diff --git a/Documentation/RelNotes/2.56.0.adoc b/Documentation/RelNotes/2.56.0.adoc
index 9e3bf38f5e5a74..811f74bc7dbcb6 100644
--- a/Documentation/RelNotes/2.56.0.adoc
+++ b/Documentation/RelNotes/2.56.0.adoc
@@ -48,6 +48,14 @@ UI, Workflows & Features
    help option ('-h' or '--help') is requested directly by the user,
    aligning with standard Unix convention.
 
+ * The '[includeIf "condition"]' conditional inclusion facility for
+   configuration files has been taught to use the location of the
+   worktree in its condition.
+
+ * The usage string and SYNOPSIS for 'git fast-export' have been
+   standardized to make them consistent with each other and with other
+   commands.
+
 
 Performance, Internal Implementation, Development Support etc.
 --------------------------------------------------------------
@@ -167,6 +175,37 @@ Performance, Internal Implementation, Development Support etc.
    'change-id' trailer, ensuring that sent tags generated by 'b4' contain
    the required tracking information for subsequent runs.
 
+ * 'git receive-pack' has been refactored to use ODB transaction
+   interfaces instead of directly managing 'tmp_objdir' for staging
+   incoming objects, bringing it closer to being ODB backend agnostic.
+
+ * The test script 't/t9811-git-p4-label-import.sh' has been
+   modernized to use 'test_path_is_file' and 'test_path_is_missing'
+   instead of raw 'test -f' and '! test -f' calls.
+
+ * A redundant strbuf_reset() call in the 'HAVE_GETDELIM' path of
+   strbuf_getwholeline() has been removed, as getdelim() overwrites the
+   buffer and the length is updated afterward.
+
+ * The object database enumeration interface odb_for_each_object() has
+   been taught to accept object filters, allowing the underlying backends
+   to optimize the traversal by using reachability bitmaps when
+   available.  'git cat-file --batch-all-objects' has been updated to use
+   this generic interface, simplifying its code and avoiding direct
+   access to ODB backend internals.
+
+ * The test script 't/t1100-commit-tree-options.sh' has been modernized
+   by converting test cases to the modern style (using single quotes and
+   tab indentation) and moving the creation of the expected file inside
+   the setup test so it runs under the protection of the test harness.
+
+ * The test script 't/t7614-merge-signoff.sh' has been updated to avoid
+   suppressing the exit code of 'git' commands in a pipe.
+
+ * The 'git rev-list --no-walk' command has been corrected to restore
+   pathspec filtering, which was lost when the streaming walk was
+   refactored.
+
 
 Fixes since v2.55
 -----------------
@@ -306,3 +345,8 @@ Fixes since v2.55
  * The stream-based object signature verification path has been
    corrected to avoid double-closing the stream on read errors.
    (merge cfd52a74a0 ps/odb-stream-double-close-fix later to maint).
+
+ * The '-i' shorthand for the '--init' option, which was accepted by the
+   'git submodule update' command until it was broken in a modernization
+   of the option-parsing code, has been restored.
+   (merge ff1da37f58 dm/submodule-update-i-shorthand later to maint).
diff --git a/Documentation/config.adoc b/Documentation/config.adoc
index 15b1a4d5934758..1ef72de62f2ba6 100644
--- a/Documentation/config.adoc
+++ b/Documentation/config.adoc
@@ -146,6 +146,51 @@ refer to linkgit:gitignore[5] for details. For convenience:
 	This is the same as `gitdir` except that matching is done
 	case-insensitively (e.g. on case-insensitive file systems)
 
+`worktree`::
+	The data that follows the keyword `worktree` and a colon is used as a
+	glob pattern. If the working directory of the current worktree matches
+	the pattern, the include condition is met.
++
+The worktree location is the path where files are checked out (as returned
+by `git rev-parse --show-toplevel`). This is different from `gitdir`, which
+matches the `.git` directory path. In a linked worktree, the worktree path
+is the directory where that worktree's files are located, not the main
+repository's `.git` directory.
++
+The pattern uses the same glob syntax as `gitdir` (including `~/`, `./`,
+`**/`, and trailing-`/` prefix matching). This condition will never match
+in a bare repository (which has no worktree).
++
+Unlike `gitdir`, the `worktree` condition currently matches only the
+realpath-resolved worktree location. If the working tree was entered via a
+symbolic link, a pattern that uses the symbolic-link spelling may not match;
+use the real path instead.
++
+This is useful when you want to apply configuration based on where the
+working tree is located on the filesystem. For example, a contributor who
+works on the same project both personally and as an employee can use
+different `user.name` and `user.email` values depending on which directory
+the worktree is checked out under:
++
+----
+[includeIf "worktree:/home/user/work/"]
+    path = ~/.config/git/work.inc
+[includeIf "worktree:/home/user/personal/"]
+    path = ~/.config/git/personal.inc
+----
++
+While `extensions.worktreeConfig` (see linkgit:git-worktree[1]) also supports
+per-worktree configuration, it stores the config inside each repository's
+`.git/config.worktree` file and requires running `git config --worktree`
+inside each worktree individually. In contrast, `includeIf "worktree:..."`
+can be set once in a global or system-level configuration file (e.g.
+`~/.config/git/config`) and applies to all repositories at once based on
+their worktree location.
+
+`worktree/i`::
+	This is the same as `worktree` except that matching is done
+	case-insensitively (e.g. on case-insensitive file systems)
+
 `onbranch`::
 	The data that follows the keyword `onbranch` and a colon is taken to be a
 	pattern with standard globbing wildcards and two additional
@@ -244,6 +289,14 @@ Example
 [includeIf "gitdir:~/to/group/"]
 	path = /path/to/foo.inc
 
+; include if the worktree is at /path/to/project-build
+[includeIf "worktree:/path/to/project-build"]
+	path = build-config.inc
+
+; include for all worktrees inside /path/to/group
+[includeIf "worktree:/path/to/group/"]
+	path = group-config.inc
+
 ; relative paths are always relative to the including
 ; file (if the condition is true); their location is not
 ; affected by the condition
diff --git a/Documentation/git-fast-export.adoc b/Documentation/git-fast-export.adoc
index 297b57bb2efdc2..719aeca244d534 100644
--- a/Documentation/git-fast-export.adoc
+++ b/Documentation/git-fast-export.adoc
@@ -9,7 +9,7 @@ git-fast-export - Git data exporter
 SYNOPSIS
 --------
 [verse]
-'git fast-export' [<options>] | 'git fast-import'
+'git fast-export' [<options>] [<revision-range>] [[--] <path>...]
 
 DESCRIPTION
 -----------
diff --git a/builtin/add.c b/builtin/add.c
index c859f665199efa..60ffbede2be58a 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -581,7 +581,7 @@ int cmd_add(int argc,
 		string_list_clear(&only_match_skip_worktree, 0);
 	}
 
-	transaction = odb_transaction_begin(repo->objects);
+	odb_transaction_begin_or_die(repo->objects, &transaction, 0);
 
 	ps_matched = xcalloc(pathspec.nr, 1);
 	if (add_renormalize)
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index b4b99a73da9696..1458dd76d683e0 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -20,7 +20,6 @@
 #include "userdiff.h"
 #include "oid-array.h"
 #include "packfile.h"
-#include "pack-bitmap.h"
 #include "object-file.h"
 #include "object-name.h"
 #include "odb.h"
@@ -844,28 +843,6 @@ static int batch_one_object_oi(const struct object_id *oid,
 	return payload->callback(oid, NULL, 0, payload->payload);
 }
 
-static int batch_one_object_packed(const struct object_id *oid,
-				   struct packed_git *pack,
-				   uint32_t pos,
-				   void *_payload)
-{
-	struct for_each_object_payload *payload = _payload;
-	return payload->callback(oid, pack, nth_packed_object_offset(pack, pos),
-				 payload->payload);
-}
-
-static int batch_one_object_bitmapped(const struct object_id *oid,
-				      enum object_type type UNUSED,
-				      int flags UNUSED,
-				      uint32_t hash UNUSED,
-				      struct packed_git *pack,
-				      off_t offset,
-				      void *_payload)
-{
-	struct for_each_object_payload *payload = _payload;
-	return payload->callback(oid, pack, offset, payload->payload);
-}
-
 static void batch_each_object(struct batch_options *opt,
 			      for_each_object_fn callback,
 			      unsigned flags,
@@ -875,56 +852,17 @@ static void batch_each_object(struct batch_options *opt,
 		.callback = callback,
 		.payload = _payload,
 	};
+	struct odb_source_info source_info;
+	struct object_info oi = {
+		.source_infop = &source_info,
+	};
 	struct odb_for_each_object_options opts = {
 		.flags = flags,
+		.filter = &opt->objects_filter,
 	};
-	struct bitmap_index *bitmap = NULL;
-	struct odb_source *source;
-
-	/*
-	 * TODO: we still need to tap into implementation details of the object
-	 * database sources. Ideally, we should extend `odb_for_each_object()`
-	 * to handle object filters itself so that we can move the filtering
-	 * logic into the individual sources.
-	 */
-	odb_prepare_alternates(the_repository->objects);
-	for (source = the_repository->objects->sources; source; source = source->next) {
-		struct odb_source_files *files = odb_source_files_downcast(source);
-		int ret = odb_source_for_each_object(&files->loose->base, NULL, batch_one_object_oi,
-						     &payload, &opts);
-		if (ret)
-			break;
-	}
-
-	if (opt->objects_filter.choice != LOFC_DISABLED &&
-	    (bitmap = prepare_bitmap_git(the_repository)) &&
-	    !for_each_bitmapped_object(bitmap, &opt->objects_filter,
-				       batch_one_object_bitmapped, &payload)) {
-		struct packed_git *pack;
-
-		repo_for_each_pack(the_repository, pack) {
-			if (bitmap_index_contains_pack(bitmap, pack) ||
-			    open_pack_index(pack))
-				continue;
-			for_each_object_in_pack(pack, batch_one_object_packed,
-						&payload, flags);
-		}
-	} else {
-		struct odb_source_info source_info;
-		struct object_info oi = {
-			.source_infop = &source_info,
-		};
-
-		for (source = the_repository->objects->sources; source; source = source->next) {
-			struct odb_source_files *files = odb_source_files_downcast(source);
-			int ret = odb_source_for_each_object(&files->packed->base, &oi,
-							     batch_one_object_oi, &payload, &opts);
-			if (ret)
-				break;
-		}
-	}
 
