_addf(buf, "sizeof-long: %d\n", (int)sizeof(long));
+		strbuf_addf(buf, "sizeof-size_t: %d\n", (int)sizeof(size_t));
+		strbuf_addf(buf, "shell-path: %s\n", SHELL_PATH);
+		/* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
+	}
+}
+
 int cmd_version(int argc, const char **argv, const char *prefix)
 {
+	struct strbuf buf = STRBUF_INIT;
 	int build_options = 0;
 	const char * const usage[] = {
 		N_("git version [<options>]"),
@@ -722,25 +662,11 @@
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
-	/*
-	 * The format of this string should be kept stable for compatibility
-	 * with external projects that rely on the output of "git version".
-	 *
-	 * Always show the version, even if other options are given.
-	 */
-	printf("git version %s\n", git_version_string);
+	get_version_info(&buf, build_options);
+	printf("%s", buf.buf);
 
-	if (build_options) {
-		printf("cpu: %s\n", GIT_HOST_CPU);
-		if (git_built_from_commit_string[0])
-			printf("built from commit: %s\n",
-			       git_built_from_commit_string);
-		else
-			printf("no commit associated with this build\n");
-		printf("sizeof-long: %d\n", (int)sizeof(long));
-		printf("sizeof-size_t: %d\n", (int)sizeof(size_t));
-		/* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
-	}
+	strbuf_release(&buf);
+
 	return 0;
 }
 
diff --git a/help.h b/help.h
index 7a455be..500521b 100644
--- a/help.h
+++ b/help.h
@@ -22,7 +22,6 @@
 void list_common_cmds_help(void);
 void list_all_cmds_help(void);
 void list_common_guides_help(void);
-void list_config_help(int for_human);
 
 void list_all_main_cmds(struct string_list *list);
 void list_all_other_cmds(struct string_list *list);
@@ -38,6 +37,7 @@
 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes);
 int is_in_cmdlist(struct cmdnames *cmds, const char *name);
 void list_commands(unsigned int colopts, struct cmdnames *main_cmds, struct cmdnames *other_cmds);
+void get_version_info(struct strbuf *buf, int show_build_options);
 
 /*
  * call this to die(), when it is suspected that the user mistyped a
diff --git a/http.c b/http.c
index 5f34816..00a0e50 100644
--- a/http.c
+++ b/http.c
@@ -680,8 +680,8 @@
 	for (header = headers; *header; header++) {
 		if (hide_sensitive_header)
 			redact_sensitive_header(*header);
-		strbuf_insert((*header), 0, text, strlen(text));
-		strbuf_insert((*header), strlen(text), ": ", 2);
+		strbuf_insertstr((*header), 0, text);
+		strbuf_insertstr((*header), strlen(text), ": ");
 		strbuf_rtrim((*header));
 		strbuf_addch((*header), '\n');
 		trace_strbuf(&trace_curl, (*header));
diff --git a/log-tree.c b/log-tree.c
index 4e32638..cae38dc 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -501,7 +501,8 @@
 	int status, nth;
 	size_t payload_size, gpg_message_offset;
 
-	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &oid);
+	hash_object_file(the_hash_algo, extra->value, extra->len,
+			 type_name(OBJ_TAG), &oid);
 	tag = lookup_tag(the_repository, &oid);
 	if (!tag)
 		return -1; /* error message already given */
diff --git a/mailinfo.c b/mailinfo.c
index b395adb..cf92255 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -254,7 +254,7 @@
 	mi->delsp = has_attr_value(line->buf, "delsp=", "yes");
 
 	if (slurp_attr(line->buf, "boundary=", boundary)) {
-		strbuf_insert(boundary, 0, "--", 2);
+		strbuf_insertstr(boundary, 0, "--");
 		if (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) {
 			error("Too many boundaries to handle");
 			mi->input_error = -1;
@@ -346,11 +346,17 @@
 	"From","Subject","Date",
 };
 
