diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 82d45f4f42c351..be34a81b4ec9ab 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -342,8 +342,8 @@ jobs:
           image: alpine
           distro: alpine-latest
         - jobname: linux32
-          image: daald/ubuntu32:xenial
-          distro: ubuntu32-16.04
+          image: i386/ubuntu:focal
+          distro: ubuntu32-20.04
         - jobname: pedantic
           image: fedora
           distro: fedora-latest
@@ -353,17 +353,17 @@ jobs:
     runs-on: ubuntu-latest
     container: ${{matrix.vector.image}}
     steps:
-    - uses: actions/checkout@v4
-      if: matrix.vector.jobname != 'linux32'
-    - uses: actions/checkout@v1 # cannot be upgraded because Node.js Actions aren't supported in this container
+    - name: prepare libc6 for actions
       if: matrix.vector.jobname == 'linux32'
+      run: apt -q update && apt -q -y install libc6-amd64 lib64stdc++6
+    - uses: actions/checkout@v4
     - run: ci/install-dependencies.sh
     - run: ci/run-build-and-tests.sh
     - name: print test failures
       if: failure() && env.FAILED_TEST_ARTIFACTS != ''
       run: ci/print-test-failures.sh
     - name: Upload failed tests' directories
-      if: failure() && env.FAILED_TEST_ARTIFACTS != '' && matrix.vector.jobname != 'linux32'
+      if: failure() && env.FAILED_TEST_ARTIFACTS != ''
       uses: actions/upload-artifact@v4
       with:
         name: failed-tests-${{matrix.vector.jobname}}
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 37b991e08079fc..c4c45dad2f956f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -25,6 +25,9 @@ test:linux:
       fi
   parallel:
     matrix:
+      - jobname: linux-old
+        image: ubuntu:16.04
+        CC: gcc
       - jobname: linux-sha256
         image: ubuntu:latest
         CC: clang
diff --git a/Documentation/RelNotes/2.46.2.txt b/Documentation/RelNotes/2.46.2.txt
new file mode 100644
index 00000000000000..613386878d44c9
--- /dev/null
+++ b/Documentation/RelNotes/2.46.2.txt
@@ -0,0 +1,23 @@
+Git 2.46.2 Release Notes
+========================
+
+This release is primarily to merge changes to unbreak the 32-bit
+GitHub actions jobs we use for CI testing, so that we can release
+real fixes for the 2.46.x track after they pass CI.
+
+It also reverts the "git patch-id" change that went into 2.46.1,
+as it seems to have got a regression reported (I haven't verified,
+but it is better to keep a known breakage than adding an unintended
+regression).
+
+Other than that, a handful of minor bugfixes are included.
+
+ * In a few corner cases "git diff --exit-code" failed to report
+   "changes" (e.g., renamed without any content change), which has
+   been corrected.
+
+ * Cygwin does have /dev/tty support that is needed by things like
+   single-key input mode.
+
+ * The interpret-trailers command failed to recognise the end of the
+   message when the commit log ends in an incomplete line.
diff --git a/Documentation/config/feature.txt b/Documentation/config/feature.txt
index f061b64b748449..cb49ff2604a632 100644
--- a/Documentation/config/feature.txt
+++ b/Documentation/config/feature.txt
@@ -20,6 +20,10 @@ walking fewer objects.
 +
 * `pack.allowPackReuse=multi` may improve the time it takes to create a pack by
 reusing objects from multiple packs instead of just one.
++
+* `pack.usePathWalk` may speed up packfile creation and make the packfiles be
+significantly smaller in the presence of certain filename collisions with Git's
+default name-hash.
 
 feature.manyFiles::
 	Enable config options that optimize for repos with many files in the
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index da527377fafcb6..08d06271177006 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -155,6 +155,14 @@ pack.useSparse::
 	commits contain certain types of direct renames. Default is
 	`true`.
 
+pack.usePathWalk::
+	When true, git will default to using the '--path-walk' option in
+	'git pack-objects' when the '--revs' option is present. This
+	algorithm groups objects by path to maximize the ability to
+	compute delta chains across historical versions of the same
+	object. This may disable other options, such as using bitmaps to
+	enumerate objects.
+
 pack.preferBitmapTips::
 	When selecting which commits will receive bitmaps, prefer a
 	commit at the tip of any reference that is a suffix of any value
diff --git a/Documentation/config/remote.txt b/Documentation/config/remote.txt
index 8efc53e836d20b..36e771556c67aa 100644
--- a/Documentation/config/remote.txt
+++ b/Documentation/config/remote.txt
@@ -42,14 +42,15 @@ remote.<name>.mirror::
 	as if the `--mirror` option was given on the command line.
 
 remote.<name>.skipDefaultUpdate::
-	If true, this remote will be skipped by default when updating
-	using linkgit:git-fetch[1] or the `update` subcommand of
-	linkgit:git-remote[1].
+	A deprecated synonym to `remote.<name>.skipFetchAll` (if
+	both are set in the configuration files with different
+	values, the value of the last occurrence will be used).
 
 remote.<name>.skipFetchAll::
-	If true, this remote will be skipped by default when updating
-	using linkgit:git-fetch[1] or the `update` subcommand of
-	linkgit:git-remote[1].
+	If true, this remote will be skipped when updating
+	using linkgit:git-fetch[1], the `update` subcommand of
+	linkgit:git-remote[1], and ignored by the prefetch task
+	of `git maitenance`.
 
 remote.<name>.receivepack::
 	The default program to execute on the remote side when pushing.  See
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index e22b217fba9e2c..80838fe37ef30e 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -1,6 +1,7 @@
 --[no-]all::
-	Fetch all remotes. This overrides the configuration variable
-	`fetch.all`.
+	Fetch all remotes, except for the ones that has the
+	`remote.<name>.skipFetchAll` configuration variable set.
+	This overrides the configuration variable fetch.all`.
 
 -a::
 --append::
diff --git a/Documentation/git-maintenance.txt b/Documentation/git-maintenance.txt
index 51d0f7e94b6a01..9d968191331080 100644
--- a/Documentation/git-maintenance.txt
+++ b/Documentation/git-maintenance.txt
@@ -107,6 +107,9 @@ with the prefetch task, the objects necessary to complete a later real fetch
 would already be obtained, making the real fetch faster.  In the ideal case,
 it will just become an update to a bunch of remote-tracking branches without
 any object transfer.
++
+The `remote.<name>.skipFetchAll` configuration can be used to
+exclude a particular remote from getting prefetched.
 
 gc::
 	Clean up unnecessary files and optimize the local repository. "GC"
diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt
index 93861d9f85b3b1..1a3023e2067f28 100644
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -16,7 +16,7 @@ SYNOPSIS
 	[--cruft] [--cruft-expiration=<time>]
 	[--stdout [--filter=<filter-spec>] | <base-name>]
 	[--shallow] [--keep-true-parents] [--[no-]sparse]
-	[--full-name-hash] < <object-list>
+	[--full-name-hash] [--path-walk] < <object-list>
 
 
 DESCRIPTION
@@ -346,6 +346,16 @@ raise an error.
 	Restrict delta matches based on "islands". See DELTA ISLANDS
 	below.
 
+--path-walk::
+	By default, `git pack-objects` walks objects in an order that
+	presents trees and blobs in an order unrelated to the path they
+	appear relative to a commit's root tree. The `--path-walk` option
+	enables a different walking algorithm that organizes trees and
+	blobs by path. This has the potential to improve delta compression
+	especially in the presence of filenames that cause collisions in
+	Git's default name-hash algorithm. Due to changing how the objects
+	are walked, this option is not compatible with `--delta-islands`,
+	`--shallow`, or `--filter`.
 
 DELTA ISLANDS
 -------------
diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
index 457a793fa89b2e..717e0a8e41a03b 100644
--- a/Documentation/git-repack.txt
+++ b/Documentation/git-repack.txt
@@ -11,7 +11,7 @@ SYNOPSIS
 [verse]
 'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m]
 	[--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
-	[--write-midx] [--full-name-hash]
+	[--write-midx] [--full-name-hash] [--path-walk]
 
 DESCRIPTION
 -----------
@@ -251,6 +251,19 @@ linkgit:git-multi-pack-index[1]).
 	Write a multi-pack index (see linkgit:git-multi-pack-index[1])
 	containing the non-redundant packs.
 
+--path-walk::
+	This option passes the `--path-walk` option to the underlying
+	`git pack-options` process (see linkgit:git-pack-objects[1]).
+	By default, `git pack-objects` walks objects in an order that
+	presents trees and blobs in an order unrelated to the path they
+	appear relative to a commit's root tree. The `--path-walk` option
+	enables a different walking algorithm that organizes trees and
+	blobs by path. This has the potential to improve delta compression
+	especially in the presence of filenames that cause collisions in
+	Git's default name-hash algorithm. Due to changing how the objects
+	are walked, this option is not compatible with `--delta-islands`
+	or `--filter`.
+
 CONFIGURATION
 -------------
 
diff --git a/Documentation/technical/api-path-walk.txt b/Documentation/technical/api-path-walk.txt
new file mode 100644
index 00000000000000..2d25281774d43d
--- /dev/null
+++ b/Documentation/technical/api-path-walk.txt
@@ -0,0 +1,73 @@
+Path-Walk API
+=============
+
+The path-walk API is used to walk reachable objects, but to visit objects
+in batches based on a common path they appear in, or by type.
+
+For example, all reachable commits are visited in a group. All tags are
+visited in a group. Then, all root trees are visited. At some point, all
+blobs reachable via a path `my/dir/to/A` are visited. When there are
+multiple paths possible to reach the same object, then only one of those
+paths is used to visit the object.
+
+When walking a range of commits with some `UNINTERESTING` objects, the
+objects with the `UNINTERESTING` flag are included in these batches. In
+order to walk `UNINTERESTING` objects, the `--boundary` option must be
+used in the commit walk in order to visit `UNINTERESTING` commits.
+
+Basics
+------
+
+To use the path-walk API, include `path-walk.h` and call
+`walk_objects_by_path()` with a customized `path_walk_info` struct. The
+struct is used to set all of the options for how the walk should proceed.
+Let's dig into the different options and their use.
+
+`path_fn` and `path_fn_data`::
+	The most important option is the `path_fn` option, which is a
+	function pointer to the callback that can execute logic on the
+	object IDs for objects grouped by type and path. This function
+	also receives a `data` value that corresponds to the
+	`path_fn_data` member, for providing custom data structures to
+	this callback function.
+
+`revs`::
+	To configure the exact details of the reachable set of objects,
+	use the `revs` member and initialize it using the revision
+	machinery in `revision.h`. Initialize `revs` using calls such as
+	`setup_revisions()` or `parse_revision_opt()`. Do not call
+	`prepare_revision_walk()`, as that will be called within
+	`walk_objects_by_path()`.
++
+It is also important that you do not specify the `--objects` flag for the
+`revs` struct. The revision walk should only be used to walk commits, and
+the objects will be walked in a separate way based on those starting
+commits.
++
+If you want the path-walk API to emit `UNINTERESTING` objects based on the
+commit walk's boundary, be sure to set `revs.boundary` so the boundary
+commits are emitted.
+
+`commits`, `blobs`, `trees`, `tags`::
+	By default, these members are enabled and signal that the path-walk
+	API should call the `path_fn` on objects of these types. Specialized
+	applications could disable some options to make it simpler to walk
+	the objects or to have fewer calls to `path_fn`.
++
+While it is possible to walk only commits in this way, consumers would be
+better off using the revision walk API instead.
+
+`prune_all_uninteresting`::
+	By default, all reachable paths are emitted by the path-walk API.
+	This option allows consumers to declare that they are not
+	interested in paths where all included objects are marked with the
+	`UNINTERESTING` flag. This requires using the `boundary` option in
+	the revision walk so that the walk emits commits marked with the
+	`UNINTERESTING` flag.
+
+Examples
+--------
+
+See example usages in:
+	`t/helper/test-path-walk.c`,
+	`builtin/pack-objects.c`
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index 55850912d13034..05fa12fec794eb 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.46.1
+DEF_VER=v2.46.2
 
