diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index fd4df93..802a4bf 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -6,7 +6,39 @@
   DEVELOPER: 1
 
 jobs:
+  ci-config:
+      runs-on: ubuntu-latest
+      outputs:
+        enabled: ${{ steps.check-ref.outputs.enabled }}
+      steps:
+        - name: try to clone ci-config branch
+          continue-on-error: true
+          run: |
+            git -c protocol.version=2 clone \
+              --no-tags \
+              --single-branch \
+              -b ci-config \
+              --depth 1 \
+              --no-checkout \
+              --filter=blob:none \
+              https://github.com/${{ github.repository }} \
+              config-repo &&
+              cd config-repo &&
+              git checkout HEAD -- ci/config
+        - id: check-ref
+          name: check whether CI is enabled for ref
+          run: |
+            enabled=yes
+            if test -x config-repo/ci/config/allow-ref &&
+               ! config-repo/ci/config/allow-ref '${{ github.ref }}'
+            then
+              enabled=no
+            fi
+            echo "::set-output name=enabled::$enabled"
+
   windows-build:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v1
@@ -70,6 +102,8 @@
         name: failed-tests-windows
         path: ${{env.FAILED_TEST_ARTIFACTS}}
   vs-build:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     env:
       MSYSTEM: MINGW64
       NO_PERL: 1
@@ -154,6 +188,8 @@
                           ${{matrix.nr}} 10 t[0-9]*.sh)
         "@
   regular:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     strategy:
       matrix:
         vector:
@@ -189,6 +225,8 @@
         name: failed-tests-${{matrix.vector.jobname}}
         path: ${{env.FAILED_TEST_ARTIFACTS}}
   dockerized:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     strategy:
       matrix:
         vector:
@@ -213,6 +251,8 @@
         name: failed-tests-${{matrix.vector.jobname}}
         path: ${{env.FAILED_TEST_ARTIFACTS}}
   static-analysis:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     env:
       jobname: StaticAnalysis
     runs-on: ubuntu-latest
@@ -221,6 +261,8 @@
     - run: ci/install-dependencies.sh
     - run: ci/run-static-analysis.sh
   documentation:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
     env:
       jobname: Documentation
     runs-on: ubuntu-latest
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index a89e8dc..227f46a 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -232,6 +232,18 @@
         while( condition )
 		func (bar+1);
 
+ - Do not explicitly compare an integral value with constant 0 or '\0',
+   or a pointer value with constant NULL.  For instance, to validate that
+   counted array <ptr, cnt> is initialized but has no elements, write:
+
+	if (!ptr || cnt)
+		BUG("empty array expected");
+
+   and not:
+
+	if (ptr == NULL || cnt != 0);
+		BUG("empty array expected");
+
  - We avoid using braces unnecessarily.  I.e.
 
 	if (bla) {
diff --git a/Documentation/RelNotes/2.27.0.txt b/Documentation/RelNotes/2.27.0.txt
index 2a8c6e8..b398961 100644
--- a/Documentation/RelNotes/2.27.0.txt
+++ b/Documentation/RelNotes/2.27.0.txt
@@ -161,6 +161,12 @@
 
  * The "bugreport" tool has been added.
 
+ * The object walk with object filter "--filter=tree:0" can now take
+   advantage of the pack bitmap when available.
+
+ * Instead of always building all branches at GitHub via Actions,
+   users can specify which branches to build.
+
 
 Fixes since v2.26
 -----------------
@@ -420,6 +426,24 @@
    been corrected.
    (merge 0555e4af58 cb/t0000-use-the-configured-shell later to maint).
 
+ * Minor in-code comments and documentation updates around credential
+   API.
+   (merge 1aed817f99 cb/credential-doc-fixes later to maint).
+
+ * Teach "am", "commit", "merge" and "rebase", when they are run with
+   the "--quiet" option, to pass "--quiet" down to "gc --auto".
+   (merge 7c3e9e8cfb jc/auto-gc-quiet later to maint).
+
+ * The code to skip unmerged paths in the index when sparse checkout
+   is in use would have made out-of-bound access of the in-core index
+   when the last path was unmerged, which has been corrected.
+
+ * Serving a "git fetch" client over "git://" and "ssh://" protocols
+   using the on-wire protocol version 2 was buggy on the server end
+   when the client needs to make a follow-up request to
+   e.g. auto-follow tags.
+   (merge 08450ef791 cc/upload-pack-v2-fetch-fix later to maint).
+
  * Other code cleanup, docfix, build fix, etc.
    (merge 564956f358 jc/maintain-doc later to maint).
    (merge 7422b2a0a1 sg/commit-slab-clarify-peek later to maint).
diff --git a/Documentation/git-bugreport.txt b/Documentation/git-bugreport.txt
index 643d1b2..7fe9aef 100644
--- a/Documentation/git-bugreport.txt
+++ b/Documentation/git-bugreport.txt
@@ -28,6 +28,7 @@
  - 'git version --build-options'
  - uname sysname, release, version, and machine strings
  - Compiler-specific info string
+ - A list of enabled hooks
 
 This tool is invoked via the typical Git setup process, which means that in some
 cases, it might not be able to launch - for example, if a relevant config file
diff --git a/Documentation/git-credential.txt b/Documentation/git-credential.txt
index 6f0c7ca..8d990e9 100644
--- a/Documentation/git-credential.txt
+++ b/Documentation/git-credential.txt
@@ -103,17 +103,20 @@
 `git credential` reads and/or writes (depending on the action used)
 credential information in its standard input/output. This information
 can correspond either to keys for which `git credential` will obtain
-the login/password information (e.g. host, protocol, path), or to the
-actual credential data to be obtained (login/password).
+the login information (e.g. host, protocol, path), or to the actual
+credential data to be obtained (username/password).
 
 The credential is split into a set of named attributes, with one
-attribute per line. Each attribute is
-specified by a key-value pair, separated by an `=` (equals) sign,
-followed by a newline. The key may contain any bytes except `=`,
-newline, or NUL. The value may contain any bytes except newline or NUL.
+attribute per line. Each attribute is specified by a key-value pair,
+separated by an `=` (equals) sign, followed by a newline.
+
+The key may contain any bytes except `=`, newline, or NUL. The value may
+contain any bytes except newline or NUL.
+
 In both cases, all bytes are treated as-is (i.e., there is no quoting,
 and one cannot transmit a value with newline or NUL in it). The list of
 attributes is terminated by a blank line or end-of-file.
+
 Git understands the following attributes:
 
 `protocol`::
@@ -123,7 +126,8 @@
 
 `host`::
 
-	The remote hostname for a network credential.
+	The remote hostname for a network credential.  This includes
+	the port number if one was specified (e.g., "example.com:8088").
 
 `path`::
 
@@ -134,7 +138,7 @@
 `username`::
 
 	The credential's username, if we already have one (e.g., from a
-	URL, from the user, or from a previously run helper).
+	URL, the configuration, the user, or from a previously run helper).
 
 `password`::
 
@@ -146,8 +150,12 @@
 	value is parsed as a URL and treated as if its constituent parts
 	were read (e.g., `url=https://example.com` would behave as if
 	`protocol=https` and `host=example.com` had been provided). This
-	can help callers avoid parsing URLs themselves.  Note that any
-	components which are missing from the URL (e.g., there is no
-	username in the example above) will be set to empty; if you want
-	to provide a URL and override some attributes, provide the URL
-	attribute first, followed by any overrides.
+	can help callers avoid parsing URLs themselves.
+
+	Note that specifying a protocol is mandatory and if the URL
+	doesn't specify a hostname (e.g., "cert:///path/to/file") the
+	credential will contain a hostname attribute whose value is an
+	empty string.
+
+	Components which are missing from the URL (e.g., there is no
+	username in the example above) will be left unset.
diff --git a/Documentation/git-multi-pack-index.txt b/Documentation/git-multi-pack-index.txt
index 642d9ac..0c66194 100644
--- a/Documentation/git-multi-pack-index.txt
+++ b/Documentation/git-multi-pack-index.txt
@@ -56,6 +56,9 @@
 	file is created, rewrite the multi-pack-index to reference the
 	new pack-file. A later run of 'git multi-pack-index expire' will
 	delete the pack-files that were part of this batch.
++
+If `repack.packKeptObjects` is `false`, then any pack-files with an
+associated `.keep` file will not be selected for the batch to repack.
 
 
 EXAMPLES
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 0d0f714..9e481ae 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -268,16 +268,26 @@
 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).
+overwrite those already known about by Git's credential subsystem.
+
+While it is possible to override all attributes, well behaving helpers
+should refrain from doing so for any attribute other than username and
+password.
+
+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).
+
+Similarly, no more helpers will be consulted once both username and
+password had been provided.
 
 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 fails to perform the requested operation or needs to notify
+the user of a potential issue, it may write to stderr.
+
+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
diff --git a/Documentation/gitfaq.txt b/Documentation/gitfaq.txt
index 1cf83df..370d62d 100644
--- a/Documentation/gitfaq.txt
+++ b/Documentation/gitfaq.txt
@@ -223,6 +223,24 @@
 can then be copied alongside and modified as appropriate.  This second, modified
 file is usually ignored to prevent accidentally committing it.
 