-static inline int cmp_header(const struct strbuf *line, const char *hdr)
+static inline int skip_header(const struct strbuf *line, const char *hdr,
+			      const char **outval)
 {
-	int len = strlen(hdr);
-	return !strncasecmp(line->buf, hdr, len) && line->len > len &&
-			line->buf[len] == ':' && isspace(line->buf[len + 1]);
+	const char *val;
+	if (!skip_iprefix(line->buf, hdr, &val) ||
+	    *val++ != ':')
+		return 0;
+	while (isspace(*val))
+		val++;
+	*outval = val;
+	return 1;
 }
 
 static int is_format_patch_separator(const char *line, int len)
@@ -543,22 +549,36 @@
 		mi->input_error = -1;
 }
 
+/*
+ * Returns true if "line" contains a header matching "hdr", in which case "val"
+ * will contain the value of the header with any RFC2047 B and Q encoding
+ * unwrapped, and optionally normalize the meta information to utf8.
+ */
+static int parse_header(const struct strbuf *line,
+			const char *hdr,
+			struct mailinfo *mi,
+			struct strbuf *val)
+{
+	const char *val_str;
+
+	if (!skip_header(line, hdr, &val_str))
+		return 0;
+	strbuf_addstr(val, val_str);
+	decode_header(mi, val);
+	return 1;
+}
+
 static int check_header(struct mailinfo *mi,
 			const struct strbuf *line,
 			struct strbuf *hdr_data[], int overwrite)
 {
-	int i, ret = 0, len;
+	int i, ret = 0;
 	struct strbuf sb = STRBUF_INIT;
 
 	/* search for the interesting parts */
 	for (i = 0; header[i]; i++) {
-		int len = strlen(header[i]);
-		if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
-			/* Unwrap inline B and Q encoding, and optionally
-			 * normalize the meta information to utf8.
-			 */
-			strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
-			decode_header(mi, &sb);
+		if ((!hdr_data[i] || overwrite) &&
+		    parse_header(line, header[i], mi, &sb)) {
 			handle_header(&hdr_data[i], &sb);
 			ret = 1;
 			goto check_header_out;
@@ -566,27 +586,17 @@
 	}
 
 	/* Content stuff */
-	if (cmp_header(line, "Content-Type")) {
-		len = strlen("Content-Type: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
-		decode_header(mi, &sb);
-		strbuf_insert(&sb, 0, "Content-Type: ", len);
+	if (parse_header(line, "Content-Type", mi, &sb)) {
 		handle_content_type(mi, &sb);
 		ret = 1;
 		goto check_header_out;
 	}
-	if (cmp_header(line, "Content-Transfer-Encoding")) {
-		len = strlen("Content-Transfer-Encoding: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
-		decode_header(mi, &sb);
+	if (parse_header(line, "Content-Transfer-Encoding", mi, &sb)) {
 		handle_content_transfer_encoding(mi, &sb);
 		ret = 1;
 		goto check_header_out;
 	}
-	if (cmp_header(line, "Message-Id")) {
-		len = strlen("Message-Id: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
-		decode_header(mi, &sb);
+	if (parse_header(line, "Message-Id", mi, &sb)) {
 		if (mi->add_message_id)
 			mi->message_id = strbuf_detach(&sb, NULL);
 		ret = 1;
@@ -607,8 +617,9 @@
 			    const struct strbuf *line)
 {
 	int i;
+	const char *val;
 	for (i = 0; header[i]; i++)
-		if (!mi->s_hdr_data[i] && cmp_header(line, header[i]))
+		if (!mi->s_hdr_data[i] && skip_header(line, header[i], &val))
 			return 1;
 	return 0;
 }
diff --git a/merge-recursive.c b/merge-recursive.c
index 10dca56..aee1769 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1712,6 +1712,14 @@
 	return new_path;
 }
 