 LF='
 '
diff --git a/Makefile b/Makefile
index 522c8a612c9882..b970bd81fc81c2 100644
--- a/Makefile
+++ b/Makefile
@@ -822,6 +822,7 @@ TEST_BUILTINS_OBJS += test-parse-options.o
 TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
 TEST_BUILTINS_OBJS += test-partial-clone.o
 TEST_BUILTINS_OBJS += test-path-utils.o
+TEST_BUILTINS_OBJS += test-path-walk.o
 TEST_BUILTINS_OBJS += test-pcre2-config.o
 TEST_BUILTINS_OBJS += test-pkt-line.o
 TEST_BUILTINS_OBJS += test-proc-receive.o
@@ -1098,6 +1099,7 @@ LIB_OBJS += parse-options.o
 LIB_OBJS += patch-delta.o
 LIB_OBJS += patch-ids.o
 LIB_OBJS += path.o
+LIB_OBJS += path-walk.o
 LIB_OBJS += pathspec.o
 LIB_OBJS += pkt-line.o
 LIB_OBJS += preload-index.o
diff --git a/RelNotes b/RelNotes
index 89b65f22b19959..0dfe046c8855e5 120000
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.46.1.txt
\ No newline at end of file
+Documentation/RelNotes/2.46.2.txt
\ No newline at end of file
diff --git a/builtin/interpret-trailers.c b/builtin/interpret-trailers.c
index 1d969494cf5471..e6f22459f15334 100644
--- a/builtin/interpret-trailers.c
+++ b/builtin/interpret-trailers.c
@@ -132,6 +132,7 @@ static void read_input_file(struct strbuf *sb, const char *file)
 		if (strbuf_read(sb, fileno(stdin), 0) < 0)
 			die_errno(_("could not read from stdin"));
 	}
+	strbuf_complete_line(sb);
 }
 
 static void interpret_trailers(const struct process_trailer_options *opts,
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index e93ec82756238a..2a5cf31a30c745 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -39,6 +39,9 @@
 #include "promisor-remote.h"
 #include "pack-mtimes.h"
 #include "parse-options.h"
+#include "blob.h"
+#include "tree.h"
+#include "path-walk.h"
 
 /*
  * Objects we are going to pack are collected in the `to_pack` structure.
@@ -215,6 +218,7 @@ static int delta_search_threads;
 static int pack_to_stdout;
 static int sparse;
 static int thin;
+static int path_walk = -1;
 static int num_preferred_base;
 static struct progress *progress_state;
 
@@ -2905,6 +2909,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
 struct thread_params {
 	pthread_t thread;
 	struct object_entry **list;
+	struct packing_region *regions;
 	unsigned list_size;
 	unsigned remaining;
 	int window;
@@ -3147,6 +3152,234 @@ static int add_ref_tag(const char *tag UNUSED, const struct object_id *oid,
 	return 0;
 }
 
+static int should_attempt_deltas(struct object_entry *entry)
+{
+	if (DELTA(entry))
+		return 0;
+
+	if (!entry->type_valid ||
+	    oe_size_less_than(&to_pack, entry, 50))
+		return 0;
+
+	if (entry->no_try_delta)
+		return 0;
+
+	if (!entry->preferred_base) {
+		if (oe_type(entry) < 0)
+			die(_("unable to get type of object %s"),
+				oid_to_hex(&entry->idx.oid));
+	} else if (oe_type(entry) < 0) {
+		/*
+		 * This object is not found, but we
+		 * don't have to include it anyway.
+		 */
+		return 0;
+	}
+
+	return 1;
+}
+
+static void find_deltas_for_region(struct object_entry *list,
+				   struct packing_region *region,
+				   unsigned int *processed)
+{
+	struct object_entry **delta_list;
+	uint32_t delta_list_nr = 0;
+
+	ALLOC_ARRAY(delta_list, region->nr);
+	for (uint32_t i = 0; i < region->nr; i++) {
+		struct object_entry *entry = to_pack.objects + region->start + i;
+		if (should_attempt_deltas(entry))
+			delta_list[delta_list_nr++] = entry;
+	}
+
+	QSORT(delta_list, delta_list_nr, type_size_sort);
+	find_deltas(delta_list, &delta_list_nr, window, depth, processed);
+	free(delta_list);
+}
+
+static void find_deltas_by_region(struct object_entry *list,
+				  struct packing_region *regions,
+				  uint32_t start, uint32_t nr)
+{
+	unsigned int processed = 0;
+	uint32_t progress_nr;
+
+	if (!nr)
+		return;
+
+	progress_nr = regions[nr - 1].start + regions[nr - 1].nr;
+
+	if (progress)
+		progress_state = start_progress(_("Compressing objects by path"),
+						progress_nr);
+
+	while (nr--)
+		find_deltas_for_region(list,
+				       &regions[start++],
+				       &processed);
+
+	display_progress(progress_state, progress_nr);
+	stop_progress(&progress_state);
+}
+
+static void *threaded_find_deltas_by_path(void *arg)
+{
+	struct thread_params *me = arg;
+
+	progress_lock();
+	while (me->remaining) {
+		while (me->remaining) {
+			progress_unlock();
+			find_deltas_for_region(to_pack.objects,
+					       me->regions,
+					       me->processed);
+			progress_lock();
+			me->remaining--;
+			me->regions++;
+		}
+
+		me->working = 0;
+		pthread_cond_signal(&progress_cond);
+		progress_unlock();
+
+		/*
+		 * We must not set ->data_ready before we wait on the
+		 * condition because the main thread may have set it to 1
+		 * before we get here. In order to be sure that new
+		 * work is available if we see 1 in ->data_ready, it
+		 * was initialized to 0 before this thread was spawned
+		 * and we reset it to 0 right away.
+		 */
+		pthread_mutex_lock(&me->mutex);
+		while (!me->data_ready)
+			pthread_cond_wait(&me->cond, &me->mutex);
+		me->data_ready = 0;
+		pthread_mutex_unlock(&me->mutex);
+
+		progress_lock();
+	}
+	progress_unlock();
+	/* leave ->working 1 so that this doesn't get more work assigned */
+	return NULL;
+}
+
+static void ll_find_deltas_by_region(struct object_entry *list,
+				     struct packing_region *regions,
+				     uint32_t start, uint32_t nr)
+{
+	struct thread_params *p;
+	int i, ret, active_threads = 0;
+	unsigned int processed = 0;
+	uint32_t progress_nr;
+	init_threaded_search();
+
+	if (!nr)
+		return;
+
+	progress_nr =  regions[nr - 1].start + regions[nr - 1].nr;
+	if (delta_search_threads <= 1) {
+		find_deltas_by_region(list, regions, start, nr);
+		cleanup_threaded_search();
+		return;
+	}
+
+	if (progress > pack_to_stdout)
+		fprintf_ln(stderr, _("Path-based delta compression using up to %d threads"),
+			   delta_search_threads);
+	CALLOC_ARRAY(p, delta_search_threads);
+
+	if (progress)
+		progress_state = start_progress(_("Compressing objects by path"),
+						progress_nr);
+	/* Partition the work amongst work threads. */
+	for (i = 0; i < delta_search_threads; i++) {
+		unsigned sub_size = nr / (delta_search_threads - i);
+
+		p[i].window = window;
+		p[i].depth = depth;
+		p[i].processed = &processed;
+		p[i].working = 1;
+		p[i].data_ready = 0;
+
+		p[i].regions = regions;
+		p[i].list_size = sub_size;
+		p[i].remaining = sub_size;
+
+		regions += sub_size;
+		nr -= sub_size;
+	}
+
+	/* Start work threads. */
+	for (i = 0; i < delta_search_threads; i++) {
+		if (!p[i].list_size)
+			continue;
+		pthread_mutex_init(&p[i].mutex, NULL);
+		pthread_cond_init(&p[i].cond, NULL);
+		ret = pthread_create(&p[i].thread, NULL,
+				     threaded_find_deltas_by_path, &p[i]);
+		if (ret)
+			die(_("unable to create thread: %s"), strerror(ret));
+		active_threads++;
+	}
+
+	/*
+	 * Now let's wait for work completion.  Each time a thread is done
+	 * with its work, we steal half of the remaining work from the
+	 * thread with the largest number of unprocessed objects and give
+	 * it to that newly idle thread.  This ensure good load balancing
+	 * until the remaining object list segments are simply too short
+	 * to be worth splitting anymore.
+	 */
+	while (active_threads) {
+		struct thread_params *target = NULL;
+		struct thread_params *victim = NULL;
+		unsigned sub_size = 0;
+
+		progress_lock();
+		for (;;) {
+			for (i = 0; !target && i < delta_search_threads; i++)
+				if (!p[i].working)
+					target = &p[i];
+			if (target)
+				break;
+			pthread_cond_wait(&progress_cond, &progress_mutex);
+		}
+
+		for (i = 0; i < delta_search_threads; i++)
+			if (p[i].remaining > 2*window &&
+			    (!victim || victim->remaining < p[i].remaining))
+				victim = &p[i];
+		if (victim) {
+			sub_size = victim->remaining / 2;
+			target->regions = victim->regions + victim->remaining - sub_size;
+			victim->list_size -= sub_size;
+			victim->remaining -= sub_size;
+		}
+		target->list_size = sub_size;
+		target->remaining = sub_size;
+		target->working = 1;
+		progress_unlock();
+
+		pthread_mutex_lock(&target->mutex);
+		target->data_ready = 1;
+		pthread_cond_signal(&target->cond);
+		pthread_mutex_unlock(&target->mutex);
+
+		if (!sub_size) {
+			pthread_join(target->thread, NULL);
+			pthread_cond_destroy(&target->cond);
+			pthread_mutex_destroy(&target->mutex);
+			active_threads--;
+		}
+	}
+	cleanup_threaded_search();
+	free(p);
+
+	display_progress(progress_state, progress_nr);
+	stop_progress(&progress_state);
+}
+
 static void prepare_pack(int window, int depth)
 {
 	struct object_entry **delta_list;
@@ -3171,39 +3404,21 @@ static void prepare_pack(int window, int depth)
 	if (!to_pack.nr_objects || !window || !depth)
 		return;
 
+	if (path_walk)
+		ll_find_deltas_by_region(to_pack.objects, to_pack.regions,
+					 0, to_pack.nr_regions);
+
 	ALLOC_ARRAY(delta_list, to_pack.nr_objects);
 	nr_deltas = n = 0;
 
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		struct object_entry *entry = to_pack.objects + i;
 
-		if (DELTA(entry))
-			/* This happens if we decided to reuse existing
-			 * delta from a pack.  "reuse_delta &&" is implied.
-			 */
-			continue;
-
-		if (!entry->type_valid ||
-		    oe_size_less_than(&to_pack, entry, 50))
+		if (!should_attempt_deltas(entry))
 			continue;
 
-		if (entry->no_try_delta)
-			continue;
-
-		if (!entry->preferred_base) {
+		if (!entry->preferred_base)
 			nr_deltas++;
-			if (oe_type(entry) < 0)
-				die(_("unable to get type of object %s"),
-				    oid_to_hex(&entry->idx.oid));
-		} else {
-			if (oe_type(entry) < 0) {
-				/*
-				 * This object is not found, but we
-				 * don't have to include it anyway.
-				 */
-				continue;
-			}
-		}
 
 		delta_list[n++] = entry;
 	}
@@ -4117,6 +4332,88 @@ static void mark_bitmap_preferred_tips(void)
 	}
 }
 