+[[files-in-.gitignore-are-tracked]]
+I asked Git to ignore various files, yet they are still tracked::
+	A `gitignore` file ensures that certain file(s) which are not
+	tracked by Git remain untracked.  However, sometimes particular
+	file(s) may have been tracked before adding them into the
+	`.gitignore`, hence they still remain tracked.  To untrack and
+	ignore files/patterns, use `git rm --cached <file/pattern>`
+	and add a pattern to `.gitignore` that matches the <file>.
+	See linkgit:gitignore[5] for details.
+
+[[fetching-and-pulling]]
+How do I know if I want to do a fetch or a pull?::
+	A fetch stores a copy of the latest changes from the remote
+	repository, without modifying the working tree or current branch.
+	You can then at your leisure inspect, merge, rebase on top of, or
+	ignore the upstream changes.  A pull consists of a fetch followed
+	immediately by either a merge or rebase.  See linkgit:git-pull[1].
+
 Hooks
 -----
 
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
index de56f9f..1beef17 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/technical/commit-graph-format.txt
@@ -97,10 +97,10 @@
       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 ith entry, BIDX[i], stores the number of bytes 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]
diff --git a/bloom.c b/bloom.c
index dd9bab9..9b86aa3 100644
--- a/bloom.c
+++ b/bloom.c
@@ -9,7 +9,7 @@
 
 define_commit_slab(bloom_filter_slab, struct bloom_filter);
 
-struct bloom_filter_slab bloom_filters;
+static struct bloom_filter_slab bloom_filters;
 
 struct pathmap_hash_entry {
     struct hashmap_entry entry;
@@ -29,8 +29,8 @@
 }
 
 static int load_bloom_filter_from_graph(struct commit_graph *g,
-				   struct bloom_filter *filter,
-				   struct commit *c)
+					struct bloom_filter *filter,
+					struct commit *c)
 {
 	uint32_t lex_pos, start_index, end_index;
 
@@ -123,9 +123,9 @@
 }
 
 void fill_bloom_key(const char *data,
-					size_t len,
-					struct bloom_key *key,
-					const struct bloom_filter_settings *settings)
+		    size_t len,
+		    struct bloom_key *key,
+		    const struct bloom_filter_settings *settings)
 {
 	int i;
 	const uint32_t seed0 = 0x293ae76f;
@@ -139,8 +139,8 @@
 }
 
 void add_key_to_filter(const struct bloom_key *key,
-					   struct bloom_filter *filter,
-					   const struct bloom_filter_settings *settings)
+		       struct bloom_filter *filter,
+		       const struct bloom_filter_settings *settings)
 {
 	int i;
 	uint64_t mod = filter->len * BITS_PER_WORD;
@@ -158,9 +158,22 @@
 	init_bloom_filter_slab(&bloom_filters);
 }
 
+static int pathmap_cmp(const void *hashmap_cmp_fn_data,
+		       const struct hashmap_entry *eptr,
+		       const struct hashmap_entry *entry_or_key,
+		       const void *keydata)
+{
+	const struct pathmap_hash_entry *e1, *e2;
+
+	e1 = container_of(eptr, const struct pathmap_hash_entry, entry);
+	e2 = container_of(entry_or_key, const struct pathmap_hash_entry, entry);
+
+	return strcmp(e1->path, e2->path);
+}
+
 struct bloom_filter *get_bloom_filter(struct repository *r,
 				      struct commit *c,
-					  int compute_if_not_present)
+				      int compute_if_not_present)
 {
 	struct bloom_filter *filter;
 	struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
@@ -193,35 +206,42 @@
 	diffopt.max_changes = max_changes;
 	diff_setup_done(&diffopt);
 
+	/* ensure commit is parsed so we have parent information */
+	repo_parse_commit(r, c);
+
 	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) {
+	if (diffopt.num_changes <= max_changes) {
 		struct hashmap pathmap;
 		struct pathmap_hash_entry *e;
 		struct hashmap_iter iter;
-		hashmap_init(&pathmap, NULL, NULL, 0);
+		hashmap_init(&pathmap, pathmap_cmp, NULL, 0);
 
 		for (i = 0; i < diff_queued_diff.nr; i++) {
 			const char *path = diff_queued_diff.queue[i]->two->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 '/'.
-			*/
+			 * 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(path, '/');
 
 				FLEX_ALLOC_STR(e, path, path);
 				hashmap_entry_init(&e->entry, strhash(path));
-				hashmap_add(&pathmap, &e->entry);
+
+				if (!hashmap_get(&pathmap, &e->entry, NULL))
+					hashmap_add(&pathmap, &e->entry);
+				else
+					free(e);
 
 				if (!last_slash)
 					last_slash = (char*)path;
@@ -273,4 +293,4 @@
 	}
 
 	return 1;
-}
\ No newline at end of file
+}
diff --git a/bloom.h b/bloom.h
index b935186..b2a8379 100644
--- a/bloom.h
+++ b/bloom.h
@@ -74,8 +74,8 @@
 		    const struct bloom_filter_settings *settings);
 
 void add_key_to_filter(const struct bloom_key *key,
-					   struct bloom_filter *filter,
-					   const struct bloom_filter_settings *settings);
+		       struct bloom_filter *filter,
+		       const struct bloom_filter_settings *settings);
 
 void init_bloom_filters(void);
 
@@ -87,4 +87,4 @@
 			  const struct bloom_key *key,
 			  const struct bloom_filter_settings *settings);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/bugreport.c b/bugreport.c
index acacca8..aa8a489 100644
--- a/bugreport.c
+++ b/bugreport.c
@@ -3,6 +3,8 @@
 #include "strbuf.h"
 #include "help.h"
 #include "compat/compiler.h"
+#include "run-command.h"
+
 
 static void get_system_info(struct strbuf *sys_info)
 {
@@ -31,6 +33,53 @@
 	get_libc_info(sys_info);
 }
 
+static void get_populated_hooks(struct strbuf *hook_info, int nongit)
+{
+	/*
+	 * NEEDSWORK: Doesn't look like there is a list of all possible hooks;
+	 * so below is a transcription of `git help hooks`. Later, this should
+	 * be replaced with some programmatically generated list (generated from
+	 * doc or else taken from some library which tells us about all the
+	 * hooks)
+	 */
+	static const char *hook[] = {
+		"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-change",
+	};
+	int i;
+
+	if (nongit) {
+		strbuf_addstr(hook_info,
+			_("not run from a git repository - no hooks to show\n"));
+		return;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(hook); i++)
+		if (find_hook(hook[i]))
+			strbuf_addf(hook_info, "%s\n", hook[i]);
+}
+
 static const char * const bugreport_usage[] = {
 	N_("git bugreport [-o|--output-directory <file>] [-s|--suffix <format>]"),
 	NULL
@@ -114,6 +163,9 @@
 	get_header(&buffer, _("System Info"));
 	get_system_info(&buffer);
 
+	get_header(&buffer, _("Enabled Hooks"));
+	get_populated_hooks(&buffer, nongit_ok);
+
 	/* fopen doesn't offer us an O_EXCL alternative, except with glibc. */
 	report = open(report_path.buf, O_CREAT | O_EXCL | O_WRONLY, 0666);
 
diff --git a/builtin/am.c b/builtin/am.c
index e3dfd93..69e50de 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1691,7 +1691,6 @@
  */
 static void am_run(struct am_state *state, int resume)
 {
-	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
 	struct strbuf sb = STRBUF_INIT;
 
 	unlink(am_path(state, "dirtyindex"));
@@ -1796,7 +1795,7 @@
 	if (!state->rebasing) {
 		am_destroy(state);
 		close_object_store(the_repository->objects);
-		run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+		run_auto_gc(state->quiet);
 	}
 }
 
diff --git a/builtin/commit.c b/builtin/commit.c
index a73de0a..d1b7396 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1494,7 +1494,6 @@
 
 int cmd_commit(int argc, const char **argv, const char *prefix)
 {
-	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
 	static struct wt_status s;
 	static struct option builtin_commit_options[] = {
 		OPT__QUIET(&quiet, N_("suppress summary after successful commit")),
@@ -1703,7 +1702,7 @@
 	git_test_write_commit_graph_or_die();
 
 	repo_rerere(the_repository, 0);
-	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+	run_auto_gc(quiet);
 	run_commit_hook(use_editor, get_index_file(), "post-commit", NULL);
 	if (amend && !no_post_rewrite) {
 		commit_post_rewrite(the_repository, current_head, &oid);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 3ae52c0..b5788c1 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -27,6 +27,7 @@
 #include "branch.h"
 #include "promisor-remote.h"
 #include "commit-graph.h"
+#include "shallow.h"
 
 #define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
 
@@ -1752,7 +1753,6 @@
 	struct remote *remote = NULL;
 	int result = 0;
 	int prune_tags_ok = 1;
-	struct argv_array argv_gc_auto = ARGV_ARRAY_INIT;
 
 	packet_trace_identity("fetch");
 
@@ -1879,13 +1879,8 @@
 
 	close_object_store(the_repository->objects);
 
-	if (enable_auto_gc) {
-		argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
-		if (verbosity < 0)
-			argv_array_push(&argv_gc_auto, "--quiet");
-		run_command_v_opt(argv_gc_auto.argv, RUN_GIT_CMD);
-		argv_array_clear(&argv_gc_auto);
-	}
+	if (enable_auto_gc)
+		run_auto_gc(verbosity < 0);
 
 	return result;
 }
diff --git a/builtin/merge.c b/builtin/merge.c
index 923e32a..ca6a5dc 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -450,7 +450,6 @@
 		if (verbosity >= 0 && !merge_msg.len)
 			printf(_("No merge message -- not updating HEAD\n"));
 		else {
-			const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 			update_ref(reflog_message.buf, "HEAD", new_head, head,
 				   0, UPDATE_REFS_DIE_ON_ERR);
 			/*
@@ -458,7 +457,7 @@
 			 * user should see them.
 			 */
 			close_object_store(the_repository->objects);
-			run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+			run_auto_gc(verbosity < 0);
 		}
 	}
 	if (new_head && show_diffstat) {
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 03b85f5..c5b433a 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -34,6 +34,7 @@
 #include "dir.h"
 #include "midx.h"
 #include "trace2.h"
+#include "shallow.h"
 