+/*
+ * Toggle the stage number between "ours" and "theirs" (2 and 3).
+ */
+static inline int flip_stage(int stage)
+{
+	return (2 + 3) - stage;
+}
+
 static int handle_rename_rename_1to2(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
@@ -1756,14 +1764,14 @@
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		add = &ci->ren1->dst_entry->stages[flip_stage(2)];
 		if (is_valid(add)) {
 			if (update_file(opt, 0, add, a->path))
 				return -1;
 		}
 		else
 			remove_file_from_index(opt->repo->index, a->path);
-		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		add = &ci->ren2->dst_entry->stages[flip_stage(3)];
 		if (is_valid(add)) {
 			if (update_file(opt, 0, add, b->path))
 				return -1;
@@ -1776,7 +1784,7 @@
 		 * rename/add collision.  If not, we can write the file out
 		 * to the specified location.
 		 */
-		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		add = &ci->ren1->dst_entry->stages[flip_stage(2)];
 		if (is_valid(add)) {
 			add->path = mfi.blob.path = a->path;
 			if (handle_file_collision(opt, a->path,
@@ -1797,7 +1805,7 @@
 				return -1;
 		}
 
-		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		add = &ci->ren2->dst_entry->stages[flip_stage(3)];
 		if (is_valid(add)) {
 			add->path = mfi.blob.path = b->path;
 			if (handle_file_collision(opt, b->path,
@@ -1846,7 +1854,7 @@
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
 	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
-	ostage2 = ostage1 ^ 1;
+	ostage2 = flip_stage(ostage1);
 	ci->ren1->src_entry->stages[ostage1].path = a->path;
 	ci->ren2->src_entry->stages[ostage2].path = b->path;
 	if (merge_mode_and_contents(opt, a, c1,
diff --git a/notes-utils.c b/notes-utils.c
index a819410..4bf4888 100644
--- a/notes-utils.c
+++ b/notes-utils.c
@@ -52,7 +52,7 @@
 	strbuf_complete_line(&buf);
 
 	create_notes_commit(r, t, NULL, buf.buf, buf.len, &commit_oid);
-	strbuf_insert(&buf, 0, "notes: ", 7); /* commit message starts at index 7 */
+	strbuf_insertstr(&buf, 0, "notes: ");
 	update_ref(buf.buf, t->update_ref, &commit_oid, NULL, 0,
 		   UPDATE_REFS_DIE_ON_ERR);
 
diff --git a/notes.c b/notes.c
index 0c79964..564baac 100644
--- a/notes.c
+++ b/notes.c
@@ -576,16 +576,16 @@
 			 * the note tree that have not yet been explored. There
 			 * is a direct relationship between subtree entries at
 			 * level 'n' in the tree, and the 'fanout' variable:
-			 * Subtree entries at level 'n <= 2 * fanout' should be
+			 * Subtree entries at level 'n < 2 * fanout' should be
 			 * preserved, since they correspond exactly to a fanout
 			 * directory in the on-disk structure. However, subtree
-			 * entries at level 'n > 2 * fanout' should NOT be
+			 * entries at level 'n >= 2 * fanout' should NOT be
 			 * preserved, but rather consolidated into the above
 			 * notes tree level. We achieve this by unconditionally
 			 * unpacking subtree entries that exist below the
 			 * threshold level at 'n = 2 * fanout'.
 			 */
-			if (n <= 2 * fanout &&
+			if (n < 2 * fanout &&
 			    flags & FOR_EACH_NOTE_YIELD_SUBTREES) {
 				/* invoke callback with subtree */
 				unsigned int path_len =
@@ -602,7 +602,7 @@
 					 path,
 					 cb_data);
 			}
-			if (n > fanout * 2 ||
+			if (n >= 2 * fanout ||
 			    !(flags & FOR_EACH_NOTE_DONT_UNPACK_SUBTREES)) {
 				/* unpack subtree and resume traversal */
 				tree->a[i] = NULL;
@@ -723,13 +723,15 @@
 
 struct write_each_note_data {
 	struct tree_write_stack *root;
-	struct non_note *next_non_note;
+	struct non_note **nn_list;
+	struct non_note *nn_prev;
 };
 
 static int write_each_non_note_until(const char *note_path,
 		struct write_each_note_data *d)
 {
-	struct non_note *n = d->next_non_note;
+	struct non_note *p = d->nn_prev;
+	struct non_note *n = p ? p->next : *d->nn_list;
 	int cmp = 0, ret;
 	while (n && (!note_path || (cmp = strcmp(n->path, note_path)) <= 0)) {
 		if (note_path && cmp == 0)
@@ -740,9 +742,10 @@
 			if (ret)
 				return ret;
 		}
+		p = n;
 		n = n->next;
 	}
-	d->next_non_note = n;
+	d->nn_prev = p;
 	return 0;
 }
 