+static inline int is_oid_interesting(struct repository *repo,
+				     struct object_id *oid)
+{
+	struct object *o = lookup_object(repo, oid);
+	return o && !(o->flags & UNINTERESTING);
+}
+
+static int add_objects_by_path(const char *path,
+			       struct oid_array *oids,
+			       enum object_type type,
+			       void *data)
+{
+	size_t oe_start = to_pack.nr_objects;
+	size_t oe_end;
+	unsigned int *processed = data;
+
+	/*
+	 * First, add all objects to the packing data, including the ones
+	 * marked UNINTERESTING (translated to 'exclude') as they can be
+	 * used as delta bases.
+	 */
+	for (size_t i = 0; i < oids->nr; i++) {
+		int exclude;
+		struct object_info oi = OBJECT_INFO_INIT;
+		struct object_id *oid = &oids->oid[i];
+
+		/* Skip objects that do not exist locally. */
+		if ((exclude_promisor_objects || arg_missing_action != MA_ERROR) &&
+		    oid_object_info_extended(the_repository, oid, &oi,
+					     OBJECT_INFO_FOR_PREFETCH) < 0)
+			continue;
+
+		exclude = !is_oid_interesting(the_repository, oid);
+
+		if (exclude && !thin)
+			continue;
+
+		add_object_entry(oid, type, path, exclude);
+	}
+
+	oe_end = to_pack.nr_objects;
+
+	/* We can skip delta calculations if it is a no-op. */
+	if (oe_end == oe_start || !window)
+		return 0;
+
+	ALLOC_GROW(to_pack.regions,
+		   to_pack.nr_regions + 1,
+		   to_pack.nr_regions_alloc);
+
+	to_pack.regions[to_pack.nr_regions].start = oe_start;
+	to_pack.regions[to_pack.nr_regions].nr = oe_end - oe_start;
+	to_pack.nr_regions++;
+
+	*processed += oids->nr;
+	display_progress(progress_state, *processed);
+
+	return 0;
+}
+
+static void get_object_list_path_walk(struct rev_info *revs)
+{
+	struct path_walk_info info = PATH_WALK_INFO_INIT;
+	unsigned int processed = 0;
+
+	info.revs = revs;
+	info.path_fn = add_objects_by_path;
+	info.path_fn_data = &processed;
+	revs->tag_objects = 1;
+
+	/*
+	 * Allow the --[no-]sparse option to be interesting here, if only
+	 * for testing purposes. Paths with no interesting objects will not
+	 * contribute to the resulting pack, but only create noisy preferred
+	 * base objects.
+	 */
+	info.prune_all_uninteresting = sparse;
+
+	if (walk_objects_by_path(&info))
+		die(_("failed to pack objects via path-walk"));
+}
+
 static void get_object_list(struct rev_info *revs, int ac, const char **av)
 {
 	struct setup_revision_opt s_r_opt = {
@@ -4163,7 +4460,7 @@ static void get_object_list(struct rev_info *revs, int ac, const char **av)
 
 	warn_on_object_refname_ambiguity = save_warning;
 
-	if (use_bitmap_index && !get_object_list_from_bitmap(revs))
+	if (use_bitmap_index && !path_walk && !get_object_list_from_bitmap(revs))
 		return;
 
 	if (use_delta_islands)
@@ -4172,15 +4469,19 @@ static void get_object_list(struct rev_info *revs, int ac, const char **av)
 	if (write_bitmap_index)
 		mark_bitmap_preferred_tips();
 
-	if (prepare_revision_walk(revs))
-		die(_("revision walk setup failed"));
-	mark_edges_uninteresting(revs, show_edge, sparse);
-
 	if (!fn_show_object)
 		fn_show_object = show_object;
-	traverse_commit_list(revs,
-			     show_commit, fn_show_object,
-			     NULL);
+
+	if (path_walk) {
+		get_object_list_path_walk(revs);
+	} else {
+		if (prepare_revision_walk(revs))
+			die(_("revision walk setup failed"));
+		mark_edges_uninteresting(revs, show_edge, sparse);
+		traverse_commit_list(revs,
+				show_commit, fn_show_object,
+				NULL);
+	}
 
 	if (unpack_unreachable_expiration) {
 		revs->ignore_missing_links = 1;
@@ -4375,6 +4676,8 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 			 N_("use the sparse reachability algorithm")),
 		OPT_BOOL(0, "thin", &thin,
 			 N_("create thin packs")),
+		OPT_BOOL(0, "path-walk", &path_walk,
+			 N_("use the path-walk API to walk objects when possible")),
 		OPT_BOOL(0, "shallow", &shallow,
 			 N_("create packs suitable for shallow fetches")),
 		OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep_on_disk,
@@ -4441,6 +4744,17 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (pack_to_stdout != !base_name || argc)
 		usage_with_options(pack_usage, pack_objects_options);
 
+	if (path_walk < 0) {
+		if (use_bitmap_index > 0 ||
+		    !use_internal_rev_list)
+			path_walk = 0;
+		else if (the_repository->gitdir &&
+			 the_repository->settings.pack_use_path_walk)
+			path_walk = 1;
+		else
+			path_walk = git_env_bool("GIT_TEST_PACK_PATH_WALK", 0);
+	}
+
 	if (depth < 0)
 		depth = 0;
 	if (depth >= (1 << OE_DEPTH_BITS)) {
@@ -4457,7 +4771,27 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		window = 0;
 
 	strvec_push(&rp, "pack-objects");
-	if (thin) {
+
+	if (path_walk && filter_options.choice) {
+		warning(_("cannot use --filter with --path-walk"));
+		path_walk = 0;
+	}
+	if (path_walk && use_delta_islands) {
+		warning(_("cannot use delta islands with --path-walk"));
+		path_walk = 0;
+	}
+	if (path_walk && shallow) {
+		warning(_("cannot use --shallow with --path-walk"));
+		path_walk = 0;
+	}
+	if (path_walk) {
+		strvec_push(&rp, "--boundary");
+		 /*
+		  * We must disable the bitmaps because we are removing
+		  * the --objects / --objects-edge[-aggressive] options.
+		  */
+		use_bitmap_index = 0;
+	} else if (thin) {
 		use_internal_rev_list = 1;
 		strvec_push(&rp, shallow
 				? "--objects-edge-aggressive"
diff --git a/builtin/patch-id.c b/builtin/patch-id.c
index 35c1179f7e94ba..d790ae6354b415 100644
--- a/builtin/patch-id.c
+++ b/builtin/patch-id.c
@@ -7,9 +7,10 @@
 #include "parse-options.h"
 #include "setup.h"
 
-static void flush_current_id(struct object_id *id, struct object_id *result)
+static void flush_current_id(int patchlen, struct object_id *id, struct object_id *result)
 {
-	printf("%s %s\n", oid_to_hex(result), oid_to_hex(id));
+	if (patchlen)
+		printf("%s %s\n", oid_to_hex(result), oid_to_hex(id));
 }
 
 static int remove_space(char *line)
@@ -59,27 +60,9 @@ static int scan_hunk_header(const char *p, int *p_before, int *p_after)
 	return 1;
 }
 
-/*
- * flag bits to control get_one_patchid()'s behaviour.
- *
- * STABLE/VERBATIM are given from the command line option as
- * --stable/--verbatim.  FIND_HEADER conveys the internal state
- * maintained by the caller to allow the function to avoid mistaking
- * lines of log message before seeing the "diff" part as the beginning
- * of the next patch.
- */
-enum {
-	GOPID_STABLE = (1<<0),		/* --stable */
-	GOPID_VERBATIM = (1<<1),	/* --verbatim */
-	GOPID_FIND_HEADER = (1<<2),	/* stop at the beginning of patch message */
-};
-
 static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
-			   struct strbuf *line_buf, unsigned flags)
+			   struct strbuf *line_buf, int stable, int verbatim)
 {
-	int stable = flags & GOPID_STABLE;
-	int verbatim = flags & GOPID_VERBATIM;
-	int find_header = flags & GOPID_FIND_HEADER;
 	int patchlen = 0, found_next = 0;
 	int before = -1, after = -1;
 	int diff_is_binary = 0;
@@ -94,40 +77,24 @@ static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
 		const char *p = line;
 		int len;
 
-		/*
-		 * The caller hasn't seen us find a patch header and
-		 * return to it, or we have started processing patch
-		 * and may encounter the beginning of the next patch.
-		 */
-		if (find_header) {
-			/*
-			 * If we see a line that begins with "<object name>",
-			 * "commit <object name>" or "From <object name>", it is
-			 * the beginning of a patch.  Return to the caller, as
-			 * we are done with the one we have been processing.
-			 */
-			if (skip_prefix(line, "commit ", &p))
-				;
-			else if (skip_prefix(line, "From ", &p))
-				;
-			if (!get_oid_hex(p, next_oid)) {
-				if (verbatim)
-					the_hash_algo->update_fn(&ctx, line, strlen(line));
-				found_next = 1;
-				break;
-			}
+		/* Possibly skip over the prefix added by "log" or "format-patch" */
+		if (!skip_prefix(line, "commit ", &p) &&
+		    !skip_prefix(line, "From ", &p) &&
+		    starts_with(line, "\\ ") && 12 < strlen(line)) {
+			if (verbatim)
+				the_hash_algo->update_fn(&ctx, line, strlen(line));
+			continue;
+		}
+
+		if (!get_oid_hex(p, next_oid)) {
+			found_next = 1;
+			break;
 		}
 
 		/* Ignore commit comments */
 		if (!patchlen && !starts_with(line, "diff "))
 			continue;
 
-		/*
-		 * We are past the commit log message.  Prepare to
-		 * stop at the beginning of the next patch header.
-		 */
-		find_header = 1;
-
 		/* Parsing diff header?  */
 		if (before == -1) {
 			if (starts_with(line, "GIT binary patch") ||
@@ -160,16 +127,6 @@ static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
 				break;
 		}
 
-		/*
-		 * A hunk about an incomplete line may have this
-		 * marker at the end, which should just be ignored.
-		 */
-		if (starts_with(line, "\\ ") && 12 < strlen(line)) {
-			if (verbatim)
-				the_hash_algo->update_fn(&ctx, line, strlen(line));
-			continue;
-		}
-
 		if (diff_is_binary) {
 			if (starts_with(line, "diff ")) {
 				diff_is_binary = 0;
@@ -216,20 +173,17 @@ static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
 	return patchlen;
 }
 
-static void generate_id_list(unsigned flags)
+static void generate_id_list(int stable, int verbatim)
 {
 	struct object_id oid, n, result;
 	int patchlen;
 	struct strbuf line_buf = STRBUF_INIT;
 
 	oidclr(&oid, the_repository->hash_algo);
-	flags |= GOPID_FIND_HEADER;
 	while (!feof(stdin)) {
-		patchlen = get_one_patchid(&n, &result, &line_buf, flags);
-		if (patchlen)
-			flush_current_id(&oid, &result);
+		patchlen = get_one_patchid(&n, &result, &line_buf, stable, verbatim);
+		flush_current_id(patchlen, &oid, &result);
 		oidcpy(&oid, &n);
-		flags &= ~GOPID_FIND_HEADER;
 	}
 	strbuf_release(&line_buf);
 }
@@ -265,7 +219,6 @@ int cmd_patch_id(int argc, const char **argv, const char *prefix)
 	/* if nothing is set, default to unstable */
 	struct patch_id_opts config = {0, 0};
 	int opts = 0;
-	unsigned flags = 0;
 	struct option builtin_patch_id_options[] = {
 		OPT_CMDMODE(0, "unstable", &opts,
 		    N_("use the unstable patch-id algorithm"), 1),
@@ -297,11 +250,7 @@ int cmd_patch_id(int argc, const char **argv, const char *prefix)
 	if (!the_hash_algo)
 		repo_set_hash_algo(the_repository, GIT_HASH_SHA1);
 
-	if (opts ? opts > 1 : config.stable)
-		flags |= GOPID_STABLE;
-	if (opts ? opts == 3 : config.verbatim)
-		flags |= GOPID_VERBATIM;
-	generate_id_list(flags);
-
+	generate_id_list(opts ? opts > 1 : config.stable,
+			 opts ? opts == 3 : config.verbatim);
 	return 0;
 }
diff --git a/builtin/repack.c b/builtin/repack.c
index c113eb378575e8..e2a7d661560732 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -40,7 +40,7 @@ static char *packdir, *packtmp_name, *packtmp;
 static const char *const git_repack_usage[] = {
 	N_("git repack [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m]\n"
 	   "[--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]\n"
-	   "[--write-midx] [--full-name-hash]"),
+	   "[--write-midx] [--full-name-hash] [--path-walk]"),
 	NULL
 };
 
@@ -60,6 +60,7 @@ struct pack_objects_args {
 	int quiet;
 	int local;
 	int full_name_hash;
+	int path_walk;
 	struct list_objects_filter_options filter_options;
 };
 
@@ -293,6 +294,8 @@ static void prepare_pack_objects(struct child_process *cmd,
 		strvec_pushf(&cmd->args, "--no-reuse-object");
 	if (args->full_name_hash)
 		strvec_pushf(&cmd->args, "--full-name-hash");
+	if (args->path_walk)
+		strvec_pushf(&cmd->args, "--path-walk");
 	if (args->local)
 		strvec_push(&cmd->args,  "--local");
 	if (args->quiet)
@@ -1164,6 +1167,8 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 				N_("pass --no-reuse-object to git-pack-objects")),
 		OPT_BOOL(0, "full-name-hash", &po_args.full_name_hash,
 				N_("(EXPERIMENTAL!) pass --full-name-hash to git-pack-objects")),
+		OPT_BOOL(0, "path-walk", &po_args.path_walk,
+				N_("(EXPERIMENTAL!) pass --path-walk to git-pack-objects")),
 		OPT_NEGBIT('n', NULL, &run_update_server_info,
 				N_("do not run git-update-server-info"), 1),
 		OPT__QUIET(&po_args.quiet, N_("be quiet")),
diff --git a/ci/install-dependencies.sh b/ci/install-dependencies.sh
index b59fd7c1fd6af1..e2c6ef0f662b9e 100755
--- a/ci/install-dependencies.sh
+++ b/ci/install-dependencies.sh
@@ -33,37 +33,49 @@ fedora-*)
 	dnf -yq update >/dev/null &&
 	dnf -yq install make gcc findutils diffutils perl python3 gettext zlib-devel expat-devel openssl-devel curl-devel pcre2-devel >/dev/null
 	;;
-ubuntu-*)
+ubuntu-*|ubuntu32-*)
 	# Required so that apt doesn't wait for user input on certain packages.
 	export DEBIAN_FRONTEND=noninteractive
 