 #define IN_PACK(obj) oe_in_pack(&to_pack, obj)
 #define SIZE(obj) oe_size(&to_pack, obj)
diff --git a/builtin/prune.c b/builtin/prune.c
index fd9acc7..02c6ab7 100644
--- a/builtin/prune.c
+++ b/builtin/prune.c
@@ -8,6 +8,7 @@
 #include "progress.h"
 #include "prune-packed.h"
 #include "object-store.h"
+#include "shallow.h"
 
 static const char * const prune_usage[] = {
 	N_("git prune [-n] [-v] [--progress] [--expire <time>] [--] [<head>...]"),
diff --git a/builtin/rebase.c b/builtin/rebase.c
index ca6aa0d..37ba76a 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -722,7 +722,6 @@
 static int finish_rebase(struct rebase_options *opts)
 {
 	struct strbuf dir = STRBUF_INIT;
-	const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 	int ret = 0;
 
 	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
@@ -732,7 +731,7 @@
 	 * We ignore errors in 'gc --auto', since the
 	 * user should see them.
 	 */
-	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+	run_auto_gc(!(opts->flags & (REBASE_NO_QUIET|REBASE_VERBOSE)));
 	if (opts->type == REBASE_MERGE) {
 		struct replay_opts replay = REPLAY_OPTS_INIT;
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index d37ab77..ea3d0f0 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -28,6 +28,7 @@
 #include "protocol.h"
 #include "commit-reach.h"
 #include "worktree.h"
+#include "shallow.h"
 
 static const char * const receive_pack_usage[] = {
 	N_("git receive-pack <git-dir>"),
@@ -876,7 +877,7 @@
 static int command_singleton_iterator(void *cb_data, struct object_id *oid);
 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 {
-	struct lock_file shallow_lock = LOCK_INIT;
+	struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
 	struct oid_array extra = OID_ARRAY_INIT;
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	uint32_t mask = 1 << (cmd->index % 32);
diff --git a/builtin/repack.c b/builtin/repack.c
index 1b686ee..df28773 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -13,6 +13,7 @@
 #include "prune-packed.h"
 #include "object-store.h"
 #include "promisor-remote.h"
+#include "shallow.h"
 
 static int delta_base_offset = 1;
 static int pack_kept_objects = -1;
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 0605643..669dd2f 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -16,6 +16,7 @@
 #include "split-index.h"
 #include "submodule.h"
 #include "commit-reach.h"
+#include "shallow.h"
 
 #define DO_REVS		1
 #define DO_NOREV	2
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1a4b391..46c03d2 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2246,6 +2246,37 @@
 	usage_with_options(git_submodule_helper_usage, module_config_options);
 }
 
+static int module_set_url(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	const char *newurl;
+	const char *path;
+	char *config_name;
+
+	struct option options[] = {
+		OPT__QUIET(&quiet, N_("Suppress output for setting url of a submodule")),
+		OPT_END()
+	};
+	const char *const usage[] = {
+		N_("git submodule--helper set-url [--quiet] <path> <newurl>"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+	if (argc != 2 || !(path = argv[0]) || !(newurl = argv[1]))
+		usage_with_options(usage, options);
+
+	config_name = xstrfmt("submodule.%s.url", path);
+
+	config_set_in_gitmodules_file_gently(config_name, newurl);
+	sync_submodule(path, prefix, quiet ? OPT_QUIET : 0);
+
+	free(config_name);
+
+	return 0;
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -2276,6 +2307,7 @@
 	{"is-active", is_active, 0},
 	{"check-name", check_name, 0},
 	{"config", module_config, 0},
+	{"set-url", module_set_url, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/ci/config/allow-refs.sample b/ci/config/allow-refs.sample
new file mode 100755
index 0000000..f157f19
--- /dev/null
+++ b/ci/config/allow-refs.sample
@@ -0,0 +1,26 @@
+#!/bin/sh
+#
+# Sample script for enabling/disabling GitHub Actions CI runs on
+# particular refs. By default, CI is run for all branches pushed to
+# GitHub. You can override this by dropping the ".sample" from the script,
+# editing it, committing, and pushing the result to the "ci-config" branch of
+# your repository:
+#
+#   git checkout -b ci-config
+#   cp allow-refs.sample allow-refs
+#   $EDITOR allow-refs
+#   git commit -am "implement my ci preferences"
+#   git push
+#
+# This script will then be run when any refs are pushed to that repository. It
+# gets the fully qualified refname as the first argument, and should exit with
+# success only for refs for which you want to run CI.
+
+case "$1" in
+# allow one-off tests by pushing to "for-ci" or "for-ci/mybranch"
+refs/heads/for-ci*) true ;;
+# always build your integration branch
+refs/heads/my-integration-branch) true ;;
+# don't build any other branches or tags
+*) false ;;
+esac
diff --git a/commit-graph.c b/commit-graph.c
index 5ea0c8e..e3420dd 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -18,6 +18,7 @@
 #include "progress.h"
 #include "bloom.h"
 #include "commit-slab.h"
+#include "shallow.h"
 
 void git_test_write_commit_graph_or_die(void)
 {
diff --git a/commit.c b/commit.c
index c7099da..87686a7 100644
--- a/commit.c
+++ b/commit.c
@@ -20,6 +20,7 @@
 #include "refs.h"
 #include "commit-reach.h"
 #include "run-command.h"
+#include "shallow.h"
 
 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
 
@@ -110,7 +111,7 @@
 	return commit_graft_table[index]->oid.hash;
 }
 
-static int commit_graft_pos(struct repository *r, const unsigned char *sha1)
+int commit_graft_pos(struct repository *r, const unsigned char *sha1)
 {
 	return sha1_pos(sha1, r->parsed_objects->grafts,
 			r->parsed_objects->grafts_nr,
@@ -245,19 +246,6 @@
 	return ret;
 }
 
-int unregister_shallow(const struct object_id *oid)
-{
-	int pos = commit_graft_pos(the_repository, oid->hash);
-	if (pos < 0)
-		return -1;
-	if (pos + 1 < the_repository->parsed_objects->grafts_nr)
-		MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
-			   the_repository->parsed_objects->grafts + pos + 1,
-			   the_repository->parsed_objects->grafts_nr - pos - 1);
-	the_repository->parsed_objects->grafts_nr--;
-	return 0;
-}
-
 struct commit_buffer {
 	void *buffer;
 	unsigned long size;
diff --git a/commit.h b/commit.h
index ab91d21..1b2dea5 100644
--- a/commit.h
+++ b/commit.h
@@ -236,6 +236,8 @@
 typedef int (*each_commit_graft_fn)(const struct commit_graft *, void *);
 
 struct commit_graft *read_graft_line(struct strbuf *line);
+/* commit_graft_pos returns an index into r->parsed_objects->grafts. */
+int commit_graft_pos(struct repository *r, const unsigned char *sha1);
 int register_commit_graft(struct repository *r, struct commit_graft *, int);
 void prepare_commit_graft(struct repository *r);
 struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid);
@@ -247,55 +249,7 @@
 
 struct oid_array;
 struct ref;
-int register_shallow(struct repository *r, const struct object_id *oid);
-int unregister_shallow(const struct object_id *oid);
-int commit_shallow_file(struct repository *r, struct lock_file *lk);
-void rollback_shallow_file(struct repository *r, struct lock_file *lk);
 int for_each_commit_graft(each_commit_graft_fn, void *);
-int is_repository_shallow(struct repository *r);
-struct commit_list *get_shallow_commits(struct object_array *heads,
-					int depth, int shallow_flag, int not_shallow_flag);
-struct commit_list *get_shallow_commits_by_rev_list(
-		int ac, const char **av, int shallow_flag, int not_shallow_flag);
-void set_alternate_shallow_file(struct repository *r, const char *path, int override);
-int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
-			  const struct oid_array *extra);
-void setup_alternate_shallow(struct lock_file *shallow_lock,
-			     const char **alternate_shallow_file,
-			     const struct oid_array *extra);
-const char *setup_temporary_shallow(const struct oid_array *extra);
-void advertise_shallow_grafts(int);
-
-/*
- * Initialize with prepare_shallow_info() or zero-initialize (equivalent to
- * prepare_shallow_info with a NULL oid_array).
- */
-struct shallow_info {
-	struct oid_array *shallow;
-	int *ours, nr_ours;
-	int *theirs, nr_theirs;
-	struct oid_array *ref;
-
-	/* for receive-pack */
-	uint32_t **used_shallow;
-	int *need_reachability_test;
-	int *reachable;
-	int *shallow_ref;
-	struct commit **commits;
-	int nr_commits;
-};
-
-void prepare_shallow_info(struct shallow_info *, struct oid_array *);
-void clear_shallow_info(struct shallow_info *);
-void remove_nonexistent_theirs_shallow(struct shallow_info *);
-void assign_shallow_commits_to_refs(struct shallow_info *info,
-				    uint32_t **used,
-				    int *ref_status);
-int delayed_reachability_test(struct shallow_info *si, int c);
-#define PRUNE_SHOW_ONLY 1
-#define PRUNE_QUICK 2
-void prune_shallow(unsigned options);
-extern struct trace_key trace_shallow;
 
 int interactive_add(int argc, const char **argv, const char *prefix, int patch);
 int run_add_interactive(const char *revision, const char *patch_mode,
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index b1d6e5e..70ad04e 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1860,6 +1860,7 @@
 			$merge
 			$__git_diff_common_options
 			--pickaxe-all --pickaxe-regex
+			--patch --no-patch
 			"
 		return
 		;;
diff --git a/credential.h b/credential.h
index d99ec42..c0e17e3 100644
--- a/credential.h
+++ b/credential.h
@@ -177,8 +177,8 @@
  * Parse a url into a credential struct, replacing any existing contents.
  *
  * If the url can't be parsed (e.g., a missing "proto://" component), the
- * resulting credential will be empty but we'll still return success from the
- * "gently" form.
+ * resulting credential will be empty and the function will return an
+ * error (even in the "gently" form).
  *
  * If we encounter a component which cannot be represented as a credential
  * value (e.g., because it contains a newline), the "gently" form will return
@@ -189,7 +189,7 @@
 void credential_from_url(struct credential *, const char *url);
 int credential_from_url_gently(struct credential *, const char *url, int quiet);
 