-	free_bitmap_index(bitmap);
+	odb_for_each_object_ext(the_repository->objects, &oi,
+				batch_one_object_oi, &payload, &opts);
 }
 
 static int batch_objects(struct batch_options *opt)
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 0be43104dc0d23..629d7c591a9d70 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -33,7 +33,7 @@
 #include "gpg-interface.h"
 
 static const char *const fast_export_usage[] = {
-	N_("git fast-export [<rev-list-opts>]"),
+	N_("git fast-export [<options>] [<revision-range>] [[--] <path>...]"),
 	NULL
 };
 
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index ea5eab4cf841bf..3673b14b89b275 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1867,8 +1867,8 @@ static const char no_closure_warning[] = N_(
 "disabling bitmap writing, as some objects are not being packed"
 );
 
-static int add_object_entry(const struct object_id *oid, enum object_type type,
-			    const char *name, int exclude)
+static void add_object_entry(const struct object_id *oid, enum object_type type,
+			     const char *name, int exclude)
 {
 	struct packed_git *found_pack = NULL;
 	off_t found_offset = 0;
@@ -1876,7 +1876,7 @@ static int add_object_entry(const struct object_id *oid, enum object_type type,
 	display_progress(progress_state, ++nr_seen);
 
 	if (have_duplicate_entry(oid, exclude))
-		return 0;
+		return;
 
 	if (!want_object_in_pack(oid, exclude, &found_pack, &found_offset)) {
 		/* The pack is missing an object, so it will not have closure */
@@ -1885,13 +1885,12 @@ static int add_object_entry(const struct object_id *oid, enum object_type type,
 				warning(_(no_closure_warning));
 			write_bitmap_index = 0;
 		}
-		return 0;
+		return;
 	}
 
 	create_object_entry(oid, type, pack_name_hash_fn(name),
 			    exclude, name && no_try_delta(name),
 			    found_pack, found_offset);
-	return 1;
 }
 
 static int add_object_entry_from_bitmap(const struct object_id *oid,
@@ -1909,7 +1908,7 @@ static int add_object_entry_from_bitmap(const struct object_id *oid,
 		return 0;
 
 	create_object_entry(oid, type, name_hash, 0, 0, pack, offset);
-	return 1;
+	return 0;
 }
 
 struct pbase_tree_cache {
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index faf0f120ac186b..7190d7f43063c9 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -37,7 +37,6 @@
 #include "sigchain.h"
 #include "string-list.h"
 #include "strvec.h"
-#include "tmp-objdir.h"
 #include "trace.h"
 #include "trace2.h"
 #include "version.h"
@@ -112,8 +111,6 @@ static enum {
 } use_keepalive;
 static int keepalive_in_sec = 5;
 
-static struct tmp_objdir *tmp_objdir;
-
 static struct proc_receive_ref {
 	unsigned int want_add:1,
 		     want_delete:1,
@@ -926,6 +923,7 @@ static void receive_hook_feed_state_free(void *data)
 static int run_receive_hook(struct command *commands,
 			    const char *hook_name,
 			    int skip_broken,
+			    struct odb_transaction *transaction,
 			    const struct string_list *push_options)
 {
 	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
@@ -959,8 +957,8 @@ static int run_receive_hook(struct command *commands,
 		strvec_push(&opt.env, "GIT_PUSH_OPTION_COUNT");
 	}
 
-	if (tmp_objdir)
-		strvec_pushv(&opt.env, tmp_objdir_env(tmp_objdir));
+	if (transaction)
+		odb_transaction_env(transaction, &opt.env);
 
 	prepare_push_cert_sha1(&opt);
 
@@ -1363,7 +1361,6 @@ static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 		    !delayed_reachability_test(si, i))
 			oid_array_append(&extra, &si->shallow->oid[i]);
 
-	opt.env = tmp_objdir_env(tmp_objdir);
 	setup_alternate_shallow(&shallow_lock, &opt.shallow_file, &extra);
 	if (check_connected(command_singleton_iterator, cmd, &opt)) {
 		rollback_shallow_file(the_repository, &shallow_lock);
@@ -1790,24 +1787,30 @@ static const struct object_id *command_singleton_iterator(void *cb_data)
 }
 
 static void set_connectivity_errors(struct command *commands,
-				    struct shallow_info *si)
+				    struct shallow_info *si,
+				    struct odb_transaction *transaction)
 {
 	struct command *cmd;
 
 	for (cmd = commands; cmd; cmd = cmd->next) {
 		struct command *singleton = cmd;
 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
+		struct strvec env = STRVEC_INIT;
 
 		if (shallow_update && si->shallow_ref[cmd->index])
 			/* to be checked in update_shallow_ref() */
 			continue;
 
-		opt.env = tmp_objdir_env(tmp_objdir);
+		odb_transaction_env(transaction, &env);
+		opt.env = env.v;
+
 		if (!check_connected(command_singleton_iterator, &singleton,
 				     &opt))
 			continue;
 
 		cmd->error_string = "missing necessary objects";
+
+		strvec_clear(&env);
 	}
 }
 
@@ -2028,6 +2031,7 @@ static void execute_commands_atomic(struct command *commands,
 static void execute_commands(struct command *commands,
 			     const char *unpacker_error,
 			     struct shallow_info *si,
+			     struct odb_transaction *transaction,
 			     const struct string_list *push_options)
 {
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
@@ -2044,6 +2048,8 @@ static void execute_commands(struct command *commands,
 	}
 
 	if (!skip_connectivity_check) {
+		struct strvec env = STRVEC_INIT;
+
 		if (use_sideband) {
 			memset(&muxer, 0, sizeof(muxer));
 			muxer.proc = copy_to_sideband;
@@ -2057,14 +2063,17 @@ static void execute_commands(struct command *commands,
 		data.si = si;
 		opt.err_fd = err_fd;
 		opt.progress = err_fd && !quiet;
-		opt.env = tmp_objdir_env(tmp_objdir);
+		odb_transaction_env(transaction, &env);
+		opt.env = env.v;
 		opt.exclude_hidden_refs_section = "receive";
 
 		if (check_connected(iterate_receive_command_list, &data, &opt))
-			set_connectivity_errors(commands, si);
+			set_connectivity_errors(commands, si, transaction);
 
 		if (use_sideband)
 			finish_async(&muxer);
+
+		strvec_clear(&env);
 	}
 
 	reject_updates_to_hidden(commands);
@@ -2085,7 +2094,7 @@ static void execute_commands(struct command *commands,
 		}
 	}
 
-	if (run_receive_hook(commands, "pre-receive", 0, push_options)) {
+	if (run_receive_hook(commands, "pre-receive", 0, transaction, push_options)) {
 		for (cmd = commands; cmd; cmd = cmd->next) {
 			if (!cmd->error_string)
 				cmd->error_string = "pre-receive hook declined";
@@ -2106,14 +2115,13 @@ static void execute_commands(struct command *commands,
 	 * Now we'll start writing out refs, which means the objects need
 	 * to be in their final positions so that other processes can see them.
 	 */
-	if (tmp_objdir_migrate(tmp_objdir) < 0) {
+	if (odb_transaction_commit(transaction)) {
 		for (cmd = commands; cmd; cmd = cmd->next) {
 			if (!cmd->error_string)
 				cmd->error_string = "unable to migrate objects to permanent storage";
 		}
 		return;
 	}
-	tmp_objdir = NULL;
 
 	check_aliased_updates(commands);
 
@@ -2326,7 +2334,8 @@ static void push_header_arg(struct strvec *args, struct pack_header *hdr)
 		     ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
 }
 
-static const char *unpack(int err_fd, struct shallow_info *si)
+static const char *unpack(int err_fd, struct shallow_info *si,
+			  struct odb_transaction *transaction)
 {
 	struct pack_header hdr;
 	const char *hdr_err;
@@ -2351,20 +2360,7 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 		strvec_push(&child.args, alt_shallow_file);
 	}
 
-	tmp_objdir = tmp_objdir_create(the_repository, "incoming");
-	if (!tmp_objdir) {
-		if (err_fd > 0)
-			close(err_fd);
-		return "unable to create temporary object directory";
-	}
-	strvec_pushv(&child.env, tmp_objdir_env(tmp_objdir));
-
-	/*
-	 * Normally we just pass the tmp_objdir environment to the child
-	 * processes that do the heavy lifting, but we may need to see these
-	 * objects ourselves to set up shallow information.
-	 */
-	tmp_objdir_add_as_alternate(tmp_objdir);
+	odb_transaction_env(transaction, &child.env);
 
 	if (ntohl(hdr.hdr_entries) < unpack_limit) {
 		strvec_push(&child.args, "unpack-objects");
@@ -2431,13 +2427,14 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 	return NULL;
 }
 
-static const char *unpack_with_sideband(struct shallow_info *si)
+static const char *unpack_with_sideband(struct shallow_info *si,
+					struct odb_transaction *transaction)
 {
 	struct async muxer;
 	const char *ret;
 
 	if (!use_sideband)
-		return unpack(0, si);
+		return unpack(0, si, transaction);
 
 	use_keepalive = KEEPALIVE_AFTER_NUL;
 	memset(&muxer, 0, sizeof(muxer));
@@ -2446,7 +2443,7 @@ static const char *unpack_with_sideband(struct shallow_info *si)
 	if (start_async(&muxer))
 		return NULL;
 
-	ret = unpack(muxer.in, si);
+	ret = unpack(muxer.in, si, transaction);
 
 	finish_async(&muxer);
 	return ret;
@@ -2623,6 +2620,7 @@ int cmd_receive_pack(int argc,
 	struct oid_array ref = OID_ARRAY_INIT;
 	struct shallow_info si;
 	struct packet_reader reader;
+	struct odb_transaction *transaction = NULL;
 