+	case "$distro" in
+	ubuntu-*)
+		SVN='libsvn-perl subversion'
+		;;
+	*)
+		SVN=
+		;;
+	esac
+
 	sudo apt-get -q update
 	sudo apt-get -q -y install \
-		language-pack-is libsvn-perl apache2 cvs cvsps git gnupg subversion \
+		language-pack-is apache2 cvs cvsps git gnupg $SVN \
 		make libssl-dev libcurl4-openssl-dev libexpat-dev wget sudo default-jre \
 		tcl tk gettext zlib1g-dev perl-modules liberror-perl libauthen-sasl-perl \
 		libemail-valid-perl libio-pty-perl libio-socket-ssl-perl libnet-smtp-ssl-perl libdbd-sqlite3-perl libcgi-pm-perl \
 		${CC_PACKAGE:-${CC:-gcc}} $PYTHON_PACKAGE
 
-	mkdir --parents "$CUSTOM_PATH"
-	wget --quiet --directory-prefix="$CUSTOM_PATH" \
-		"$P4WHENCE/bin.linux26x86_64/p4d" "$P4WHENCE/bin.linux26x86_64/p4"
-	chmod a+x "$CUSTOM_PATH/p4d" "$CUSTOM_PATH/p4"
-
-	wget --quiet "$LFSWHENCE/git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz"
-	tar -xzf "git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz" \
-		-C "$CUSTOM_PATH" --strip-components=1 "git-lfs-$LINUX_GIT_LFS_VERSION/git-lfs"
-	rm "git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz"
-
-	wget --quiet "$JGITWHENCE" --output-document="$CUSTOM_PATH/jgit"
-	chmod a+x "$CUSTOM_PATH/jgit"
-	;;
-ubuntu32-*)
-	sudo linux32 --32bit i386 sh -c '
-		apt update >/dev/null &&
-		apt install -y build-essential libcurl4-openssl-dev \
-			libssl-dev libexpat-dev gettext python >/dev/null
-	'
+	case "$distro" in
+	ubuntu-16.04)
+		# Does not support JGit, but we also don't really care about
+		# the others. We rather care whether Git still compiles and
+		# runs fine overall.
+		;;
+	ubuntu-*)
+		mkdir --parents "$CUSTOM_PATH"
+
+		wget --quiet --directory-prefix="$CUSTOM_PATH" \
+			"$P4WHENCE/bin.linux26x86_64/p4d" "$P4WHENCE/bin.linux26x86_64/p4"
+		chmod a+x "$CUSTOM_PATH/p4d" "$CUSTOM_PATH/p4"
+
+		wget --quiet "$LFSWHENCE/git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz"
+		tar -xzf "git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz" \
+			-C "$CUSTOM_PATH" --strip-components=1 "git-lfs-$LINUX_GIT_LFS_VERSION/git-lfs"
+		rm "git-lfs-linux-amd64-$LINUX_GIT_LFS_VERSION.tar.gz"
+
+		wget --quiet "$JGITWHENCE" --output-document="$CUSTOM_PATH/jgit"
+		chmod a+x "$CUSTOM_PATH/jgit"
+		;;
+	esac
 	;;
 macos-*)
 	export HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1
diff --git a/ci/lib.sh b/ci/lib.sh
index e75108a72f9fbc..d1d40991c4ba42 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -342,7 +342,14 @@ ubuntu-*)
 	fi
 	MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=/usr/bin/$PYTHON_PACKAGE"
 
-	export GIT_TEST_HTTPD=true
+	case "$distro" in
+	ubuntu-16.04)
+		# Apache is too old for HTTP/2.
+		;;
+	*)
+		export GIT_TEST_HTTPD=true
+		;;
+	esac
 
 	# The Linux build installs the defined dependency versions below.
 	# The OS X build installs much more recent versions, whichever
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index f7a2d655773165..eccd69c56c4665 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -26,6 +26,7 @@ linux-TEST-vars)
 	export GIT_TEST_CHECKOUT_WORKERS=2
 	export GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL=1
 	export GIT_TEST_FULL_NAME_HASH=1
+	export GIT_TEST_PACK_PATH_WALK=1
 	;;
 linux-clang)
 	export GIT_TEST_DEFAULT_HASH=sha1
diff --git a/ci/run-docker-build.sh b/ci/run-docker-build.sh
deleted file mode 100755
index 6cd832efb9cb59..00000000000000
--- a/ci/run-docker-build.sh
+++ /dev/null
@@ -1,66 +0,0 @@
-#!/bin/sh
-#
-# Build and test Git inside container
-#
-# Usage:
-#   run-docker-build.sh <host-user-id>
-#
-
-set -ex
-
-if test $# -ne 1 || test -z "$1"
-then
-	echo >&2 "usage: run-docker-build.sh <host-user-id>"
-	exit 1
-fi
-
-case "$jobname" in
-linux32)
-	switch_cmd="linux32 --32bit i386"
-	;;
-linux-musl)
-	switch_cmd=
-	useradd () { adduser -D "$@"; }
-	;;
-*)
-	exit 1
-	;;
-esac
-
-"${0%/*}/install-docker-dependencies.sh"
-
-# If this script runs inside a docker container, then all commands are
-# usually executed as root. Consequently, the host user might not be
-# able to access the test output files.
-# If a non 0 host user id is given, then create a user "ci" with that
-# user id to make everything accessible to the host user.
-HOST_UID=$1
-if test $HOST_UID -eq 0
-then
-	# Just in case someone does want to run the test suite as root.
-	CI_USER=root
-else
-	CI_USER=ci
-	if test "$(id -u $CI_USER 2>/dev/null)" = $HOST_UID
-	then
-		echo "user '$CI_USER' already exists with the requested ID $HOST_UID"
-	else
-		useradd -u $HOST_UID $CI_USER
-	fi
-fi
-
-# Build and test
-command $switch_cmd su -m -l $CI_USER -c "
-	set -ex
-	export DEVELOPER='$DEVELOPER'
-	export DEFAULT_TEST_TARGET='$DEFAULT_TEST_TARGET'
-	export GIT_PROVE_OPTS='$GIT_PROVE_OPTS'
-	export GIT_TEST_OPTS='$GIT_TEST_OPTS'
-	export GIT_TEST_CLONE_2GB='$GIT_TEST_CLONE_2GB'
-	export MAKEFLAGS='$MAKEFLAGS'
-	export cache_dir='$cache_dir'
-	cd /usr/src/git
-	test -n '$cache_dir' && ln -s '$cache_dir/.prove' t/.prove
-	make
-	make test
-"
diff --git a/ci/run-docker.sh b/ci/run-docker.sh
deleted file mode 100755
index af89d1624a41cb..00000000000000
--- a/ci/run-docker.sh
+++ /dev/null
@@ -1,47 +0,0 @@
-#!/bin/sh
-#
-# Download and run Docker image to build and test Git
-#
-
-. ${0%/*}/lib.sh
-
-case "$jobname" in
-linux32)
-	CI_CONTAINER="daald/ubuntu32:xenial"
-	;;
-linux-musl)
-	CI_CONTAINER=alpine
-	;;
-*)
-	exit 1
-	;;
-esac
-
-docker pull "$CI_CONTAINER"
-
-# Use the following command to debug the docker build locally:
-# <host-user-id> must be 0 if podman is used as drop-in replacement for docker
-# $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/sh "$CI_CONTAINER"
-# root@container:/# export jobname=<jobname>
-# root@container:/# /usr/src/git/ci/run-docker-build.sh <host-user-id>
-
-container_cache_dir=/tmp/container-cache
-
-docker run \
-	--interactive \
-	--env DEVELOPER \
-	--env DEFAULT_TEST_TARGET \
-	--env GIT_PROVE_OPTS \
-	--env GIT_TEST_OPTS \
-	--env GIT_TEST_CLONE_2GB \
-	--env MAKEFLAGS \
-	--env jobname \
-	--env cache_dir="$container_cache_dir" \
-	--volume "${PWD}:/usr/src/git" \
-	--volume "$cache_dir:$container_cache_dir" \
-	"$CI_CONTAINER" \
-	/usr/src/git/ci/run-docker-build.sh $(id -u $USER)
-
-check_unignored_build_artifacts
-
-save_good_tree
diff --git a/config.mak.uname b/config.mak.uname
index 2a491021a78a5d..d500245d814efd 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -249,6 +249,7 @@ ifeq ($(uname_O),Cygwin)
         else
 		NO_REGEX = UnfortunatelyYes
         endif
+	HAVE_DEV_TTY = YesPlease
 	HAVE_ALLOCA_H = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes
diff --git a/diff.c b/diff.c
index ebb7538e040a71..a83409944b0243 100644
--- a/diff.c
+++ b/diff.c
@@ -3565,6 +3565,7 @@ static void builtin_diff(const char *name_a,
 		show_submodule_diff_summary(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
+		o->found_changes = 1;
 		return;
 	} else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
 		   (!one->mode || S_ISGITLINK(one->mode)) &&
@@ -3573,6 +3574,7 @@ static void builtin_diff(const char *name_a,
 		show_submodule_inline_diff(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
+		o->found_changes = 1;
 		return;
 	}
 
@@ -4587,6 +4589,9 @@ static void run_diff_cmd(const struct external_diff *pgm,
 		builtin_diff(name, other ? other : name,
 			     one, two, xfrm_msg, must_show_header,
 			     o, complete_rewrite);
+		if (p->status == DIFF_STATUS_COPIED ||
+		    p->status == DIFF_STATUS_RENAMED)
+			o->found_changes = 1;
 	} else {
 		fprintf(o->file, "* Unmerged path %s\n", name);
 		o->found_changes = 1;
diff --git a/pack-objects.h b/pack-objects.h
index 88360aa3e8e79d..93f05b62231500 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -118,11 +118,23 @@ struct object_entry {
 	unsigned ext_base:1; /* delta_idx points outside packlist */
 };
 
+/**
+ * A packing region is a section of the packing_data.objects array
+ * as given by a starting index and a number of elements.
+ */
+struct packing_region {
+	uint32_t start;
+	uint32_t nr;
+};
+
 struct packing_data {
 	struct repository *repo;
 	struct object_entry *objects;
 	uint32_t nr_objects, nr_alloc;
 