-int credential_match(const struct credential *have,
-		     const struct credential *want);
+int credential_match(const struct credential *want,
+		     const struct credential *have);
 
 #endif /* CREDENTIAL_H */
diff --git a/environment.c b/environment.c
index 10c9061..aaca0e9 100644
--- a/environment.c
+++ b/environment.c
@@ -17,6 +17,7 @@
 #include "argv-array.h"
 #include "object-store.h"
 #include "chdir-notify.h"
+#include "shallow.h"
 
 int trust_executable_bit = 1;
 int trust_ctime = 1;
diff --git a/fetch-pack.c b/fetch-pack.c
index f73a2ce..7eaa19d 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -22,6 +22,7 @@
 #include "connected.h"
 #include "fetch-negotiator.h"
 #include "fsck.h"
+#include "shallow.h"
 
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
@@ -34,7 +35,7 @@
 static int transfer_fsck_objects = -1;
 static int agent_supported;
 static int server_supports_filtering;
-static struct lock_file shallow_lock;
+static struct shallow_lock shallow_lock;
 static const char *alternate_shallow_file;
 static struct strbuf fsck_msg_types = STRBUF_INIT;
 
diff --git a/fsck.c b/fsck.c
index 087a7f1..8bb3ecf 100644
--- a/fsck.c
+++ b/fsck.c
@@ -523,6 +523,28 @@
 	}
 }
 
+struct name_stack {
+	const char **names;
+	size_t nr, alloc;
+};
+
+static void name_stack_push(struct name_stack *stack, const char *name)
+{
+	ALLOC_GROW(stack->names, stack->nr + 1, stack->alloc);
+	stack->names[stack->nr++] = name;
+}
+
+static const char *name_stack_pop(struct name_stack *stack)
+{
+	return stack->nr ? stack->names[--stack->nr] : NULL;
+}
+
+static void name_stack_clear(struct name_stack *stack)
+{
+	FREE_AND_NULL(stack->names);
+	stack->nr = stack->alloc = 0;
+}
+
 /*
  * The entries in a tree are ordered in the _path_ order,
  * which means that a directory entry is ordered by adding
@@ -534,7 +556,14 @@
 #define TREE_UNORDERED (-1)
 #define TREE_HAS_DUPS  (-2)
 
-static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
+static int is_less_than_slash(unsigned char c)
+{
+	return '\0' < c && c < '/';
+}
+
+static int verify_ordered(unsigned mode1, const char *name1,
+			  unsigned mode2, const char *name2,
+			  struct name_stack *candidates)
 {
 	int len1 = strlen(name1);
 	int len2 = strlen(name2);
@@ -566,6 +595,41 @@
 		c1 = '/';
 	if (!c2 && S_ISDIR(mode2))
 		c2 = '/';
+
+	/*
+	 * There can be non-consecutive duplicates due to the implicitly
+	 * add slash, e.g.:
+	 *
+	 *   foo
+	 *   foo.bar
+	 *   foo.bar.baz
+	 *   foo.bar/
+	 *   foo/
+	 *
+	 * Record non-directory candidates (like "foo" and "foo.bar" in
+	 * the example) on a stack and check directory candidates (like
+	 * foo/" and "foo.bar/") against that stack.
+	 */
+	if (!c1 && is_less_than_slash(c2)) {
+		name_stack_push(candidates, name1);
+	} else if (c2 == '/' && is_less_than_slash(c1)) {
+		for (;;) {
+			const char *p;
+			const char *f_name = name_stack_pop(candidates);
+
+			if (!f_name)
+				break;
+			if (!skip_prefix(name2, f_name, &p))
+				break;
+			if (!*p)
+				return TREE_HAS_DUPS;
+			if (is_less_than_slash(*p)) {
+				name_stack_push(candidates, f_name);
+				break;
+			}
+		}
+	}
+
 	return c1 < c2 ? 0 : TREE_UNORDERED;
 }
 
@@ -587,6 +651,7 @@
 	struct tree_desc desc;
 	unsigned o_mode;
 	const char *o_name;
+	struct name_stack df_dup_candidates = { NULL };
 
 	if (init_tree_desc_gently(&desc, buffer, size)) {
 		retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
@@ -666,7 +731,8 @@
 		}
 
 		if (o_name) {
-			switch (verify_ordered(o_mode, o_name, mode, name)) {
+			switch (verify_ordered(o_mode, o_name, mode, name,
+					       &df_dup_candidates)) {
 			case TREE_UNORDERED:
 				not_properly_sorted = 1;
 				break;
@@ -682,6 +748,8 @@
 		o_name = name;
 	}
 
+	name_stack_clear(&df_dup_candidates);
+
 	if (has_null_sha1)
 		retval += report(options, oid, OBJ_TREE, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 	if (has_full_path)
diff --git a/git-bisect.sh b/git-bisect.sh
index efee12b..71b367a 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -209,6 +209,7 @@
 	test "$#" -eq 1 || die "$(gettext "No logfile given")"
 	test -r "$file" || die "$(eval_gettext "cannot read \$file for replaying")"
 	git bisect--helper --bisect-reset || exit
+	oIFS="$IFS" IFS="$IFS$(printf '\015')"
 	while read git bisect command rev
 	do
 		test "$git $bisect" = "git bisect" || test "$git" = "git-bisect" || continue
@@ -232,6 +233,7 @@
 			die "$(gettext "?? what are you talking about?")" ;;
 		esac
 	done <"$file"
+	IFS="$oIFS"
 	bisect_auto_next
 }
 
diff --git a/git-p4.py b/git-p4.py
index b8b2a16..d551efb 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -3214,6 +3214,42 @@
             print('Ignoring file outside of prefix: {0}'.format(path))
         return hasPrefix
 
+    def findShadowedFiles(self, files, change):
+        # Perforce allows you commit files and directories with the same name,
+        # so you could have files //depot/foo and //depot/foo/bar both checked
+        # in.  A p4 sync of a repository in this state fails.  Deleting one of
+        # the files recovers the repository.
+        #
+        # Git will not allow the broken state to exist and only the most recent
+        # of the conflicting names is left in the repository.  When one of the
+        # conflicting files is deleted we need to re-add the other one to make
+        # sure the git repository recovers in the same way as perforce.
+        deleted = [f for f in files if f['action'] in self.delete_actions]
+        to_check = set()
+        for f in deleted:
+            path = decode_path(f['path'])
+            to_check.add(path + '/...')
+            while True:
+                path = path.rsplit("/", 1)[0]
+                if path == "/" or path in to_check:
+                    break
+                to_check.add(path)
+        to_check = ['%s@%s' % (wildcard_encode(p), change) for p in to_check
+            if self.hasBranchPrefix(p)]
+        if to_check:
+            stat_result = p4CmdList(["-x", "-", "fstat", "-T",
+                "depotFile,headAction,headRev,headType"], stdin=to_check)
+            for record in stat_result:
+                if record['code'] != 'stat':
+                    continue
+                if record['headAction'] in self.delete_actions:
+                    continue
+                files.append({
+                    'action': 'add',
+                    'path': record['depotFile'],
+                    'rev': record['headRev'],
+                    'type': record['headType']})
+
     def commit(self, details, files, branch, parent = "", allow_empty=False):
         epoch = details["time"]
         author = details["user"]
@@ -3222,11 +3258,14 @@
         if self.verbose:
             print('commit into {0}'.format(branch))
 
+        files = [f for f in files
+            if self.hasBranchPrefix(decode_path(f['path']))]
+        self.findShadowedFiles(files, details['change'])
+
         if self.clientSpecDirs:
             self.clientSpecDirs.update_client_spec_path_cache(files)
 
-        files = [f for (f, path) in ((f, decode_path(f['path'])) for f in files)
-            if self.inClientSpec(path) and self.hasBranchPrefix(path)]
+        files = [f for f in files if self.inClientSpec(decode_path(f['path']))]
 
         if gitConfigBool('git-p4.keepEmptyCommits'):
             allow_empty = True
diff --git a/git-submodule.sh b/git-submodule.sh
index 08e0439..39ebdf2 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -805,27 +805,7 @@
 		shift
 	done
 
-	if test $# -ne 2
-	then
-		usage
-	fi
-
-	# we can't use `git submodule--helper name` here because internally, it
-	# hashes the path so a trailing slash could lead to an unintentional no match
-	name="$(git submodule--helper list "$1" | cut -f2)"
-	if test -z "$name"
-	then
-		exit 1
-	fi
-
-	url="$2"
-	if test -z "$url"
-	then
-		exit 1
-	fi
-
-	git submodule--helper config submodule."$name".url "$url"
-	git submodule--helper sync ${GIT_QUIET:+--quiet} "$name"
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper set-url ${GIT_QUIET:+--quiet} -- "$@"
 }
 