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("quiet")),
@@ -2707,11 +2705,14 @@ int cmd_receive_pack(int argc,
 		if (!si.nr_ours && !si.nr_theirs)
 			shallow_update = 0;
 		if (!delete_only(commands)) {
-			unpack_status = unpack_with_sideband(&si);
+			if (odb_transaction_begin(the_repository->objects, &transaction, ODB_TRANSACTION_RECEIVE))
+				unpack_status = "unable to start object transaction";
+			else
+				unpack_status = unpack_with_sideband(&si, transaction);
 			update_shallow_info(commands, &si, &ref);
 		}
 		use_keepalive = KEEPALIVE_ALWAYS;
-		execute_commands(commands, unpack_status, &si,
+		execute_commands(commands, unpack_status, &si, transaction,
 				 &push_options);
 		delete_tempfile(&pack_lockfile);
 		sigchain_push(SIGPIPE, SIG_IGN);
@@ -2720,7 +2721,7 @@ int cmd_receive_pack(int argc,
 		else if (report_status)
 			report(commands, unpack_status);
 		sigchain_pop(SIGPIPE);
-		run_receive_hook(commands, "post-receive", 1,
+		run_receive_hook(commands, "post-receive", 1, NULL,
 				 &push_options);
 		run_update_post_hook(commands);
 		free_commands(commands);
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 8f63003709242e..02818b81c63fd7 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -486,7 +486,7 @@ static int show_object_fast(
 	void *payload UNUSED)
 {
 	fprintf(stdout, "%s\n", oid_to_hex(oid));
-	return 1;
+	return 0;
 }
 
 static void print_disk_usage(off_t size)
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 510f193a15b682..2b3c9762afec0a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2990,7 +2990,7 @@ static int module_update(int argc, const char **argv, const char *prefix,
 	struct option module_update_options[] = {
 		OPT__SUPER_PREFIX(&opt.super_prefix),
 		OPT__FORCE(&opt.force, N_("force checkout updates"), 0),
-		OPT_BOOL(0, "init", &opt.init,
+		OPT_BOOL('i', "init", &opt.init,
 			 N_("initialize uninitialized submodules before update")),
 		OPT_BOOL(0, "remote", &opt.remote,
 			 N_("use SHA-1 of submodule's remote tracking branch")),
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 93a9caa58269ab..4263edfbecdd39 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -598,7 +598,7 @@ static void unpack_all(void)
 		progress = start_progress(the_repository,
 					  _("Unpacking objects"), nr_objects);
 	CALLOC_ARRAY(obj_list, nr_objects);
-	transaction = odb_transaction_begin(the_repository->objects);
+	odb_transaction_begin_or_die(the_repository->objects, &transaction, 0);
 	for (i = 0; i < nr_objects; i++) {
 		unpack_one(i);
 		display_progress(progress, i + 1);
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 5d80d4827d8aa1..4c4b39a1575a38 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -1124,7 +1124,7 @@ int cmd_update_index(int argc,
 	 * Allow the object layer to optimize adding multiple objects in
 	 * a batch.
 	 */
-	transaction = odb_transaction_begin(the_repository->objects);
+	odb_transaction_begin_or_die(the_repository->objects, &transaction, 0);
 	while (ctx.argc) {
 		if (parseopt_state != PARSE_OPT_DONE)
 			parseopt_state = parse_options_step(&ctx, options,
diff --git a/cache-tree.c b/cache-tree.c
index 9204eb3ac7a120..d92f5132865f13 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -516,6 +516,7 @@ static int update_one(struct cache_tree *it,
 
 int cache_tree_update(struct index_state *istate, int flags)
 {
+	int inflight = !!the_repository->objects->transaction;
 	struct odb_transaction *transaction;
 	int skip, i;
 
@@ -532,10 +533,12 @@ int cache_tree_update(struct index_state *istate, int flags)
 
 	trace_performance_enter();
 	trace2_region_enter("cache_tree", "update", istate->repo);
-	transaction = odb_transaction_begin(the_repository->objects);
+	if (!inflight)
+		odb_transaction_begin_or_die(the_repository->objects, &transaction, 0);
 	i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 		       "", 0, &skip, flags);
-	odb_transaction_commit(transaction);
+	if (!inflight)
+		odb_transaction_commit(transaction);
 	trace2_region_leave("cache_tree", "update", istate->repo);
 	trace_performance_leave("cache_tree_update");
 	if (i < 0)
diff --git a/config.c b/config.c
index 6a0de86e3ae958..9d6d7872d76c10 100644
--- a/config.c
+++ b/config.c
@@ -235,23 +235,20 @@ static int prepare_include_condition_pattern(const struct key_value_info *kvi,
 	return 0;
 }
 
-static int include_by_gitdir(const struct key_value_info *kvi,
-			     const struct config_options *opts,
-			     const char *cond, size_t cond_len, int icase)
+static int include_by_path(const struct key_value_info *kvi,
+			   const char *path,
+			   const char *cond, size_t cond_len, int icase)
 {
 	struct strbuf text = STRBUF_INIT;
 	struct strbuf pattern = STRBUF_INIT;
 	size_t prefix;
 	int ret = 0;
-	const char *git_dir;
 	int already_tried_absolute = 0;
 
-	if (opts->git_dir)
-		git_dir = opts->git_dir;
-	else
+	if (!path)
 		goto done;
 
-	strbuf_realpath(&text, git_dir, 1);
+	strbuf_realpath(&text, path, 1);
 	strbuf_add(&pattern, cond, cond_len);
 	ret = prepare_include_condition_pattern(kvi, &pattern, &prefix);
 	if (ret < 0)
@@ -284,7 +281,7 @@ static int include_by_gitdir(const struct key_value_info *kvi,
 		 * which'll do the right thing
 		 */
 		strbuf_reset(&text);
-		strbuf_add_absolute_path(&text, git_dir);
+		strbuf_add_absolute_path(&text, path);
 		already_tried_absolute = 1;
 		goto again;
 	}
@@ -400,9 +397,15 @@ static int include_condition_is_true(const struct key_value_info *kvi,
 	const struct config_options *opts = inc->opts;
 
 	if (skip_prefix_mem(cond, cond_len, "gitdir:", &cond, &cond_len))
-		return include_by_gitdir(kvi, opts, cond, cond_len, 0);
+		return include_by_path(kvi, opts->git_dir, cond, cond_len, 0);
 	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
-		return include_by_gitdir(kvi, opts, cond, cond_len, 1);
+		return include_by_path(kvi, opts->git_dir, cond, cond_len, 1);
+	else if (skip_prefix_mem(cond, cond_len, "worktree:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 0);
+	else if (skip_prefix_mem(cond, cond_len, "worktree/i:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 1);
 	else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
 		return include_by_branch(inc, cond, cond_len);
 	else if (skip_prefix_mem(cond, cond_len, "hasconfig:remote.*.url:", &cond,
diff --git a/object-file.c b/object-file.c
index 2d84f0871363e6..7ff2b730ac0ead 100644
--- a/object-file.c
+++ b/object-file.c
@@ -27,6 +27,7 @@
 #include "path.h"
 #include "read-cache-ll.h"
 #include "setup.h"
+#include "strvec.h"
 #include "tempfile.h"
 #include "tmp-objdir.h"
 
@@ -494,9 +495,10 @@ struct odb_transaction_files {
 
 	struct tmp_objdir *objdir;
 	struct transaction_packfile packfile;
+	const char *prefix;
 };
 
-static void prepare_loose_object_transaction(struct odb_transaction *base)
+static int odb_transaction_files_prepare(struct odb_transaction *base)
 {
 	struct odb_transaction_files *transaction =
 		container_of_or_null(base, struct odb_transaction_files, base);
@@ -508,19 +510,28 @@ static void prepare_loose_object_transaction(struct odb_transaction *base)
 	 * added at the time they call odb_transaction_files_begin.
 	 */
 	if (!transaction || transaction->objdir)
-		return;
+		return 0;
+
+	transaction->objdir = tmp_objdir_create(base->source->odb->repo, transaction->prefix);
+	if (!transaction->objdir)
+		return error(_("unable to create temporary object directory"));
 
-	transaction->objdir = tmp_objdir_create(base->source->odb->repo, "bulk-fsync");
-	if (transaction->objdir)
-		tmp_objdir_replace_primary_odb(transaction->objdir, 0);
+	tmp_objdir_replace_primary_odb(transaction->objdir, 0);
+
+	return 0;
 }
 
-static void fsync_loose_object_transaction(struct odb_transaction *base,
-					   int fd, const char *filename)
+static void odb_transaction_files_fsync(struct odb_transaction *base,
+					int fd, const char *filename)
 {
 	struct odb_transaction_files *transaction =
 		container_of_or_null(base, struct odb_transaction_files, base);
 
+	if (!transaction || !transaction->objdir) {
+		fsync_or_die(fd, filename);
+		return;
+	}
+
 	/*
 	 * If we have an active ODB transaction, we issue a call that
 	 * cleans the filesystem page cache but avoids a hardware flush
@@ -528,49 +539,13 @@ static void fsync_loose_object_transaction(struct odb_transaction *base,
 	 * before renaming the objects to their final names as part of
 	 * flush_batch_fsync.
 	 */
-	if (!transaction || !transaction->objdir ||
-	    git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0) {
+	if (git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0) {
 		if (errno == ENOSYS)
 			warning(_("core.fsyncMethod = batch is unsupported on this platform"));
 		fsync_or_die(fd, filename);
 	}
 }
 