+	struct packing_region *regions;
+	uint32_t nr_regions, nr_regions_alloc;
+
 	int32_t *index;
 	uint32_t index_size;
 
diff --git a/path-walk.c b/path-walk.c
new file mode 100644
index 00000000000000..aaa2cce7471941
--- /dev/null
+++ b/path-walk.c
@@ -0,0 +1,399 @@
+/*
+ * path-walk.c: implementation for path-based walks of the object graph.
+ */
+#include "git-compat-util.h"
+#include "path-walk.h"
+#include "blob.h"
+#include "commit.h"
+#include "dir.h"
+#include "hashmap.h"
+#include "hex.h"
+#include "object.h"
+#include "oid-array.h"
+#include "revision.h"
+#include "string-list.h"
+#include "strmap.h"
+#include "tag.h"
+#include "trace2.h"
+#include "tree.h"
+#include "tree-walk.h"
+
+struct type_and_oid_list
+{
+	enum object_type type;
+	struct oid_array oids;
+	int maybe_interesting;
+};
+
+#define TYPE_AND_OID_LIST_INIT { \
+	.type = OBJ_NONE, 	 \
+	.oids = OID_ARRAY_INIT	 \
+}
+
+struct path_walk_context {
+	/**
+	 * Repeats of data in 'struct path_walk_info' for
+	 * access with fewer characters.
+	 */
+	struct repository *repo;
+	struct rev_info *revs;
+	struct path_walk_info *info;
+
+	/**
+	 * Map a path to a 'struct type_and_oid_list'
+	 * containing the objects discovered at that
+	 * path.
+	 */
+	struct strmap paths_to_lists;
+
+	/**
+	 * Store the current list of paths in a stack, to
+	 * facilitate depth-first-search without recursion.
+	 */
+	struct string_list path_stack;
+};
+
+static int add_children(struct path_walk_context *ctx,
+			const char *base_path,
+			struct object_id *oid)
+{
+	struct tree_desc desc;
+	struct name_entry entry;
+	struct strbuf path = STRBUF_INIT;
+	size_t base_len;
+	struct tree *tree = lookup_tree(ctx->repo, oid);
+
+	if (!tree) {
+		error(_("failed to walk children of tree %s: not found"),
+		      oid_to_hex(oid));
+		return -1;
+	} else if (parse_tree_gently(tree, 1)) {
+		die("bad tree object %s", oid_to_hex(oid));
+	}
+
+	strbuf_addstr(&path, base_path);
+	base_len = path.len;
+
+	parse_tree(tree);
+	init_tree_desc(&desc, &tree->object.oid, tree->buffer, tree->size);
+	while (tree_entry(&desc, &entry)) {
+		struct type_and_oid_list *list;
+		struct object *o;
+		/* Not actually true, but we will ignore submodules later. */
+		enum object_type type = S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB;
+
+		/* Skip submodules. */
+		if (S_ISGITLINK(entry.mode))
+			continue;
+
+		/* If the caller doesn't want blobs, then don't bother. */
+		if (!ctx->info->blobs && type == OBJ_BLOB)
+			continue;
+
+		if (type == OBJ_TREE) {
+			struct tree *child = lookup_tree(ctx->repo, &entry.oid);
+			o = child ? &child->object : NULL;
+		} else if (type == OBJ_BLOB) {
+			struct blob *child = lookup_blob(ctx->repo, &entry.oid);
+			o = child ? &child->object : NULL;
+		} else {
+			/* Wrong type? */
+			continue;
+		}
+
+		if (!o) /* report error?*/
+			continue;
+
+		/* Skip this object if already seen. */
+		if (o->flags & SEEN)
+			continue;
+		o->flags |= SEEN;
+
+		strbuf_setlen(&path, base_len);
+		strbuf_add(&path, entry.path, entry.pathlen);
+
+		/*
+		 * Trees will end with "/" for concatenation and distinction
+		 * from blobs at the same path.
+		 */
+		if (type == OBJ_TREE)
+			strbuf_addch(&path, '/');
+
+		if (!(list = strmap_get(&ctx->paths_to_lists, path.buf))) {
+			CALLOC_ARRAY(list, 1);
+			list->type = type;
+			strmap_put(&ctx->paths_to_lists, path.buf, list);
+			string_list_append(&ctx->path_stack, path.buf);
+		}
+		if (!(o->flags & UNINTERESTING))
+			list->maybe_interesting = 1;
+		oid_array_append(&list->oids, &entry.oid);
+	}
+
+	free_tree_buffer(tree);
+	strbuf_release(&path);
+	return 0;
+}
+
+/*
+ * For each path in paths_to_explore, walk the trees another level
+ * and add any found blobs to the batch (but only if they exist and
+ * haven't been added yet).
+ */
+static int walk_path(struct path_walk_context *ctx,
+		     const char *path)
+{
+	struct type_and_oid_list *list;
+	int ret = 0;
+
+	list = strmap_get(&ctx->paths_to_lists, path);
+
+	if (ctx->info->prune_all_uninteresting) {
+		/*
+		 * This is true if all objects were UNINTERESTING
+		 * when added to the list.
+		 */
+		if (!list->maybe_interesting)
+			return 0;
+
+		/*
+		 * But it's still possible that the objects were set
+		 * as UNINTERESTING after being added. Do a quick check.
+		 */
+		list->maybe_interesting = 0;
+		for (size_t i = 0;
+		     !list->maybe_interesting && i < list->oids.nr;
+		     i++) {
+			if (list->type == OBJ_TREE) {
+				struct tree *t = lookup_tree(ctx->repo,
+							     &list->oids.oid[i]);
+				if (t && !(t->object.flags & UNINTERESTING))
+					list->maybe_interesting = 1;
+			} else {
+				struct blob *b = lookup_blob(ctx->repo,
+							     &list->oids.oid[i]);
+				if (b && !(b->object.flags & UNINTERESTING))
+					list->maybe_interesting = 1;
+			}
+		}
+
+		/* We have confirmed that all objects are UNINTERESTING. */
+		if (!list->maybe_interesting)
+			return 0;
+	}
+
+	/* Evaluate function pointer on this data, if requested. */
+	if ((list->type == OBJ_TREE && ctx->info->trees) ||
+	    (list->type == OBJ_BLOB && ctx->info->blobs))
+		ret = ctx->info->path_fn(path, &list->oids, list->type,
+					ctx->info->path_fn_data);
+
+	/* Expand data for children. */
+	if (list->type == OBJ_TREE) {
+		for (size_t i = 0; i < list->oids.nr; i++) {
+			ret |= add_children(ctx,
+					    path,
+					    &list->oids.oid[i]);
+		}
+	}
+
+	oid_array_clear(&list->oids);
+	strmap_remove(&ctx->paths_to_lists, path, 1);
+	return ret;
+}
+
+static void clear_strmap(struct strmap *map)
+{
+	struct hashmap_iter iter;
+	struct strmap_entry *e;
+
+	hashmap_for_each_entry(&map->map, &iter, e, ent) {
+		struct type_and_oid_list *list = e->value;
+		oid_array_clear(&list->oids);
+	}
+	strmap_clear(map, 1);
+	strmap_init(map);
+}
+
+/**
+ * Given the configuration of 'info', walk the commits based on 'info->revs' and
+ * call 'info->path_fn' on each discovered path.
+ *
+ * Returns nonzero on an error.
+ */
+int walk_objects_by_path(struct path_walk_info *info)
+{
+	const char *root_path = "";
+	int ret = 0, has_uninteresting = 0;
+	size_t commits_nr = 0, paths_nr = 0;
+	struct commit *c;
+	struct type_and_oid_list *root_tree_list;
+	struct type_and_oid_list *commit_list;
+	struct path_walk_context ctx = {
+		.repo = info->revs->repo,
+		.revs = info->revs,
+		.info = info,
+		.path_stack = STRING_LIST_INIT_DUP,
+		.paths_to_lists = STRMAP_INIT
+	};
+	struct oidset root_tree_set = OIDSET_INIT;
+
+	trace2_region_enter("path-walk", "commit-walk", info->revs->repo);
+
+	CALLOC_ARRAY(commit_list, 1);
+	commit_list->type = OBJ_COMMIT;
+
+	if (info->tags)
+		info->revs->tag_objects = 1;
+
+	/* Insert a single list for the root tree into the paths. */
+	CALLOC_ARRAY(root_tree_list, 1);
+	root_tree_list->type = OBJ_TREE;
+	root_tree_list->maybe_interesting = 1;
+	strmap_put(&ctx.paths_to_lists, root_path, root_tree_list);
+
+	/*
+	 * Set these values before preparing the walk to catch
+	 * lightweight tags pointing to non-commits.
+	 */
+	info->revs->blob_objects = info->blobs;
+	info->revs->tree_objects = info->trees;
+
+	if (prepare_revision_walk(info->revs))
+		die(_("failed to setup revision walk"));
+
+	info->revs->blob_objects = info->revs->tree_objects = 0;
+
+	if (info->tags) {
+		struct oid_array tagged_blob_list = OID_ARRAY_INIT;
+		struct oid_array tags = OID_ARRAY_INIT;
+
+		trace2_region_enter("path-walk", "tag-walk", info->revs->repo);
+
+		/*
+		 * Walk any pending objects at this point, but they should only
+		 * be tags.
+		 */
+		for (size_t i = 0; i < info->revs->pending.nr; i++) {
+			struct object_array_entry *pending = info->revs->pending.objects + i;
+			struct object *obj = pending->item;
+
+			if (obj->type == OBJ_COMMIT)
+				continue;
+
+			while (obj->type == OBJ_TAG) {
+				struct tag *tag = lookup_tag(info->revs->repo,
+							     &obj->oid);
+				if (oid_array_lookup(&tags, &obj->oid) < 0)
+					oid_array_append(&tags, &obj->oid);
+				obj = tag->tagged;
+			}
+
+			switch (obj->type) {
+			case OBJ_TREE:
+				if (info->trees &&
+				    oid_array_lookup(&root_tree_list->oids, &obj->oid) < 0)
+					oid_array_append(&root_tree_list->oids, &obj->oid);
+				break;
+
+			case OBJ_BLOB:
+				if (info->blobs &&
+				    oid_array_lookup(&tagged_blob_list, &obj->oid) < 0)
+					oid_array_append(&tagged_blob_list, &obj->oid);
+				break;
+
+			case OBJ_COMMIT:
+				/* Make sure it is in the object walk */
+				add_pending_object(info->revs, obj, "");
+				break;
+
+			default:
+				BUG("should not see any other type here");
+			}
+		}
+
+		info->path_fn("", &tags, OBJ_TAG, info->path_fn_data);
+
+		if (tagged_blob_list.nr && info->blobs)
+			info->path_fn("/tagged-blobs", &tagged_blob_list, OBJ_BLOB,
+				      info->path_fn_data);
+
+		trace2_data_intmax("path-walk", ctx.repo, "tags", tags.nr);
+		trace2_region_leave("path-walk", "tag-walk", info->revs->repo);
+		oid_array_clear(&tags);
+		oid_array_clear(&tagged_blob_list);
+	}
+
+	while ((c = get_revision(info->revs))) {
+		struct object_id *oid;
+		struct tree *t;
+		commits_nr++;
+
+		if (info->commits)
+			oid_array_append(&commit_list->oids,
+					 &c->object.oid);
+
+		/* If we only care about commits, then skip trees. */
+		if (!info->trees && !info->blobs)
+			continue;
+
+		oid = get_commit_tree_oid(c);
+		t = lookup_tree(info->revs->repo, oid);
+
+		if (t) {
+			oidset_insert(&root_tree_set, oid);
+			oid_array_append(&root_tree_list->oids, oid);
+		} else {
+			warning("could not find tree %s", oid_to_hex(oid));
+		}
+
+		if (t && (c->object.flags & UNINTERESTING)) {
+			t->object.flags |= UNINTERESTING;
+			has_uninteresting = 1;
+		}
+	}
+
+	trace2_data_intmax("path-walk", ctx.repo, "commits", commits_nr);
+	trace2_region_leave("path-walk", "commit-walk", info->revs->repo);
+
+	/* Track all commits. */
+	if (info->commits)
+		ret = info->path_fn("", &commit_list->oids, OBJ_COMMIT,
+				    info->path_fn_data);
+	oid_array_clear(&commit_list->oids);
+	free(commit_list);
+
+	/*
+	 * Before performing a DFS of our paths and emitting them as interesting,
+	 * do a full walk of the trees to distribute the UNINTERESTING bit. Use
+	 * the sparse algorithm if prune_all_uninteresting was set.
+	 */
+	if (has_uninteresting) {
+		trace2_region_enter("path-walk", "uninteresting-walk", info->revs->repo);
+		if (info->prune_all_uninteresting)
+			mark_trees_uninteresting_sparse(ctx.repo, &root_tree_set);
+		else
+			mark_trees_uninteresting_dense(ctx.repo, &root_tree_set);
+		trace2_region_leave("path-walk", "uninteresting-walk", info->revs->repo);
+	}
+	oidset_clear(&root_tree_set);
+
+	string_list_append(&ctx.path_stack, root_path);
+
+	trace2_region_enter("path-walk", "path-walk", info->revs->repo);
+	while (!ret && ctx.path_stack.nr) {
+		char *path = ctx.path_stack.items[ctx.path_stack.nr - 1].string;
+		ctx.path_stack.nr--;
+		paths_nr++;
+
+		ret = walk_path(&ctx, path);
+
+		free(path);
+	}
+	trace2_data_intmax("path-walk", ctx.repo, "paths", paths_nr);
+	trace2_region_leave("path-walk", "path-walk", info->revs->repo);
+
+	clear_strmap(&ctx.paths_to_lists);
+	string_list_clear(&ctx.path_stack, 0);
+	return ret;
+}
diff --git a/path-walk.h b/path-walk.h
new file mode 100644
index 00000000000000..3e44c4b8a588e9
--- /dev/null
+++ b/path-walk.h
@@ -0,0 +1,64 @@
+/*
+ * path-walk.h : Methods and structures for walking the object graph in batches
+ * by the paths that can reach those objects.
+ */
+#include "object.h" /* Required for 'enum object_type'. */
+
+struct rev_info;
+struct oid_array;
+
+/**
+ * The type of a function pointer for the method that is called on a list of
+ * objects reachable at a given path.
+ */
+typedef int (*path_fn)(const char *path,
+		       struct oid_array *oids,
+		       enum object_type type,
+		       void *data);
+
+struct path_walk_info {
+	/**
+	 * revs provides the definitions for the commit walk, including
+	 * which commits are UNINTERESTING or not.
+	 */
+	struct rev_info *revs;
+
+	/**
+	 * The caller wishes to execute custom logic on objects reachable at a
+	 * given path. Every reachable object will be visited exactly once, and
+	 * the first path to see an object wins. This may not be a stable choice.
+	 */
+	path_fn path_fn;
+	void *path_fn_data;
+	/**
+	 * Initialize which object types the path_fn should be called on. This
+	 * could also limit the walk to skip blobs if not set.
+	 */
+	int commits;
+	int trees;
+	int blobs;
+	int tags;
+
+	/**
+	 * When 'prune_all_uninteresting' is set and a path has all objects
+	 * marked as UNINTERESTING, then the path-walk will not visit those
+	 * objects. It will not call path_fn on those objects and will not
+	 * walk the children of such trees.
+	 */
+	int prune_all_uninteresting;
+};
+
+#define PATH_WALK_INFO_INIT {   \
+	.blobs = 1,		\
+	.trees = 1,		\
+	.commits = 1,		\
+	.tags = 1,		\
+}
+
+/**
+ * Given the configuration of 'info', walk the commits based on 'info->revs' and
+ * call 'info->path_fn' on each discovered path.
+ *
+ * Returns nonzero on an error.
+ */
+int walk_objects_by_path(struct path_walk_info *info);
diff --git a/repo-settings.c b/repo-settings.c
index f104e6fc73c38f..6e4a931c802ba8 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -47,6 +47,7 @@ void prepare_repo_settings(struct repository *r)
 		r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
 		r->settings.pack_use_bitmap_boundary_traversal = 1;
 		r->settings.pack_use_multi_pack_reuse = 1;
+		r->settings.pack_use_path_walk = 1;
 
 		/*
 		 * Force enable the builtin FSMonitor (unless the repo
@@ -76,6 +77,7 @@ void prepare_repo_settings(struct repository *r)
 		r->settings.index_version = 4;
 		r->settings.index_skip_hash = 1;
 		r->settings.core_untracked_cache = UNTRACKED_CACHE_WRITE;
+		r->settings.pack_use_path_walk = 1;
 	}
 
 	/* Commit graph config or default, does not cascade (simple) */
@@ -90,6 +92,7 @@ void prepare_repo_settings(struct repository *r)
 
 	/* Boolean config or default, does not cascade (simple)  */
 	repo_cfg_bool(r, "pack.usesparse", &r->settings.pack_use_sparse, 1);
+	repo_cfg_bool(r, "pack.usepathwalk", &r->settings.pack_use_path_walk, 0);
 	repo_cfg_bool(r, "core.multipackindex", &r->settings.core_multi_pack_index, 1);
 	repo_cfg_bool(r, "index.sparse", &r->settings.sparse_index, 0);
 	repo_cfg_bool(r, "index.skiphash", &r->settings.index_skip_hash, r->settings.index_skip_hash);
diff --git a/repository.h b/repository.h
index af6ea0a62cdb70..2ae9c2b1741528 100644
--- a/repository.h
+++ b/repository.h
@@ -62,6 +62,7 @@ struct repo_settings {
 	enum untracked_cache_setting core_untracked_cache;
 
 	int pack_use_sparse;
+	int pack_use_path_walk;
 	enum fetch_negotiation_setting fetch_negotiation_algorithm;
 
 	int core_multi_pack_index;
diff --git a/revision.c b/revision.c
index 5fecd7e0d75c03..346fe3cd2169d3 100644
--- a/revision.c
+++ b/revision.c
@@ -219,6 +219,21 @@ static void add_children_by_path(struct repository *r,
 	free_tree_buffer(tree);
 }
 
+void mark_trees_uninteresting_dense(struct repository *r,
+				    struct oidset *trees)
+{
+	struct object_id *oid;
+	struct oidset_iter iter;
+
+	oidset_iter_init(trees, &iter);
+	while ((oid = oidset_iter_next(&iter))) {
+		struct tree *tree = lookup_tree(r, oid);
+
+		if (tree->object.flags & UNINTERESTING)
+			mark_tree_contents_uninteresting(r, tree);
+	}
+}
+
 void mark_trees_uninteresting_sparse(struct repository *r,
 				     struct oidset *trees)
 {
diff --git a/revision.h b/revision.h
index 0e470d1df19f69..6c3df8e42bfa6d 100644
--- a/revision.h
+++ b/revision.h
@@ -487,6 +487,7 @@ void put_revision_mark(const struct rev_info *revs,
 
 void mark_parents_uninteresting(struct rev_info *revs, struct commit *commit);
 void mark_tree_uninteresting(struct repository *r, struct tree *tree);
+void mark_trees_uninteresting_dense(struct repository *r, struct oidset *trees);
 void mark_trees_uninteresting_sparse(struct repository *r, struct oidset *trees);
 
 void show_object_with_name(FILE *, struct object *, const char *);
diff --git a/scalar.c b/scalar.c
index 1fe8a93e6529a2..1c41a2916227c1 100644
--- a/scalar.c
+++ b/scalar.c
@@ -170,6 +170,7 @@ static int set_recommended_config(int reconfigure)
 		{ "core.autoCRLF", "false" },
 		{ "core.safeCRLF", "false" },
 		{ "fetch.showForcedUpdates", "false" },
+		{ "push.usePathWalk", "true" },
 		{ NULL, NULL },
 	};
 	int i;
diff --git a/t/README b/t/README
index 87285a29151cc1..6c1fe33e9198a9 100644
--- a/t/README
+++ b/t/README
@@ -433,6 +433,10 @@ GIT_TEST_PACK_SPARSE=<boolean> if disabled will default the pack-objects
 builtin to use the non-sparse object walk. This can still be overridden by
 the --sparse command-line argument.
 
+GIT_TEST_PACK_PATH_WALK=<boolean> if enabled will default the pack-objects
+builtin to use the path-walk API for the object walk. This can still be
+overridden by the --no-path-walk command-line argument.
+
 GIT_TEST_PRELOAD_INDEX=<boolean> exercises the preload-index code path
 by overriding the minimum number of cache entries required per thread.
 
diff --git a/t/helper/test-path-walk.c b/t/helper/test-path-walk.c
new file mode 100644
index 00000000000000..06b103d87607dd
--- /dev/null
+++ b/t/helper/test-path-walk.c
@@ -0,0 +1,114 @@
+#define USE_THE_REPOSITORY_VARIABLE
+
+#include "test-tool.h"
+#include "environment.h"
+#include "hex.h"
+#include "object-name.h"
+#include "object.h"
+#include "pretty.h"
+#include "revision.h"
+#include "setup.h"
+#include "parse-options.h"
+#include "path-walk.h"
+#include "oid-array.h"
+
+static const char * const path_walk_usage[] = {
+	N_("test-tool path-walk <options> -- <revision-options>"),
+	NULL
+};
+
+struct path_walk_test_data {
+	uintmax_t commit_nr;
+	uintmax_t tree_nr;
+	uintmax_t blob_nr;
+	uintmax_t tag_nr;
+};
+
+static int emit_block(const char *path, struct oid_array *oids,
+		      enum object_type type, void *data)
+{
+	struct path_walk_test_data *tdata = data;
+	const char *typestr;
+
+	switch (type) {
+	case OBJ_COMMIT:
+		typestr = "COMMIT";
+		tdata->commit_nr += oids->nr;
+		break;
+
+	case OBJ_TREE:
+		typestr = "TREE";
+		tdata->tree_nr += oids->nr;
+		break;
+
+	case OBJ_BLOB:
+		typestr = "BLOB";
+		tdata->blob_nr += oids->nr;
+		break;
+
+	case OBJ_TAG:
+		typestr = "TAG";
+		tdata->tag_nr += oids->nr;
+		break;
+
+	default:
+		BUG("we do not understand this type");
+	}
+
+	for (size_t i = 0; i < oids->nr; i++) {
+		struct object *o = lookup_unknown_object(the_repository,
+							 &oids->oid[i]);
+		printf("%s:%s:%s%s\n", typestr, path, oid_to_hex(&oids->oid[i]),
+		       o->flags & UNINTERESTING ? ":UNINTERESTING" : "");
+	}
+
+	return 0;
+}
+
+int cmd__path_walk(int argc, const char **argv)
+{
+	int res;
+	struct rev_info revs = REV_INFO_INIT;
+	struct path_walk_info info = PATH_WALK_INFO_INIT;
+	struct path_walk_test_data data = { 0 };
+	struct option options[] = {
+		OPT_BOOL(0, "blobs", &info.blobs,
+			 N_("toggle inclusion of blob objects")),
+		OPT_BOOL(0, "commits", &info.commits,
+			 N_("toggle inclusion of commit objects")),
+		OPT_BOOL(0, "tags", &info.tags,
+			 N_("toggle inclusion of tag objects")),
+		OPT_BOOL(0, "trees", &info.trees,
+			 N_("toggle inclusion of tree objects")),
+		OPT_BOOL(0, "prune", &info.prune_all_uninteresting,
+			 N_("toggle pruning of uninteresting paths")),
+		OPT_END(),
+	};
+
+	initialize_repository(the_repository);
+	setup_git_directory();
+	revs.repo = the_repository;
+
+	argc = parse_options(argc, argv, NULL,
+			     options, path_walk_usage,
+			     PARSE_OPT_KEEP_UNKNOWN_OPT | PARSE_OPT_KEEP_ARGV0);
+
+	if (argc > 1)
+		setup_revisions(argc, argv, &revs, NULL);
+	else
+		usage(path_walk_usage[0]);
+
+	info.revs = &revs;
+	info.path_fn = emit_block;
+	info.path_fn_data = &data;
+
+	res = walk_objects_by_path(&info);
+
+	printf("commits:%" PRIuMAX "\n"
+	       "trees:%" PRIuMAX "\n"
+	       "blobs:%" PRIuMAX "\n"
+	       "tags:%" PRIuMAX "\n",
+	       data.commit_nr, data.tree_nr, data.blob_nr, data.tag_nr);
+
+	return res;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index eeb10fae59cf8b..93f5ce32edfa18 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -54,6 +54,7 @@ static struct test_cmd cmds[] = {
 	{ "parse-subcommand", cmd__parse_subcommand },
 	{ "partial-clone", cmd__partial_clone },
 	{ "path-utils", cmd__path_utils },
+	{ "path-walk", cmd__path_walk },
 	{ "pcre2-config", cmd__pcre2_config },
 	{ "pkt-line", cmd__pkt_line },
 	{ "proc-receive", cmd__proc_receive },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index bd5f26d8a7c3a2..483b9188efc501 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -47,6 +47,7 @@ int cmd__parse_pathspec_file(int argc, const char** argv);
 int cmd__parse_subcommand(int argc, const char **argv);
 int cmd__partial_clone(int argc, const char **argv);
 int cmd__path_utils(int argc, const char **argv);
+int cmd__path_walk(int argc, const char **argv);
 int cmd__pcre2_config(int argc, const char **argv);
 int cmd__pkt_line(int argc, const char **argv);
 int cmd__proc_receive(int argc, const char **argv);
diff --git a/t/perf/p5313-pack-objects.sh b/t/perf/p5313-pack-objects.sh
index bf6f0d69e48373..2e10895621ce75 100755
--- a/t/perf/p5313-pack-objects.sh
+++ b/t/perf/p5313-pack-objects.sh
@@ -36,6 +36,14 @@ test_size 'thin pack size with --full-name-hash' '
 	test_file_size out
 '
 
+test_perf 'thin pack with --path-walk' '
+	git pack-objects --thin --stdout --revs --sparse --path-walk <in-thin >out
+'
+
+test_size 'thin pack size with --path-walk' '
+	test_file_size out
+'
+
 test_perf 'big pack' '
 	git pack-objects --stdout --revs --sparse  <in-big >out
 '
@@ -52,6 +60,14 @@ test_size 'big pack size with --full-name-hash' '
 	test_file_size out
 '
 