 #
diff --git a/git.c b/git.c
index 2e4efb4..a2d337e 100644
--- a/git.c
+++ b/git.c
@@ -4,6 +4,7 @@
 #include "help.h"
 #include "run-command.h"
 #include "alias.h"
+#include "shallow.h"
 
 #define RUN_SETUP		(1<<0)
 #define RUN_SETUP_GENTLY	(1<<1)
diff --git a/list-objects-filter.c b/list-objects-filter.c
index 1e8d4e7..0a3ef3c 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -663,6 +663,9 @@
 
 	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
 
+	if (!filter_options)
+		return NULL;
+
 	if (filter_options->choice >= LOFC__COUNT)
 		BUG("invalid list-objects filter choice: %d",
 		    filter_options->choice);
diff --git a/midx.c b/midx.c
index 9a61d3b..6d1584c 100644
--- a/midx.c
+++ b/midx.c
@@ -1293,15 +1293,26 @@
 	return 0;
 }
 
-static int fill_included_packs_all(struct multi_pack_index *m,
+static int fill_included_packs_all(struct repository *r,
+				   struct multi_pack_index *m,
 				   unsigned char *include_pack)
 {
-	uint32_t i;
+	uint32_t i, count = 0;
+	int pack_kept_objects = 0;
 
-	for (i = 0; i < m->num_packs; i++)
+	repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
+
+	for (i = 0; i < m->num_packs; i++) {
+		if (prepare_midx_pack(r, m, i))
+			continue;
+		if (!pack_kept_objects && m->packs[i]->pack_keep)
+			continue;
+
 		include_pack[i] = 1;
+		count++;
+	}
 
-	return m->num_packs < 2;
+	return count < 2;
 }
 
 static int fill_included_packs_batch(struct repository *r,
@@ -1312,6 +1323,9 @@
 	uint32_t i, packs_to_repack;
 	size_t total_size;
 	struct repack_info *pack_info = xcalloc(m->num_packs, sizeof(struct repack_info));
+	int pack_kept_objects = 0;
+
+	repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
 
 	for (i = 0; i < m->num_packs; i++) {
 		pack_info[i].pack_int_id = i;
@@ -1338,6 +1352,8 @@
 
 		if (!p)
 			continue;
+		if (!pack_kept_objects && p->pack_keep)
+			continue;
 		if (open_pack_index(p) || !p->num_objects)
 			continue;
 
@@ -1370,6 +1386,14 @@
 	struct strbuf base_name = STRBUF_INIT;
 	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
 
+	/*
+	 * When updating the default for these configuration
+	 * variables in builtin/repack.c, these must be adjusted
+	 * to match.
+	 */
+	int delta_base_offset = 1;
+	int use_delta_islands = 0;
+
 	if (!m)
 		return 0;
 
@@ -1378,15 +1402,23 @@
 	if (batch_size) {
 		if (fill_included_packs_batch(r, m, include_pack, batch_size))
 			goto cleanup;
-	} else if (fill_included_packs_all(m, include_pack))
+	} else if (fill_included_packs_all(r, m, include_pack))
 		goto cleanup;
 
+	repo_config_get_bool(r, "repack.usedeltabaseoffset", &delta_base_offset);
+	repo_config_get_bool(r, "repack.usedeltaislands", &use_delta_islands);
+
 	argv_array_push(&cmd.args, "pack-objects");
 
 	strbuf_addstr(&base_name, object_dir);
 	strbuf_addstr(&base_name, "/pack/pack");
 	argv_array_push(&cmd.args, base_name.buf);
 
+	if (delta_base_offset)
+		argv_array_push(&cmd.args, "--delta-base-offset");
+	if (use_delta_islands)
+		argv_array_push(&cmd.args, "--delta-islands");
+
 	if (flags & MIDX_PROGRESS)
 		argv_array_push(&cmd.args, "--progress");
 	else
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 49a8d10..4077e73 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -506,7 +506,8 @@
 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 				   struct rev_info *revs,
 				   struct object_list *roots,
-				   struct bitmap *seen)
+				   struct bitmap *seen,
+				   struct list_objects_filter_options *filter)
 {
 	struct bitmap *base = NULL;
 	int needs_walk = 0;
@@ -599,8 +600,9 @@
 		show_data.bitmap_git = bitmap_git;
 		show_data.base = base;
 
-		traverse_commit_list(revs, show_commit, show_object,
-				     &show_data);
+		traverse_commit_list_filtered(filter, revs,
+					      show_commit, show_object,
+					      &show_data, NULL);
 	}
 
 	return base;
@@ -715,8 +717,9 @@
 	return 0;
 }
 
-static struct bitmap *find_tip_blobs(struct bitmap_index *bitmap_git,
-				     struct object_list *tip_objects)
+static struct bitmap *find_tip_objects(struct bitmap_index *bitmap_git,
+				       struct object_list *tip_objects,
+				       enum object_type type)
 {
 	struct bitmap *result = bitmap_new();
 	struct object_list *p;
@@ -724,7 +727,7 @@
 	for (p = tip_objects; p; p = p->next) {
 		int pos;
 
-		if (p->item->type != OBJ_BLOB)
+		if (p->item->type != type)
 			continue;
 
 		pos = bitmap_position(bitmap_git, &p->item->oid);
@@ -737,9 +740,10 @@
 	return result;
 }
 
-static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
-				    struct object_list *tip_objects,
-				    struct bitmap *to_filter)
+static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
+				       struct object_list *tip_objects,
+				       struct bitmap *to_filter,
+				       enum object_type type)
 {
 	struct eindex *eindex = &bitmap_git->ext_index;
 	struct bitmap *tips;
@@ -747,18 +751,21 @@
 	eword_t mask;
 	uint32_t i;
 
+	if (type != OBJ_BLOB && type != OBJ_TREE)
+		BUG("filter_bitmap_exclude_type: unsupported type '%d'", type);
+
 	/*
 	 * The non-bitmap version of this filter never removes
-	 * blobs which the other side specifically asked for,
+	 * objects which the other side specifically asked for,
 	 * so we must match that behavior.
 	 */
-	tips = find_tip_blobs(bitmap_git, tip_objects);
+	tips = find_tip_objects(bitmap_git, tip_objects, type);
 
 	/*
 	 * We can use the blob type-bitmap to work in whole words
 	 * for the objects that are actually in the bitmapped packfile.
 	 */
-	for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
+	for (i = 0, init_type_iterator(&it, bitmap_git, type);
 	     i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 	     i++) {
 		if (i < tips->word_alloc)
@@ -773,7 +780,7 @@
 	 */
 	for (i = 0; i < eindex->count; i++) {
 		uint32_t pos = i + bitmap_git->pack->num_objects;
-		if (eindex->objects[i]->type == OBJ_BLOB &&
+		if (eindex->objects[i]->type == type &&
 		    bitmap_get(to_filter, pos) &&
 		    !bitmap_get(tips, pos))
 			bitmap_unset(to_filter, pos);
@@ -782,6 +789,14 @@
 	bitmap_free(tips);
 }
 
+static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
+				    struct object_list *tip_objects,
+				    struct bitmap *to_filter)
+{
+	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
+				   OBJ_BLOB);
+}
+
 static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 				     uint32_t pos)
 {
@@ -820,7 +835,7 @@
 	eword_t mask;
 	uint32_t i;
 
-	tips = find_tip_blobs(bitmap_git, tip_objects);
+	tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);
 
 	for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
 	     i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
@@ -854,6 +869,20 @@
 	bitmap_free(tips);
 }
 
+static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
+				     struct object_list *tip_objects,
+				     struct bitmap *to_filter,
+				     unsigned long limit)
+{
+	if (limit)
+		BUG("filter_bitmap_tree_depth given non-zero limit");
+
+	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
+				   OBJ_TREE);
+	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
+				   OBJ_BLOB);
+}
+
 static int filter_bitmap(struct bitmap_index *bitmap_git,
 			 struct object_list *tip_objects,
 			 struct bitmap *to_filter,
@@ -877,6 +906,15 @@
 		return 0;
 	}
 
+	if (filter->choice == LOFC_TREE_DEPTH &&
+	    filter->tree_exclude_depth == 0) {
+		if (bitmap_git)
+			filter_bitmap_tree_depth(bitmap_git, tip_objects,
+						 to_filter,
+						 filter->tree_exclude_depth);
+		return 0;
+	}
+
 	/* filter choice not handled */
 	return -1;
 }
@@ -963,7 +1001,8 @@
 
 	if (haves) {
 		revs->ignore_missing_links = 1;
-		haves_bitmap = find_objects(bitmap_git, revs, haves, NULL);
+		haves_bitmap = find_objects(bitmap_git, revs, haves, NULL,
+					    filter);
 		reset_revision_walk();
 		revs->ignore_missing_links = 0;
 
@@ -971,7 +1010,8 @@
 			BUG("failed to perform bitmap walk");
 	}
 
-	wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap);
+	wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap,
+				    filter);
 
 	if (!wants_bitmap)
 		BUG("failed to perform bitmap walk");
diff --git a/run-command.c b/run-command.c
index 0f41af3..9b3a57d 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1864,3 +1864,16 @@
 
 	return result;
 }
+
+int run_auto_gc(int quiet)
+{
+	struct argv_array argv_gc_auto = ARGV_ARRAY_INIT;
+	int status;
+
+	argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
+	if (quiet)
+		argv_array_push(&argv_gc_auto, "--quiet");
+	status = run_command_v_opt(argv_gc_auto.argv, RUN_GIT_CMD);
+	argv_array_clear(&argv_gc_auto);
+	return status;
+}
diff --git a/run-command.h b/run-command.h
index 0f3cc73..191dfcd 100644
--- a/run-command.h
+++ b/run-command.h
@@ -218,6 +218,11 @@
 int run_hook_le(const char *const *env, const char *name, ...);
 int run_hook_ve(const char *const *env, const char *name, va_list args);
 