@@ -1177,7 +1180,8 @@
 	strbuf_init(&root.buf, 256 * (32 + the_hash_algo->hexsz)); /* assume 256 entries */
 	root.path[0] = root.path[1] = '\0';
 	cb_data.root = &root;
-	cb_data.next_non_note = t->first_non_note;
+	cb_data.nn_list = &(t->first_non_note);
+	cb_data.nn_prev = NULL;
 
 	/* Write tree objects representing current notes tree */
 	flags = FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
@@ -1279,10 +1283,8 @@
 		if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
 			strbuf_addstr(sb, "\nNotes:\n");
 		} else {
-			if (starts_with(ref, "refs/"))
-				ref += 5;
-			if (starts_with(ref, "notes/"))
-				ref += 6;
+			skip_prefix(ref, "refs/", &ref);
+			skip_prefix(ref, "notes/", &ref);
 			strbuf_addf(sb, "\nNotes (%s):\n", ref);
 		}
 	}
@@ -1332,9 +1334,9 @@
 	if (starts_with(sb->buf, "refs/notes/"))
 		return; /* we're happy */
 	else if (starts_with(sb->buf, "notes/"))
-		strbuf_insert(sb, 0, "refs/", 5);
+		strbuf_insertstr(sb, 0, "refs/");
 	else
-		strbuf_insert(sb, 0, "refs/notes/", 11);
+		strbuf_insertstr(sb, 0, "refs/notes/");
 }
 
 void expand_loose_notes_ref(struct strbuf *sb)
diff --git a/object-store.h b/object-store.h
index 55ee639..f881a17 100644
--- a/object-store.h
+++ b/object-store.h
@@ -6,6 +6,8 @@
 #include "list.h"
 #include "sha1-array.h"
 #include "strbuf.h"
+#include "thread-utils.h"
+#include "packfile.h"
 
 struct object_directory {
 	struct object_directory *next;
@@ -125,6 +127,8 @@
 	 * (see git-replace(1)).
 	 */
 	struct oidmap *replace_map;
+	unsigned replace_map_initialized : 1;
+	pthread_mutex_t replace_mutex; /* protect object replace functions */
 
 	struct commit_graph *commit_graph;
 	unsigned commit_graph_attempted : 1; /* if loading has been attempted */
@@ -198,8 +202,9 @@
 /* Read and unpack an object file into memory, write memory to an object file */
 int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
 
-int hash_object_file(const void *buf, unsigned long len,
-		     const char *type, struct object_id *oid);
+int hash_object_file(const struct git_hash_algo *algo, const void *buf,
+		     unsigned long len, const char *type,
+		     struct object_id *oid);
 
 int write_object_file(const void *buf, unsigned long len,
 		      const char *type, struct object_id *oid);
@@ -208,6 +213,14 @@
 			       const char *type, struct object_id *oid,
 			       unsigned flags);
 
+/*
+ * Add an object file to the in-memory object store, without writing it
+ * to disk.
+ *
+ * Callers are responsible for calling write_object_file to record the
+ * object in persistent storage before writing any other new objects
+ * that reference it.
+ */
 int pretend_object_file(void *, unsigned long, enum object_type,
 			struct object_id *oid);
 
@@ -249,6 +262,40 @@
 
 void assert_oid_type(const struct object_id *oid, enum object_type expect);
 
+/*
+ * Enabling the object read lock allows multiple threads to safely call the
+ * following functions in parallel: repo_read_object_file(), read_object_file(),
+ * read_object_file_extended(), read_object_with_reference(), read_object(),
+ * oid_ob