-/*
- * Cleanup after batch-mode fsync_object_files.
- */
-static void flush_loose_object_transaction(struct odb_transaction_files *transaction)
-{
-	struct strbuf temp_path = STRBUF_INIT;
-	struct tempfile *temp;
-
-	if (!transaction->objdir)
-		return;
-
-	/*
-	 * Issue a full hardware flush against a temporary file to ensure
-	 * that all objects are durable before any renames occur. The code in
-	 * fsync_loose_object_transaction has already issued a writeout
-	 * request, but it has not flushed any writeback cache in the storage
-	 * hardware or any filesystem logs. This fsync call acts as a barrier
-	 * to ensure that the data in each new object file is durable before
-	 * the final name is visible.
-	 */
-	strbuf_addf(&temp_path, "%s/bulk_fsync_XXXXXX",
-		    repo_get_object_directory(transaction->base.source->odb->repo));
-	temp = xmks_tempfile(temp_path.buf);
-	fsync_or_die(get_tempfile_fd(temp), get_tempfile_path(temp));
-	delete_tempfile(&temp);
-	strbuf_release(&temp_path);
-
-	/*
-	 * Make the object files visible in the primary ODB after their data is
-	 * fully durable.
-	 */
-	tmp_objdir_migrate(transaction->objdir);
-	transaction->objdir = NULL;
-}
-
 /* Finalize a file on disk, and close it. */
 static void close_loose_object(struct odb_source_loose *loose,
 			       int fd, const char *filename)
@@ -579,7 +554,7 @@ static void close_loose_object(struct odb_source_loose *loose,
 		goto out;
 
 	if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
-		fsync_loose_object_transaction(loose->base.odb->transaction, fd, filename);
+		odb_transaction_files_fsync(loose->base.odb->transaction, fd, filename);
 	else if (fsync_object_files > 0)
 		fsync_or_die(fd, filename);
 	else
@@ -758,7 +733,7 @@ int write_loose_object(struct odb_source_loose *loose,
 	static struct strbuf filename = STRBUF_INIT;
 
 	if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
-		prepare_loose_object_transaction(loose->base.odb->transaction);
+		odb_transaction_files_prepare(loose->base.odb->transaction);
 
 	odb_loose_path(loose, &filename, oid);
 
@@ -822,7 +797,7 @@ int odb_source_loose_write_stream(struct odb_source_loose *loose,
 	int hdrlen;
 
 	if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
-		prepare_loose_object_transaction(loose->base.odb->transaction);
+		odb_transaction_files_prepare(loose->base.odb->transaction);
 
 	/* Since oid is not determined, save tmp file to odb path. */
 	strbuf_addf(&filename, "%s/", loose->base.path);
@@ -1380,13 +1355,17 @@ int index_fd(struct index_state *istate, struct object_id *oid,
 
 		if (flags & INDEX_WRITE_OBJECT) {
 			struct object_database *odb = the_repository->objects;
-			struct odb_transaction *transaction = odb_transaction_begin(odb);
+			struct odb_transaction *transaction = odb->transaction;
+			int inflight = !!transaction;
 
-			ret = odb_transaction_write_object_stream(odb->transaction,
+			if (!inflight)
+				odb_transaction_begin_or_die(odb, &transaction, 0);
+			ret = odb_transaction_write_object_stream(transaction,
 								  &stream,
 								  xsize_t(st->st_size),
 								  oid);
-			odb_transaction_commit(transaction);
+			if (!inflight)
+				odb_transaction_commit(transaction);
 		} else {
 			ret = hash_blob_stream(&stream,
 					       the_repository->hash_algo, oid,
@@ -1671,27 +1650,93 @@ int read_loose_object(struct repository *repo,
 	return ret;
 }
 
-static void odb_transaction_files_commit(struct odb_transaction *base)
+static int odb_transaction_files_commit(struct odb_transaction *base)
 {
 	struct odb_transaction_files *transaction =
 		container_of(base, struct odb_transaction_files, base);
 
-	flush_loose_object_transaction(transaction);
+	if (transaction->objdir) {
+		struct strbuf temp_path = STRBUF_INIT;
+		struct tempfile *temp;
+
+		/*
+		 * Issue a full hardware flush against a temporary file to ensure
+		 * that all objects are durable before any renames occur. The code in
+		 * odb_transaction_files_fsync has already issued a writeout
+		 * request, but it has not flushed any writeback cache in the storage
+		 * hardware or any filesystem logs. This fsync call acts as a barrier
+		 * to ensure that the data in each new object file is durable before
+		 * the final name is visible.
+		 */
+		strbuf_addf(&temp_path, "%s/bulk_fsync_XXXXXX",
+			    repo_get_object_directory(transaction->base.source->odb->repo));
+		temp = xmks_tempfile(temp_path.buf);
+		fsync_or_die(get_tempfile_fd(temp), get_tempfile_path(temp));
+		delete_tempfile(&temp);
+		strbuf_release(&temp_path);
+
+		/*
+		 * Make the object files visible in the primary ODB after their data is
+		 * fully durable.
+		 */
+		if (tmp_objdir_migrate(transaction->objdir))
+			return error(_("unable to migrate temporary objects"));
+
+		transaction->objdir = NULL;
+	}
+
 	flush_packfile_transaction(transaction);
+
+	return 0;
 }
 
-struct odb_transaction *odb_transaction_files_begin(struct odb_source *source)
+static int odb_transaction_files_env(struct odb_transaction *base,
+				     struct strvec *env)
 {
-	struct odb_transaction_files *transaction;
-	struct object_database *odb = source->odb;
+	struct odb_transaction_files *transaction =
+		container_of(base, struct odb_transaction_files, base);
+	int ret;
 
-	if (odb->transaction)
-		return NULL;
+	ret = odb_transaction_files_prepare(&transaction->base);
+	if (!ret)
+		strvec_pushv(env, tmp_objdir_env(transaction->objdir));
+
+	return ret;
+}
+
+int odb_transaction_files_begin(struct odb_source *source,
+				struct odb_transaction **out,
+				enum odb_transaction_flags flags)
+{
+	struct odb_transaction_files *transaction;
 
 	transaction = xcalloc(1, sizeof(*transaction));
 	transaction->base.source = source;
 	transaction->base.commit = odb_transaction_files_commit;
 	transaction->base.write_object_stream = odb_transaction_files_write_object_stream;
+	transaction->base.env = odb_transaction_files_env;
 
-	return &transaction->base;
+	transaction->prefix = "bulk-fsync";
+	if (flags & ODB_TRANSACTION_RECEIVE) {
+		/*
+		 * ODB transactions for git-receive-pack(1) eagerly create a
+		 * temporary directory and use a different temporary directory
+		 * prefix.
+		 *
+		 * NEEDSWORK: This transaction flag is only used by the "files"
+		 * backend to special case temporary directory set up and
+		 * handling. Ideally transaction users should not have to care
+		 * though. To avoid this, we could eagerly create the temporary
+		 * directory and use the same prefix name for all transactions.
+		 */
+		transaction->prefix = "incoming";
+		if (odb_transaction_files_prepare(&transaction->base)) {
+			free(transaction);
+			return -1;
+		}
+	}
+
+	*out = &transaction->base;
+
+	return 0;
 }
diff --git a/object-file.h b/object-file.h
index 4c87cd160bb58a..d04ffa6493ff17 100644
--- a/object-file.h
+++ b/object-file.h
@@ -5,6 +5,7 @@
 #include "object.h"
 #include "odb.h"
 #include "odb/source-loose.h"
+#include "odb/transaction.h"
 
 /* The maximum size for an object header. */
 #define MAX_HEADER_LEN 32
@@ -194,9 +195,10 @@ struct odb_transaction;
 /*
  * Tell the object database to optimize for adding
  * multiple objects. odb_transaction_files_commit must be called
- * to make new objects visible. If a transaction is already
- * pending, NULL is returned.
+ * to make new objects visible.
  */
-struct odb_transaction *odb_transaction_files_begin(struct odb_source *source);
+int odb_transaction_files_begin(struct odb_source *source,
+				struct odb_transaction **out,
+				enum odb_transaction_flags flags);
 
 #endif /* OBJECT_FILE_H */
diff --git a/odb.h b/odb.h
index 94754643d24997..7995bed97bc36e 100644
--- a/odb.h
+++ b/odb.h
@@ -8,6 +8,7 @@
 #include "thread-utils.h"
 
 struct cached_object_entry;
+struct list_objects_filter_options;
 struct odb_source_inmemory;
 struct packed_git;
 struct repository;
@@ -502,6 +503,17 @@ struct odb_for_each_object_options {
 	 */
 	const struct object_id *prefix;
 	size_t prefix_hex_len;
+
+	/*
+	 * Optional object filter that allows backends to skip yielding
+	 * objects that are excluded by the filter as an optimization. The
+	 * filter is a best-effort hint: backends may use it to skip
+	 * excluded objects (e.g. by consulting a reachability bitmap), but
+	 * are also free to ignore it entirely and yield every object. As a
+	 * consequence, callers must re-apply the filter on yielded objects
+	 * if they require strict filtering semantics.
+	 */
+	const struct list_objects_filter_options *filter;
 };
 
 /*
diff --git a/odb/source-files.c b/odb/source-files.c
index 6c8e935c753983..413875851135a5 100644
--- a/odb/source-files.c
+++ b/odb/source-files.c
@@ -181,13 +181,10 @@ static int odb_source_files_write_object_stream(struct odb_source *source,
 }
 
 static int odb_source_files_begin_transaction(struct odb_source *source,
-					      struct odb_transaction **out)
+					      struct odb_transaction **out,
+					      enum odb_transaction_flags flags)
 {
-	struct odb_transaction *tx = odb_transaction_files_begin(source);
-	if (!tx)
-		return -1;
-	*out = tx;
-	return 0;
+	return odb_transaction_files_begin(source, out, flags);
 }
 
 static int odb_source_files_read_alternates(struct odb_source *source,
diff --git a/odb/source-inmemory.c b/odb/source-inmemory.c
index f41a602e641897..e47bfd8fccabf0 100644
--- a/odb/source-inmemory.c
+++ b/odb/source-inmemory.c
@@ -305,7 +305,8 @@ static int odb_source_inmemory_freshen_object(struct odb_source *source,
 }
 
 static int odb_source_inmemory_begin_transaction(struct odb_source *source UNUSED,
-						 struct odb_transaction **out UNUSED)
+						 struct odb_transaction **out UNUSED,
+						 enum odb_transaction_flags flags UNUSED)
 {
 	return error("in-memory source does not support transactions");
 }
diff --git a/odb/source-loose.c b/odb/source-loose.c
index 091e8e00a77bf4..3f7d04a56e36ce 100644
--- a/odb/source-loose.c
+++ b/odb/source-loose.c
@@ -638,7 +638,8 @@ static int odb_source_loose_write_object_stream(struct odb_source *source,
 }
 
 static int odb_source_loose_begin_transaction(struct odb_source *source UNUSED,
-					      struct odb_transaction **out UNUSED)
+					      struct odb_transaction **out UNUSED,
+					      enum odb_transaction_flags flags UNUSED)
 {
 	/* TODO: this is a known omission that we'll want to address eventually. */
 	return error("loose source does not support transactions");
diff --git a/odb/source-packed.c b/odb/source-packed.c
index 647f23cdb9edc9..d00aec5a452c58 100644
--- a/odb/source-packed.c
+++ b/odb/source-packed.c
@@ -3,11 +3,13 @@
 #include "chdir-notify.h"
 #include "dir.h"
 #include "git-zlib.h"
+#include "list-objects-filter-options.h"
 #include "mergesort.h"
 #include "midx.h"
 #include "odb/source-packed.h"
 #include "odb/streaming.h"
 #include "packfile.h"
+#include "pack-bitmap.h"
 
 static int find_pack_entry(struct odb_source_packed *store,
 			   const struct object_id *oid,
@@ -143,7 +145,7 @@ static bool should_exclude_pack(struct packed_git *p, enum odb_for_each_object_f
 }
 
 static int for_each_prefixed_object_in_midx(
-	struct odb_source_packed *store,
+	struct odb_source_packed *source,
 	struct multi_pack_index *m,
 	const struct odb_for_each_object_options *opts,
 	struct odb_source_packed_for_each_object_wrapper_data *data)
@@ -170,6 +172,7 @@ static int for_each_prefixed_object_in_midx(
 		 */
 		for (i = first; i < num; i++) {
 			const struct object_id *current = NULL;
+			struct packed_git *pack;
 			struct object_id oid;
 
 			current = nth_midxed_object_oid(&oid, m, i);
@@ -177,9 +180,8 @@ static int for_each_prefixed_object_in_midx(
 			if (!match_hash(len, opts->prefix->hash, current->hash))
 				break;
 
-			if (opts->flags) {
+			if (opts->flags || data->request) {
 				uint32_t pack_id = nth_midxed_pack_int_id(m, i);
-				struct packed_git *pack;
 
 				if (prepare_midx_pack(m, pack_id)) {
 					pack_errors = true;
@@ -193,9 +195,9 @@ static int for_each_prefixed_object_in_midx(
 
 			if (data->request) {
 				struct object_info oi = *data->request;
+				off_t offset = nth_midxed_offset(m, i);
 
-				ret = odb_source_read_object_info(&store->base, current,
-								  &oi, 0);
+				ret = packed_object_info(source, pack, offset, &oi);
 				if (ret)
 					goto out;
 
@@ -219,7 +221,7 @@ static int for_each_prefixed_object_in_midx(
 }
 
 static int for_each_prefixed_object_in_pack(
-	struct odb_source_packed *store,
+	struct odb_source_packed *source,
 	struct packed_git *p,
 	const struct odb_for_each_object_options *opts,
 	struct odb_source_packed_for_each_object_wrapper_data *data)
@@ -246,8 +248,9 @@ static int for_each_prefixed_object_in_pack(
 
 		if (data->request) {
 			struct object_info oi = *data->request;
+			off_t offset = nth_packed_object_offset(p, i);
 
-			ret = odb_source_read_object_info(&store->base, &oid, &oi, 0);
+			ret = packed_object_info(source, p, offset, &oi);
 			if (ret)
 				goto out;
 
@@ -314,6 +317,37 @@ static int odb_source_packed_for_each_prefixed_object(
 	return ret;
 }
 
+struct bitmapped_for_each_object_data {
+	struct odb_source_packed *packed;
+	const struct object_info *request;
+	const struct odb_for_each_object_options *opts;
+	odb_for_each_object_cb cb;
+	void *cb_data;
+};
+
+static int bitmapped_for_each_object(const struct object_id *oid,
+				     enum object_type type UNUSED,
+				     int flags UNUSED,
+				     uint32_t hash UNUSED,
+				     struct packed_git *pack,
+				     off_t offset,
+				     void *cb_data)
+{
+	struct bitmapped_for_each_object_data *data = cb_data;
+
+	if (should_exclude_pack(pack, data->opts->flags))
+		return 0;
+
+	if (data->request) {
+		struct object_info oi = *data->request;
+		if (packed_object_info(data->packed, pack, offset, &oi) < 0)
+			return -1;
+		return data->cb(oid, &oi, data->cb_data);
+	}
+
+	return data->cb(oid, NULL, data->cb_data);
+}
+
 static int odb_source_packed_for_each_object(struct odb_source *source,
 					     const struct object_info *request,
 					     odb_for_each_object_cb cb,
@@ -327,12 +361,33 @@ static int odb_source_packed_for_each_object(struct odb_source *source,
 		.cb = cb,
 		.cb_data = cb_data,
 	};
+	struct bitmap_index *bitmap = NULL;
 	struct packfile_list_entry *e;
 	int pack_errors = 0, ret;
 
 	if (opts->prefix)
 		return odb_source_packed_for_each_prefixed_object(packed, opts, &data);
 
+	if (opts->filter &&
+	    opts->filter->choice != LOFC_DISABLED &&
+	    can_filter_bitmap(opts->filter))
+		bitmap = prepare_bitmap_git_for_source(packed);
+	if (bitmap) {
+		struct bitmapped_for_each_object_data bitmap_data = {
+			.packed = packed,
+			.request = request,
+			.opts = opts,
+			.cb = cb,
+			.cb_data = cb_data,
+		};
+
+		ret = for_each_bitmapped_object(bitmap, opts->filter,
+						bitmapped_for_each_object,
+						&bitmap_data);
+		if (ret)
+			goto out;
+	}
+
 	packed->skip_mru_updates = true;
 
 	for (e = packfile_store_get_packs(packed); e; e = e->next) {
@@ -341,6 +396,13 @@ static int odb_source_packed_for_each_object(struct odb_source *source,
 		if (should_exclude_pack(p, opts->flags))
 			continue;
 
+		/*
+		 * Objects covered by the bitmap have already been yielded
+		 * above; skip them here to avoid duplicates.
+		 */
+		if (bitmap && bitmap_index_contains_pack(bitmap, p))
+			continue;
+
 		if (open_pack_index(p)) {
 			pack_errors = 1;
 			continue;
@@ -356,6 +418,7 @@ static int odb_source_packed_for_each_object(struct odb_source *source,
 
 out:
 	packed->skip_mru_updates = false;
+	free_bitmap_index(bitmap);
 
 	if (!ret && pack_errors)
 		ret = -1;
@@ -545,7 +608,8 @@ static int odb_source_packed_write_object_stream(struct odb_source *source UNUSE
 }
 
 static int odb_source_packed_begin_transaction(struct odb_source *source UNUSED,
-					       struct odb_transaction **out UNUSED)
+					       struct odb_transaction **out UNUSED,
+					       enum odb_transaction_flags flags UNUSED)
 {
 	return error("packed backend cannot begin transactions");
 }
diff --git a/odb/source.h b/odb/source.h
index efeff7ed12adbb..cd63dba91f4e2f 100644
--- a/odb/source.h
+++ b/odb/source.h
@@ -3,6 +3,7 @@
 
 #include "object.h"
 #include "odb.h"
+#include "odb/transaction.h"
 
 enum odb_source_type {
 	/*
@@ -232,7 +233,8 @@ struct odb_source {
 	 * negative error code otherwise.
 	 */
 	int (*begin_transaction)(struct odb_source *source,
-				 struct odb_transaction **out);
+				 struct odb_transaction **out,
+				 enum odb_transaction_flags flags);
 
 	/*
 	 * This callback is expected to read the list of alternate object
@@ -472,9 +474,10 @@ static inline int odb_source_write_alternate(struct odb_source *source,
  * Returns 0 on success, a negative error code otherwise.
  */
 static inline int odb_source_begin_transaction(struct odb_source *source,
-					       struct odb_transaction **out)
+					       struct odb_transaction **out,
+					       enum odb_transaction_flags flags)
 {
-	return source->begin_transaction(source, out);
+	return source->begin_transaction(source, out, flags);
 }
 
 #endif
diff --git a/odb/transaction.c b/odb/transaction.c
index b16e07aebfc5ac..dab7da6a9a4f55 100644
--- a/odb/transaction.c
+++ b/odb/transaction.c
@@ -1,30 +1,41 @@
 #include "git-compat-util.h"
+#include "gettext.h"
 #include "odb/source.h"
 #include "odb/transaction.h"
 
-struct odb_transaction *odb_transaction_begin(struct object_database *odb)
+int odb_transaction_begin(struct object_database *odb,
+			  struct odb_transaction **out,
+			  enum odb_transaction_flags flags)
 {
+	int ret;
+
 	if (odb->transaction)
-		return NULL;
+		return error(_("object database transaction already pending"));
 
-	odb_source_begin_transaction(odb->sources, &odb->transaction);
+	ret = odb_source_begin_transaction(odb->sources, out, flags);
+	if (!ret)
+		odb->transaction = *out;
 
-	return odb->transaction;
+	return ret;
 }
 
-void odb_transaction_commit(struct odb_transaction *transaction)
+int odb_transaction_commit(struct odb_transaction *transaction)
 {
+	int ret;
+
 	if (!transaction)
-		return;
+		return 0;
 
 	/*
 	 * Ensure the transaction ending matches the pending transaction.
 	 */
 	ASSERT(transaction == transaction->source->odb->transaction);
 
-	transaction->commit(transaction);
+	ret = transaction->commit(transaction);
 	transaction->source->odb->transaction = NULL;
 	free(transaction);
+
+	return ret;
 }
 
 int odb_transaction_write_object_stream(struct odb_transaction *transaction,
@@ -33,3 +44,11 @@ int odb_transaction_write_object_stream(struct odb_transaction *transaction,
 {
 	return transaction->write_object_stream(transaction, stream, len, oid);
 }
+
+int odb_transaction_env(struct odb_transaction *transaction, struct strvec *env)
+{
+	if (!transaction)
+		return 0;
+
+	return transaction->env(transaction, env);
+}
diff --git a/odb/transaction.h b/odb/transaction.h
index 854fda06f576e4..4cb2eafcbf08f5 100644
--- a/odb/transaction.h
+++ b/odb/transaction.h
@@ -1,8 +1,8 @@
 #ifndef ODB_TRANSACTION_H
 #define ODB_TRANSACTION_H
 
+#include "gettext.h"
 #include "odb.h"
-#include "odb/source.h"
 
 /*
  * A transaction may be started for an object database prior to writing new
@@ -16,8 +16,11 @@ struct odb_transaction {
 	/* The ODB source the transaction is opened against. */
 	struct odb_source *source;
 
-	/* The ODB source specific callback invoked to commit a transaction. */
-	void (*commit)(struct odb_transaction *transaction);
+	/*
+	 * The ODB source specific callback invoked to commit a transaction.
+	 * Returns 0 on success, a negative error code otherwise.
+	 */
+	int (*commit)(struct odb_transaction *transaction);
 
 	/*
 	 * This callback is expected to write the given object stream into
@@ -30,20 +33,47 @@ struct odb_transaction {
 	int (*write_object_stream)(struct odb_transaction *transaction,
 				   struct odb_write_stream *stream, size_t len,
 				   struct object_id *oid);
+
+	/*
+	 * This callback is expected to populate the provided strvec with the
+	 * environment variables that a child process should inherit so that its
+	 * object writes participate in the transaction. Returns 0 on success, a
+	 * negative error code otherwise.
+	 */
+	int (*env)(struct odb_transaction *transaction, struct strvec *env);
+};
+
+/* Flags used to configure an ODB transaction. */
+enum odb_transaction_flags {
+	/* Configures the transaction for use with git-receive-pack(1). */
+	ODB_TRANSACTION_RECEIVE = (1 << 0),
 };
 
 /*
- * Starts an ODB transaction. Subsequent objects are written to the transaction
- * and not committed until odb_transaction_commit() is invoked on the
- * transaction. If the ODB already has a pending transaction, NULL is returned.
+ * Starts an ODB transaction and returns it via `out`. Subsequent objects are
+ * written to the transaction and not committed until odb_transaction_commit()
+ * is invoked on the transaction. Returns 0 on success and a negative value on
+ * error. Note that it is considered an error to start a new transaction if the
+ * ODB already has an inflight transaction pending.
  */
-struct odb_transaction *odb_transaction_begin(struct object_database *odb);
+int odb_transaction_begin(struct object_database *odb,
+			  struct odb_transaction **out,
+			  enum odb_transaction_flags flags);
+
+static inline void odb_transaction_begin_or_die(struct object_database *odb,
+						struct odb_transaction **out,
+						enum odb_transaction_flags flags)
+{
+	if (odb_transaction_begin(odb, out, flags))
+		die(_("failed to start ODB transaction"));
+}
 
 /*
- * Commits an ODB transaction making the written objects visible. If the
- * specified transaction is NULL, the function is a no-op.
+ * Commits an ODB transaction making the written objects visible. Returns 0 on
+ * success, a negative error code otherwise. Note that, if the specified
+ * transaction is NULL, the function is a no-op and no error is returned.
  */
-void odb_transaction_commit(struct odb_transaction *transaction);
+int odb_transaction_commit(struct odb_transaction *transaction);
 
 /*
  * Writes the object in the provided stream into the transaction. The resulting
@@ -54,4 +84,13 @@ int odb_transaction_write_object_stream(struct odb_transaction *transaction,
 					struct odb_write_stream *stream,
 					size_t len, struct object_id *oid);
 
+/*
+ * Populates the provided strvec with the environment variables that a child
+ * process should inherit so that its object writes participate in the
+ * transaction, suitable for using via child_process.env. Returns 0 on success,
+ * a negative error code otherwise. Note that, if the specified transaction is
+ * NULL, the function is a no-op and no error is returned.
+ */
+int odb_transaction_env(struct odb_transaction *transaction, struct strvec *env);
+
 #endif
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 1fc3e62d5e154d..d8dc4ae8d1633c 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -460,8 +460,8 @@ char *pack_bitmap_filename(struct packed_git *p)
 	return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 }
 
-static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
-			      struct multi_pack_index *midx)
+static int open_midx_bitmap(struct bitmap_index *bitmap_git,
+			    struct multi_pack_index *midx)
 {
 	struct stat st;
 	char *bitmap_name = midx_bitmap_filename(midx);
@@ -543,7 +543,7 @@ static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
 	return -1;
 }
 
-static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
+static int open_pack_bitmap(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 {
 	int fd;
 	struct stat st;
@@ -607,7 +607,7 @@ static int load_reverse_index(struct repository *r, struct bitmap_index *bitmap_
 
 		/*
 		 * The multi-pack-index's .rev file is already loaded via
-		 * open_pack_bitmap_1().
+		 * open_pack_bitmap().
 		 *
 		 * But we still need to open the individual pack .rev files,
 		 * since we will need to make use of them in pack-objects.
@@ -684,60 +684,53 @@ static int load_bitmap(struct repository *r, struct bitmap_index *bitmap_git,
 	return 0;
 }
 
-static int open_pack_bitmap(struct repository *r,
-			    struct bitmap_index *bitmap_git)
+static int open_bitmap_for_source(struct odb_source_packed *source,
+				  struct bitmap_index *bitmap_git)
 {
-	struct packed_git *p;
-	int ret = -1;
+	struct multi_pack_index *midx = get_multi_pack_index(source);
+	struct packfile_list_entry *e;
+	bool found = false;
 
-	repo_for_each_pack(r, p) {
-		if (open_pack_bitmap_1(bitmap_git, p) == 0) {
-			ret = 0;
-			/*
-			 * The only reason to keep looking is to report
-			 * duplicates.
-			 */
-			if (!trace2_is_enabled())
-				break;
-		}
+	if (midx && !open_midx_bitmap(bitmap_git, midx))
+		found = true;
+
+	for (e = packfile_store_get_packs(source); e; e = e->next) {
+		/*
+		 * When tracing is enabled we want to keep looking to report
+		 * duplicates even if we have already found a bitmap.
+		 */
+		if (found && !trace2_is_enabled())
+			break;
+
+		if (!open_pack_bitmap(bitmap_git, e->pack))
+			found = true;
 	}
 
-	return ret;
+	return found ? 0 : -1;
 }
 
-static int open_midx_bitmap(struct repository *r,
-			    struct bitmap_index *bitmap_git)
+static int open_bitmap(struct repository *r,
+		       struct bitmap_index *bitmap_git)
 {
 	struct odb_source *source;
-	int ret = -1;
+	bool found = false;
 
 	assert(!bitmap_git->map);
 
 	odb_prepare_alternates(r->objects);
 	for (source = r->objects->sources; source; source = source->next) {
 		struct odb_source_files *files = odb_source_files_downcast(source);
-		struct multi_pack_index *midx = get_multi_pack_index(files->packed);
-		if (midx && !open_midx_bitmap_1(bitmap_git, midx))
-			ret = 0;
-	}
-	return ret;
-}
 
-static int open_bitmap(struct repository *r,
-		       struct bitmap_index *bitmap_git)
-{
-	int found;
-
-	assert(!bitmap_git->map);
+		if (!open_bitmap_for_source(files->packed, bitmap_git))
+			found = true;
 
-	found = !open_midx_bitmap(r, bitmap_git);
-
-	/*
-	 * these will all be skipped if we opened a midx bitmap; but run it
-	 * anyway if tracing is enabled to report the duplicates
-	 */
-	if (!found || trace2_is_enabled())
-		found |= !open_pack_bitmap(r, bitmap_git);
+		/*
+		 * The only reason to keep looking after having found a bitmap
+		 * is to report duplicates.
+		 */
+		if (found && !trace2_is_enabled())
+			break;
+	}
 
 	return found ? 0 : -1;
 }
@@ -757,7 +750,19 @@ struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx)
 {
 	struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 
-	if (!open_midx_bitmap_1(bitmap_git, midx))
+	if (!open_midx_bitmap(bitmap_git, midx))
+		return bitmap_git;
+
+	free_bitmap_index(bitmap_git);
+	return NULL;
+}
+
+struct bitmap_index *prepare_bitmap_git_for_source(struct odb_source_packed *source)
+{
+	struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
+
+	if (!open_bitmap_for_source(source, bitmap_git) &&
+	    !load_bitmap(source->base.odb->repo, bitmap_git, 0))
 		return bitmap_git;
 
 	free_bitmap_index(bitmap_git);
@@ -1699,7 +1704,7 @@ static void init_type_iterator(struct ewah_or_iterator *it,
 	}
 }
 
-static void show_objects_for_type(
+static int show_objects_for_type(
 	struct bitmap_index *bitmap_git,
 	struct bitmap *objects,
 	enum object_type object_type,
@@ -1708,6 +1713,7 @@ static void show_objects_for_type(
 {
 	size_t i = 0;
 	uint32_t offset;
+	int ret;
 
 	struct ewah_or_iterator it;
 	eword_t filter;
@@ -1753,11 +1759,17 @@ static void show_objects_for_type(
 
 			hash = bitmap_name_hash(bitmap_git, index_pos);
 
-			show_reach(&oid, object_type, 0, hash, pack, ofs, payload);
+			ret = show_reach(&oid, object_type, 0, hash, pack, ofs, payload);
+			if (ret)
+				goto out;
 		}
 	}
 