+/*
+ * Trigger an auto-gc
+ */
+int run_auto_gc(int quiet);
+
 #define RUN_COMMAND_NO_STDIN 1
 #define RUN_GIT_CMD	     2	/*If this is to be git sub-command */
 #define RUN_COMMAND_STDOUT_TO_STDERR 4
diff --git a/send-pack.c b/send-pack.c
index d1b7edc..0abee22 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -15,6 +15,7 @@
 #include "oid-array.h"
 #include "gpg-interface.h"
 #include "cache.h"
+#include "shallow.h"
 
 int option_parse_push_signed(const struct option *opt,
 			     const char *arg, int unset)
diff --git a/sequencer.c b/sequencer.c
index 9d1b3e7..fd7701c 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -5385,10 +5385,13 @@
 			todo_list->items[i].command =
 				starts_with(subject, "fixup!") ?
 				TODO_FIXUP : TODO_SQUASH;
-			if (next[i2] < 0)
+			if (tail[i2] < 0) {
+				next[i] = next[i2];
 				next[i2] = i;
-			else
+			} else {
+				next[i] = next[tail[i2]];
 				next[tail[i2]] = i;
+			}
 			tail[i2] = i;
 		} else if (!hashmap_get_from_hash(&subject2item,
 						strhash(subject), subject)) {
diff --git a/shallow.c b/shallow.c
index 321a276..b826de9 100644
--- a/shallow.c
+++ b/shallow.c
@@ -14,6 +14,7 @@
 #include "commit-slab.h"
 #include "list-objects.h"
 #include "commit-reach.h"
+#include "shallow.h"
 
 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
 {
@@ -38,6 +39,19 @@
 	return register_commit_graft(r, graft, 0);
 }
 
+int unregister_shallow(const struct object_id *oid)
+{
+	int pos = commit_graft_pos(the_repository, oid->hash);
+	if (pos < 0)
+		return -1;
+	if (pos + 1 < the_repository->parsed_objects->grafts_nr)
+		MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
+			   the_repository->parsed_objects->grafts + pos + 1,
+			   the_repository->parsed_objects->grafts_nr - pos - 1);
+	the_repository->parsed_objects->grafts_nr--;
+	return 0;
+}
+
 int is_repository_shallow(struct repository *r)
 {
 	FILE *fp;
@@ -78,16 +92,16 @@
 	stat_validity_clear(r->parsed_objects->shallow_stat);
 }
 
-int commit_shallow_file(struct repository *r, struct lock_file *lk)
+int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
 {
-	int res = commit_lock_file(lk);
+	int res = commit_lock_file(&lk->lock);
 	reset_repository_shallow(r);
 	return res;
 }
 
-void rollback_shallow_file(struct repository *r, struct lock_file *lk)
+void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
 {
-	rollback_lock_file(lk);
+	rollback_lock_file(&lk->lock);
 	reset_repository_shallow(r);
 }
 
@@ -352,22 +366,22 @@
 	return "";
 }
 
-void setup_alternate_shallow(struct lock_file *shallow_lock,
+void setup_alternate_shallow(struct shallow_lock *shallow_lock,
 			     const char **alternate_shallow_file,
 			     const struct oid_array *extra)
 {
 	struct strbuf sb = STRBUF_INIT;
 	int fd;
 
-	fd = hold_lock_file_for_update(shallow_lock,
+	fd = hold_lock_file_for_update(&shallow_lock->lock,
 				       git_path_shallow(the_repository),
 				       LOCK_DIE_ON_ERROR);
 	check_shallow_file_for_update(the_repository);
 	if (write_shallow_commits(&sb, 0, extra)) {
 		if (write_in_full(fd, sb.buf, sb.len) < 0)
 			die_errno("failed to write to %s",
-				  get_lock_file_path(shallow_lock));
-		*alternate_shallow_file = get_lock_file_path(shallow_lock);
+				  get_lock_file_path(&shallow_lock->lock));
+		*alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
 	} else
 		/*
 		 * is_repository_shallow() sees empty string as "no
@@ -400,7 +414,7 @@
  */
 void prune_shallow(unsigned options)
 {
-	struct lock_file shallow_lock = LOCK_INIT;
+	struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	unsigned flags = SEEN_ONLY;
 	int fd;
@@ -414,14 +428,14 @@
 		strbuf_release(&sb);
 		return;
 	}
-	fd = hold_lock_file_for_update(&shallow_lock,
+	fd = hold_lock_file_for_update(&shallow_lock.lock,
 				       git_path_shallow(the_repository),
 				       LOCK_DIE_ON_ERROR);
 	check_shallow_file_for_update(the_repository);
 	if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
 		if (write_in_full(fd, sb.buf, sb.len) < 0)
 			die_errno("failed to write to %s",
-				  get_lock_file_path(&shallow_lock));
+				  get_lock_file_path(&shallow_lock.lock));
 		commit_shallow_file(the_repository, &shallow_lock);
 	} else {
 		unlink(git_path_shallow(the_repository));
diff --git a/shallow.h b/shallow.h
new file mode 100644
index 0000000..5b4a96d
--- /dev/null
+++ b/shallow.h
@@ -0,0 +1,81 @@
+#ifndef SHALLOW_H
+#define SHALLOW_H
+
+#include "lockfile.h"
+#include "object.h"
+#include "repository.h"
+#include "strbuf.h"
+
+void set_alternate_shallow_file(struct repository *r, const char *path, int override);
+int register_shallow(struct repository *r, const struct object_id *oid);
+int unregister_shallow(const struct object_id *oid);
+int is_repository_shallow(struct repository *r);
+
+/*
+ * Lock for updating the $GIT_DIR/shallow file.
+ *
+ * Use `commit_shallow_file()` to commit an update, or
+ * `rollback_shallow_file()` to roll it back. In either case, any
+ * in-memory cached information about which commits are shallow will be
+ * appropriately invalidated so that future operations reflect the new
+ * state.
+ */
+struct shallow_lock {
+	struct lock_file lock;
+};
+#define SHALLOW_LOCK_INIT { LOCK_INIT }
+
+/* commit $GIT_DIR/shallow and reset stat-validity checks */
+int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
+/* rollback $GIT_DIR/shallow and reset stat-validity checks */
+void rollback_shallow_file(struct repository *r, struct shallow_lock *lk);
+
+struct commit_list *get_shallow_commits(struct object_array *heads,
+					int depth, int shallow_flag, int not_shallow_flag);
+struct commit_list *get_shallow_commits_by_rev_list(
+		int ac, const char **av, int shallow_flag, int not_shallow_flag);
+int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
+			  const struct oid_array *extra);
+
+void setup_alternate_shallow(struct shallow_lock *shallow_lock,
+			     const char **alternate_shallow_file,
+			     const struct oid_array *extra);
+
+const char *setup_temporary_shallow(const struct oid_array *extra);
+
+void advertise_shallow_grafts(int);
+
+#define PRUNE_SHOW_ONLY 1
+#define PRUNE_QUICK 2
+void prune_shallow(unsigned options);
+
+/*
+ * Initialize with prepare_shallow_info() or zero-initialize (equivalent to
+ * prepare_shallow_info with a NULL oid_array).
+ */
+struct shallow_info {
+	struct oid_array *shallow;
+	int *ours, nr_ours;
+	int *theirs, nr_theirs;
+	struct oid_array *ref;
+
+	/* for receive-pack */
+	uint32_t **used_shallow;
+	int *need_reachability_test;
+	int *reachable;
+	int *shallow_ref;
+	struct commit **commits;
+	int nr_commits;
+};
+
+void prepare_shallow_info(struct shallow_info *, struct oid_array *);
+void clear_shallow_info(struct shallow_info *);
+void remove_nonexistent_theirs_shallow(struct shallow_info *);
+void assign_shallow_commits_to_refs(struct shallow_info *info,
+				    uint32_t **used,
+				    int *ref_status);
+int delayed_reachability_test(struct shallow_info *si, int c);
+
+extern struct trace_key trace_shallow;
+
+#endif /* SHALLOW_H */
diff --git a/t/helper/test-bloom.c b/t/helper/test-bloom.c
index 77eb27a..f0aa80b 100644
--- a/t/helper/test-bloom.c
+++ b/t/helper/test-bloom.c
@@ -3,7 +3,7 @@
 #include "test-tool.h"
 #include "commit.h"
 
-struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
+static struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
 
 static void add_string_to_filter(const char *data, struct bloom_filter *filter) {
 		struct bloom_key key;
@@ -44,7 +44,7 @@
 }
 
 static const char *bloom_usage = "\n"
-"  test-tool bloom get_murmer3 <string>\n"
+"  test-tool bloom get_murmur3 <string>\n"
 "  test-tool bloom generate_filter <string> [<string>...]\n"
 "  test-tool get_filter_for_commit <commit-hex>\n";
 
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 80c53ed..b3e725f 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -53,6 +53,11 @@
 		--filter=blob:limit=1k >/dev/null
 '
 
+test_perf 'rev-list count with tree:0' '
+	git rev-list --use-bitmap-index --count --objects --all \
+		--filter=tree:0 >/dev/null
+'
+
 test_perf 'simulated partial clone' '
 	git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
 '
@@ -86,4 +91,9 @@
 	git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
 '
 