+test_perf 'big pack with --path-walk' '
+	git pack-objects --stdout --revs --sparse --path-walk <in-big >out
+'
+
+test_size 'big pack size with --path-walk' '
+	test_file_size out
+'
+
 test_perf 'repack' '
 	git repack -adf
 '
@@ -70,4 +86,13 @@ test_size 'repack size with --full-name-hash' '
 	test_file_size "$pack"
 '
 
+test_perf 'repack with --path-walk' '
+	git repack -adf --path-walk
+'
+
+test_size 'repack size with --path-walk' '
+	pack=$(ls .git/objects/pack/pack-*.pack) &&
+	test_file_size "$pack"
+'
+
 test_done
diff --git a/t/t0211-trace2-perf.sh b/t/t0211-trace2-perf.sh
index 070fe7a5da7c24..dddc130560ba61 100755
--- a/t/t0211-trace2-perf.sh
+++ b/t/t0211-trace2-perf.sh
@@ -337,7 +337,8 @@ test_expect_success 'expect def_params for query command' '
 # remote-curl.c rather than git.c.  Confirm that we get def_param
 # events from both layers.
 #
-test_expect_success 'expect def_params for remote-curl and _run_dashed_' '
+test_expect_success LIBCURL \
+		'expect def_params for remote-curl and _run_dashed_' '
 	test_when_finished "rm prop.perf actual" &&
 
 	test_config_global "trace2.configParams" "cfg.prop.*" &&
@@ -366,7 +367,8 @@ test_expect_success 'expect def_params for remote-curl and _run_dashed_' '
 # an executable built from http-fetch.c.  Confirm that we get
 # def_param events from both layers.
 #
-test_expect_success 'expect def_params for http-fetch and _run_dashed_' '
+test_expect_success LIBCURL \
+		'expect def_params for http-fetch and _run_dashed_' '
 	test_when_finished "rm prop.perf actual" &&
 
 	test_config_global "trace2.configParams" "cfg.prop.*" &&
diff --git a/t/t0411-clone-from-partial.sh b/t/t0411-clone-from-partial.sh
index 932bf2067daaeb..342d8d2997c892 100755
--- a/t/t0411-clone-from-partial.sh
+++ b/t/t0411-clone-from-partial.sh
@@ -63,6 +63,12 @@ test_expect_success 'pack-objects should fetch from promisor remote and execute
 
 test_expect_success 'clone from promisor remote does not lazy-fetch by default' '
 	rm -f script-executed &&
+
+	# The --path-walk feature of "git pack-objects" is not
+	# compatible with this kind of fetch from an incomplete repo.
+	GIT_TEST_PACK_PATH_WALK=0 &&
+	export GIT_TEST_PACK_PATH_WALK &&
+
 	test_must_fail git clone evil no-lazy 2>err &&
 	test_grep "lazy fetching disabled" err &&
 	test_path_is_missing script-executed
diff --git a/t/t1517-outside-repo.sh b/t/t1517-outside-repo.sh
index 990a03658214a4..342defbb617628 100755
--- a/t/t1517-outside-repo.sh
+++ b/t/t1517-outside-repo.sh
@@ -98,7 +98,7 @@ test_expect_success 'stripspace outside repository' '
 	nongit git stripspace -s </dev/null
 '
 
-test_expect_success 'remote-http outside repository' '
+test_expect_success LIBCURL 'remote-http outside repository' '
 	test_must_fail git remote-http 2>actual &&
 	test_grep "^error: remote-curl" actual &&
 	(
diff --git a/t/t4017-diff-retval.sh b/t/t4017-diff-retval.sh
index f439f469bd2bfd..d644310e22a5d1 100755
--- a/t/t4017-diff-retval.sh
+++ b/t/t4017-diff-retval.sh
@@ -143,4 +143,41 @@ test_expect_success 'option errors are not confused by --exit-code' '
 	grep '^usage:' err
 '
 
+for option in --exit-code --quiet
+do
+	test_expect_success "git diff $option returns 1 for copied file" "
+		git reset --hard &&
+		cp a copy &&
+		git add copy &&
+		test_expect_code 1 git diff $option --cached --find-copies-harder
+	"
+
+	test_expect_success "git diff $option returns 1 for renamed file" "
+		git reset --hard &&
+		git mv a renamed &&
+		test_expect_code 1 git diff $option --cached
+	"
+done
+
+test_expect_success 'setup dirty subrepo' '
+	git reset --hard &&
+	test_create_repo subrepo &&
+	test_commit -C subrepo subrepo-file &&
+	test_tick &&
+	git add subrepo &&
+	git commit -m subrepo &&
+	test_commit -C subrepo another-subrepo-file
+'
+
+for option in --exit-code --quiet
+do
+	for submodule_format in diff log short
+	do
+		opts="$option --submodule=$submodule_format" &&
+		test_expect_success "git diff $opts returns 1 for dirty subrepo" "
+			test_expect_code 1 git diff $opts
+		"
+	done
+done
+
 test_done
diff --git a/t/t4204-patch-id.sh b/t/t4204-patch-id.sh
index dc8ddb10affcea..605faea0c7baae 100755
--- a/t/t4204-patch-id.sh
+++ b/t/t4204-patch-id.sh
@@ -114,46 +114,6 @@ test_expect_success 'patch-id supports git-format-patch output' '
 	test "$2" = $(git rev-parse HEAD)
 '
 
-test_expect_success 'patch-id computes the same for various formats' '
-	# This test happens to consider "git log -p -1" output
-	# the canonical input format, so use it as the norm.
-	git log -1 -p same >log-p.output &&
-	git patch-id <log-p.output >expect &&
-
-	# format-patch begins with "From <commit object name>"
-	git format-patch -1 --stdout same >format-patch.output &&
-	git patch-id <format-patch.output >actual &&
-	test_cmp actual expect &&
-
-	# "diff-tree --stdin -p" begins with "<commit object name>"
-	same=$(git rev-parse same) &&
-	echo $same | git diff-tree --stdin -p >diff-tree.output &&
-	git patch-id <diff-tree.output >actual &&
-	test_cmp actual expect &&
-
-	# "diff-tree --stdin -v -p" begins with "commit <commit object name>"
-	echo $same | git diff-tree --stdin -p -v >diff-tree-v.output &&
-	git patch-id <diff-tree-v.output >actual &&
-	test_cmp actual expect
-'
-
-hash=$(git rev-parse same:)
-for cruft in "$hash" "commit $hash is bad" "From $hash status"
-do
-	test_expect_success "patch-id with <$cruft> in log message" '
-		git format-patch -1 --stdout same >patch-0 &&
-		git patch-id <patch-0 >expect &&
-
-		{
-			sed -e "/^$/q" patch-0 &&
-			printf "random message\n%s\n\n" "$cruft" &&
-			sed -e "1,/^$/d" patch-0
-		} >patch-cruft &&
-		git patch-id <patch-cruft >actual &&
-		test_cmp actual expect
-	'
-done
-
 test_expect_success 'whitespace is irrelevant in footer' '
 	get_patch_id main &&
 	git checkout same &&
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index fff49000c31971..db345c4e997e22 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -689,4 +689,25 @@ test_expect_success '--full-name-hash and --write-bitmap-index are incompatible'
 	git pack-objects --stdout --all --full-name-hash --write-bitmap-index >out
 '
 
+# Basic "repack everything" test
+test_expect_success '--path-walk pack everything' '
+	git -C server rev-parse HEAD >in &&
+	GIT_PROGRESS_DELAY=0 git -C server pack-objects \
+		--stdout --revs --path-walk --progress <in >out.pack 2>err &&
+	grep "Compressing objects by path" err &&
+	git -C server index-pack --stdin <out.pack
+'
+
+# Basic "thin pack" test
+test_expect_success '--path-walk thin pack' '
+	cat >in <<-EOF &&
+	$(git -C server rev-parse HEAD)
+	^$(git -C server rev-parse HEAD~2)
+	EOF
+	GIT_PROGRESS_DELAY=0 git -C server pack-objects \
+		--thin --stdout --revs --path-walk --progress <in >out.pack 2>err &&
+	grep "Compressing objects by path" err &&
+	git -C server index-pack --fix-thin --stdin <out.pack
+'
+
 test_done
diff --git a/t/t5306-pack-nobase.sh b/t/t5306-pack-nobase.sh
index 0d50c6b4bca4c0..429be5ce72464f 100755
--- a/t/t5306-pack-nobase.sh
+++ b/t/t5306-pack-nobase.sh
@@ -60,6 +60,11 @@ test_expect_success 'indirectly clone patch_clone' '
 	 git pull ../.git &&
 	 test $(git rev-parse HEAD) = $B &&
 
+	# The --path-walk feature of "git pack-objects" is not
+	# compatible with this kind of fetch from an incomplete repo.
+	GIT_TEST_PACK_PATH_WALK=0 &&
+	export GIT_TEST_PACK_PATH_WALK &&
+
 	 git pull ../patch_clone/.git &&
 	 test $(git rev-parse HEAD) = $C
 	)
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index 5568500d3fa48d..e9742a60f5f8ee 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -158,8 +158,9 @@ test_bitmap_cases () {
 		ls .git/objects/pack/ | grep bitmap >output &&
 		test_line_count = 1 output &&
 		# verify equivalent packs are generated with/without using bitmap index
-		packasha1=$(git pack-objects --no-use-bitmap-index --all packa </dev/null) &&
-		packbsha1=$(git pack-objects --use-bitmap-index --all packb </dev/null) &&
+		# Be careful to not use the path-walk option in either case.
+		packasha1=$(git pack-objects --no-use-bitmap-index --no-path-walk --all packa </dev/null) &&
+		packbsha1=$(git pack-objects --use-bitmap-index --no-path-walk --all packb </dev/null) &&
 		list_packed_objects packa-$packasha1.idx >packa.objects &&
 		list_packed_objects packb-$packbsha1.idx >packb.objects &&
 		test_cmp packa.objects packb.objects
@@ -388,6 +389,14 @@ test_bitmap_cases () {
 		git init --bare client.git &&
 		(
 			cd client.git &&
+
+			# This test relies on reusing a delta, but if the
+			# path-walk machinery is engaged, the base object
+			# is considered too small to use during the
+			# dynamic computation, so is not used.
+			GIT_TEST_PACK_PATH_WALK=0 &&
+			export GIT_TEST_PACK_PATH_WALK &&
+
 			git config transfer.unpackLimit 1 &&
 			git fetch .. delta-reuse-old:delta-reuse-old &&
 			git fetch .. delta-reuse-new:delta-reuse-new &&
diff --git a/t/t5316-pack-delta-depth.sh b/t/t5316-pack-delta-depth.sh
index eb4ef3dda4d6e5..12a6901fecb789 100755
--- a/t/t5316-pack-delta-depth.sh
+++ b/t/t5316-pack-delta-depth.sh
@@ -90,15 +90,18 @@ max_chain() {
 # adjusted (or scrapped if the heuristics have become too unreliable)
 test_expect_success 'packing produces a long delta' '
 	# Use --window=0 to make sure we are seeing reused deltas,
-	# not computing a new long chain.
-	pack=$(git pack-objects --all --window=0 </dev/null pack) &&
+	# not computing a new long chain. (Also avoid the --path-walk
+	# option as it may break delta chains.)
+	pack=$(git pack-objects --all --window=0 --no-path-walk </dev/null pack) &&
 	echo 9 >expect &&
 	max_chain pack-$pack.pack >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success '--depth limits depth' '
-	pack=$(git pack-objects --all --depth=5 </dev/null pack) &&
+	# Avoid --path-walk to avoid breaking delta chains across path
+	# boundaries.
+	pack=$(git pack-objects --all --depth=5 --no-path-walk </dev/null pack) &&
 	echo 5 >expect &&
 	max_chain pack-$pack.pack >actual &&
 	test_cmp expect actual
diff --git a/t/t5332-multi-pack-reuse.sh b/t/t5332-multi-pack-reuse.sh
index ed823f37bcdb96..de1dee5183edc1 100755
--- a/t/t5332-multi-pack-reuse.sh
+++ b/t/t5332-multi-pack-reuse.sh
@@ -6,6 +6,12 @@ TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-bitmap.sh
 