+	ret = 0;
+
+out:
 	ewah_or_iterator_release(&it);
+	return ret;
 }
 
 static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
@@ -1980,7 +1992,7 @@ static void filter_bitmap_object_type(struct bitmap_index *bitmap_git,
 static int filter_bitmap(struct bitmap_index *bitmap_git,
 			 struct object_list *tip_objects,
 			 struct bitmap *to_filter,
-			 struct list_objects_filter_options *filter)
+			 const struct list_objects_filter_options *filter)
 {
 	if (!filter || filter->choice == LOFC_DISABLED)
 		return 0;
@@ -2031,12 +2043,11 @@ static int filter_bitmap(struct bitmap_index *bitmap_git,
 	return -1;
 }
 
-static int can_filter_bitmap(struct list_objects_filter_options *filter)
+bool can_filter_bitmap(const struct list_objects_filter_options *filter)
 {
 	return !filter_bitmap(NULL, NULL, NULL, filter);
 }
 
-
 static void filter_packed_objects_from_bitmap(struct bitmap_index *bitmap_git,
 					      struct bitmap *result)
 {
@@ -2062,10 +2073,16 @@ static void filter_packed_objects_from_bitmap(struct bitmap_index *bitmap_git,
 }
 
 int for_each_bitmapped_object(struct bitmap_index *bitmap_git,
-			      struct list_objects_filter_options *filter,
+			      const struct list_objects_filter_options *filter,
 			      show_reachable_fn show_reach,
 			      void *payload)
 {
+	const enum object_type types[] = {
+		OBJ_COMMIT,
+		OBJ_TREE,
+		OBJ_BLOB,
+		OBJ_TAG,
+	};
 	struct bitmap *filtered_bitmap = NULL;
 	uint32_t objects_nr;
 	size_t full_word_count;
@@ -2090,14 +2107,12 @@ int for_each_bitmapped_object(struct bitmap_index *bitmap_git,
 		goto out;
 	}
 
-	show_objects_for_type(bitmap_git, filtered_bitmap,
-			      OBJ_COMMIT, show_reach, payload);
-	show_objects_for_type(bitmap_git, filtered_bitmap,
-			      OBJ_TREE, show_reach, payload);
-	show_objects_for_type(bitmap_git, filtered_bitmap,
-			      OBJ_BLOB, show_reach, payload);
-	show_objects_for_type(bitmap_git, filtered_bitmap,
-			      OBJ_TAG, show_reach, payload);
+	for (size_t i = 0; i < ARRAY_SIZE(types); i++) {
+		ret = show_objects_for_type(bitmap_git, filtered_bitmap,
+					    types[i], show_reach, payload);
+		if (ret)
+			goto out;
+	}
 
 	ret = 0;
 out:
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 19a86554579f7c..1385027c1ff5fa 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -9,6 +9,7 @@
 #include "string-list.h"
 
 struct commit;
+struct odb_source_packed;
 struct repository;
 struct rev_info;
 
@@ -68,6 +69,7 @@ struct bitmapped_pack {
 
 struct bitmap_index *prepare_bitmap_git(struct repository *r);
 struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx);
+struct bitmap_index *prepare_bitmap_git_for_source(struct odb_source_packed *source);
 
 /*
  * Given a bitmap index, determine whether it contains the pack either directly
@@ -90,13 +92,17 @@ int test_bitmap_pseudo_merge_objects(struct repository *r, uint32_t n);
 
 struct list_objects_filter_options;
 
+/* Check whether the filter can be computed via the bitmap. */
+bool can_filter_bitmap(const struct list_objects_filter_options *filter);
+
 /*
  * Filter bitmapped objects and iterate through all resulting objects,
  * executing `show_reach` for each of them. Returns `-1` in case the filter is
- * not supported, `0` otherwise.
+ * not supported, `0` otherwise. Aborts iteration and bubbles up the return
+ * value in case `show_reach()` returns non-zero.
  */
 int for_each_bitmapped_object(struct bitmap_index *bitmap_git,
-			      struct list_objects_filter_options *filter,
+			      const struct list_objects_filter_options *filter,
 			      show_reachable_fn show_reach,
 			      void *payload);
 
diff --git a/read-cache.c b/read-cache.c
index 797fdfc07dfbfe..38b55323dd739a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -4015,6 +4015,7 @@ int add_files_to_cache(struct repository *repo, const char *prefix,
 		       const struct pathspec *pathspec, char *ps_matched,
 		       int include_sparse, int flags, int ignored_too )
 {
+	int inflight = !!repo->objects->transaction;
 	struct odb_transaction *transaction;
 	struct update_callback_data data;
 	struct rev_info rev;
@@ -4045,9 +4046,11 @@ int add_files_to_cache(struct repository *repo, const char *prefix,
 	 * This function is invoked from commands other than 'add', which
 	 * may not have their own transaction active.
 	 */
-	transaction = odb_transaction_begin(repo->objects);
+	if (!inflight)
+		odb_transaction_begin_or_die(repo->objects, &transaction, 0);
 	run_diff_files(&rev, DIFF_RACY_IS_MODIFIED);
-	odb_transaction_commit(transaction);
+	if (!inflight)
+		odb_transaction_commit(transaction);
 
 	release_revisions(&rev);
 	return !!data.add_errors;
diff --git a/revision.c b/revision.c
index 8425f67cbeab0b..fec5472580e058 100644
--- a/revision.c
+++ b/revision.c
@@ -4424,6 +4424,7 @@ static struct commit *get_revision_1(struct rev_info *revs)
 
 		switch (mode) {
 		case REV_WALK_REFLOG:
+		case REV_WALK_NO_WALK:
 			try_to_simplify_commit(revs, commit);
 			break;
 		case REV_WALK_TOPO:
@@ -4437,7 +4438,6 @@ static struct commit *get_revision_1(struct rev_info *revs)
 					    oid_to_hex(&commit->object.oid));
 			}
 			break;
-		case REV_WALK_NO_WALK:
 		case REV_WALK_LIMITED:
 			break;
 		}
diff --git a/strbuf.c b/strbuf.c
index 764b629927f0ce..44955669e8c504 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -646,8 +646,6 @@ int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
 	if (feof(fp))
 		return EOF;
 
-	strbuf_reset(sb);
-
 	/* Translate slopbuf to NULL, as we cannot call realloc on it */
 	if (!sb->alloc)
 		sb->buf = NULL;
diff --git a/t/t0450/adoc-help-mismatches b/t/t0450/adoc-help-mismatches
index e8d6c13ccd0333..c4a55ff4e35a4f 100644
--- a/t/t0450/adoc-help-mismatches
+++ b/t/t0450/adoc-help-mismatches
@@ -12,7 +12,6 @@ column
 credential
 credential-cache
 credential-store
-fast-export
 fast-import
 fetch-pack
 fmt-merge-msg
diff --git a/t/t1100-commit-tree-options.sh b/t/t1100-commit-tree-options.sh
index ae66ba5babf347..3e888909f58d30 100755
--- a/t/t1100-commit-tree-options.sh
+++ b/t/t1100-commit-tree-options.sh
@@ -14,37 +14,35 @@ Also make sure that command line parser understands the normal
 
 . ./test-lib.sh
 
-cat >expected <<EOF
-tree $EMPTY_TREE
-author Author Name <author@email> 1117148400 +0000
-committer Committer Name <committer@email> 1117150200 +0000
-
-comment text
-EOF
-
-test_expect_success \
-    'test preparation: write empty tree' \
-    'git write-tree >treeid'
-
-test_expect_success \
-    'construct commit' \
-    'echo comment text |
-     GIT_AUTHOR_NAME="Author Name" \
-     GIT_AUTHOR_EMAIL="author@email" \
-     GIT_AUTHOR_DATE="2005-05-26 23:00" \
-     GIT_COMMITTER_NAME="Committer Name" \
-     GIT_COMMITTER_EMAIL="committer@email" \
-     GIT_COMMITTER_DATE="2005-05-26 23:30" \
-     TZ=GMT git commit-tree $(cat treeid) >commitid 2>/dev/null'
-
-test_expect_success \
-    'read commit' \
-    'git cat-file commit $(cat commitid) >commit'
-
-test_expect_success \
-    'compare commit' \
-    'test_cmp expected commit'
+test_expect_success 'test preparation: write empty tree' '
+	cat >expected <<-EOF &&
+	tree $EMPTY_TREE
+	author Author Name <author@email> 1117148400 +0000
+	committer Committer Name <committer@email> 1117150200 +0000
+
+	comment text
+	EOF
+	git write-tree >treeid
+'
+
+test_expect_success 'construct commit' '
+	echo comment text |
+	GIT_AUTHOR_NAME="Author Name" \
+	GIT_AUTHOR_EMAIL="author@email" \
+	GIT_AUTHOR_DATE="2005-05-26 23:00" \
+	GIT_COMMITTER_NAME="Committer Name" \
+	GIT_COMMITTER_EMAIL="committer@email" \
+	GIT_COMMITTER_DATE="2005-05-26 23:30" \
+	TZ=GMT git commit-tree $(cat treeid) >commitid 2>/dev/null
+'
 
+test_expect_success 'read commit' '
+	git cat-file commit $(cat commitid) >commit
+'
+
+test_expect_success 'compare commit' '
+	test_cmp expected commit
+'
 
 test_expect_success 'flags and then non flags' '
 	test_tick &&
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index f6115269f9ede0..507b8ebd061b00 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -396,4 +396,132 @@ test_expect_success 'onbranch without repository but explicit nonexistent Git di
 	test_must_fail nongit git --git-dir=nonexistent config get foo.bar
 '
 
+# worktree: conditional include tests
+
+test_expect_success 'conditional include, worktree bare repo' '
+	git init --bare wt-bare &&
+	(
+		cd wt-bare &&
+		echo "[includeIf \"worktree:/\"]path=bar-bare" >>config &&
+		echo "[test]wtbare=1" >bar-bare &&
+		test_must_fail git config test.wtbare
+	)
+'
+
+test_expect_success 'conditional include, worktree multiple worktrees' '
+	git init wt-multi &&
+	(
+		cd wt-multi &&
+		test_commit initial &&
+		git worktree add -b linked-branch ../wt-linked HEAD &&
+		git worktree add -b prefix-branch ../wt-prefix/linked HEAD
+	) &&
+	wt_main="$(cd wt-multi && pwd)" &&
+	wt_linked="$(cd wt-linked && pwd)" &&
+	wt_prefix_parent="$(cd wt-prefix && pwd)" &&
+	cat >>wt-multi/.git/config <<-EOF &&
+	[includeIf "worktree:$wt_main"]
+		path = main-config
+	[includeIf "worktree:$wt_linked"]
+		path = linked-config
+	[includeIf "worktree:$wt_prefix_parent/"]
+		path = prefix-config
+	EOF
+	echo "[test]mainvar=main" >wt-multi/.git/main-config &&
+	echo "[test]linkedvar=linked" >wt-multi/.git/linked-config &&
+	echo "[test]prefixvar=prefix" >wt-multi/.git/prefix-config &&
+	echo main >expect &&
+	git -C wt-multi config test.mainvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-multi config test.linkedvar &&
+	test_must_fail git -C wt-multi config test.prefixvar &&
+	echo linked >expect &&
+	git -C wt-linked config test.linkedvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-linked config test.mainvar &&
+	test_must_fail git -C wt-linked config test.prefixvar &&
+	echo prefix >expect &&
+	git -C wt-prefix/linked config test.prefixvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-prefix/linked config test.mainvar &&
+	test_must_fail git -C wt-prefix/linked config test.linkedvar
+'
+
+test_expect_success SYMLINKS 'conditional include, worktree resolves symlinks' '
+	mkdir real-wt &&
+	ln -s real-wt link-wt &&
+	git init link-wt/repo &&
+	(
+		cd link-wt/repo &&
+		# repo->worktree resolves symlinks, so use real path in pattern
+		echo "[includeIf \"worktree:**/real-wt/repo\"]path=bar-link" >>.git/config &&
+		echo "[test]wtlink=2" >.git/bar-link &&
+		echo 2 >expect &&
+		git config test.wtlink >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success !CASE_INSENSITIVE_FS 'conditional include, worktree, case sensitive' '
+	git init wt-case &&
+	(
+		cd wt-case &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		wt_upper=$(echo "$wt_path" | tr a-z A-Z) &&
+		echo "[includeIf \"worktree:$wt_upper\"]path=case-inc" >>.git/config &&
+		echo "[test]wtcase=1" >.git/case-inc &&
+		test_must_fail git config test.wtcase
+	)
+'
+
+test_expect_success 'conditional include, worktree, icase' '
+	git init wt-icase &&
+	(
+		cd wt-icase &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		wt_upper=$(echo "$wt_path" | tr a-z A-Z) &&
+		echo "[includeIf \"worktree/i:$wt_upper\"]path=icase-inc" >>.git/config &&
+		echo "[test]wticase=1" >.git/icase-inc &&
+		echo 1 >expect &&
+		git config test.wticase >actual &&
+		test_cmp expect actual
+	)
+'
+
+# The "worktree" condition cannot match during early config reading
+# because the repository object is not yet fully initialized and
+# repo_get_work_tree() returns NULL.
+test_expect_success 'conditional include, worktree does not match in early config' '
+	git init wt-early &&
+	(
+		cd wt-early &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		echo "[includeIf \"worktree:$wt_path\"]path=early-inc" >>.git/config &&
+		echo "[test]wtearly=1" >.git/early-inc &&
+		test-tool config read_early_config test.wtearly >actual &&
+		test_must_be_empty actual
+	)
+'
+
+# Use a loose pattern so the "present in non-worktree cases" check works
+# for Unix-style absolute paths and Windows paths like D:/a/git/...
+test_expect_success 'conditional include, worktree without repository' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.worktree:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git config get foo.bar
+'
+
+test_expect_success 'conditional include, worktree without repository but explicit nonexistent Git directory' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.worktree:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git --git-dir=nonexistent config get foo.bar
+'
+
 test_done
diff --git a/t/t6017-rev-list-stdin.sh b/t/t6017-rev-list-stdin.sh
index 4821b90e7479ad..32284f183176a7 100755
--- a/t/t6017-rev-list-stdin.sh
+++ b/t/t6017-rev-list-stdin.sh
@@ -148,4 +148,22 @@ test_expect_success '--not via stdin does not influence revisions from command l
 	test_cmp expect actual
 '
 
+test_expect_success '--no-walk filters by path (single commit, match)' '
+	git rev-parse side-1 >expect &&
+	git rev-list --no-walk side-1 -- file-1 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--no-walk filters by path (single commit, no match)' '
+	git rev-list --no-walk side-2 -- file-1 >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success '--no-walk with pathspec exclusion' '
+	git rev-parse side-3 side-2 >expect &&
+	git rev-parse side-1 side-2 side-3 >input &&
+	git rev-list --stdin --no-walk -- ":!file-1" <input >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t7614-merge-signoff.sh b/t/t7614-merge-signoff.sh
index fee258d4f0c2c0..e58bf07b7a4540 100755
--- a/t/t7614-merge-signoff.sh
+++ b/t/t7614-merge-signoff.sh
@@ -45,7 +45,8 @@ test_expect_success 'git merge --signoff adds a sign-off line' '
 	test_commit main-branch-2 file2 2 &&
 	git checkout other-branch &&
 	git merge main --signoff --no-edit &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	git cat-file commit HEAD >commit &&
+	sed -e "1,/^\$/d" commit >actual &&
 	test_cmp expected-signed actual
 '
 
@@ -55,7 +56,8 @@ test_expect_success 'git merge does not add a sign-off line' '
 	test_commit main-branch-3 file3 3 &&
 	git checkout other-branch &&
 	git merge main --no-edit &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	git cat-file commit HEAD >commit &&
+	sed -e "1,/^\$/d" commit >actual &&
 	test_cmp expected-unsigned actual
 '
 
@@ -65,7 +67,8 @@ test_expect_success 'git merge --no-signoff flag cancels --signoff flag' '
 	test_commit main-branch-4 file4 4 &&
 	git checkout other-branch &&
 	git merge main --no-edit --signoff --no-signoff &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	git cat-file commit HEAD >commit &&
+	sed -e "1,/^\$/d" commit >actual &&
 	test_cmp expected-unsigned actual
 '
 
diff --git a/t/t9811-git-p4-label-import.sh b/t/t9811-git-p4-label-import.sh
index 7614dfbd953efe..ee257011b3c97f 100755
--- a/t/t9811-git-p4-label-import.sh
+++ b/t/t9811-git-p4-label-import.sh
@@ -62,9 +62,11 @@ test_expect_success 'basic p4 labels' '
 
 		cd main &&
 		git checkout TAG_F1_ONLY &&
-		! test -f f2 &&
+		test_path_is_missing f2 &&
 		git checkout TAG_WITH\$_SHELL_CHAR &&
-		test -f f1 && test -f f2 && test -f file_with_\$metachar &&
+		test_path_is_file f1 &&
+		test_path_is_file f2 &&
+		test_path_is_file file_with_\$metachar &&
 
 		git show TAG_LONG_LABEL | grep -q "A Label second line"
 	)
@@ -102,11 +104,11 @@ test_expect_success 'two labels on the same changelist' '
 
 		git checkout TAG_F1_1 &&
 		ls &&
-		test -f f1 &&
+		test_path_is_file f1 &&
 
 		git checkout TAG_F1_2 &&
 		ls &&
-		test -f f1
+		test_path_is_file f1
 	)
 '
 
@@ -135,9 +137,9 @@ test_expect_success 'export git tags to p4' '
 		p4 labels ... | grep LIGHTWEIGHT_TAG &&
 		p4 label -o GIT_TAG_1 | grep "tag created in git:xyzzy" &&
 		p4 sync ...@GIT_TAG_1 &&
-		! test -f main/f10 &&
+		test_path_is_missing main/f10 &&
 		p4 sync ...@GIT_TAG_2 &&
-		test -f main/f10
+		test_path_is_file main/f10
 	)
 '
 
@@ -168,9 +170,9 @@ test_expect_success 'export git tags to p4 with deletion' '
 		cd "$cli" &&
 		p4 sync ... &&
 		p4 sync ...@GIT_TAG_ON_DELETED &&
-		test -f main/deleted_file &&
+		test_path_is_file main/deleted_file &&
 		p4 sync ...@GIT_TAG_AFTER_DELETION &&
-		! test -f main/deleted_file &&
+		test_path_is_missing main/deleted_file &&
 		echo "checking label contents" &&
 		p4 label -o GIT_TAG_ON_DELETED | grep "tag on deleted file"
 	)
@@ -231,17 +233,25 @@ test_expect_success 'importing labels with missing revisions' '
 		P4CLIENT=missing-revision &&
 		client_view "//depot/missing-revision/... //missing-revision/..." &&
 		cd "$cli" &&
-		>f1 && p4 add f1 && p4 submit -d "start" &&
+		>f1 &&
+		p4 add f1 &&
+		p4 submit -d "start" &&
 
 		p4 tag -l TAG_S0 ... &&
 
-		>f2 && p4 add f2 && p4 submit -d "second" &&
+		>f2 &&
+		p4 add f2 &&
+		p4 submit -d "second" &&
 
 		startrev=$(p4_head_revision //depot/missing-revision/...) &&
 
-		>f3 && p4 add f3 && p4 submit -d "third" &&
+		>f3 &&
+		p4 add f3 &&
+		p4 submit -d "third" &&
 
-		p4 edit f2 && date >f2 && p4 submit -d "change" f2 &&
+		p4 edit f2 &&
+		date >f2 &&
+		p4 submit -d "change" f2 &&
 
 		endrev=$(p4_head_revision //depot/missing-revision/...) &&