+test_perf 'rev-list with tree filter (partial bitmap)' '
+	git rev-list --use-bitmap-index --count --objects --all \
+		--filter=tree:0 >/dev/null
+'
+
 test_done
diff --git a/t/t0091-bugreport.sh b/t/t0091-bugreport.sh
index 2e73658..526304f 100755
--- a/t/t0091-bugreport.sh
+++ b/t/t0091-bugreport.sh
@@ -57,5 +57,20 @@
 	nongit git bugreport -o foo/bar/baz
 '
 
+test_expect_success 'indicates populated hooks' '
+	test_when_finished rm git-bugreport-hooks.txt &&
+	test_when_finished rm -fr .git/hooks &&
+	rm -fr .git/hooks &&
+	mkdir .git/hooks &&
+	for hook in applypatch-msg prepare-commit-msg.sample
+	do
+		write_script ".git/hooks/$hook" <<-EOF || return 1
+		echo "hook $hook exists"
+		EOF
+	done &&
+	git bugreport -s hooks &&
+	grep applypatch-msg git-bugreport-hooks.txt &&
+	! grep prepare-commit-msg git-bugreport-hooks.txt
+'
 
 test_done
diff --git a/t/t0095-bloom.sh b/t/t0095-bloom.sh
index 8f9eef1..232ba2c 100755
--- a/t/t0095-bloom.sh
+++ b/t/t0095-bloom.sh
@@ -89,8 +89,8 @@
 	git add smallDir &&
 	git commit -m "commit with 10 changes" &&
 	cat >expect <<-\EOF &&
-	Filter_Length:25
-	Filter_Data:82|a0|65|47|0c|92|90|c0|a1|40|02|a0|e2|40|e0|04|0a|9a|66|cf|80|19|85|42|23|
+	Filter_Length:14
+	Filter_Data:02|b3|c4|a0|34|e7|fe|eb|cb|47|fe|a0|e8|72|
 	EOF
 	test-tool bloom get_filter_for_commit "$(git rev-parse HEAD)" >actual &&
 	test_cmp expect actual
@@ -100,7 +100,7 @@
 	rm actual &&
 	rm expect &&
 	mkdir bigDir &&
-	for i in $(test_seq 0 512)
+	for i in $(test_seq 0 511)
 	do
 		echo $i >bigDir/$i
 	done &&
@@ -114,4 +114,4 @@
 	test_cmp expect actual
 '
 
-test_done
\ No newline at end of file
+test_done
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 449ebc5..91a6e34 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -257,6 +257,22 @@
 	test_i18ngrep "error in tree .*contains duplicate file entries" out
 '
 
+test_expect_success 'tree object with dublicate names' '
+	test_when_finished "remove_object \$blob" &&
+	test_when_finished "remove_object \$tree" &&
+	test_when_finished "remove_object \$badtree" &&
+	blob=$(echo blob | git hash-object -w --stdin) &&
+	printf "100644 blob %s\t%s\n" $blob x.2 >tree &&
+	tree=$(git mktree <tree) &&
+	printf "100644 blob %s\t%s\n" $blob x.1 >badtree &&
+	printf "100644 blob %s\t%s\n" $blob x >>badtree &&
+	printf "040000 tree %s\t%s\n" $tree x >>badtree &&
+	badtree=$(git mktree <badtree) &&
+	test_must_fail git fsck 2>out &&
+	test_i18ngrep "$badtree" out &&
+	test_i18ngrep "error in tree .*contains duplicate file entries" out
+'
+
 test_expect_success 'unparseable tree object' '
 	test_oid_cache <<-\EOF &&
 	junk sha1:twenty-bytes-of-junk
diff --git a/t/t3415-rebase-autosquash.sh b/t/t3415-rebase-autosquash.sh
index 093de90..7bab600 100755
--- a/t/t3415-rebase-autosquash.sh
+++ b/t/t3415-rebase-autosquash.sh
@@ -424,4 +424,20 @@
 	! grep first actual
 '
 
+test_expect_success 'fixup a fixup' '
+	echo 0to-fixup >file0 &&
+	test_tick &&
+	git commit -m "to-fixup" file0 &&
+	test_tick &&
+	git commit --squash HEAD -m X --allow-empty &&
+	test_tick &&
+	git commit --squash HEAD^ -m Y --allow-empty &&
+	test_tick &&
+	git commit -m "squash! $(git rev-parse HEAD^)" -m Z --allow-empty &&
+	test_tick &&
+	git commit -m "squash! $(git rev-parse HEAD^^)" -m W --allow-empty &&
+	git rebase -ki --autosquash HEAD~5 &&
+	test XZWY = $(git show | tr -cd W-Z)
+'
+
 test_done
diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh
index c7011f3..21b68dd 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -152,4 +152,4 @@
 	test_bloom_filters_used_when_some_filters_are_missing "-- A/B"
 '
 
-test_done
\ No newline at end of file
+test_done
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 030a722..7214cab 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -538,6 +538,33 @@
 	)
 '
 
+test_expect_success 'repack respects repack.packKeptObjects=false' '
+	test_when_finished rm -f dup/.git/objects/pack/*keep &&
+	(
+		cd dup &&
+		ls .git/objects/pack/*idx >idx-list &&
+		test_line_count = 5 idx-list &&
+		ls .git/objects/pack/*.pack | sed "s/\.pack/.keep/" >keep-list &&
+		test_line_count = 5 keep-list &&
+		for keep in $(cat keep-list)
+		do
+			touch $keep || return 1
+		done &&
+		git multi-pack-index repack --batch-size=0 &&
+		ls .git/objects/pack/*idx >idx-list &&
+		test_line_count = 5 idx-list &&
+		test-tool read-midx .git/objects | grep idx >midx-list &&
+		test_line_count = 5 midx-list &&
+		THIRD_SMALLEST_SIZE=$(test-tool path-utils file-size .git/objects/pack/*pack | sort -n | sed -n 3p) &&
+		BATCH_SIZE=$((THIRD_SMALLEST_SIZE + 1)) &&
+		git multi-pack-index repack --batch-size=$BATCH_SIZE &&
+		ls .git/objects/pack/*idx >idx-list &&
+		test_line_count = 5 idx-list &&
+		test-tool read-midx .git/objects | grep idx >midx-list &&
+		test_line_count = 5 midx-list
+	)
+'
+
 test_expect_success 'repack creates a new pack' '
 	(
 		cd dup &&
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 52dd1a6..8c54e34 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -386,7 +386,7 @@
 '
 
 test_expect_success 'in_vain not triggered before first ACK' '
-	rm -rf myserver myclient trace &&
+	rm -rf myserver myclient &&
 	git init myserver &&
 	test_commit -C myserver foo &&
 	git clone "file://$(pwd)/myserver" myclient &&
@@ -399,12 +399,12 @@
 	# The new commit that the client wants to fetch.
 	test_commit -C myserver bar &&
 
-	GIT_TRACE_PACKET="$(pwd)/trace" git -C myclient fetch --progress origin &&
-	test_i18ngrep "Total 3 " trace
+	git -C myclient fetch --progress origin 2>log &&
+	test_i18ngrep "remote: Total 3 " log
 '
 
 test_expect_success 'in_vain resetted upon ACK' '
-	rm -rf myserver myclient trace &&
+	rm -rf myserver myclient &&
 	git init myserver &&
 
 	# Linked list of commits on master. The first is common; the rest are
@@ -429,8 +429,8 @@
 	# first. The 256th commit is common between the client and the server,
 	# and should reset in_vain. This allows negotiation to continue until
 	# the client reports that first_anotherbranch_commit is common.
-	GIT_TRACE_PACKET="$(pwd)/trace" git -C myclient fetch --progress origin master &&
-	test_i18ngrep "Total 3 " trace
+	git -C myclient fetch --progress origin master 2>log &&
+	test_i18ngrep "Total 3 " log
 '
 
 test_expect_success 'fetch in shallow repo unreachable shallow objects' '
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 88002b2..8a27452 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -384,12 +384,11 @@
 	grep "want $(cat hash)" trace
 '
 
-# The following two tests must be in this order, or else
-# the first will not fail. It is important that the srv.bare
-# repository did not have tags during clone, but has tags
+# The following two tests must be in this order. It is important that
+# the srv.bare repository did not have tags during clone, but has tags
 # in the fetch.
 