+# The --path-walk option does not consider the preferred pack
+# at all for reusing deltas, so this variable changes the
+# behavior of this test, if enabled.
+GIT_TEST_PACK_PATH_WALK=0
+export GIT_TEST_PACK_PATH_WALK
+
 objdir=.git/objects
 packdir=$objdir/pack
 
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index bc442ec221da93..3a67992a7dc086 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -405,6 +405,7 @@ test_expect_success 'v0 clients can handle multiple symrefs' '
 test_expect_success 'helper with refspec capability fails gracefully' '
 	mkdir test-bin &&
 	write_script test-bin/git-remote-foo <<-EOF &&
+	read capabilities
 	echo import
 	echo refspec ${SQ}*:*${SQ}
 	EOF
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index 7b5ab0eae16012..85fd0a197d0356 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -381,7 +381,15 @@ test_expect_success CMDLINE_LIMIT \
 	)
 '
 
-test_expect_success 'large fetch-pack requests can be sent using chunked encoding' '
+# This is a temporary work-around for libcurl v8.10.0 on the macos-* runners;
+# see https://github.com/git-for-windows/git/issues/5159 for full details
+test_lazy_prereq UNBROKEN_HTTP2 '
+	test "$HTTP_PROTO" = HTTP/2 &&
+	test -z "$(brew info -q curl 2>/dev/null |
+		sed -n "/^Installed/{N;s/.*8\\.10\\.0.*/BROKEN HTTP2/p;}")"
+'
+
+test_expect_success UNBROKEN_HTTP2 'large fetch-pack requests can be sent using chunked encoding' '
 	GIT_TRACE_CURL=true git -c http.postbuffer=65536 \
 		clone --bare "$HTTPD_URL/smart/repo.git" split.git 2>err &&
 	{
diff --git a/t/t6601-path-walk.sh b/t/t6601-path-walk.sh
new file mode 100755
index 00000000000000..26498cab24890d
--- /dev/null
+++ b/t/t6601-path-walk.sh
@@ -0,0 +1,279 @@
+#!/bin/sh
+
+test_description='direct path-walk API tests'
+
+. ./test-lib.sh
+
+test_expect_success 'setup test repository' '
+	git checkout -b base &&
+
+	# Make some objects that will only be reachable
+	# via non-commit tags.
+	mkdir child &&
+	echo file >child/file &&
+	git add child &&
+	git commit -m "will abandon" &&
+	git tag -a -m "tree" tree-tag HEAD^{tree} &&
+	echo file2 >file2 &&
+	git add file2 &&
+	git commit --amend -m "will abandon" &&
+	git tag tree-tag2 HEAD^{tree} &&
+
+	echo blob >file &&
+	blob_oid=$(git hash-object -t blob -w --stdin <file) &&
+	git tag -a -m "blob" blob-tag "$blob_oid" &&
+	echo blob2 >file2 &&
+	blob2_oid=$(git hash-object -t blob -w --stdin <file2) &&
+	git tag blob-tag2 "$blob2_oid" &&
+
+	rm -fr child file file2 &&
+
+	mkdir left &&
+	mkdir right &&
+	echo a >a &&
+	echo b >left/b &&
+	echo c >right/c &&
+	git add . &&
+	git commit --amend -m "first" &&
+	git tag -m "first" first HEAD &&
+
+	echo d >right/d &&
+	git add right &&
+	git commit -m "second" &&
+	git tag -a -m "second (under)" second.1 HEAD &&
+	git tag -a -m "second (top)" second.2 second.1 &&
+
+	# Set up file/dir collision in history.
+	rm a &&
+	mkdir a &&
+	echo a >a/a &&
+	echo bb >left/b &&
+	git add a left &&
+	git commit -m "third" &&
+	git tag -a -m "third" third &&
+
+	git checkout -b topic HEAD~1 &&
+	echo cc >right/c &&
+	git commit -a -m "topic" &&
+	git tag -a -m "fourth" fourth
+'
+
+test_expect_success 'all' '
+	test-tool path-walk -- --all >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	COMMIT::$(git rev-parse base)
+	COMMIT::$(git rev-parse base~1)
+	COMMIT::$(git rev-parse base~2)
+	commits:4
+	TREE::$(git rev-parse topic^{tree})
+	TREE::$(git rev-parse base^{tree})
+	TREE::$(git rev-parse base~1^{tree})
+	TREE::$(git rev-parse base~2^{tree})
+	TREE::$(git rev-parse refs/tags/tree-tag^{})
+	TREE::$(git rev-parse refs/tags/tree-tag2^{})
+	TREE:a/:$(git rev-parse base:a)
+	TREE:left/:$(git rev-parse base:left)
+	TREE:left/:$(git rev-parse base~2:left)
+	TREE:right/:$(git rev-parse topic:right)
+	TREE:right/:$(git rev-parse base~1:right)
+	TREE:right/:$(git rev-parse base~2:right)
+	TREE:child/:$(git rev-parse refs/tags/tree-tag^{}:child)
+	trees:13
+	BLOB:a:$(git rev-parse base~2:a)
+	BLOB:file2:$(git rev-parse refs/tags/tree-tag2^{}:file2)
+	BLOB:left/b:$(git rev-parse base~2:left/b)
+	BLOB:left/b:$(git rev-parse base:left/b)
+	BLOB:right/c:$(git rev-parse base~2:right/c)
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	BLOB:right/d:$(git rev-parse base~1:right/d)
+	BLOB:/tagged-blobs:$(git rev-parse refs/tags/blob-tag^{})
+	BLOB:/tagged-blobs:$(git rev-parse refs/tags/blob-tag2^{})
+	BLOB:child/file:$(git rev-parse refs/tags/tree-tag^{}:child/file)
+	blobs:10
+	TAG::$(git rev-parse refs/tags/first)
+	TAG::$(git rev-parse refs/tags/second.1)
+	TAG::$(git rev-parse refs/tags/second.2)
+	TAG::$(git rev-parse refs/tags/third)
+	TAG::$(git rev-parse refs/tags/fourth)
+	TAG::$(git rev-parse refs/tags/tree-tag)
+	TAG::$(git rev-parse refs/tags/blob-tag)
+	tags:7
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic only' '
+	test-tool path-walk -- topic >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	COMMIT::$(git rev-parse base~1)
+	COMMIT::$(git rev-parse base~2)
+	commits:3
+	TREE::$(git rev-parse topic^{tree})
+	TREE::$(git rev-parse base~1^{tree})
+	TREE::$(git rev-parse base~2^{tree})
+	TREE:left/:$(git rev-parse base~2:left)
+	TREE:right/:$(git rev-parse topic:right)
+	TREE:right/:$(git rev-parse base~1:right)
+	TREE:right/:$(git rev-parse base~2:right)
+	trees:7
+	BLOB:a:$(git rev-parse base~2:a)
+	BLOB:left/b:$(git rev-parse base~2:left/b)
+	BLOB:right/c:$(git rev-parse base~2:right/c)
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	BLOB:right/d:$(git rev-parse base~1:right/d)
+	blobs:5
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic, not base' '
+	test-tool path-walk -- topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	commits:1
+	TREE::$(git rev-parse topic^{tree})
+	TREE:left/:$(git rev-parse topic:left)
+	TREE:right/:$(git rev-parse topic:right)
+	trees:3
+	BLOB:a:$(git rev-parse topic:a)
+	BLOB:left/b:$(git rev-parse topic:left/b)
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	BLOB:right/d:$(git rev-parse topic:right/d)
+	blobs:4
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic, not base, only blobs' '
+	test-tool path-walk --no-trees --no-commits \
+		-- topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	commits:0
+	trees:0
+	BLOB:a:$(git rev-parse topic:a)
+	BLOB:left/b:$(git rev-parse topic:left/b)
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	BLOB:right/d:$(git rev-parse topic:right/d)
+	blobs:4
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+# No, this doesn't make a lot of sense for the path-walk API,
+# but it is possible to do.
+test_expect_success 'topic, not base, only commits' '
+	test-tool path-walk --no-blobs --no-trees \
+		-- topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	commits:1
+	trees:0
+	blobs:0
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic, not base, only trees' '
+	test-tool path-walk --no-blobs --no-commits \
+		-- topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	commits:0
+	TREE::$(git rev-parse topic^{tree})
+	TREE:left/:$(git rev-parse topic:left)
+	TREE:right/:$(git rev-parse topic:right)
+	trees:3
+	blobs:0
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic, not base, boundary' '
+	test-tool path-walk -- --boundary topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	COMMIT::$(git rev-parse base~1):UNINTERESTING
+	commits:2
+	TREE::$(git rev-parse topic^{tree})
+	TREE::$(git rev-parse base~1^{tree}):UNINTERESTING
+	TREE:left/:$(git rev-parse base~1:left):UNINTERESTING
+	TREE:right/:$(git rev-parse topic:right)
+	TREE:right/:$(git rev-parse base~1:right):UNINTERESTING
+	trees:5
+	BLOB:a:$(git rev-parse base~1:a):UNINTERESTING
+	BLOB:left/b:$(git rev-parse base~1:left/b):UNINTERESTING
+	BLOB:right/c:$(git rev-parse base~1:right/c):UNINTERESTING
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	BLOB:right/d:$(git rev-parse base~1:right/d):UNINTERESTING
+	blobs:5
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_expect_success 'topic, not base, boundary with pruning' '
+	test-tool path-walk --prune -- --boundary topic --not base >out &&
+
+	cat >expect <<-EOF &&
+	COMMIT::$(git rev-parse topic)
+	COMMIT::$(git rev-parse base~1):UNINTERESTING
+	commits:2
+	TREE::$(git rev-parse topic^{tree})
+	TREE::$(git rev-parse base~1^{tree}):UNINTERESTING
+	TREE:right/:$(git rev-parse topic:right)
+	TREE:right/:$(git rev-parse base~1:right):UNINTERESTING
+	trees:4
+	BLOB:right/c:$(git rev-parse base~1:right/c):UNINTERESTING
+	BLOB:right/c:$(git rev-parse topic:right/c)
+	blobs:2
+	tags:0
+	EOF
+
+	sort expect >expect.sorted &&
+	sort out >out.sorted &&
+
+	test_cmp expect.sorted out.sorted
+'
+
+test_done
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 80647e440f7093..15e29f538cacc1 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -1102,12 +1102,16 @@ test_expect_success 'submodule update --quiet passes quietness to fetch with a s
 	) &&
 	git clone super4 super5 &&
 	(cd super5 &&
+	 # This test variable will create a "warning" message to stderr
+	 GIT_TEST_PACK_PATH_WALK=0 \
 	 git submodule update --quiet --init --depth=1 submodule3 >out 2>err &&
 	 test_must_be_empty out &&
 	 test_must_be_empty err
 	) &&
 	git clone super4 super6 &&
 	(cd super6 &&
+	 # This test variable will create a "warning" message to stderr
+	 GIT_TEST_PACK_PATH_WALK=0 \
 	 git submodule update --init --depth=1 submodule3 >out 2>err &&
 	 test_file_not_empty out &&
 	 test_file_not_empty err
diff --git a/t/t7513-interpret-trailers.sh b/t/t7513-interpret-trailers.sh
index 3d3e13ccf87215..0f7d8938d984d9 100755
--- a/t/t7513-interpret-trailers.sh
+++ b/t/t7513-interpret-trailers.sh
@@ -175,6 +175,46 @@ test_expect_success 'with only a title in the message' '
 	test_cmp expected actual
 '
 
+test_expect_success 'with a bodiless message that lacks a trailing newline after the subject' '
+	cat >expected <<-\EOF &&
+		area: change
+
+		Reviewed-by: Peff
+		Acked-by: Johan
+	EOF
+	printf "area: change" |
+	git interpret-trailers --trailer "Reviewed-by: Peff" \
+		--trailer "Acked-by: Johan" >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'with a bodied message that lacks a trailing newline after the body' '
+	cat >expected <<-\EOF &&
+		area: change
+
+		details about the change.
+
+		Reviewed-by: Peff
+		Acked-by: Johan
+	EOF
+	printf "area: change\n\ndetails about the change." |
+	git interpret-trailers --trailer "Reviewed-by: Peff" \
+		--trailer "Acked-by: Johan" >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'with a message that lacks a trailing newline after the trailers' '
+	cat >expected <<-\EOF &&
+		area: change
+
+		Reviewed-by: Peff
+		Acked-by: Johan
+	EOF
+	printf "area: change\n\nReviewed-by: Peff" |
+	git interpret-trailers --trailer "Acked-by: Johan" >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'with multiline title in the message' '
 	cat >expected <<-\EOF &&
 		place of