-test_expect_failure 'verify fetch succeeds when asking for new tags' '
+test_expect_success 'verify fetch succeeds when asking for new tags' '
 	git clone --filter=blob:none "file://$(pwd)/srv.bare" tag-test &&
 	for i in I J K
 	do
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 1313142..ac31fae 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -792,6 +792,13 @@
 	git bisect reset
 '
 
+test_expect_success 'bisect replay with CRLF log' '
+	append_cr <log_to_replay.txt >log_to_replay_crlf.txt &&
+	git bisect replay log_to_replay_crlf.txt >bisect_result_crlf &&
+	grep "$HASH2 is the first new commit" bisect_result_crlf &&
+	git bisect reset
+'
+
 test_expect_success 'bisect cannot mix old/new and good/bad' '
 	git bisect start &&
 	git bisect bad $HASH4 &&
diff --git a/t/t6113-rev-list-bitmap-filters.sh b/t/t6113-rev-list-bitmap-filters.sh
index 145603f..2b551e6 100755
--- a/t/t6113-rev-list-bitmap-filters.sh
+++ b/t/t6113-rev-list-bitmap-filters.sh
@@ -53,4 +53,25 @@
 	test_bitmap_traversal expect actual
 '
 
+test_expect_success 'tree:0 filter' '
+	git rev-list --objects --filter=tree:0 HEAD >expect &&
+	git rev-list --use-bitmap-index \
+		     --objects --filter=tree:0 HEAD >actual &&
+	test_bitmap_traversal expect actual
+'
+
+test_expect_success 'tree:0 filter with specified blob, tree' '
+	git rev-list --objects --filter=tree:0 HEAD HEAD:two.t >expect &&
+	git rev-list --use-bitmap-index \
+		     --objects --filter=tree:0 HEAD HEAD:two.t >actual &&
+	test_bitmap_traversal expect actual
+'
+
+test_expect_success 'tree:1 filter' '
+	git rev-list --objects --filter=tree:1 HEAD >expect &&
+	git rev-list --use-bitmap-index \
+		     --objects --filter=tree:1 HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t9834-git-p4-file-dir-bug.sh b/t/t9834-git-p4-file-dir-bug.sh
new file mode 100755
index 0000000..031e1f8
--- /dev/null
+++ b/t/t9834-git-p4-file-dir-bug.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+test_description='git p4 directory/file bug handling
+
+This test creates files and directories with the same name in perforce and
+checks that git-p4 recovers from the error at the same time as the perforce
+repository.'
+
+. ./lib-git-p4.sh
+
+test_expect_success 'start p4d' '
+	start_p4d &&
+	test_might_fail p4 configure set submit.collision.check=0
+'
+
+test_expect_success 'init depot' '
+	(
+		cd "$cli" &&
+
+		touch add_file_add_dir_del_file add_file_add_dir_del_dir &&
+		p4 add add_file_add_dir_del_file add_file_add_dir_del_dir &&
+		mkdir add_dir_add_file_del_file add_dir_add_file_del_dir &&
+		touch add_dir_add_file_del_file/file add_dir_add_file_del_dir/file &&
+		p4 add add_dir_add_file_del_file/file add_dir_add_file_del_dir/file &&
+		p4 submit -d "add initial" &&
+
+		rm -f add_file_add_dir_del_file add_file_add_dir_del_dir &&
+		mkdir add_file_add_dir_del_file add_file_add_dir_del_dir &&
+		touch add_file_add_dir_del_file/file add_file_add_dir_del_dir/file &&
+		p4 add add_file_add_dir_del_file/file add_file_add_dir_del_dir/file &&
+		rm -rf add_dir_add_file_del_file add_dir_add_file_del_dir &&
+		touch add_dir_add_file_del_file add_dir_add_file_del_dir &&
+		p4 add add_dir_add_file_del_file add_dir_add_file_del_dir &&
+		p4 submit -d "add conflicting" &&
+
+		p4 delete -k add_file_add_dir_del_file &&
+		p4 delete -k add_file_add_dir_del_dir/file &&
+		p4 delete -k add_dir_add_file_del_file &&
+		p4 delete -k add_dir_add_file_del_dir/file &&
+		p4 submit -d "delete conflicting" &&
+
+		p4 delete -k "add_file_add_dir_del_file/file" &&
+		p4 delete -k "add_file_add_dir_del_dir" &&
+		p4 delete -k "add_dir_add_file_del_file/file" &&
+		p4 delete -k "add_dir_add_file_del_dir" &&
+		p4 submit -d "delete remaining"
+	)
+'
+
+test_expect_success 'clone with git-p4' '
+	git p4 clone --dest="$git" //depot/@1,3
+'
+
+test_expect_success 'check contents' '
+	test_path_is_dir "$git/add_file_add_dir_del_file" &&
+	test_path_is_file "$git/add_file_add_dir_del_dir" &&
+	test_path_is_dir "$git/add_dir_add_file_del_file" &&
+	test_path_is_file "$git/add_dir_add_file_del_dir"
+'
+
+test_expect_success 'rebase and check empty' '
+	git -C "$git" p4 rebase &&
+
+	test_path_is_missing "$git/add_file_add_dir_del_file" &&
+	test_path_is_missing "$git/add_file_add_dir_del_dir" &&
+	test_path_is_missing "$git/add_dir_add_file_del_file" &&
+	test_path_is_missing "$git/add_dir_add_file_del_dir"
+'
+
+test_done
diff --git a/unpack-trees.c b/unpack-trees.c
index 1fe3764..02048df 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -562,11 +562,11 @@
 
 	add_rejected_path(o, WARNING_SPARSE_UNMERGED_FILE, conflicting_path);
 
-	/* Find out how many higher stage entries at same path */
-	while (++count < istate->cache_nr &&
-	       !strcmp(conflicting_path,
-		       istate->cache[i+count]->name))
-		/* do nothing */;
+	/* Find out how many higher stage entries are at same path */
+	while ((++count) + i < istate->cache_nr &&
+	       !strcmp(conflicting_path, istate->cache[count + i]->name))
+		; /* do nothing */
+
 	return count;
 }
 
diff --git a/upload-pack.c b/upload-pack.c
index 902d0ad..0478bff 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -26,6 +26,7 @@
 #include "serve.h"
 #include "commit-graph.h"
 #include "commit-reach.h"
+#include "shallow.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -68,7 +69,6 @@
 static int filter_capability_requested;
 static int allow_filter;
 static int allow_ref_in_want;
-static struct list_objects_filter_options filter_options;
 
 static int allow_sideband_all;
 
@@ -103,7 +103,8 @@
 }
 
 static void create_pack_file(const struct object_array *have_obj,
-			     const struct object_array *want_obj)
+			     const struct object_array *want_obj,
+			     struct list_objects_filter_options *filter_options)
 {
 	struct child_process pack_objects = CHILD_PROCESS_INIT;
 	char data[8193], progress[128];
@@ -140,9 +141,9 @@
 		argv_array_push(&pack_objects.args, "--delta-base-offset");
 	if (use_include_tag)
 		argv_array_push(&pack_objects.args, "--include-tag");
-	if (filter_options.choice) {
+	if (filter_options->choice) {
 		const char *spec =
-			expand_list_objects_filter_spec(&filter_options);
+			expand_list_objects_filter_spec(filter_options);
 		if (pack_objects.use_shell) {
 			struct strbuf buf = STRBUF_INIT;
 			sq_quote_buf(&buf, spec);
@@ -848,7 +849,9 @@
 	return 0;
 }
 
-static void receive_needs(struct packet_reader *reader, struct object_array *want_obj)
+static void receive_needs(struct packet_reader *reader,
+			  struct object_array *want_obj,
+			  struct list_objects_filter_options *filter_options)
 {
 	struct object_array shallows = OBJECT_ARRAY_INIT;
 	struct string_list deepen_not = STRING_LIST_INIT_DUP;
@@ -883,8 +886,8 @@
 		if (skip_prefix(reader->line, "filter ", &arg)) {
 			if (!filter_capability_requested)
 				die("git upload-pack: filtering capability not negotiated");
-			list_objects_filter_die_if_populated(&filter_options);
-			parse_list_objects_filter(&filter_options, arg);
+			list_objects_filter_die_if_populated(filter_options);
+			parse_list_objects_filter(filter_options, arg);
 			continue;
 		}
 
@@ -1087,11 +1090,14 @@
 	struct string_list symref = STRING_LIST_INIT_DUP;
 	struct object_array want_obj = OBJECT_ARRAY_INIT;
 	struct packet_reader reader;
+	struct list_objects_filter_options filter_options;
 
 	stateless_rpc = options->stateless_rpc;
 	timeout = options->timeout;
 	daemon_mode = options->daemon_mode;
 
+	memset(&filter_options, 0, sizeof(filter_options));
+
 	git_config(upload_pack_config, NULL);
 
 	head_ref_namespaced(find_symref, &symref);
@@ -1114,12 +1120,14 @@
 			   PACKET_READ_CHOMP_NEWLINE |
 			   PACKET_READ_DIE_ON_ERR_PACKET);
 
-	receive_needs(&reader, &want_obj);
+	receive_needs(&reader, &want_obj, &filter_options);
 	if (want_obj.nr) {
 		struct object_array have_obj = OBJECT_ARRAY_INIT;
 		get_common_commits(&reader, &have_obj, &want_obj);
-		create_pack_file(&have_obj, &want_obj);
+		create_pack_file(&have_obj, &want_obj, &filter_options);
 	}
+
+	list_objects_filter_release(&filter_options);
 }
 
 struct upload_pack_data {
@@ -1134,6 +1142,8 @@
 	int deepen_rev_list;
 	int deepen_relative;
 
+	struct list_objects_filter_options filter_options;
+
 	struct packet_writer writer;
 
 	unsigned stateless_rpc : 1;
@@ -1169,6 +1179,7 @@
 	oid_array_clear(&data->haves);
 	object_array_clear(&data->shallows);
 	string_list_clear(&data->deepen_not, 0);
+	list_objects_filter_release(&data->filter_options);
 }
 
 static int parse_want(struct packet_writer *writer, const char *line,
@@ -1306,8 +1317,8 @@
 		}
 
 		if (allow_filter && skip_prefix(arg, "filter ", &p)) {
-			list_objects_filter_die_if_populated(&filter_options);
-			parse_list_objects_filter(&filter_options, p);
+			list_objects_filter_die_if_populated(&data->filter_options);
+			parse_list_objects_filter(&data->filter_options, p);
 			continue;
 		}
 
@@ -1514,7 +1525,7 @@
 			send_shallow_info(&data, &want_obj);
 
 			packet_writer_write(&data.writer, "packfile\n");
-			create_pack_file(&have_obj, &want_obj);
+			create_pack_file(&have_obj, &want_obj, &data.filter_options);
 			state = FETCH_DONE;
 			break;
 		case FETCH_DONE: