diff --git a/.editorconfig b/.editorconfig
index 6e4eaa8e955341..82e121a41754b5 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -4,7 +4,11 @@ insert_final_newline = true
 
 # The settings for C (*.c and *.h) files are mirrored in .clang-format.  Keep
 # them in sync.
-[{*.{c,h,sh,bash,perl,pl,pm,txt,adoc},config.mak.*,Makefile,templates/hooks/*.sample}]
+[{*.{c,h,sh,bash,perl,pl,pm,txt,adoc},config.mak.*,Makefile}]
+indent_style = tab
+tab_width = 8
+
+[templates/hooks/*.sample]
 indent_style = tab
 tab_width = 8
 
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
index 359f5fb74e6991..d570184ec84998 100644
--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -56,6 +56,18 @@ feedback before sending a new version, rather than sending an updated
 series immediately after receiving a review. This helps collect broader
 input and avoids unnecessary churn from many rapid iterations.
 
+. These early update iterations are expected to be full replacements,
+  not incremental updates on top of what you posted already.  If you
+  are correcting mistakes you made in the previous iteration that a
+  reviewer noticed and pointed out in their review, you _fix_ that
+  mistake by rewriting your history (e.g., by using "git rebase -i")
+  to pretend that you never made the mistake in the first place.  In
+  other words, this is a chance to pretend to be a perfect developer,
+  and you are expected to take advantage of that.  In the larger
+  picture, nobody is interested in your earlier mistakes.  Just
+  present a logical progression made by a perfect developer who makes
+  no mistakes while working on the topic.
+
 . Polish, refine, and re-send your patches to the list and to the people
   who spent their time to improve your patch.  Go back to step (2).
 
diff --git a/Documentation/config.adoc b/Documentation/config.adoc
index 62eebe7c54501c..dcea3c0c15e2a9 100644
--- a/Documentation/config.adoc
+++ b/Documentation/config.adoc
@@ -523,6 +523,8 @@ include::config/sequencer.adoc[]
 
 include::config/showbranch.adoc[]
 
+include::config/sideband.adoc[]
+
 include::config/sparse.adoc[]
 
 include::config/splitindex.adoc[]
diff --git a/Documentation/config/format.adoc b/Documentation/config/format.adoc
index ab0710e86a3e2c..ea5ec5df7a2aee 100644
--- a/Documentation/config/format.adoc
+++ b/Documentation/config/format.adoc
@@ -101,6 +101,11 @@ format.coverLetter::
 	generate a cover-letter only when there's more than one patch.
 	Default is false.
 
+format.commitListFormat::
+	When the `--cover-letter-format` option is not given, `format-patch`
+	uses the value of this variable to decide how to format the title of
+	each commit. Default to `shortlog`.
+
 format.outputDirectory::
 	Set a custom directory to store the resulting files instead of the
 	current working directory. All directory components will be created.
diff --git a/Documentation/config/sideband.adoc b/Documentation/config/sideband.adoc
new file mode 100644
index 00000000000000..96fade7f5fee39
--- /dev/null
+++ b/Documentation/config/sideband.adoc
@@ -0,0 +1,27 @@
+sideband.allowControlCharacters::
+	By default, control characters that are delivered via the sideband
+	are masked, except ANSI color sequences. This prevents potentially
+	unwanted ANSI escape sequences from being sent to the terminal. Use
+	this config setting to override this behavior (the value can be
+	a comma-separated list of the following keywords):
++
+--
+	`color`::
+		Allow ANSI color sequences, line feeds and horizontal tabs,
+		but mask all other control characters. This is the default.
+	`cursor:`:
+		Allow control sequences that move the cursor. This is
+		disabled by default.
+	`erase`::
+		Allow control sequences that erase charactrs. This is
+		disabled by default.
+	`false`::
+		Mask all control characters other than line feeds and
+		horizontal tabs.
+	`true`::
+		Allow all control characters to be sent to the terminal.
+--
+
+sideband.<url>.*::
+	Apply the `sideband.*` option selectively to specific URLs. The
+	same URL matching logic applies as for `http.<url>.*` settings.
diff --git a/Documentation/git-format-patch.adoc b/Documentation/git-format-patch.adoc
index 36146006fa9855..31fa4923354b38 100644
--- a/Documentation/git-format-patch.adoc
+++ b/Documentation/git-format-patch.adoc
@@ -24,6 +24,7 @@ SYNOPSIS
 		   [(--reroll-count|-v) <n>]
 		   [--to=<email>] [--cc=<email>]
 		   [--[no-]cover-letter] [--quiet]
+		   [--cover-letter-format=<format-spec>]
 		   [--[no-]encode-email-headers]
 		   [--no-notes | --notes[=<ref>]]
 		   [--interdiff=<previous>]
@@ -322,6 +323,17 @@ feeding the result to `git send-email`.
 	containing the branch description, shortlog and the overall diffstat.  You can
 	fill in a description in the file before sending it out.
 
+--cover-letter-format=<format-spec>::
+	Specify the format in which to generate the commit list of the
+	patch series. This option is available if the user wants to use
+	an alternative to the default `shortlog` format. The accepted
+	values for format-spec are "shortlog" or a format string
+	prefixed with `log:`.
+	e.g. `log: %s (%an)`
+	If defined, defaults to the `format.commitListFormat` configuration
+	variable.
+	This option is relevant only if a cover letter is generated.
+
 --encode-email-headers::
 --no-encode-email-headers::
 	Encode email headers that have non-ASCII characters with
@@ -453,6 +465,7 @@ with configuration variables.
 	signOff = true
 	outputDirectory = <directory>
 	coverLetter = auto
+	commitListFormat = shortlog
 	coverFromDescription = auto
 ------------
 
diff --git a/Documentation/git-rebase.adoc b/Documentation/git-rebase.adoc
index e177808004fa81..f6c22d1598978a 100644
--- a/Documentation/git-rebase.adoc
+++ b/Documentation/git-rebase.adoc
@@ -497,6 +497,13 @@ See also INCOMPATIBLE OPTIONS below.
 +
 See also INCOMPATIBLE OPTIONS below.
 
+--trailer=<trailer>::
+	Append the given trailer to every rebased commit message, processed
+	via linkgit:git-interpret-trailers[1]. This option implies
+	`--force-rebase`.
++
+See also INCOMPATIBLE OPTIONS below.
+
 -i::
 --interactive::
 	Make a list of the commits which are about to be rebased.  Let the
@@ -653,6 +660,7 @@ are incompatible with the following options:
  * --[no-]reapply-cherry-picks when used without --keep-base
  * --update-refs
  * --root when used without --onto
+ * --trailer
 
 In addition, the following pairs of options are incompatible:
 
diff --git a/Documentation/git-repo.adoc b/Documentation/git-repo.adoc
index 5e2968b707eacd..42262c198347e5 100644
--- a/Documentation/git-repo.adoc
+++ b/Documentation/git-repo.adoc
@@ -64,6 +64,7 @@ supported:
 * Reachable object counts categorized by type
 * Total inflated size of reachable objects by type
 * Total disk size of reachable objects by type
+* Largest reachable objects in the repository by type
 +
 The output format can be chosen through the flag `--format`. Three formats are
 supported:
diff --git a/Documentation/git.adoc b/Documentation/git.adoc
index 2b3d1d2d0c599d..8a5cdd3b3d22c5 100644
--- a/Documentation/git.adoc
+++ b/Documentation/git.adoc
@@ -235,7 +235,10 @@ GIT COMMANDS
 ------------
 
 We divide Git into high level ("porcelain") commands and low level
-("plumbing") commands.
+("plumbing") commands.  For defining command aliases, see
+linkgit:git-config[1] and look for descriptions of `alias.*`.
+For installing custom "git" subcommands, see the description for
+the 'PATH' environment variable in this manual.
 
 High-level commands (porcelain)
 -------------------------------
diff --git a/Makefile b/Makefile
index 58fb895f4e2f23..c619b5405b5300 100644
--- a/Makefile
+++ b/Makefile
@@ -1605,6 +1605,7 @@ BASIC_CFLAGS += -DSHA1DC_FORCE_ALIGNED_ACCESS
 endif
 ifneq ($(filter leak,$(SANITIZERS)),)
 BASIC_CFLAGS += -O0
+NO_MMAP = CatchMapLeaks
 SANITIZE_LEAK = YesCompiledWithIt
 endif
 ifneq ($(filter address,$(SANITIZERS)),)
diff --git a/bloom.c b/bloom.c
index 77a6fddf720912..a805ac0c296b37 100644
--- a/bloom.c
+++ b/bloom.c
@@ -501,7 +501,7 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r,
 		struct hashmap_iter iter;
 
 		for (i = 0; i < diff_queued_diff.nr; i++) {
-			const char *path = diff_queued_diff.queue[i]->two->path;
+			char *path = diff_queued_diff.queue[i]->two->path;
 
 			/*
 			 * Add each leading directory of the changed file, i.e. for
@@ -523,7 +523,7 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r,
 					free(e);
 
 				if (!last_slash)
-					last_slash = (char*)path;
+					last_slash = path;
 				*last_slash = '\0';
 
 			} while (*path);
diff --git a/builtin/am.c b/builtin/am.c
index e0c767e223dbce..9d0b51c651924a 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1937,7 +1937,7 @@ static void am_run(struct am_state *state, int resume)
 	 */
 	if (!state->rebasing) {
 		am_destroy(state);
-		run_auto_maintenance(state->quiet);
+		run_auto_maintenance(the_repository, state->quiet);
 	}
 }
 
diff --git a/builtin/commit.c b/builtin/commit.c
index 844bdcc72803b9..02a04f68be0209 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1720,7 +1720,8 @@ int cmd_commit(int argc,
 		OPT_STRING(0, "fixup", &fixup_message, N_("[(amend|reword):]commit"), N_("use autosquash formatted message to fixup or amend/reword specified commit")),
 		OPT_STRING(0, "squash", &squash_message, N_("commit"), N_("use autosquash formatted message to squash specified commit")),
 		OPT_BOOL(0, "reset-author", &renew_authorship, N_("the commit is authored by me now (used with -C/-c/--amend)")),
-		OPT_PASSTHRU_ARGV(0, "trailer", &trailer_args, N_("trailer"), N_("add custom trailer(s)"), PARSE_OPT_NONEG),
+		OPT_STRVEC(0, "trailer", &trailer_args, N_("trailer"),
+			   N_("add custom trailer(s)")),
 		OPT_BOOL('s', "signoff", &signoff, N_("add a Signed-off-by trailer")),
 		OPT_FILENAME('t', "template", &template_file, N_("use specified template file")),
 		OPT_BOOL('e', "edit", &edit_flag, N_("force edit of commit")),
@@ -1820,6 +1821,9 @@ int cmd_commit(int argc,
 	argc = parse_and_validate_options(argc, argv, builtin_commit_options,
 					  builtin_commit_usage,
 					  prefix, current_head, &s);
+	if (trailer_args.nr)
+		trailer_config_init();
+
 	if (verbose == -1)
 		verbose = (config_commit_verbose < 0) ? 0 : config_commit_verbose;
 
@@ -1958,7 +1962,7 @@ int cmd_commit(int argc,
 	git_test_write_commit_graph_or_die(the_repository->objects->sources);
 
 	repo_rerere(the_repository, 0);
-	run_auto_maintenance(quiet);
+	run_auto_maintenance(the_repository, quiet);
 	run_commit_hook(use_editor, repo_get_index_file(the_repository),
 			NULL, "post-commit", NULL);
 	if (amend && !no_post_rewrite) {
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8a36cf67b5f140..4795b2a13c30e3 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -2873,7 +2873,7 @@ int cmd_fetch(int argc,
 			if (opt_val != 0)
 				git_config_push_parameter("maintenance.incremental-repack.auto=-1");
 		}
-		run_auto_maintenance(verbosity < 0);
+		run_auto_maintenance(the_repository, verbosity < 0);
 	}
 
  cleanup:
diff --git a/builtin/gc.c b/builtin/gc.c
index fb329c2cffab80..5d8d358f7a511d 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1030,7 +1030,7 @@ int cmd_gc(int argc,
 		struct child_process repack_cmd = CHILD_PROCESS_INIT;
 
 		repack_cmd.git_cmd = 1;
-		repack_cmd.close_object_store = 1;
+		repack_cmd.odb_to_close = the_repository->objects;
 		strvec_pushv(&repack_cmd.args, repack_args.v);
 		if (run_command(&repack_cmd))
 			die(FAILED_RUN, repack_args.v[0]);
@@ -1199,7 +1199,8 @@ static int run_write_commit_graph(struct maintenance_run_opts *opts)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = child.close_object_store = 1;
+	child.git_cmd = 1;
+	child.odb_to_close = the_repository->objects;
 	strvec_pushl(&child.args, "commit-graph", "write",
 		     "--split", "--reachable", NULL);
 
@@ -1268,7 +1269,8 @@ static int maintenance_task_gc_background(struct maintenance_run_opts *opts,
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = child.close_object_store = 1;
+	child.git_cmd = 1;
+	child.odb_to_close = the_repository->objects;
 	strvec_push(&child.args, "gc");
 
 	if (opts->auto_flag)
@@ -1484,7 +1486,8 @@ static int multi_pack_index_expire(struct maintenance_run_opts *opts)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = child.close_object_store = 1;
+	child.git_cmd = 1;
+	child.odb_to_close = the_repository->objects;
 	strvec_pushl(&child.args, "multi-pack-index", "expire", NULL);
 
 	if (opts->quiet)
@@ -1542,7 +1545,8 @@ static int multi_pack_index_repack(struct maintenance_run_opts *opts)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = child.close_object_store = 1;
+	child.git_cmd = 1;
+	child.odb_to_close = the_repository->objects;
 	strvec_pushl(&child.args, "multi-pack-index", "repack", NULL);
 
 	if (opts->quiet)
diff --git a/builtin/history.c b/builtin/history.c
index 1cf6c668cfd814..88822a184fa5bc 100644
--- a/builtin/history.c
+++ b/builtin/history.c
@@ -425,7 +425,7 @@ static int cmd_history_reword(int argc,
 	};
 	struct strbuf reflog_msg = STRBUF_INIT;
 	struct commit *original, *rewritten;
-	struct rev_info revs;
+	struct rev_info revs = { 0 };
 	int ret;
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
diff --git a/builtin/interpret-trailers.c b/builtin/interpret-trailers.c
index 41b0750e5af324..acaf42b2d9333b 100644
--- a/builtin/interpret-trailers.c
+++ b/builtin/interpret-trailers.c
@@ -93,37 +93,6 @@ static int parse_opt_parse(const struct option *opt, const char *arg,
 	return 0;
 }
 
-static struct tempfile *trailers_tempfile;
-
-static FILE *create_in_place_tempfile(const char *file)
-{
-	struct stat st;
-	struct strbuf filename_template = STRBUF_INIT;
-	const char *tail;
-	FILE *outfile;
-
-	if (stat(file, &st))
-		die_errno(_("could not stat %s"), file);
-	if (!S_ISREG(st.st_mode))
-		die(_("file %s is not a regular file"), file);
-	if (!(st.st_mode & S_IWUSR))
-		die(_("file %s is not writable by user"), file);
-
-	/* Create temporary file in the same directory as the original */
-	tail = strrchr(file, '/');
-	if (tail)
-		strbuf_add(&filename_template, file, tail - file + 1);
-	strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
-
-	trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
-	strbuf_release(&filename_template);
-	outfile = fdopen_tempfile(trailers_tempfile, "w");
-	if (!outfile)
-		die_errno(_("could not open temporary file"));
-
-	return outfile;
-}
-
 static void read_input_file(struct strbuf *sb, const char *file)
 {
 	if (file) {
@@ -140,55 +109,31 @@ static void interpret_trailers(const struct process_trailer_options *opts,
 			       struct list_head *new_trailer_head,
 			       const char *file)
 {
-	LIST_HEAD(head);
-	struct strbuf sb = STRBUF_INIT;
-	struct strbuf trailer_block_sb = STRBUF_INIT;
-	struct trailer_block *trailer_block;
-	FILE *outfile = stdout;
+	struct strbuf input = STRBUF_INIT;
+	struct strbuf out = STRBUF_INIT;
+	struct tempfile *tempfile = NULL;
+	int fd = 1;
 
 	trailer_config_init();
 
-	read_input_file(&sb, file);
-
-	if (opts->in_place)
-		outfile = create_in_place_tempfile(file);
-
-	trailer_block = parse_trailers(opts, sb.buf, &head);
-
-	/* Print the lines before the trailer block */
-	if (!opts->only_trailers)
-		fwrite(sb.buf, 1, trailer_block_start(trailer_block), outfile);
-
-	if (!opts->only_trailers && !blank_line_before_trailer_block(trailer_block))
-		fprintf(outfile, "\n");
+	read_input_file(&input, file);
 
-
-	if (!opts->only_input) {
-		LIST_HEAD(config_head);
-		LIST_HEAD(arg_head);
-		parse_trailers_from_config(&config_head);
-		parse_trailers_from_command_line_args(&arg_head, new_trailer_head);
-		list_splice(&config_head, &arg_head);
-		process_trailers_lists(&head, &arg_head);
+	if (opts->in_place) {
+		tempfile = trailer_create_in_place_tempfile(file);
+		if (!tempfile)
+			die(NULL);
+		fd = tempfile->fd;
 	}
+	process_trailers(opts, new_trailer_head, &input, &out);
 
-	/* Print trailer block. */
-	format_trailers(opts, &head, &trailer_block_sb);
-	free_trailers(&head);
-	fwrite(trailer_block_sb.buf, 1, trailer_block_sb.len, outfile);
-	strbuf_release(&trailer_block_sb);
-
-	/* Print the lines after the trailer block as is. */
-	if (!opts->only_trailers)
-		fwrite(sb.buf + trailer_block_end(trailer_block), 1,
-		       sb.len - trailer_block_end(trailer_block), outfile);
-	trailer_block_release(trailer_block);
-
+	if (write_in_full(fd, out.buf, out.len) < 0)
+		die_errno(_("could not write to temporary file '%s'"), file);
 	if (opts->in_place)
-		if (rename_tempfile(&trailers_tempfile, file))
+		if (rename_tempfile(&tempfile, file))
 			die_errno(_("could not rename temporary file to %s"), file);
 
-	strbuf_release(&sb);
+	strbuf_release(&input);
+	strbuf_release(&out);
 }
 
 int cmd_interpret_trailers(int argc,
diff --git a/builtin/log.c b/builtin/log.c
index 89e8b8f0115665..716ebc2701e495 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -886,6 +886,7 @@ struct format_config {
 	char *signature;
 	char *signature_file;
 	enum cover_setting config_cover_letter;
+	char *fmt_cover_letter_commit_list;
 	char *config_output_directory;
 	enum cover_from_description cover_from_description_mode;
 	int show_notes;
@@ -930,6 +931,7 @@ static void format_config_release(struct format_config *cfg)
 	string_list_clear(&cfg->extra_cc, 0);
 	strbuf_release(&cfg->sprefix);
 	free(cfg->fmt_patch_suffix);
+	free(cfg->fmt_cover_letter_commit_list);
 }
 
 static enum cover_from_description parse_cover_from_description(const char *arg)
@@ -1052,6 +1054,19 @@ static int git_format_config(const char *var, const char *value,
 		cfg->config_cover_letter = git_config_bool(var, value) ? COVER_ON : COVER_OFF;
 		return 0;
 	}
+	if (!strcmp(var, "format.commitlistformat")) {
+		struct strbuf tmp = STRBUF_INIT;
+		strbuf_init(&tmp, 0);
+		if (value)
+			strbuf_addstr(&tmp, value);
+		else
+			strbuf_addstr(&tmp, "log:[%(count)/%(total)] %s");
+
+		FREE_AND_NULL(cfg->fmt_cover_letter_commit_list);
+		git_config_string(&cfg->fmt_cover_letter_commit_list, var, tmp.buf);
+		strbuf_release(&tmp);
+		return 0;
+	}
 	if (!strcmp(var, "format.outputdirectory")) {
 		FREE_AND_NULL(cfg->config_output_directory);
 		return git_config_string(&cfg->config_output_directory, var, value);
@@ -1335,13 +1350,55 @@ static void get_notes_args(struct strvec *arg, struct rev_info *rev)
 	}
 }
 
+static void generate_shortlog_cover_letter(struct shortlog *log,
+					   struct rev_info *rev,
+					   struct commit **list,
+					   int nr)
+{
+	shortlog_init(log);
+	log->wrap_lines = 1;
+	log->wrap = MAIL_DEFAULT_WRAP;
+	log->in1 = 2;
+	log->in2 = 4;
+	log->file = rev->diffopt.file;
+	log->groups = SHORTLOG_GROUP_AUTHOR;
+	shortlog_finish_setup(log);
+	for (int i = 0; i < nr; i++)
+		shortlog_add_commit(log, list[i]);
+
+	shortlog_output(log);
+}
+
+static void generate_commit_list_cover(FILE *cover_file, const char *format,
+				       struct commit **list, int n)
+{
+	struct strbuf commit_line = STRBUF_INIT;
+	struct pretty_print_context ctx = {0};
+	struct rev_info rev = REV_INFO_INIT;
+
+	strbuf_init(&commit_line, 0);
+	rev.total = n;
+	ctx.rev = &rev;
+	for (int i = n - 1; i >= 0; i--) {
+		rev.nr = n - i;
+		repo_format_commit_message(the_repository, list[i], format,
+				&commit_line, &ctx);
+		fprintf(cover_file, "%s\n", commit_line.buf);
+		strbuf_reset(&commit_line);
+	}
+	fprintf(cover_file, "\n");
+
+	strbuf_release(&commit_line);
+}
+
 static void make_cover_letter(struct rev_info *rev, int use_separate_file,
 			      struct commit *origin,
 			      int nr, struct commit **list,
 			      const char *description_file,
 			      const char *branch_name,
 			      int quiet,
-			      const struct format_config *cfg)
+			      const struct format_config *cfg,
+			      const char *format)
 {
 	const char *from;
 	struct shortlog log;
@@ -1388,18 +1445,12 @@ static void make_cover_letter(struct rev_info *rev, int use_separate_file,
 	free(pp.after_subject);
 	strbuf_release(&sb);
 
-	shortlog_init(&log);
-	log.wrap_lines = 1;
-	log.wrap = MAIL_DEFAULT_WRAP;
-	log.in1 = 2;
-	log.in2 = 4;
-	log.file = rev->diffopt.file;
-	log.groups = SHORTLOG_GROUP_AUTHOR;
-	shortlog_finish_setup(&log);
-	for (i = 0; i < nr; i++)
-		shortlog_add_commit(&log, list[i]);
-
-	shortlog_output(&log);
+	if (skip_prefix(format, "log:", &format))
+		generate_commit_list_cover(rev->diffopt.file, format, list, nr);
+	else if (!strcmp(format, "shortlog"))
+		generate_shortlog_cover_letter(&log, rev, list, nr);
+	else
+		die(_("'%s' is not a valid format string"), format);
 
 	/* We can only do diffstat with a unique reference point */
 	if (origin)
@@ -1917,6 +1968,7 @@ int cmd_format_patch(int argc,
 	int just_numbers = 0;
 	int ignore_if_in_upstream = 0;
 	int cover_letter = -1;
+	const char *cover_letter_fmt = NULL;
 	int boundary_count = 0;
 	int no_binary_diff = 0;
 	int zero_commit = 0;
@@ -1963,6 +2015,8 @@ int cmd_format_patch(int argc,
 			    N_("print patches to standard out")),
 		OPT_BOOL(0, "cover-letter", &cover_letter,
 			    N_("generate a cover letter")),
+		OPT_STRING(0, "cover-letter-format", &cover_letter_fmt, N_("format-spec"),
+			    N_("format spec used for the commit list in the cover letter")),
 		OPT_BOOL(0, "numbered-files", &just_numbers,
 			    N_("use simple number sequence for output file names")),
 		OPT_STRING(0, "suffix", &fmt_patch_suffix, N_("sfx"),
@@ -2300,6 +2354,13 @@ int cmd_format_patch(int argc,
 		/* nothing to do */
 		goto done;
 	total = list.nr;
+
+	if (!cover_letter_fmt) {
+		cover_letter_fmt = cfg.fmt_cover_letter_commit_list;
+		if (!cover_letter_fmt)
+			cover_letter_fmt = "shortlog";
+	}
+
 	if (cover_letter == -1) {
 		if (cfg.config_cover_letter == COVER_AUTO)
 			cover_letter = (total > 1);
@@ -2386,12 +2447,14 @@ int cmd_format_patch(int argc,
 	}
 	rev.numbered_files = just_numbers;
 	rev.patch_suffix = fmt_patch_suffix;
+
 	if (cover_letter) {
 		if (cfg.thread)
 			gen_message_id(&rev, "cover");
 		make_cover_letter(&rev, !!output_directory,
 				  origin, list.nr, list.items,
-				  description_file, branch_name, quiet, &cfg);
+				  description_file, branch_name, quiet, &cfg,
+				  cover_letter_fmt);
 		print_bases(&bases, rev.diffopt.file);
 		print_signature(signature, rev.diffopt.file);
 		total++;
diff --git a/builtin/merge.c b/builtin/merge.c
index 4e456a381c192d..2cbce56f8da9f7 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -506,7 +506,7 @@ static void finish(struct commit *head_commit,
 			 * We ignore errors in 'gc --auto', since the
 			 * user should see them.
 			 */
-			run_auto_maintenance(verbosity < 0);
+			run_auto_maintenance(the_repository, verbosity < 0);
 		}
 	}
 	if (new_head && show_diffstat) {
diff --git a/builtin/pull.c b/builtin/pull.c
index 6ad420ce6f9b41..7e67fdce97fd1d 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -454,7 +454,7 @@ static int run_fetch(const char *repo, const char **refspecs)
 	} else if (*refspecs)
 		BUG("refspecs without repo?");
 	cmd.git_cmd = 1;
-	cmd.close_object_store = 1;
+	cmd.odb_to_close = the_repository->objects;
 	return run_command(&cmd);
 }
 
diff --git a/builtin/rebase.c b/builtin/rebase.c
index c487e1090779c2..a1c7d78196750e 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -36,6 +36,7 @@
 #include "reset.h"
 #include "trace2.h"
 #include "hook.h"
+#include "trailer.h"
 
 static char const * const builtin_rebase_usage[] = {
 	N_("git rebase [-i] [options] [--exec <cmd>] "
@@ -113,6 +114,7 @@ struct rebase_options {
 	enum action action;
 	char *reflog_action;
 	int signoff;
+	struct strvec trailer_args;
 	int allow_rerere_autoupdate;
 	int keep_empty;
 	int autosquash;
@@ -143,6 +145,7 @@ struct rebase_options {
 		.flags = REBASE_NO_QUIET, 		\
 		.git_am_opts = STRVEC_INIT,		\
 		.exec = STRING_LIST_INIT_NODUP,		\
+		.trailer_args = STRVEC_INIT,		\
 		.git_format_patch_opt = STRBUF_INIT,	\
 		.fork_point = -1,			\
 		.reapply_cherry_picks = -1,             \
@@ -166,6 +169,7 @@ static void rebase_options_release(struct rebase_options *opts)
 	free(opts->strategy);
 	string_list_clear(&opts->strategy_opts, 0);
 	strbuf_release(&opts->git_format_patch_opt);
+	strvec_clear(&opts->trailer_args);
 }
 
 static struct replay_opts get_replay_opts(const struct rebase_options *opts)
@@ -177,6 +181,10 @@ static struct replay_opts get_replay_opts(const struct rebase_options *opts)
 	sequencer_init_config(&replay);
 
 	replay.signoff = opts->signoff;
+
+	for (size_t i = 0; i < opts->trailer_args.nr; i++)
+		strvec_push(&replay.trailer_args, opts->trailer_args.v[i]);
+
 	replay.allow_ff = !(opts->flags & REBASE_FORCE);
 	if (opts->allow_rerere_autoupdate)
 		replay.allow_rerere_auto = opts->allow_rerere_autoupdate;
@@ -562,7 +570,9 @@ static int finish_rebase(struct rebase_options *opts)
 	 * We ignore errors in 'git maintenance run --auto', since the
 	 * user should see them.
 	 */
-	run_auto_maintenance(!(opts->flags & (REBASE_NO_QUIET|REBASE_VERBOSE)));
+	run_auto_maintenance(the_repository,
+			!(opts->flags & (REBASE_NO_QUIET|REBASE_VERBOSE)));
+
 	if (opts->type == REBASE_MERGE) {
 		struct replay_opts replay = REPLAY_OPTS_INIT;
 
@@ -1132,6 +1142,8 @@ int cmd_rebase(int argc,
 			.flags = PARSE_OPT_NOARG,
 			.defval = REBASE_DIFFSTAT,
 		},
+		OPT_STRVEC(0, "trailer", &options.trailer_args, N_("trailer"),
+			   N_("add custom trailer(s)")),
 		OPT_BOOL(0, "signoff", &options.signoff,
 			 N_("add a Signed-off-by trailer to each commit")),
 		OPT_BOOL(0, "committer-date-is-author-date",
@@ -1285,6 +1297,12 @@ int cmd_rebase(int argc,
 			     builtin_rebase_options,
 			     builtin_rebase_usage, 0);
 
+	if (options.trailer_args.nr) {
+		if (validate_trailer_args(&options.trailer_args))
+			die(NULL);
+		options.flags |= REBASE_FORCE;
+	}
+
 	if (preserve_merges_selected)
 		die(_("--preserve-merges was replaced by --rebase-merges\n"
 			"Note: Your `pull.rebase` configuration may also be set to 'preserve',\n"
@@ -1542,6 +1560,9 @@ int cmd_rebase(int argc,
 	if (options.root && !options.onto_name)
 		imply_merge(&options, "--root without --onto");
 
+	if (options.trailer_args.nr)
+		imply_merge(&options, "--trailer");
+
 	if (isatty(2) && options.flags & REBASE_NO_QUIET)
 		strbuf_addstr(&options.git_format_patch_opt, " --progress");
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index d6225df890d888..e34edff406959a 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -2727,7 +2727,7 @@ int cmd_receive_pack(int argc,
 		if (auto_gc) {
 			struct child_process proc = CHILD_PROCESS_INIT;
 
-			if (prepare_auto_maintenance(1, &proc)) {
+			if (prepare_auto_maintenance(the_repository, 1, &proc)) {
 				proc.no_stdin = 1;
 				proc.stdout_to_stderr = 1;
 				proc.err = use_sideband ? -1 : 0;
diff --git a/builtin/repo.c b/builtin/repo.c
index fae1141cff2e31..55f9b9095c1f92 100644
--- a/builtin/repo.c
+++ b/builtin/repo.c
@@ -1,7 +1,9 @@
 #define USE_THE_REPOSITORY_VARIABLE
 
 #include "builtin.h"
+#include "commit.h"
 #include "environment.h"
+#include "hash.h"
 #include "hex.h"
 #include "odb.h"
 #include "parse-options.h"
@@ -14,6 +16,8 @@
 #include "strbuf.h"
 #include "string-list.h"
 #include "shallow.h"
+#include "tree.h"
+#include "tree-walk.h"
 #include "utf8.h"
 
 static const char *const repo_usage[] = {
@@ -230,6 +234,21 @@ static int cmd_repo_info(int argc, const char **argv, const char *prefix,
 		return print_fields(argc, argv, repo, format);
 }
 
+struct object_data {
+	struct object_id oid;
+	size_t value;
+};
+
+struct largest_objects {
+	struct object_data tag_size;
+	struct object_data commit_size;
+	struct object_data tree_size;
+	struct object_data blob_size;
+
+	struct object_data parent_count;
+	struct object_data tree_entries;
+};
+
 struct ref_stats {
 	size_t branches;
 	size_t remotes;
@@ -248,6 +267,7 @@ struct object_stats {
 	struct object_values type_counts;
 	struct object_values inflated_sizes;
 	struct object_values disk_sizes;
+	struct largest_objects largest;
 };
 
 struct repo_structure {
@@ -257,6 +277,7 @@ struct repo_structure {
 
 struct stats_table {
 	struct string_list rows;
+	struct string_list annotations;
 
 	int name_col_width;
 	int value_col_width;
@@ -269,6 +290,8 @@ struct stats_table {
 struct stats_table_entry {
 	char *value;
 	const char *unit;
+	size_t index;
+	struct object_id *oid;
 };
 
 static void stats_table_vaddf(struct stats_table *table,
@@ -291,6 +314,12 @@ static void stats_table_vaddf(struct stats_table *table,
 		table->name_col_width = name_width;
 	if (!entry)
 		return;
+	if (entry->oid) {
+		entry->index = table->annotations.nr + 1;
+		strbuf_addf(&buf, "[%" PRIuMAX "] %s", (uintmax_t)entry->index,
+			    oid_to_hex(entry->oid));
+		string_list_append_nodup(&table->annotations, strbuf_detach(&buf, NULL));
+	}
 	if (entry->value) {
 		int value_width = utf8_strwidth(entry->value);
 		if (value_width > table->value_col_width)
@@ -301,6 +330,8 @@ static void stats_table_vaddf(struct stats_table *table,
 		if (unit_width > table->unit_col_width)
 			table->unit_col_width = unit_width;
 	}
+
+	strbuf_release(&buf);
 }
 
 static void stats_table_addf(struct stats_table *table, const char *format, ...)
@@ -326,6 +357,27 @@ static void stats_table_count_addf(struct stats_table *table, size_t value,
 	va_end(ap);
 }
 
+static void stats_table_object_count_addf(struct stats_table *table,
+					  struct object_id *oid, size_t value,
+					  const char *format, ...)
+{
+	struct stats_table_entry *entry;
+	va_list ap;
+
+	CALLOC_ARRAY(entry, 1);
+	humanise_count(value, &entry->value, &entry->unit);
+
+	/*
+	 * A NULL OID should not have a table annotation.
+	 */
+	if (!is_null_oid(oid))
+		entry->oid = oid;
+
+	va_start(ap, format);
+	stats_table_vaddf(table, entry, format, ap);
+	va_end(ap);
+}
+
 static void stats_table_size_addf(struct stats_table *table, size_t value,
 				  const char *format, ...)
 {
@@ -340,6 +392,27 @@ static void stats_table_size_addf(struct stats_table *table, size_t value,
 	va_end(ap);
 }
 
+static void stats_table_object_size_addf(struct stats_table *table,
+					 struct object_id *oid, size_t value,
+					 const char *format, ...)
+{
+	struct stats_table_entry *entry;
+	va_list ap;
+
+	CALLOC_ARRAY(entry, 1);
+	humanise_bytes(value, &entry->value, &entry->unit, HUMANISE_COMPACT);
+
+	/*
+	 * A NULL OID should not have a table annotation.
+	 */
+	if (!is_null_oid(oid))
+		entry->oid = oid;
+
+	va_start(ap, format);
+	stats_table_vaddf(table, entry, format, ap);
+	va_end(ap);
+}
+
 static inline size_t get_total_reference_count(struct ref_stats *stats)
 {
 	return stats->branches + stats->remotes + stats->tags + stats->others;
@@ -404,8 +477,41 @@ static void stats_table_setup_structure(struct stats_table *table,
 			      "    * %s", _("Blobs"));
 	stats_table_size_addf(table, objects->disk_sizes.tags,
 			      "    * %s", _("Tags"));
+
+	stats_table_addf(table, "");
+	stats_table_addf(table, "* %s", _("Largest objects"));
+	stats_table_addf(table, "  * %s", _("Commits"));
+	stats_table_object_size_addf(table,
+				     &objects->largest.commit_size.oid,
+				     objects->largest.commit_size.value,
+				     "    * %s", _("Maximum size"));
+	stats_table_object_count_addf(table,
+				      &objects->largest.parent_count.oid,
+				      objects->largest.parent_count.value,
+				      "    * %s", _("Maximum parents"));
+	stats_table_addf(table, "  * %s", _("Trees"));
+	stats_table_object_size_addf(table,
+				     &objects->largest.tree_size.oid,
+				     objects->largest.tree_size.value,
+				     "    * %s", _("Maximum size"));
+	stats_table_object_count_addf(table,
+				      &objects->largest.tree_entries.oid,
+				      objects->largest.tree_entries.value,
+				      "    * %s", _("Maximum entries"));
+	stats_table_addf(table, "  * %s", _("Blobs"));
+	stats_table_object_size_addf(table,
+				     &objects->largest.blob_size.oid,
+				     objects->largest.blob_size.value,
+				     "    * %s", _("Maximum size"));
+	stats_table_addf(table, "  * %s", _("Tags"));
+	stats_table_object_size_addf(table,
+				     &objects->largest.tag_size.oid,
+				     objects->largest.tag_size.value,
+				     "    * %s", _("Maximum size"));
 }
 
+#define INDEX_WIDTH 4
+
 static void stats_table_print_structure(const struct stats_table *table)
 {
 	const char *name_col_title = _("Repository structure");
@@ -424,7 +530,8 @@ static void stats_table_print_structure(const struct stats_table *table)
 		value_col_width = title_value_width - unit_col_width;
 
 	strbuf_addstr(&buf, "| ");
-	strbuf_utf8_align(&buf, ALIGN_LEFT, name_col_width, name_col_title);
+	strbuf_utf8_align(&buf, ALIGN_LEFT, name_col_width + INDEX_WIDTH,
+			  name_col_title);
 	strbuf_addstr(&buf, " | ");
 	strbuf_utf8_align(&buf, ALIGN_LEFT,
 			  value_col_width + unit_col_width + 1, value_col_title);
@@ -432,7 +539,7 @@ static void stats_table_print_structure(const struct stats_table *table)
 	printf("%s\n", buf.buf);
 
 	printf("| ");
-	for (int i = 0; i < name_col_width; i++)
+	for (int i = 0; i < name_col_width + INDEX_WIDTH; i++)
 		putchar('-');
 	printf(" | ");
 	for (int i = 0; i < value_col_width + unit_col_width + 1; i++)
@@ -453,6 +560,13 @@ static void stats_table_print_structure(const struct stats_table *table)
 		strbuf_reset(&buf);
 		strbuf_addstr(&buf, "| ");
 		strbuf_utf8_align(&buf, ALIGN_LEFT, name_col_width, item->string);
+
+		if (entry && entry->oid)
+			strbuf_addf(&buf, " [%" PRIuMAX "]",
+				    (uintmax_t)entry->index);
+		else
+			strbuf_addchars(&buf, ' ', INDEX_WIDTH);
+
 		strbuf_addstr(&buf, " | ");
 		strbuf_utf8_align(&buf, ALIGN_RIGHT, value_col_width, value);
 		strbuf_addch(&buf, ' ');
@@ -461,6 +575,12 @@ static void stats_table_print_structure(const struct stats_table *table)
 		printf("%s\n", buf.buf);
 	}
 
+	if (table->annotations.nr) {
+		printf("\n");
+		for_each_string_list_item(item, &table->annotations)
+			printf("%s\n", item->string);
+	}
+
 	strbuf_release(&buf);
 }
 
@@ -476,46 +596,76 @@ static void stats_table_clear(struct stats_table *table)
 	}
 
 	string_list_clear(&table->rows, 1);
+	string_list_clear(&table->annotations, 1);
+}
+
+static inline void print_keyvalue(const char *key, char key_delim, size_t value,
+				  char value_delim)
+{
+	printf("%s%c%" PRIuMAX "%c", key, key_delim, (uintmax_t)value,
+	       value_delim);
+}
+
+static void print_object_data(const char *key, char key_delim,
+			      struct object_data *data, char value_delim)
+{
+	print_keyvalue(key, key_delim, data->value, value_delim);
+	printf("%s_oid%c%s%c", key, key_delim, oid_to_hex(&data->oid),
+	       value_delim);
 }
 
 static void structure_keyvalue_print(struct repo_structure *stats,
 				     char key_delim, char value_delim)
 {
-	printf("references.branches.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->refs.branches, value_delim);
-	printf("references.tags.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->refs.tags, value_delim);
-	printf("references.remotes.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->refs.remotes, value_delim);
-	printf("references.others.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->refs.others, value_delim);
-
-	printf("objects.commits.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.type_counts.commits, value_delim);
-	printf("objects.trees.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.type_counts.trees, value_delim);
-	printf("objects.blobs.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.type_counts.blobs, value_delim);
-	printf("objects.tags.count%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.type_counts.tags, value_delim);
-
-	printf("objects.commits.inflated_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.inflated_sizes.commits, value_delim);
-	printf("objects.trees.inflated_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.inflated_sizes.trees, value_delim);
-	printf("objects.blobs.inflated_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.inflated_sizes.blobs, value_delim);
-	printf("objects.tags.inflated_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.inflated_sizes.tags, value_delim);
-
-	printf("objects.commits.disk_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.disk_sizes.commits, value_delim);
-	printf("objects.trees.disk_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.disk_sizes.trees, value_delim);
-	printf("objects.blobs.disk_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.disk_sizes.blobs, value_delim);
-	printf("objects.tags.disk_size%c%" PRIuMAX "%c", key_delim,
-	       (uintmax_t)stats->objects.disk_sizes.tags, value_delim);
+	print_keyvalue("references.branches.count", key_delim,
+		       stats->refs.branches, value_delim);
+	print_keyvalue("references.tags.count", key_delim,
+		       stats->refs.tags, value_delim);
+	print_keyvalue("references.remotes.count", key_delim,
+		       stats->refs.remotes, value_delim);
+	print_keyvalue("references.others.count", key_delim,
+		       stats->refs.others, value_delim);
+
+	print_keyvalue("objects.commits.count", key_delim,
+		       stats->objects.type_counts.commits, value_delim);
+	print_keyvalue("objects.trees.count", key_delim,
+		       stats->objects.type_counts.trees, value_delim);
+	print_keyvalue("objects.blobs.count", key_delim,
+		       stats->objects.type_counts.blobs, value_delim);
+	print_keyvalue("objects.tags.count", key_delim,
+		       stats->objects.type_counts.tags, value_delim);
+
+	print_keyvalue("objects.commits.inflated_size", key_delim,
+		       stats->objects.inflated_sizes.commits, value_delim);
+	print_keyvalue("objects.trees.inflated_size", key_delim,
+		       stats->objects.inflated_sizes.trees, value_delim);
+	print_keyvalue("objects.blobs.inflated_size", key_delim,
+		       stats->objects.inflated_sizes.blobs, value_delim);
+	print_keyvalue("objects.tags.inflated_size", key_delim,
+		       stats->objects.inflated_sizes.tags, value_delim);
+
+	print_keyvalue("objects.commits.disk_size", key_delim,
+		       stats->objects.disk_sizes.commits, value_delim);
+	print_keyvalue("objects.trees.disk_size", key_delim,
+		       stats->objects.disk_sizes.trees, value_delim);
+	print_keyvalue("objects.blobs.disk_size", key_delim,
+		       stats->objects.disk_sizes.blobs, value_delim);
+	print_keyvalue("objects.tags.disk_size", key_delim,
+		       stats->objects.disk_sizes.tags, value_delim);
+
+	print_object_data("objects.commits.max_size", key_delim,
+			  &stats->objects.largest.commit_size, value_delim);
+	print_object_data("objects.trees.max_size", key_delim,
+			  &stats->objects.largest.tree_size, value_delim);
+	print_object_data("objects.blobs.max_size", key_delim,
+			  &stats->objects.largest.blob_size, value_delim);
+	print_object_data("objects.tags.max_size", key_delim,
+			  &stats->objects.largest.tag_size, value_delim);
+
+	print_object_data("objects.commits.max_parents", key_delim,
+			  &stats->objects.largest.parent_count, value_delim);
+	print_object_data("objects.trees.max_entries", key_delim,
+			  &stats->objects.largest.tree_entries, value_delim);
 
 	fflush(stdout);
 }
@@ -585,55 +735,97 @@ struct count_objects_data {
 	struct progress *progress;
 };
 
+static void check_largest(struct object_data *data, struct object_id *oid,
+			  size_t value)
+{
+	if (value > data->value || is_null_oid(&data->oid)) {
+		oidcpy(&data->oid, oid);
+		data->value = value;
+	}
+}
+
+static size_t count_tree_entries(struct object *obj)
+{
+	struct tree *t = object_as_type(obj, OBJ_TREE, 0);
+	struct name_entry entry;
+	struct tree_desc desc;
+	size_t count = 0;
+
+	init_tree_desc(&desc, &t->object.oid, t->buffer, t->size);
+	while (tree_entry(&desc, &entry))
+		count++;
+
+	return count;
+}
+
 static int count_objects(const char *path UNUSED, struct oid_array *oids,
 			 enum object_type type, void *cb_data)
 {
 	struct count_objects_data *data = cb_data;
 	struct object_stats *stats = data->stats;
-	size_t inflated_total = 0;
-	size_t disk_total = 0;
 	size_t object_count;
 
 	for (size_t i = 0; i < oids->nr; i++) {
 		struct object_info oi = OBJECT_INFO_INIT;
 		unsigned long inflated;
+		struct commit *commit;
+		struct object *obj;
+		void *content;
 		off_t disk;
+		int eaten;
 
 		oi.sizep = &inflated;
 		oi.disk_sizep = &disk;
+		oi.contentp = &content;
 
 		if (odb_read_object_info_extended(data->odb, &oids->oid[i], &oi,
 						  OBJECT_INFO_SKIP_FETCH_OBJECT |
 						  OBJECT_INFO_QUICK) < 0)
 			continue;
 
-		inflated_total += inflated;
-		disk_total += disk;
-	}
+		obj = parse_object_buffer(the_repository, &oids->oid[i], type,
+					  inflated, content, &eaten);
+
+		switch (type) {
+		case OBJ_TAG:
+			stats->type_counts.tags++;
+			stats->inflated_sizes.tags += inflated;
+			stats->disk_sizes.tags += disk;
+			check_largest(&stats->largest.tag_size, &oids->oid[i],
+				      inflated);
+			break;
+		case OBJ_COMMIT:
+			commit = object_as_type(obj, OBJ_COMMIT, 0);
+			stats->type_counts.commits++;
+			stats->inflated_sizes.commits += inflated;
+			stats->disk_sizes.commits += disk;
+			check_largest(&stats->largest.commit_size, &oids->oid[i],
+				      inflated);
+			check_largest(&stats->largest.parent_count, &oids->oid[i],
+				      commit_list_count(commit->parents));
+			break;
+		case OBJ_TREE:
+			stats->type_counts.trees++;
+			stats->inflated_sizes.trees += inflated;
+			stats->disk_sizes.trees += disk;
+			check_largest(&stats->largest.tree_size, &oids->oid[i],
+				      inflated);
+			check_largest(&stats->largest.tree_entries, &oids->oid[i],
+				      count_tree_entries(obj));
+			break;
+		case OBJ_BLOB:
+			stats->type_counts.blobs++;
+			stats->inflated_sizes.blobs += inflated;
+			stats->disk_sizes.blobs += disk;
+			check_largest(&stats->largest.blob_size, &oids->oid[i],
+				      inflated);
+			break;
+		default:
+			BUG("invalid object type");
+		}
 
-	switch (type) {
-	case OBJ_TAG:
-		stats->type_counts.tags += oids->nr;
-		stats->inflated_sizes.tags += inflated_total;
-		stats->disk_sizes.tags += disk_total;
-		break;
-	case OBJ_COMMIT:
-		stats->type_counts.commits += oids->nr;
-		stats->inflated_sizes.commits += inflated_total;
-		stats->disk_sizes.commits += disk_total;
-		break;
-	case OBJ_TREE:
-		stats->type_counts.trees += oids->nr;
-		stats->inflated_sizes.trees += inflated_total;
-		stats->disk_sizes.trees += disk_total;
-		break;
-	case OBJ_BLOB:
-		stats->type_counts.blobs += oids->nr;
-		stats->inflated_sizes.blobs += inflated_total;
-		stats->disk_sizes.blobs += disk_total;
-		break;
-	default:
-		BUG("invalid object type");
+		if (!eaten)
+			free(content);
 	}
 
 	object_count = get_total_object_values(&stats->type_counts);
@@ -669,6 +861,7 @@ static int cmd_repo_structure(int argc, const char **argv, const char *prefix,
 {
 	struct stats_table table = {
 		.rows = STRING_LIST_INIT_DUP,
+		.annotations = STRING_LIST_INIT_DUP,
 	};
 	enum output_format format = FORMAT_TABLE;
 	struct repo_structure stats = { 0 };
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 143f7cb3cca7d0..f3e132888fabd4 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1160,7 +1160,7 @@ static void submodule_summary_callback(struct diff_queue_struct *q,
 
 		if (!S_ISGITLINK(p->one->mode) && !S_ISGITLINK(p->two->mode))
 			continue;
-		temp = (struct module_cb*)malloc(sizeof(struct module_cb));
+		temp = xmalloc(sizeof(*temp));
 		temp->mod_src = p->one->mode;
 		temp->mod_dst = p->two->mode;
 		temp->oid_src = p->one->oid;
diff --git a/builtin/tag.c b/builtin/tag.c
index aeb04c487fe95a..e0f05f94fdbe3e 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -499,8 +499,8 @@ int cmd_tag(int argc,
 		OPT_CALLBACK_F('m', "message", &msg, N_("message"),
 			       N_("tag message"), PARSE_OPT_NONEG, parse_msg_arg),
 		OPT_FILENAME('F', "file", &msgfile, N_("read message from file")),
-		OPT_PASSTHRU_ARGV(0, "trailer", &trailer_args, N_("trailer"),
-				  N_("add custom trailer(s)"), PARSE_OPT_NONEG),
+		OPT_STRVEC(0, "trailer", &trailer_args, N_("trailer"),
+			   N_("add custom trailer(s)")),
 		OPT_BOOL('e', "edit", &edit_flag, N_("force edit of tag message")),
 		OPT_BOOL('s', "sign", &opt.sign, N_("annotated and GPG-signed tag")),
 		OPT_CLEANUP(&cleanup_arg),
@@ -568,6 +568,9 @@ int cmd_tag(int argc,
 	if (cmdmode == 'l')
 		setup_auto_pager("tag", 1);
 
+	if (trailer_args.nr)
+		trailer_config_init();
+
 	if (opt.sign == -1)
 		opt.sign = cmdmode ? 0 : config_sign_tag > 0;
 
diff --git a/builtin/worktree.c b/builtin/worktree.c
index bc2d0d645ba945..4035b1cb06cba7 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -539,7 +539,7 @@ static int add_worktree(const char *path, const char *refname,
 
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
-	write_worktree_linking_files(sb_git, sb, opts->relative_paths);
+	write_worktree_linking_files(sb_git.buf, sb.buf, opts->relative_paths);
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
diff --git a/connected.c b/connected.c
index 79403108dd8f57..6718503649da8a 100644
--- a/connected.c
+++ b/connected.c
@@ -45,20 +45,6 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 		return err;
 	}
 
-	if (transport && transport->smart_options &&
-	    transport->smart_options->self_contained_and_connected &&
-	    transport->pack_lockfiles.nr == 1 &&
-	    strip_suffix(transport->pack_lockfiles.items[0].string,
-			 ".keep", &base_len)) {
-		struct strbuf idx_file = STRBUF_INIT;
-		strbuf_add(&idx_file, transport->pack_lockfiles.items[0].string,
-			   base_len);
-		strbuf_addstr(&idx_file, ".idx");
-		new_pack = add_packed_git(the_repository, idx_file.buf,
-					  idx_file.len, 1);
-		strbuf_release(&idx_file);
-	}
-
 	if (repo_has_promisor_remote(the_repository)) {
 		/*
 		 * For partial clones, we don't want to have to do a regular
@@ -90,7 +76,6 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 promisor_pack_found:
 			;
 		} while ((oid = fn(cb_data)) != NULL);
-		free(new_pack);
 		return 0;
 	}
 
@@ -127,15 +112,27 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 	else
 		rev_list.no_stderr = opt->quiet;
 
-	if (start_command(&rev_list)) {
-		free(new_pack);
+	if (start_command(&rev_list))
 		return error(_("Could not run 'git rev-list'"));
-	}
 
 	sigchain_push(SIGPIPE, SIG_IGN);
 
 	rev_list_in = xfdopen(rev_list.in, "w");
 
+	if (transport && transport->smart_options &&
+	    transport->smart_options->self_contained_and_connected &&
+	    transport->pack_lockfiles.nr == 1 &&
+	    strip_suffix(transport->pack_lockfiles.items[0].string,
+			 ".keep", &base_len)) {
+		struct strbuf idx_file = STRBUF_INIT;
+		strbuf_add(&idx_file, transport->pack_lockfiles.items[0].string,
+			   base_len);
+		strbuf_addstr(&idx_file, ".idx");
+		new_pack = add_packed_git(the_repository, idx_file.buf,
+					  idx_file.len, 1);
+		strbuf_release(&idx_file);
+	}
+
 	do {
 		/*
 		 * If index-pack already checked that:
@@ -162,6 +159,9 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 		err = error_errno(_("failed to close rev-list's stdin"));
 
 	sigchain_pop(SIGPIPE);
-	free(new_pack);
+	if (new_pack) {
+		close_pack(new_pack);
+		free(new_pack);
+	}
 	return finish_command(&rev_list) || err;
 }
diff --git a/dir.c b/dir.c
index 026d8516a912af..fcb8f6dd2aa969 100644
--- a/dir.c
+++ b/dir.c
@@ -3518,15 +3518,15 @@ int get_sparse_checkout_patterns(struct pattern_list *pl)
 
 int remove_path(const char *name)
 {
-	char *slash;
+	const char *last;
 
 	if (unlink(name) && !is_missing_file_error(errno))
 		return -1;
 
-	slash = strrchr(name, '/');
-	if (slash) {
+	last = strrchr(name, '/');
+	if (last) {
 		char *dirs = xstrdup(name);
-		slash = dirs + (slash - name);
+		char *slash = dirs + (last - name);
 		do {
 			*slash = '\0';
 			if (startup_info->original_cwd &&
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 7f3e7b8f505ebc..cef67e591954a9 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -125,9 +125,9 @@ int gently_parse_list_objects_filter(
 static const char *RESERVED_NON_WS = "~`!@#$^&*()[]{}\\;'\",<>?";
 
 static int has_reserved_character(
-	struct strbuf *sub_spec, struct strbuf *errbuf)
+	const char *sub_spec, struct strbuf *errbuf)
 {
-	const char *c = sub_spec->buf;
+	const char *c = sub_spec;
 	while (*c) {
 		if (*c <= ' ' || strchr(RESERVED_NON_WS, *c)) {
 			strbuf_addf(
@@ -144,7 +144,7 @@ static int has_reserved_character(
 
 static int parse_combine_subfilter(
 	struct list_objects_filter_options *filter_options,
-	struct strbuf *subspec,
+	const char *subspec,
 	struct strbuf *errbuf)
 {
 	size_t new_index = filter_options->sub_nr;
@@ -155,7 +155,7 @@ static int parse_combine_subfilter(
 		      filter_options->sub_alloc);
 	list_objects_filter_init(&filter_options->sub[new_index]);
 
-	decoded = url_percent_decode(subspec->buf);
+	decoded = url_percent_decode(subspec);
 
 	result = has_reserved_character(subspec, errbuf);
 	if (result)
@@ -182,34 +182,34 @@ static int parse_combine_filter(
 	const char *arg,
 	struct strbuf *errbuf)
 {
-	struct strbuf **subspecs = strbuf_split_str(arg, '+', 0);
-	size_t sub;
+	const char *p = arg;
+	struct strbuf sub = STRBUF_INIT;
 	int result = 0;
 
-	if (!subspecs[0]) {
+	if (!*p) {
 		strbuf_addstr(errbuf, _("expected something after combine:"));
 		result = 1;
 		goto cleanup;
 	}
 
-	for (sub = 0; subspecs[sub] && !result; sub++) {
-		if (subspecs[sub + 1]) {
-			/*
-			 * This is not the last subspec. Remove trailing "+" so
-			 * we can parse it.
-			 */
-			size_t last = subspecs[sub]->len - 1;
-			assert(subspecs[sub]->buf[last] == '+');
-			strbuf_remove(subspecs[sub], last, 1);
-		}
-		result = parse_combine_subfilter(
-			filter_options, subspecs[sub], errbuf);
+	while (*p && !result) {
+		const char *end = strchrnul(p, '+');
+
+		strbuf_reset(&sub);
+		strbuf_add(&sub, p, end - p);
+
+		if (sub.len)
+			result = parse_combine_subfilter(filter_options, sub.buf, errbuf);
+
+		if (!*end)
+			break;
+		p = end + 1;
 	}
+	strbuf_release(&sub);
 
 	filter_options->choice = LOFC_COMBINE;
 
 cleanup:
-	strbuf_list_free(subspecs);
 	if (result)
 		list_objects_filter_release(filter_options);
 	return result;
diff --git a/meson.build b/meson.build
index 1036eafc3c0d0c..9e9ba9b82b80ea 100644
--- a/meson.build
+++ b/meson.build
@@ -1438,7 +1438,7 @@ else
     'getpagesize' : [],
   }
 
-  if get_option('b_sanitize').contains('address')
+  if get_option('b_sanitize').contains('address') or get_option('b_sanitize').contains('leak')
     libgit_c_args += '-DNO_MMAP'
     libgit_sources += 'compat/mmap.c'
   else
diff --git a/object-file.c b/object-file.c
index a3ff7f586c91f3..c62e5496e0795d 100644
--- a/object-file.c
+++ b/object-file.c
@@ -2211,7 +2211,7 @@ int odb_source_loose_read_object_stream(struct odb_read_stream **out,
 	return 0;
 error:
 	git_inflate_end(&st->z);
-	munmap(st->mapped, st->mapsize);
+	munmap(mapped, mapsize);
 	free(st);
 	return -1;
 }
diff --git a/pack-revindex.c b/pack-revindex.c
index 56cd803a6798d5..1fe0afe89907c5 100644
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -277,6 +277,10 @@ int load_pack_revindex_from_disk(struct packed_git *p)
 {
 	char *revindex_name;
 	int ret;
+
+	if (p->revindex_data)
+		return 0;
+
 	if (open_pack_index(p))
 		return -1;
 
diff --git a/patch-ids.c b/patch-ids.c
index a5683b462c6e76..1fbc88cbec874e 100644
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -41,7 +41,14 @@ static int patch_id_neq(const void *cmpfn_data,
 			const struct hashmap_entry *entry_or_key,
 			const void *keydata UNUSED)
 {
-	/* NEEDSWORK: const correctness? */
+	/*
+	 * We drop the 'const' modifier here intentionally.
+	 *
+	 * Even though eptr and entry_or_key are const, we want to
+	 * lazily compute their .patch_id members; see b3dfeebb (rebase:
+	 * avoid computing unnecessary patch IDs, 2016-07-29). So we cast
+	 * the constness away with container_of().
+	 */
 	struct diff_options *opt = (void *)cmpfn_data;
 	struct patch_id *a, *b;
 
diff --git a/pretty.c b/pretty.c
index ebf4da4834075f..74673714c8d39a 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1549,6 +1549,21 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 	if (!commit->object.parsed)
 		parse_object(the_repository, &commit->object.oid);
 
+	if (starts_with(placeholder, "(count)")) {
+		if (!c->pretty_ctx->rev)
+			die(_("this format specifier can't be used with this command"));
+		strbuf_addf(sb, "%0*d", decimal_width(c->pretty_ctx->rev->total),
+			    c->pretty_ctx->rev->nr);
+		return 7;
+	}
+
+	if (starts_with(placeholder, "(total)")) {
+		if (!c->pretty_ctx->rev)
+			die(_("this format specifier can't be used with this command"));
+		strbuf_addf(sb, "%d", c->pretty_ctx->rev->total);
+		return 7;
+	}
+
 	switch (placeholder[0]) {
 	case 'H':		/* commit hash */
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_COMMIT));
diff --git a/run-command.c b/run-command.c
index a8a8974638d7ef..32c290ee6a221f 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1,4 +1,3 @@
-#define USE_THE_REPOSITORY_VARIABLE
 #define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "git-compat-util.h"
@@ -742,8 +741,8 @@ int start_command(struct child_process *cmd)
 
 	fflush(NULL);
 
-	if (cmd->close_object_store)
-		odb_close(the_repository->objects);
+	if (cmd->odb_to_close)
+		odb_close(cmd->odb_to_close);
 
 #ifndef GIT_WINDOWS_NATIVE
 {
@@ -1937,11 +1936,12 @@ void run_processes_parallel(const struct run_process_parallel_opts *opts)
 		trace2_region_leave(tr2_category, tr2_label, NULL);
 }
 
-int prepare_auto_maintenance(int quiet, struct child_process *maint)
+int prepare_auto_maintenance(struct repository *r, int quiet,
+			     struct child_process *maint)
 {
 	int enabled, auto_detach;
 
-	if (!repo_config_get_bool(the_repository, "maintenance.auto", &enabled) &&
+	if (!repo_config_get_bool(r, "maintenance.auto", &enabled) &&
 	    !enabled)
 		return 0;
 
@@ -1950,12 +1950,12 @@ int prepare_auto_maintenance(int quiet, struct child_process *maint)
 	 * honoring `gc.autoDetach`. This is somewhat weird, but required to
 	 * retain behaviour from when we used to run git-gc(1) here.
 	 */
-	if (repo_config_get_bool(the_repository, "maintenance.autodetach", &auto_detach) &&
-	    repo_config_get_bool(the_repository, "gc.autodetach", &auto_detach))
+	if (repo_config_get_bool(r, "maintenance.autodetach", &auto_detach) &&
+	    repo_config_get_bool(r, "gc.autodetach", &auto_detach))
 		auto_detach = git_env_bool("GIT_TEST_MAINT_AUTO_DETACH", true);
 
 	maint->git_cmd = 1;
-	maint->close_object_store = 1;
+	maint->odb_to_close = r->objects;
 	strvec_pushl(&maint->args, "maintenance", "run", "--auto", NULL);
 	strvec_push(&maint->args, quiet ? "--quiet" : "--no-quiet");
 	strvec_push(&maint->args, auto_detach ? "--detach" : "--no-detach");
@@ -1963,10 +1963,10 @@ int prepare_auto_maintenance(int quiet, struct child_process *maint)
 	return 1;
 }
 
-int run_auto_maintenance(int quiet)
+int run_auto_maintenance(struct repository *r, int quiet)
 {
 	struct child_process maint = CHILD_PROCESS_INIT;
-	if (!prepare_auto_maintenance(quiet, &maint))
+	if (!prepare_auto_maintenance(r, quiet, &maint))
 		return 0;
 	return run_command(&maint);
 }
diff --git a/run-command.h b/run-command.h
index 428d76ebd620ff..8ca496d7bdebfd 100644
--- a/run-command.h
+++ b/run-command.h
@@ -5,6 +5,8 @@
 
 #include "strvec.h"
 
+struct repository;
+
 /**
  * The run-command API offers a versatile tool to run sub-processes with
  * redirected input and output as well as with a modified environment
@@ -136,7 +138,7 @@ struct child_process {
 	 * want to repack because that would delete `.pack` files (and on
 	 * Windows, you cannot delete files that are still in use).
 	 */
-	unsigned close_object_store:1;
+	struct object_database *odb_to_close;
 
 	unsigned stdout_to_stderr:1;
 	unsigned clean_on_exit:1;
@@ -227,12 +229,13 @@ int run_command(struct child_process *);
  * process has been prepared and is ready to run, or 0 in case auto-maintenance
  * should be skipped.
  */
-int prepare_auto_maintenance(int quiet, struct child_process *maint);
+int prepare_auto_maintenance(struct repository *r, int quiet,
+			     struct child_process *maint);
 
 /*
  * Trigger an auto-gc
  */
-int run_auto_maintenance(int quiet);
+int run_auto_maintenance(struct repository *r, int quiet);
 
 /**
  * Execute the given command, sending "in" to its stdin, and capturing its
diff --git a/sequencer.c b/sequencer.c
index aafd0bc959664a..e5af49cecd0859 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -209,6 +209,7 @@ static GIT_PATH_FUNC(rebase_path_reschedule_failed_exec, "rebase-merge/reschedul
 static GIT_PATH_FUNC(rebase_path_no_reschedule_failed_exec, "rebase-merge/no-reschedule-failed-exec")
 static GIT_PATH_FUNC(rebase_path_drop_redundant_commits, "rebase-merge/drop_redundant_commits")
 static GIT_PATH_FUNC(rebase_path_keep_redundant_commits, "rebase-merge/keep_redundant_commits")
+static GIT_PATH_FUNC(rebase_path_trailer, "rebase-merge/trailer")
 
 /*
  * A 'struct replay_ctx' represents the private state of the sequencer.
@@ -420,6 +421,7 @@ void replay_opts_release(struct replay_opts *opts)
 	if (opts->revs)
 		release_revisions(opts->revs);
 	free(opts->revs);
+	strvec_clear(&opts->trailer_args);
 	replay_ctx_release(ctx);
 	free(opts->ctx);
 }
@@ -2027,12 +2029,15 @@ static int append_squash_message(struct strbuf *buf, const char *body,
 	if (is_fixup_flag(command, flag) && !seen_squash(ctx)) {
 		/*
 		 * We're replacing the commit message so we need to
-		 * append the Signed-off-by: trailer if the user
-		 * requested '--signoff'.
+		 * append any trailers if the user requested
+		 * '--signoff' or '--trailer'.
 		 */
 		if (opts->signoff)
 			append_signoff(buf, 0, 0);
 
+		if (opts->trailer_args.nr)
+			amend_strbuf_with_trailers(buf, &opts->trailer_args);
+
 		if ((command == TODO_FIXUP) &&
 		    (flag & TODO_REPLACE_FIXUP_MSG) &&
 		    (file_exists(rebase_path_fixup_msg()) ||
@@ -2451,6 +2456,9 @@ static int do_pick_commit(struct repository *r,
 	if (opts->signoff && !is_fixup(command))
 		append_signoff(&ctx->message, 0, 0);
 
+	if (opts->trailer_args.nr && !is_fixup(command))
+		amend_strbuf_with_trailers(&ctx->message, &opts->trailer_args);
+
 	if (is_rebase_i(opts) && write_author_script(msg.message) < 0)
 		res = -1;
 	else if (!opts->strategy ||
@@ -3180,6 +3188,33 @@ static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
 	parse_strategy_opts(opts, buf->buf);
 }
 
+static int read_trailers(struct replay_opts *opts, struct strbuf *buf)
+{
+	ssize_t len;
+
+	strbuf_reset(buf);
+	len = strbuf_read_file(buf, rebase_path_trailer(), 0);
+	if (len > 0) {
+		char *p = buf->buf, *nl;
+
+		trailer_config_init();
+
+		while ((nl = strchr(p, '\n'))) {
+			*nl = '\0';
+			if (!*p)
+				return error(_("trailers file contains empty line"));
+			strvec_push(&opts->trailer_args, p);
+			p = nl + 1;
+		}
+	} else if (!len) {
+		return error(_("trailers file is empty"));
+	} else if (errno != ENOENT) {
+		return error(_("cannot read trailers files"));
+	}
+
+	return 0;
+}
+
 static int read_populate_opts(struct replay_opts *opts)
 {
 	struct replay_ctx *ctx = opts->ctx;
@@ -3241,6 +3276,11 @@ static int read_populate_opts(struct replay_opts *opts)
 			opts->keep_redundant_commits = 1;
 
 		read_strategy_opts(opts, &buf);
+
+		if (read_trailers(opts, &buf)) {
+			ret = -1;
+			goto done_rebase_i;
+		}
 		strbuf_reset(&buf);
 
 		if (read_oneliner(&ctx->current_fixups,
@@ -3336,6 +3376,14 @@ int write_basic_state(struct replay_opts *opts, const char *head_name,
 		write_file(rebase_path_reschedule_failed_exec(), "%s", "");
 	else
 		write_file(rebase_path_no_reschedule_failed_exec(), "%s", "");
+	if (opts->trailer_args.nr) {
+		struct strbuf buf = STRBUF_INIT;
+
+		for (size_t i = 0; i < opts->trailer_args.nr; i++)
+			strbuf_addf(&buf, "%s\n", opts->trailer_args.v[i]);
+		write_file(rebase_path_trailer(), "%s", buf.buf);
+		strbuf_release(&buf);
+	}
 
 	return 0;
 }
diff --git a/sequencer.h b/sequencer.h
index 719684c8a9fb2e..bea20da085f0a2 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -57,6 +57,8 @@ struct replay_opts {
 	int ignore_date;
 	int commit_use_reference;
 
+	struct strvec trailer_args;
+
 	int mainline;
 
 	char *gpg_sign;
@@ -84,6 +86,7 @@ struct replay_opts {
 #define REPLAY_OPTS_INIT {			\
 	.edit = -1,				\
 	.action = -1,				\
+	.trailer_args = STRVEC_INIT,		\
 	.xopts = STRVEC_INIT,			\
 	.ctx = replay_ctx_new(),		\
 }
diff --git a/setup.c b/setup.c
index 393b970ae4f96d..7ec4427368a2a7 100644
--- a/setup.c
+++ b/setup.c
@@ -920,8 +920,10 @@ int verify_repository_format(const struct repository_format *format,
 void read_gitfile_error_die(int error_code, const char *path, const char *dir)
 {
 	switch (error_code) {
-	case READ_GITFILE_ERR_STAT_FAILED:
 	case READ_GITFILE_ERR_NOT_A_FILE:
+	case READ_GITFILE_ERR_STAT_FAILED:
+	case READ_GITFILE_ERR_MISSING:
+	case READ_GITFILE_ERR_IS_A_DIR:
 		/* non-fatal; follow return path */
 		break;
 	case READ_GITFILE_ERR_OPEN_FAILED:
@@ -964,8 +966,14 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
 	static struct strbuf realpath = STRBUF_INIT;
 
 	if (stat(path, &st)) {
-		/* NEEDSWORK: discern between ENOENT vs other errors */
-		error_code = READ_GITFILE_ERR_STAT_FAILED;
+		if (errno == ENOENT || errno == ENOTDIR)
+			error_code = READ_GITFILE_ERR_MISSING;
+		else
+			error_code = READ_GITFILE_ERR_STAT_FAILED;
+		goto cleanup_return;
+	}
+	if (S_ISDIR(st.st_mode)) {
+		error_code = READ_GITFILE_ERR_IS_A_DIR;
 		goto cleanup_return;
 	}
 	if (!S_ISREG(st.st_mode)) {
@@ -1601,20 +1609,37 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
 		if (offset > min_offset)
 			strbuf_addch(dir, '/');
 		strbuf_addstr(dir, DEFAULT_GIT_DIR_ENVIRONMENT);
-		gitdirenv = read_gitfile_gently(dir->buf, die_on_error ?
-						NULL : &error_code);
+		gitdirenv = read_gitfile_gently(dir->buf, &error_code);
 		if (!gitdirenv) {
-			if (die_on_error ||
-			    error_code == READ_GITFILE_ERR_NOT_A_FILE) {
-				/* NEEDSWORK: fail if .git is not file nor dir */
+			switch (error_code) {
+			case READ_GITFILE_ERR_MISSING:
+				/* no .git in this directory, move on */
+				break;
+			case READ_GITFILE_ERR_IS_A_DIR:
 				if (is_git_directory(dir->buf)) {
 					gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 					gitdir_path = xstrdup(dir->buf);
 				}
-			} else if (error_code != READ_GITFILE_ERR_STAT_FAILED)
-				return GIT_DIR_INVALID_GITFILE;
-		} else
+				break;
+			case READ_GITFILE_ERR_STAT_FAILED:
+				if (die_on_error)
+					die(_("error reading '%s'"), dir->buf);
+				else
+					return GIT_DIR_INVALID_GITFILE;
+			case READ_GITFILE_ERR_NOT_A_FILE:
+				if (die_on_error)
+					die(_("not a regular file: '%s'"), dir->buf);
+				else
+					return GIT_DIR_INVALID_GITFILE;
+			default:
+				if (die_on_error)
+					read_gitfile_error_die(error_code, dir->buf, NULL);
+				else
+					return GIT_DIR_INVALID_GITFILE;
+			}
+		} else {
 			gitfile = xstrdup(dir->buf);
+		}
 		/*
 		 * Earlier, we tentatively added DEFAULT_GIT_DIR_ENVIRONMENT
 		 * to check that directory for a repository.
diff --git a/setup.h b/setup.h
index bcb16b0b4a6662..80bc6e5f078af8 100644
--- a/setup.h
+++ b/setup.h
@@ -36,6 +36,8 @@ int is_nonbare_repository_dir(struct strbuf *path);
 #define READ_GITFILE_ERR_NO_PATH 6
 #define READ_GITFILE_ERR_NOT_A_REPO 7
 #define READ_GITFILE_ERR_TOO_LARGE 8
+#define READ_GITFILE_ERR_MISSING 9
+#define READ_GITFILE_ERR_IS_A_DIR 10
 void read_gitfile_error_die(int error_code, const char *path, const char *dir);
 const char *read_gitfile_gently(const char *path, int *return_error_code);
 #define read_gitfile(path) read_gitfile_gently((path), NULL)
diff --git a/sideband.c b/sideband.c
index ea7c25211ef7e1..04282a568edd90 100644
--- a/sideband.c
+++ b/sideband.c
@@ -10,6 +10,7 @@
 #include "help.h"
 #include "pkt-line.h"
 #include "write-or-die.h"
+#include "urlmatch.h"
 
 struct keyword_entry {
 	/*
@@ -26,6 +27,85 @@ static struct keyword_entry keywords[] = {
 	{ "error",	GIT_COLOR_BOLD_RED },
 };
 
+static enum {
+	ALLOW_CONTROL_SEQUENCES_UNSET = -1,
+	ALLOW_NO_CONTROL_CHARACTERS   = 0,
+	ALLOW_ANSI_COLOR_SEQUENCES    = 1<<0,
+	ALLOW_ANSI_CURSOR_MOVEMENTS   = 1<<1,
+	ALLOW_ANSI_ERASE              = 1<<2,
+	ALLOW_ALL_CONTROL_CHARACTERS  = 1<<3,
+	ALLOW_DEFAULT_ANSI_SEQUENCES  = ALLOW_ANSI_COLOR_SEQUENCES
+} allow_control_characters = ALLOW_CONTROL_SEQUENCES_UNSET;
+
+static inline int skip_prefix_in_csv(const char *value, const char *prefix,
+				     const char **out)
+{
+	if (!skip_prefix(value, prefix, &value) ||
+	    (*value && *value != ','))
+		return 0;
+	*out = value + !!*value;
+	return 1;
+}
+
+int sideband_allow_control_characters_config(const char *var, const char *value)
+{
+	switch (git_parse_maybe_bool(value)) {
+	case 0:
+		allow_control_characters = ALLOW_NO_CONTROL_CHARACTERS;
+		return 0;
+	case 1:
+		allow_control_characters = ALLOW_ALL_CONTROL_CHARACTERS;
+		return 0;
+	default:
+		break;
+	}
+
+	allow_control_characters = ALLOW_NO_CONTROL_CHARACTERS;
+	while (*value) {
+		if (skip_prefix_in_csv(value, "color", &value))
+			allow_control_characters |= ALLOW_ANSI_COLOR_SEQUENCES;
+		else if (skip_prefix_in_csv(value, "cursor", &value))
+			allow_control_characters |= ALLOW_ANSI_CURSOR_MOVEMENTS;
+		else if (skip_prefix_in_csv(value, "erase", &value))
+			allow_control_characters |= ALLOW_ANSI_ERASE;
+		else if (skip_prefix_in_csv(value, "true", &value))
+			allow_control_characters = ALLOW_ALL_CONTROL_CHARACTERS;
+		else if (skip_prefix_in_csv(value, "false", &value))
+			allow_control_characters = ALLOW_NO_CONTROL_CHARACTERS;
+		else
+			warning(_("unrecognized value for '%s': '%s'"), var, value);
+	}
+	return 0;
+}
+
+static int sideband_config_callback(const char *var, const char *value,
+				    const struct config_context *ctx UNUSED,
+				    void *data UNUSED)
+{
+	if (!strcmp(var, "sideband.allowcontrolcharacters"))
+		return sideband_allow_control_characters_config(var, value);
+
+	return 0;
+}
+
+void sideband_apply_url_config(const char *url)
+{
+	struct urlmatch_config config = URLMATCH_CONFIG_INIT;
+	char *normalized_url;
+
+	if (!url)
+		BUG("must not call sideband_apply_url_config(NULL)");
+
+	config.section = "sideband";
+	config.collect_fn = sideband_config_callback;
+
+	normalized_url = url_normalize(url, &config.url);
+	repo_config(the_repository, urlmatch_config_entry, &config);
+	free(normalized_url);
+	string_list_clear(&config.vars, 1);
+	urlmatch_config_release(&config);
+}
+
 /* Returns a color setting (GIT_COLOR_NEVER, etc). */
 static enum git_colorbool use_sideband_colors(void)
 {
@@ -39,6 +119,14 @@ static enum git_colorbool use_sideband_colors(void)
 	if (use_sideband_colors_cached != GIT_COLOR_UNKNOWN)
 		return use_sideband_colors_cached;
 
+	if (allow_control_characters == ALLOW_CONTROL_SEQUENCES_UNSET) {
+		if (!repo_config_get_value(the_repository, "sideband.allowcontrolcharacters", &value))
+			sideband_allow_control_characters_config("sideband.allowcontrolcharacters", value);
+
+		if (allow_control_characters == ALLOW_CONTROL_SEQUENCES_UNSET)
+			allow_control_characters = ALLOW_DEFAULT_ANSI_SEQUENCES;
+	}
+
 	if (!repo_config_get_string_tmp(the_repository, key, &value))
 		use_sideband_colors_cached = git_config_colorbool(key, value);
 	else if (!repo_config_get_string_tmp(the_repository, "color.ui", &value))
@@ -66,6 +154,93 @@ void list_config_color_sideband_slots(struct string_list *list, const char *pref
 		list_config_item(list, prefix, keywords[i].keyword);
 }
 
+static int handle_ansi_sequence(struct strbuf *dest, const char *src, int n)
+{
+	int i;
+
+	/*
+	 * Valid ANSI color sequences are of the form
+	 *
+	 * ESC [ [<n> [; <n>]*] m
+	 *
+	 * These are part of the Select Graphic Rendition sequences which
+	 * contain more than just color sequences, for more details see
+	 * https://en.wikipedia.org/wiki/ANSI_escape_code#SGR.
+	 *
+	 * The cursor movement sequences are:
+	 *
+	 * ESC [ n A - Cursor up n lines (CUU)
+	 * ESC [ n B - Cursor down n lines (CUD)
+	 * ESC [ n C - Cursor forward n columns (CUF)
+	 * ESC [ n D - Cursor back n columns (CUB)
+	 * ESC [ n E - Cursor next line, beginning (CNL)
+	 * ESC [ n F - Cursor previous line, beginning (CPL)
+	 * ESC [ n G - Cursor to column n (CHA)
+	 * ESC [ n ; m H - Cursor position (row n, col m) (CUP)
+	 * ESC [ n ; m f - Same as H (HVP)
+	 *
+	 * The sequences to erase characters are:
+	 *
+	 *
+	 * ESC [ 0 J - Clear from cursor to end of screen (ED)
+	 * ESC [ 1 J - Clear from cursor to beginning of screen (ED)
+	 * ESC [ 2 J - Clear entire screen (ED)
+	 * ESC [ 3 J - Clear entire screen + scrollback (ED) - xterm extension
+	 * ESC [ 0 K - Clear from cursor to end of line (EL)
+	 * ESC [ 1 K - Clear from cursor to beginning of line (EL)
+	 * ESC [ 2 K - Clear entire line (EL)
+	 * ESC [ n M - Delete n lines (DL)
+	 * ESC [ n P - Delete n characters (DCH)
+	 * ESC [ n X - Erase n characters (ECH)
+	 *
+	 * For a comprehensive list of common ANSI Escape sequences, see
+	 * https://www.xfree86.org/current/ctlseqs.html
+	 */
+
+	if (n < 3 || src[0] != '\x1b' || src[1] != '[')
+		return 0;
+
+	for (i = 2; i < n; i++) {
+		if (((allow_control_characters & ALLOW_ANSI_COLOR_SEQUENCES) &&
+		     src[i] == 'm') ||
+		    ((allow_control_characters & ALLOW_ANSI_CURSOR_MOVEMENTS) &&
+		     strchr("ABCDEFGHf", src[i])) ||
+		    ((allow_control_characters & ALLOW_ANSI_ERASE) &&
+		     strchr("JKMPX", src[i]))) {
+			strbuf_add(dest, src, i + 1);
+			return i;
+		}
+		if (!isdigit(src[i]) && src[i] != ';')
+			break;
+	}
+
+	return 0;
+}
+
+static void strbuf_add_sanitized(struct strbuf *dest, const char *src, int n)
+{
+	int i;
+
+	if ((allow_control_characters & ALLOW_ALL_CONTROL_CHARACTERS)) {
+		strbuf_add(dest, src, n);
+		return;
+	}
+
+	strbuf_grow(dest, n);
+	for (; n && *src; src++, n--) {
+		if (!iscntrl(*src) || *src == '\t' || *src == '\n') {
+			strbuf_addch(dest, *src);
+		} else if (allow_control_characters != ALLOW_NO_CONTROL_CHARACTERS &&
+			   (i = handle_ansi_sequence(dest, src, n))) {
+			src += i;
+			n -= i;
+		} else {
+			strbuf_addch(dest, '^');
+			strbuf_addch(dest, *src == 0x7f ? '?' : 0x40 + *src);
+		}
+	}
+}
+
 /*
  * Optionally highlight one keyword in remote output if it appears at the start
  * of the line. This should be called for a single line only, which is
@@ -81,7 +256,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
 	int i;
 
 	if (!want_color_stderr(use_sideband_colors())) {
-		strbuf_add(dest, src, n);
+		strbuf_add_sanitized(dest, src, n);
 		return;
 	}
 
@@ -114,7 +289,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
 		}
 	}
 
-	strbuf_add(dest, src, n);
+	strbuf_add_sanitized(dest, src, n);
 }
 
 
diff --git a/sideband.h b/sideband.h
index 5a25331be55d30..d15fa4015fa0a3 100644
--- a/sideband.h
+++ b/sideband.h
@@ -30,4 +30,18 @@ int demultiplex_sideband(const char *me, int status,
 
 void send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max);
 
+/*
+ * Apply sideband configuration for the given URL. This should be called
+ * when a transport is created to allow URL-specific configuration of
+ * sideband behavior (e.g., sideband.<url>.allowControlCharacters).
+ */
+void sideband_apply_url_config(const char *url);
+
+/*
+ * Parse and set the sideband allow control characters configuration.
+ * The var parameter should be the key name (without section prefix).
+ * Returns 0 if the variable was recognized and handled, non-zero otherwise.
+ */
+int sideband_allow_control_characters_config(const char *var, const char *value);
+
 #endif
diff --git a/submodule.c b/submodule.c
index 4f9aaa2c75679b..cd879a5cfe73ec 100644
--- a/submodule.c
+++ b/submodule.c
@@ -2559,7 +2559,7 @@ void absorb_git_dir_into_superproject(const char *path,
 		const struct submodule *sub;
 		struct strbuf sub_gitdir = STRBUF_INIT;
 
-		if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
+		if (err_code == READ_GITFILE_ERR_MISSING) {
 			/* unpopulated as expected */
 			strbuf_release(&gitdir);
 			return;
diff --git a/t/helper/test-example-tap.c b/t/helper/test-example-tap.c
index 229d495ecfa668..998a1f0b428bed 100644
--- a/t/helper/test-example-tap.c
+++ b/t/helper/test-example-tap.c
@@ -63,6 +63,8 @@ static void t_messages(void)
 	check_str("NULL", NULL);
 	check_char('a', ==, '\n');
 	check_char('\\', ==, '\'');
+	check_char('\a', ==, '\v');
+	check_char('\x00', ==, '\x01');
 }
 
 static void t_empty(void)
@@ -123,6 +125,8 @@ int cmd__example_tap(int argc UNUSED, const char **argv UNUSED)
 		check_str("NULL", NULL);
 		check_char('a', ==, '\n');
 		check_char('\\', ==, '\'');
+		check_char('\a', ==, '\v');
+		check_char('\x00', ==, '\x01');
 	}
 	if_test ("if_test test with no checks")
 		; /* nothing */
diff --git a/t/meson.build b/t/meson.build
index f66a73f8a07d93..e539117ca4fedd 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -81,6 +81,7 @@ integration_tests = [
   't0006-date.sh',
   't0007-git-var.sh',
   't0008-ignores.sh',
+  't0009-git-dir-validation.sh',
   't0010-racy-git.sh',
   't0012-help.sh',
   't0013-sha1dc.sh',
@@ -392,6 +393,7 @@ integration_tests = [
   't3436-rebase-more-options.sh',
   't3437-rebase-fixup-options.sh',
   't3438-rebase-broken-files.sh',
+  't3440-rebase-trailer.sh',
   't3450-history.sh',
   't3451-history-reword.sh',
   't3500-cherry.sh',
diff --git a/t/t0009-git-dir-validation.sh b/t/t0009-git-dir-validation.sh
new file mode 100755
index 00000000000000..33d21ed9ea1061
--- /dev/null
+++ b/t/t0009-git-dir-validation.sh
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+test_description='setup: validation of .git file/directory types
+
+Verify that setup_git_directory() correctly handles:
+1. Valid .git directories (including symlinks to them).
+2. Invalid .git files (FIFOs, sockets) by erroring out.
+3. Invalid .git files (garbage) by erroring out.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup: create parent git repository' '
+	git init parent &&
+	test_commit -C parent "root-commit"
+'
+
+test_expect_success SYMLINKS 'setup: .git as a symlink to a directory is valid' '
+	test_when_finished "rm -rf parent/link-to-dir" &&
+	mkdir -p parent/link-to-dir &&
+	(
+		cd parent/link-to-dir &&
+		git init real-repo &&
+		ln -s real-repo/.git .git &&
+		git rev-parse --git-dir >actual &&
+		echo .git >expect &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success PIPE 'setup: .git as a FIFO (named pipe) is rejected' '
+	test_when_finished "rm -rf parent/fifo-trap" &&
+	mkdir -p parent/fifo-trap &&
+	(
+		cd parent/fifo-trap &&
+		mkfifo .git &&
+		test_must_fail git rev-parse --git-dir 2>stderr &&
+		grep "not a regular file" stderr
+	)
+'
+
+test_expect_success SYMLINKS,PIPE 'setup: .git as a symlink to a FIFO is rejected' '
+	test_when_finished "rm -rf parent/symlink-fifo-trap" &&
+	mkdir -p parent/symlink-fifo-trap &&
+	(
+		cd parent/symlink-fifo-trap &&
+		mkfifo target-fifo &&
+		ln -s target-fifo .git &&
+		test_must_fail git rev-parse --git-dir 2>stderr &&
+		grep "not a regular file" stderr
+	)
+'
+
+test_expect_success 'setup: .git with garbage content is rejected' '
+	test_when_finished "rm -rf parent/garbage-trap" &&
+	mkdir -p parent/garbage-trap &&
+	(
+		cd parent/garbage-trap &&
+		echo "garbage" >.git &&
+		test_must_fail git rev-parse --git-dir 2>stderr &&
+		grep "invalid gitfile format" stderr
+	)
+'
+
+test_expect_success 'setup: .git as an empty directory is ignored' '
+	test_when_finished "rm -rf parent/empty-dir" &&
+	mkdir -p parent/empty-dir &&
+	(
+		cd parent/empty-dir &&
+		git rev-parse --git-dir >expect &&
+		mkdir .git &&
+		git rev-parse --git-dir >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_done
diff --git a/t/t0080-unit-test-output.sh b/t/t0080-unit-test-output.sh
index 3db10f095c2edc..66838a00b220cc 100755
--- a/t/t0080-unit-test-output.sh
+++ b/t/t0080-unit-test-output.sh
@@ -6,10 +6,10 @@ test_description='Test the output of the unit test framework'
 
 test_expect_success 'TAP output from unit tests' - <<\EOT
 	cat >expect <<-EOF &&
-	# BUG: check outside of test at t/helper/test-example-tap.c:75
+	# BUG: check outside of test at t/helper/test-example-tap.c:77
 	ok 1 - passing test
 	ok 2 - passing test and assertion return 1
-	# check "1 == 2" failed at t/helper/test-example-tap.c:79
+	# check "1 == 2" failed at t/helper/test-example-tap.c:81
 	#    left: 1
 	#   right: 2
 	not ok 3 - failing test
@@ -34,53 +34,65 @@ test_expect_success 'TAP output from unit tests' - <<\EOT
 	not ok 15 - failing check after TEST_TODO()
 	ok 16 - failing check after TEST_TODO() returns 0
 	# check "!strcmp("\thello\\\\", "there\"\n")" failed at t/helper/test-example-tap.c:62
-	#    left: "\011hello\\\\"
-	#   right: "there\"\012"
+	#    left: "\thello\\\\"
+	#   right: "there\"\n"
 	# check "!strcmp("NULL", NULL)" failed at t/helper/test-example-tap.c:63
 	#    left: "NULL"
 	#   right: NULL
 	# check "'a' == '\n'" failed at t/helper/test-example-tap.c:64
 	#    left: 'a'
-	#   right: '\012'
+	#   right: '\n'
 	# check "'\\\\' == '\\''" failed at t/helper/test-example-tap.c:65
 	#    left: '\\\\'
 	#   right: '\\''
+	# check "'\a' == '\v'" failed at t/helper/test-example-tap.c:66
+	#    left: '\a'
+	#   right: '\v'
+	# check "'\x00' == '\x01'" failed at t/helper/test-example-tap.c:67
+	#    left: '\000'
+	#   right: '\001'
 	not ok 17 - messages from failing string and char comparison
-	# BUG: test has no checks at t/helper/test-example-tap.c:94
+	# BUG: test has no checks at t/helper/test-example-tap.c:96
 	not ok 18 - test with no checks
 	ok 19 - test with no checks returns 0
 	ok 20 - if_test passing test
-	# check "1 == 2" failed at t/helper/test-example-tap.c:100
+	# check "1 == 2" failed at t/helper/test-example-tap.c:102
 	#    left: 1
 	#   right: 2
 	not ok 21 - if_test failing test
 	not ok 22 - if_test passing TEST_TODO() # TODO
-	# todo check 'check(1)' succeeded at t/helper/test-example-tap.c:104
+	# todo check 'check(1)' succeeded at t/helper/test-example-tap.c:106
 	not ok 23 - if_test failing TEST_TODO()
-	# check "0" failed at t/helper/test-example-tap.c:106
+	# check "0" failed at t/helper/test-example-tap.c:108
 	# skipping test - missing prerequisite
-	# skipping check '1' at t/helper/test-example-tap.c:108
+	# skipping check '1' at t/helper/test-example-tap.c:110
 	ok 24 - if_test test_skip() # SKIP
 	# skipping test - missing prerequisite
 	ok 25 - if_test test_skip() inside TEST_TODO() # SKIP
-	# check "0" failed at t/helper/test-example-tap.c:113
+	# check "0" failed at t/helper/test-example-tap.c:115
 	not ok 26 - if_test TEST_TODO() after failing check
-	# check "0" failed at t/helper/test-example-tap.c:119
+	# check "0" failed at t/helper/test-example-tap.c:121
 	not ok 27 - if_test failing check after TEST_TODO()
-	# check "!strcmp("\thello\\\\", "there\"\n")" failed at t/helper/test-example-tap.c:122
-	#    left: "\011hello\\\\"
-	#   right: "there\"\012"
-	# check "!strcmp("NULL", NULL)" failed at t/helper/test-example-tap.c:123
+	# check "!strcmp("\thello\\\\", "there\"\n")" failed at t/helper/test-example-tap.c:124
+	#    left: "\thello\\\\"
+	#   right: "there\"\n"
+	# check "!strcmp("NULL", NULL)" failed at t/helper/test-example-tap.c:125
 	#    left: "NULL"
 	#   right: NULL
-	# check "'a' == '\n'" failed at t/helper/test-example-tap.c:124
+	# check "'a' == '\n'" failed at t/helper/test-example-tap.c:126
 	#    left: 'a'
-	#   right: '\012'
-	# check "'\\\\' == '\\''" failed at t/helper/test-example-tap.c:125
+	#   right: '\n'
+	# check "'\\\\' == '\\''" failed at t/helper/test-example-tap.c:127
 	#    left: '\\\\'
 	#   right: '\\''
+	# check "'\a' == '\v'" failed at t/helper/test-example-tap.c:128
+	#    left: '\a'
+	#   right: '\v'
+	# check "'\x00' == '\x01'" failed at t/helper/test-example-tap.c:129
+	#    left: '\000'
+	#   right: '\001'
 	not ok 28 - if_test messages from failing string and char comparison
-	# BUG: test has no checks at t/helper/test-example-tap.c:127
+	# BUG: test has no checks at t/helper/test-example-tap.c:131
 	not ok 29 - if_test test with no checks
 	1..29
 	EOF
diff --git a/t/t1901-repo-structure.sh b/t/t1901-repo-structure.sh
index a67b38ab178125..98921ce1cbb66f 100755
--- a/t/t1901-repo-structure.sh
+++ b/t/t1901-repo-structure.sh
@@ -27,31 +27,43 @@ test_expect_success 'empty repository' '
 	(
 		cd repo &&
 		cat >expect <<-\EOF &&
-		| Repository structure | Value  |
-		| -------------------- | ------ |
-		| * References         |        |
-		|   * Count            |    0   |
-		|     * Branches       |    0   |
-		|     * Tags           |    0   |
-		|     * Remotes        |    0   |
-		|     * Others         |    0   |
-		|                      |        |
-		| * Reachable objects  |        |
-		|   * Count            |    0   |
-		|     * Commits        |    0   |
-		|     * Trees          |    0   |
-		|     * Blobs          |    0   |
-		|     * Tags           |    0   |
-		|   * Inflated size    |    0 B |
-		|     * Commits        |    0 B |
-		|     * Trees          |    0 B |
-		|     * Blobs          |    0 B |
-		|     * Tags           |    0 B |
-		|   * Disk size        |    0 B |
-		|     * Commits        |    0 B |
-		|     * Trees          |    0 B |
-		|     * Blobs          |    0 B |
-		|     * Tags           |    0 B |
+		| Repository structure      | Value  |
+		| ------------------------- | ------ |
+		| * References              |        |
+		|   * Count                 |    0   |
+		|     * Branches            |    0   |
+		|     * Tags                |    0   |
+		|     * Remotes             |    0   |
+		|     * Others              |    0   |
+		|                           |        |
+		| * Reachable objects       |        |
+		|   * Count                 |    0   |
+		|     * Commits             |    0   |
+		|     * Trees               |    0   |
+		|     * Blobs               |    0   |
+		|     * Tags                |    0   |
+		|   * Inflated size         |    0 B |
+		|     * Commits             |    0 B |
+		|     * Trees               |    0 B |
+		|     * Blobs               |    0 B |
+		|     * Tags                |    0 B |
+		|   * Disk size             |    0 B |
+		|     * Commits             |    0 B |
+		|     * Trees               |    0 B |
+		|     * Blobs               |    0 B |
+		|     * Tags                |    0 B |
+		|                           |        |
+		| * Largest objects         |        |
+		|   * Commits               |        |
+		|     * Maximum size        |    0 B |
+		|     * Maximum parents     |    0   |
+		|   * Trees                 |        |
+		|     * Maximum size        |    0 B |
+		|     * Maximum entries     |    0   |
+		|   * Blobs                 |        |
+		|     * Maximum size        |    0 B |
+		|   * Tags                  |        |
+		|     * Maximum size        |    0 B |
 		EOF
 
 		git repo structure >out 2>err &&
@@ -79,31 +91,50 @@ test_expect_success SHA1 'repository with references and objects' '
 		# git-rev-list(1) --disk-usage=human option printing the full
 		# "byte/bytes" unit string instead of just "B".
 		cat >expect <<-EOF &&
-		| Repository structure | Value      |
-		| -------------------- | ---------- |
-		| * References         |            |
-		|   * Count            |      4     |
-		|     * Branches       |      1     |
-		|     * Tags           |      1     |
-		|     * Remotes        |      1     |
-		|     * Others         |      1     |
-		|                      |            |
-		| * Reachable objects  |            |
-		|   * Count            |   3.02 k   |
-		|     * Commits        |   1.01 k   |
-		|     * Trees          |   1.01 k   |
-		|     * Blobs          |   1.01 k   |
-		|     * Tags           |      1     |
-		|   * Inflated size    |  16.03 MiB |
-		|     * Commits        | 217.92 KiB |
-		|     * Trees          |  15.81 MiB |
-		|     * Blobs          |  11.68 KiB |
-		|     * Tags           |    132 B   |
-		|   * Disk size        | $(object_type_disk_usage all true) |
-		|     * Commits        | $(object_type_disk_usage commit true) |
-		|     * Trees          | $(object_type_disk_usage tree true) |
-		|     * Blobs          |  $(object_type_disk_usage blob true) |
-		|     * Tags           |    $(object_type_disk_usage tag) B   |
+		| Repository structure      | Value      |
+		| ------------------------- | ---------- |
+		| * References              |            |
+		|   * Count                 |      4     |
+		|     * Branches            |      1     |
+		|     * Tags                |      1     |
+		|     * Remotes             |      1     |
+		|     * Others              |      1     |
+		|                           |            |
+		| * Reachable objects       |            |
+		|   * Count                 |   3.02 k   |
+		|     * Commits             |   1.01 k   |
+		|     * Trees               |   1.01 k   |
+		|     * Blobs               |   1.01 k   |
+		|     * Tags                |      1     |
+		|   * Inflated size         |  16.03 MiB |
+		|     * Commits             | 217.92 KiB |
+		|     * Trees               |  15.81 MiB |
+		|     * Blobs               |  11.68 KiB |
+		|     * Tags                |    132 B   |
+		|   * Disk size             | $(object_type_disk_usage all true) |
+		|     * Commits             | $(object_type_disk_usage commit true) |
+		|     * Trees               | $(object_type_disk_usage tree true) |
+		|     * Blobs               |  $(object_type_disk_usage blob true) |
+		|     * Tags                |    $(object_type_disk_usage tag) B   |
+		|                           |            |
+		| * Largest objects         |            |
+		|   * Commits               |            |
+		|     * Maximum size    [1] |    223 B   |
+		|     * Maximum parents [2] |      1     |
+		|   * Trees                 |            |
+		|     * Maximum size    [3] |  32.29 KiB |
+		|     * Maximum entries [4] |   1.01 k   |
+		|   * Blobs                 |            |
+		|     * Maximum size    [5] |     13 B   |
+		|   * Tags                  |            |
+		|     * Maximum size    [6] |    132 B   |
+
+		[1] 0dc91eb18580102a3a216c8bfecedeba2b9f9b9a
+		[2] 0dc91eb18580102a3a216c8bfecedeba2b9f9b9a
+		[3] 60665251ab71dbd8c18d9bf2174f4ee0d58aa06c
+		[4] 60665251ab71dbd8c18d9bf2174f4ee0d58aa06c
+		[5] 97d808e45116bf02103490294d3d46dad7a2ac62
+		[6] 4dae4f5954f5e6feb3577cfb1b181daa3fd3afd2
 		EOF
 
 		git repo structure >out 2>err &&
@@ -138,6 +169,18 @@ test_expect_success SHA1 'lines and nul format' '
 		objects.trees.disk_size=$(object_type_disk_usage tree)
 		objects.blobs.disk_size=$(object_type_disk_usage blob)
 		objects.tags.disk_size=$(object_type_disk_usage tag)
+		objects.commits.max_size=221
+		objects.commits.max_size_oid=de3508174b5c2ace6993da67cae9be9069e2df39
+		objects.trees.max_size=1335
+		objects.trees.max_size_oid=09931deea9d81ec21300d3e13c74412f32eacec5
+		objects.blobs.max_size=11
+		objects.blobs.max_size_oid=eaeeedced46482bd4281fda5a5f05ce24854151f
+		objects.tags.max_size=132
+		objects.tags.max_size_oid=1ee0f2b16ea37d895dbe9dbd76cd2ac70446176c
+		objects.commits.max_parents=1
+		objects.commits.max_parents_oid=de3508174b5c2ace6993da67cae9be9069e2df39
+		objects.trees.max_entries=42
+		objects.trees.max_entries_oid=09931deea9d81ec21300d3e13c74412f32eacec5
 		EOF
 
 		git repo structure --format=lines >out 2>err &&
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index c58e505c43f9b9..e7829c2c4bfdc3 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -1494,7 +1494,8 @@ test_expect_success 'refuse --edit-description on unborn branch for now' '
 '
 
 test_expect_success '--merged catches invalid object names' '
-	test_must_fail git branch --merged 0000000000000000000000000000000000000000
+	test_must_fail git branch --merged $ZERO_OID 2>err &&
+	test_grep "must point to a commit" err
 '
 
 test_expect_success '--list during rebase' '
diff --git a/t/t3310-notes-merge-manual-resolve.sh b/t/t3310-notes-merge-manual-resolve.sh
index f0054b0a39c541..0bb366fdb8fce1 100755
--- a/t/t3310-notes-merge-manual-resolve.sh
+++ b/t/t3310-notes-merge-manual-resolve.sh
@@ -227,7 +227,8 @@ test_expect_success 'merge z into m (== y) with default ("manual") resolver => C
 	# Verify that current notes tree (pre-merge) has not changed (m == y)
 	verify_notes y &&
 	verify_notes m &&
-	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)"
+	git rev-parse refs/notes/m >actual &&
+	test_cmp pre_merge_y actual
 '
 
 cat <<EOF | sort >expect_notes_z
@@ -375,8 +376,10 @@ EOF
 	git notes merge --commit &&
 	notes_merge_files_gone &&
 	# Merge commit has pre-merge y and pre-merge z as parents
-	test "$(git rev-parse refs/notes/m^1)" = "$(cat pre_merge_y)" &&
-	test "$(git rev-parse refs/notes/m^2)" = "$(cat pre_merge_z)" &&
+	git rev-parse refs/notes/m^1 >actual &&
+	test_cmp pre_merge_y actual &&
+	git rev-parse refs/notes/m^2 >actual &&
+	test_cmp pre_merge_z actual &&
 	# Merge commit mentions the notes refs merged
 	git log -1 --format=%B refs/notes/m > merge_commit_msg &&
 	grep -q refs/notes/m merge_commit_msg &&
@@ -428,14 +431,16 @@ test_expect_success 'redo merge of z into m (== y) with default ("manual") resol
 	# Verify that current notes tree (pre-merge) has not changed (m == y)
 	verify_notes y &&
 	verify_notes m &&
-	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)"
+	git rev-parse refs/notes/m >actual &&
+	test_cmp pre_merge_y actual
 '
 
 test_expect_success 'abort notes merge' '
 	git notes merge --abort &&
 	notes_merge_files_gone &&
 	# m has not moved (still == y)
-	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)" &&
+	git rev-parse refs/notes/m >actual &&
+	test_cmp pre_merge_y actual &&
 	# Verify that other notes refs has not changed (w, x, y and z)
 	verify_notes w &&
 	verify_notes x &&
@@ -460,7 +465,8 @@ test_expect_success 'redo merge of z into m (== y) with default ("manual") resol
 	# Verify that current notes tree (pre-merge) has not changed (m == y)
 	verify_notes y &&
 	verify_notes m &&
-	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)"
+	git rev-parse refs/notes/m >actual &&
+	test_cmp pre_merge_y actual
 '
 
 cat <<EOF | sort >expect_notes_m
@@ -500,8 +506,10 @@ EOF
 	git notes merge --commit &&
 	notes_merge_files_gone &&
 	# Merge commit has pre-merge y and pre-merge z as parents
-	test "$(git rev-parse refs/notes/m^1)" = "$(cat pre_merge_y)" &&
-	test "$(git rev-parse refs/notes/m^2)" = "$(cat pre_merge_z)" &&
+	git rev-parse refs/notes/m^1 >actual &&
+	test_cmp pre_merge_y actual &&
+	git rev-parse refs/notes/m^2 >actual &&
+	test_cmp pre_merge_z actual &&
 	# Merge commit mentions the notes refs merged
 	git log -1 --format=%B refs/notes/m > merge_commit_msg &&
 	grep -q refs/notes/m merge_commit_msg &&
@@ -539,7 +547,8 @@ test_expect_success 'redo merge of z into m (== y) with default ("manual") resol
 	# Verify that current notes tree (pre-merge) has not changed (m == y)
 	verify_notes y &&
 	verify_notes m &&
-	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)"
+	git rev-parse refs/notes/m >actual &&
+	test_cmp pre_merge_y actual
 '
 
 cp expect_notes_w expect_notes_m
@@ -548,7 +557,7 @@ cp expect_log_w expect_log_m
 test_expect_success 'reset notes ref m to somewhere else (w)' '
 	git update-ref refs/notes/m refs/notes/w &&
 	verify_notes m &&
-	test "$(git rev-parse refs/notes/m)" = "$(git rev-parse refs/notes/w)"
+	test_cmp_rev refs/notes/m refs/notes/w
 '
 
 test_expect_success 'fail to finalize conflicting merge if underlying ref has moved in the meantime (m != NOTES_MERGE_PARTIAL^1)' '
@@ -569,13 +578,15 @@ EOF
 	test_path_is_file .git/NOTES_MERGE_WORKTREE/$commit_sha3 &&
 	test_path_is_file .git/NOTES_MERGE_WORKTREE/$commit_sha4 &&
 	# Refs are unchanged
-	test "$(git rev-parse refs/notes/m)" = "$(git rev-parse refs/notes/w)" &&
-	test "$(git rev-parse refs/notes/y)" = "$(git rev-parse NOTES_MERGE_PARTIAL^1)" &&
-	test "$(git rev-parse refs/notes/m)" != "$(git rev-parse NOTES_MERGE_PARTIAL^1)" &&
+	test_cmp_rev refs/notes/m refs/notes/w &&
+	test_cmp_rev refs/notes/y NOTES_MERGE_PARTIAL^1 &&
+	test_cmp_rev ! refs/notes/m NOTES_MERGE_PARTIAL^1 &&
 	# Mention refs/notes/m, and its current and expected value in output
 	test_grep -q "refs/notes/m" output &&
-	test_grep -q "$(git rev-parse refs/notes/m)" output &&
-	test_grep -q "$(git rev-parse NOTES_MERGE_PARTIAL^1)" output &&
+	oid=$(git rev-parse refs/notes/m) &&
+	test_grep -q "$oid" output &&
+	oid=$(git rev-parse NOTES_MERGE_PARTIAL^1) &&
+	test_grep -q "$oid" output &&
 	# Verify that other notes refs has not changed (w, x, y and z)
 	verify_notes w &&
 	verify_notes x &&
@@ -587,7 +598,7 @@ test_expect_success 'resolve situation by aborting the notes merge' '
 	git notes merge --abort &&
 	notes_merge_files_gone &&
 	# m has not moved (still == w)
-	test "$(git rev-parse refs/notes/m)" = "$(git rev-parse refs/notes/w)" &&
+	test_cmp_rev refs/notes/m refs/notes/w &&
 	# Verify that other notes refs has not changed (w, x, y and z)
 	verify_notes w &&
 	verify_notes x &&
@@ -606,8 +617,8 @@ test_expect_success 'switch cwd before committing notes merge' '
 	test_must_fail git notes merge refs/notes/other &&
 	(
 		cd .git/NOTES_MERGE_WORKTREE &&
-		echo "foo" > $(git rev-parse HEAD) &&
-		echo "bar" >> $(git rev-parse HEAD) &&
+		oid=$(git rev-parse HEAD) &&
+		test_write_lines foo bar >"$oid" &&
 		git notes merge --commit
 	) &&
 	git notes show HEAD > actual_notes &&
diff --git a/t/t3440-rebase-trailer.sh b/t/t3440-rebase-trailer.sh
new file mode 100755
index 00000000000000..8b4757956603db
--- /dev/null
+++ b/t/t3440-rebase-trailer.sh
@@ -0,0 +1,147 @@
+#!/bin/sh
+#
+
+test_description='git rebase --trailer integration tests
+We verify that --trailer works with the merge backend,
+and that it is rejected early when the apply backend is requested.'
+
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-rebase.sh # test_commit_message, helpers
+
+REVIEWED_BY_TRAILER="Reviewed-by: Dev <dev@example.com>"
+SP=" "
+
+test_expect_success 'setup repo with a small history' '
+	git commit --allow-empty -m "Initial empty commit" &&
+	test_commit first file a &&
+	test_commit second file &&
+	git checkout -b conflict-branch first &&
+	test_commit file-2 file-2 &&
+	test_commit conflict file &&
+	test_commit third file &&
+	git checkout main
+'
+
+test_expect_success 'apply backend is rejected with --trailer' '
+	git checkout -B apply-backend third &&
+	test_expect_code 128 \
+		git rebase --apply --trailer "$REVIEWED_BY_TRAILER" HEAD^ 2>err &&
+	test_grep "fatal: --trailer requires the merge backend" err
+'
+
+test_expect_success 'reject empty --trailer argument' '
+	git checkout -B empty-trailer third &&
+	test_expect_code 128 git rebase --trailer "" HEAD^ 2>err &&
+	test_grep "empty --trailer" err
+'
+
+test_expect_success 'reject trailer with missing key before separator' '
+	git checkout -B missing-key third &&
+	test_expect_code 128 git rebase --trailer ": no-key" HEAD^ 2>err &&
+	test_grep "missing key before separator" err
+'
+
+test_expect_success 'allow trailer with missing value after separator' '
+	git checkout -B missing-value third &&
+	git rebase --trailer "Acked-by:" HEAD^ &&
+	test_commit_message HEAD <<-EOF
+	third
+
+	Acked-by:${SP}
+	EOF
+'
+
+test_expect_success 'CLI trailer duplicates allowed; replace policy keeps last' '
+	git checkout -B replace-policy third &&
+	git -c trailer.Bug.ifexists=replace -c trailer.Bug.ifmissing=add \
+		rebase --trailer "Bug: 123" --trailer "Bug: 456" HEAD^ &&
+	test_commit_message HEAD <<-EOF
+	third
+
+	Bug: 456
+	EOF
+'
+
+test_expect_success 'multiple Signed-off-by trailers all preserved' '
+	git checkout -B multiple-signoff third &&
+	git rebase --trailer "Signed-off-by: Dev A <a@example.com>" \
+		--trailer "Signed-off-by: Dev B <b@example.com>" HEAD^ &&
+	test_commit_message HEAD <<-EOF
+	third
+
+	Signed-off-by: Dev A <a@example.com>
+	Signed-off-by: Dev B <b@example.com>
+	EOF
+'
+
+test_expect_success 'rebase --trailer adds trailer after conflicts' '
+	git checkout -B trailer-conflict third &&
+	test_commit fourth file &&
+	test_must_fail git rebase --trailer "$REVIEWED_BY_TRAILER" second &&
+	git checkout --theirs file &&
+	git add file &&
+	git rebase --continue &&
+	test_commit_message HEAD <<-EOF &&
+	fourth
+
+	$REVIEWED_BY_TRAILER
+	EOF
+	test_commit_message HEAD^ <<-EOF
+	third
+
+	$REVIEWED_BY_TRAILER
+	EOF
+'
+
+test_expect_success '--trailer handles fixup commands in todo list' '
+	git checkout -B fixup-trailer third &&
+	test_commit fixup-base base &&
+	test_commit fixup-second second &&
+	cat >todo <<-\EOF &&
+	pick fixup-base fixup-base
+	fixup fixup-second fixup-second
+	EOF
+	(
+		set_replace_editor todo &&
+		git rebase -i --trailer "$REVIEWED_BY_TRAILER" HEAD~2
+	) &&
+	test_commit_message HEAD <<-EOF &&
+	fixup-base
+
+	$REVIEWED_BY_TRAILER
+	EOF
+	git reset --hard fixup-second &&
+	cat >todo <<-\EOF &&
+	pick fixup-base fixup-base
+	fixup -C fixup-second fixup-second
+	EOF
+	(
+		set_replace_editor todo &&
+		git rebase -i --trailer "$REVIEWED_BY_TRAILER" HEAD~2
+	) &&
+	test_commit_message HEAD <<-EOF
+	fixup-second
+
+	$REVIEWED_BY_TRAILER
+	EOF
+'
+
+test_expect_success 'rebase --root honors trailer.<name>.key' '
+	git checkout -B root-trailer first &&
+	git -c trailer.review.key=Reviewed-by rebase --root \
+		--trailer=review="Dev <dev@example.com>" &&
+	test_commit_message HEAD <<-EOF &&
+	first
+
+	Reviewed-by: Dev <dev@example.com>
+	EOF
+	test_commit_message HEAD^ <<-EOF
+	Initial empty commit
+
+	Reviewed-by: Dev <dev@example.com>
+	EOF
+'
+test_done
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index bcdb944017da4d..7c67bdf92267f6 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -380,6 +380,107 @@ test_expect_success 'filename limit applies only to basename' '
 	done
 '
 
+test_expect_success 'cover letter with subject, author and count' '
+	rm -rf patches &&
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf patches result test_file" &&
+	touch test_file &&
+	git add test_file &&
+	git commit -m "This is a subject" &&
+	git format-patch --cover-letter \
+	--cover-letter-format="log:[%(count)/%(total)] %s (%an)" -o patches HEAD~1 &&
+	grep "^\[1/1\] This is a subject (A U Thor)$" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
+test_expected_success 'cover letter with author and count' '
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf patches result test_file" &&
+	touch test_file &&
+	git add test_file &&
+	git commit -m "This is a subject" &&
+	git format-patch --cover-letter \
+	--cover-letter-format="log:[%(count)/%(total)] %an" -o patches HEAD~1 &&
+	grep "^\[1/1\] A U Thor$" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
+test_expect_success 'cover letter shortlog' '
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf patches result test_file" &&
+	touch test_file &&
+	git add test_file &&
+	git commit -m "This is a subject" &&
+	git format-patch --cover-letter --cover-letter-format=shortlog \
+	-o patches HEAD~1 &&
+	sed -n -e "/^A U Thor/p;" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
+test_expect_success 'cover letter no format' '
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf patches result test_file" &&
+	touch test_file &&
+	git add test_file &&
+	git commit -m "This is a subject" &&
+	git format-patch --cover-letter -o patches HEAD~1 &&
+	sed -n -e "/^A U Thor/p;" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
+test_expect_success 'cover letter config with count, subject and author' '
+	test_when_finished "rm -rf patches result" &&
+	test_when_finished "git config unset format.coverletter" &&
+	test_when_finished "git config unset format.commitlistformat" &&
+	git config set format.coverletter true &&
+	git config set format.commitlistformat "log:[%(count)/%(total)] %s (%an)" &&
+	git format-patch -o patches HEAD~2 &&
+	grep -E "^[[[:digit:]]+/[[:digit:]]+] .* \(A U Thor\)" patches/0000-cover-letter.patch >result &&
+	test_line_count = 2 result
+'
+
+test_expect_success 'cover letter config with count and author' '
+	test_when_finished "rm -rf patches result" &&
+	test_when_finished "git config unset format.coverletter" &&
+	test_when_finished "git config unset format.commitlistformat" &&
+	git config set format.coverletter true &&
+	git config set format.commitlistformat "log:[%(count)/%(total)] (%an)" &&
+	git format-patch -o patches HEAD~2 &&
+	grep -E "^[[[:digit:]]+/[[:digit:]]+] \(A U Thor\)" patches/0000-cover-letter.patch >result &&
+	test_line_count = 2 result
+'
+
+test_expect_success 'cover letter config commitlistformat set but no format' '
+	test_when_finished "rm -rf patches result" &&
+	test_when_finished "git config unset format.coverletter" &&
+	test_when_finished "git config unset format.commitlistformat" &&
+	git config set format.coverletter true &&
+	printf "\tcommitlistformat" >> .git/config &&
+	git format-patch -o patches HEAD~2 &&
+	grep -E "^[[[:digit:]]+/[[:digit:]]+] .*" patches/0000-cover-letter.patch >result &&
+	test_line_count = 2 result
+'
+
+test_expect_success 'cover letter config commitlistformat set to shortlog' '
+	test_when_finished "rm -rf patches result" &&
+	test_when_finished "git config unset format.coverletter" &&
+	test_when_finished "git config unset format.commitlistformat" &&
+	git config set format.coverletter true &&
+	git config set format.commitlistformat shortlog &&
+	git format-patch -o patches HEAD~2 &&
+	grep -E "^A U Thor \([[:digit:]]+\)" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
+test_expect_success 'cover letter config commitlistformat not set' '
+	test_when_finished "rm -rf patches result" &&
+	test_when_finished "git config unset format.coverletter" &&
+	git config set format.coverletter true &&
+	git format-patch -o patches HEAD~2 &&
+	grep -E "^A U Thor \([[:digit:]]+\)" patches/0000-cover-letter.patch >result &&
+	test_line_count = 1 result
+'
+
 test_expect_success 'reroll count' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter --reroll-count 4 main..side >list &&
diff --git a/t/t5409-colorize-remote-messages.sh b/t/t5409-colorize-remote-messages.sh
index fa5de4500a4f50..3010913bb113e4 100755
--- a/t/t5409-colorize-remote-messages.sh
+++ b/t/t5409-colorize-remote-messages.sh
@@ -98,4 +98,96 @@ test_expect_success 'fallback to color.ui' '
 	grep "<BOLD;RED>error<RESET>: error" decoded
 '
 
+test_expect_success 'disallow (color) control sequences in sideband' '
+	write_script .git/color-me-surprised <<-\EOF &&
+	printf "error: Have you \\033[31mread\\033[m this?\\a\\n" >&2
+	exec "$@"
+	EOF
+	test_config_global uploadPack.packObjectsHook ./color-me-surprised &&
+	test_commit need-at-least-one-commit &&
+
+	git clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >decoded &&
+	test_grep RED decoded &&
+	test_grep "\\^G" stderr &&
+	tr -dc "\\007" <stderr >actual &&
+	test_must_be_empty actual &&
+
+	rm -rf throw-away &&
+	git -c sideband.allowControlCharacters=false \
+		clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >decoded &&
+	test_grep ! RED decoded &&
+	test_grep "\\^G" stderr &&
+
+	rm -rf throw-away &&
+	git -c sideband.allowControlCharacters clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >decoded &&
+	test_grep RED decoded &&
+	tr -dc "\\007" <stderr >actual &&
+	test_file_not_empty actual
+'
+
+test_decode_csi() {
+	awk '{
+		while (match($0, /\033/) != 0) {
+			printf "%sCSI ", substr($0, 1, RSTART-1);
+			$0 = substr($0, RSTART + RLENGTH, length($0) - RSTART - RLENGTH + 1);
+		}
+		print
+	}'
+}
+
+test_expect_success 'control sequences in sideband allowed by default' '
+	write_script .git/color-me-surprised <<-\EOF &&
+	printf "error: \\033[31mcolor\\033[m\\033[Goverwrite\\033[Gerase\\033[K\\033?25l\\n" >&2
+	exec "$@"
+	EOF
+	test_config_global uploadPack.packObjectsHook ./color-me-surprised &&
+	test_commit need-at-least-one-commit-at-least &&
+
+	rm -rf throw-away &&
+	git clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >color-decoded &&
+	test_decode_csi <color-decoded >decoded &&
+	test_grep ! "CSI \\[K" decoded &&
+	test_grep ! "CSI \\[G" decoded &&
+	test_grep "\\^\\[?25l" decoded &&
+
+	rm -rf throw-away &&
+	git -c sideband.allowControlCharacters=erase,cursor,color \
+		clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >color-decoded &&
+	test_decode_csi <color-decoded >decoded &&
+	test_grep "RED" decoded &&
+	test_grep "CSI \\[K" decoded &&
+	test_grep "CSI \\[G" decoded &&
+	test_grep ! "\\^\\[\\[K" decoded &&
+	test_grep ! "\\^\\[\\[G" decoded
+'
+
+test_expect_success 'allow all control sequences for a specific URL' '
+	write_script .git/eraser <<-\EOF &&
+	printf "error: Ohai!\\r\\033[K" >&2
+	exec "$@"
+	EOF
+	test_config_global uploadPack.packObjectsHook ./eraser &&
+	test_commit one-more-please &&
+
+	rm -rf throw-away &&
+	git clone --no-local . throw-away 2>stderr &&
+	test_decode_color <stderr >color-decoded &&
+	test_decode_csi <color-decoded >decoded &&
+	test_grep ! "CSI \\[K" decoded &&
+	test_grep "\\^\\[\\[K" decoded &&
+
+	rm -rf throw-away &&
+	git -c "sideband.file://.allowControlCharacters=true" \
+		clone --no-local "file://$PWD" throw-away 2>stderr &&
+	test_decode_color <stderr >color-decoded &&
+	test_decode_csi <color-decoded >decoded &&
+	test_grep "CSI \\[K" decoded &&
+	test_grep ! "\\^\\[\\[K" decoded
+'
+
 test_done
diff --git a/t/t6112-rev-list-filters-objects.sh b/t/t6112-rev-list-filters-objects.sh
index 0387f35a326d74..39211ef989cc58 100755
--- a/t/t6112-rev-list-filters-objects.sh
+++ b/t/t6112-rev-list-filters-objects.sh
@@ -483,10 +483,6 @@ test_expect_success 'combine:... with non-encoded reserved chars' '
 		"must escape char in sub-filter-spec: .\~."
 '
 
-test_expect_success 'validate err msg for "combine:<valid-filter>+"' '
-	expect_invalid_filter_spec combine:tree:2+ "expected .tree:<depth>."
-'
-
 test_expect_success 'combine:... with edge-case hex digits: Ff Aa 0 9' '
 	git -C r3 rev-list --objects --filter="combine:tree:2+bl%6Fb:n%6fne" \
 		HEAD >actual &&
diff --git a/t/t9200-git-cvsexportcommit.sh b/t/t9200-git-cvsexportcommit.sh
index a44eabf0d80fa8..14cbe9652779bc 100755
--- a/t/t9200-git-cvsexportcommit.sh
+++ b/t/t9200-git-cvsexportcommit.sh
@@ -30,13 +30,17 @@ export CVSROOT CVSWORK GIT_DIR
 
 rm -rf "$CVSROOT" "$CVSWORK"
 
-cvs init &&
-test -d "$CVSROOT" &&
-cvs -Q co -d "$CVSWORK" . &&
-echo >empty &&
-git add empty &&
-git commit -q -a -m "Initial" 2>/dev/null ||
-exit 1
+if ! cvs init || ! test -d "$CVSROOT" || ! cvs -Q co -d "$CVSWORK" .
+then
+	skip_all="cvs repository set-up fails"
+	test_done
+fi
+
+test_expect_success 'git setup' '
+	echo >empty &&
+	git add empty &&
+	git commit -q -a -m Initial
+'
 
 check_entries () {
 	# $1 == directory, $2 == expected
@@ -303,7 +307,7 @@ test_expect_success 're-commit a removed filename which remains in CVS attic' '
 	git commit -m "Added attic_gremlin" &&
 	git cvsexportcommit -w "$CVSWORK" -c HEAD &&
 	(cd "$CVSWORK" && cvs -Q update -d) &&
-	test -f "$CVSWORK/attic_gremlin"
+	test_path_is_file "$CVSWORK/attic_gremlin"
 '
 
 # the state of the CVS sandbox may be indeterminate for ' space'
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 2f9a597ec7f493..35e20b53511499 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -2775,6 +2775,7 @@ test_expect_success PERL 'send-email' '
 	test_completion "git send-email --cov" <<-\EOF &&
 	--cover-from-description=Z
 	--cover-letter Z
+	--cover-letter-format=Z
 	EOF
 	test_completion "git send-email --val" <<-\EOF &&
 	--validate Z
diff --git a/t/unit-tests/test-lib.c b/t/unit-tests/test-lib.c
index 87e1f5c201f253..72ee20a06f3951 100644
--- a/t/unit-tests/test-lib.c
+++ b/t/unit-tests/test-lib.c
@@ -396,8 +396,23 @@ int check_uint_loc(const char *loc, const char *check, int ok,
 static void print_one_char(char ch, char quote)
 {
 	if ((unsigned char)ch < 0x20u || ch == 0x7f) {
-		/* TODO: improve handling of \a, \b, \f ... */
-		printf("\\%03o", (unsigned char)ch);
+		char esc;
+		switch (ch) {
+		case '\a': esc = 'a'; break;
+		case '\b': esc = 'b'; break;
+		case '\t': esc = 't'; break;
+		case '\n': esc = 'n'; break;
+		case '\v': esc = 'v'; break;
+		case '\f': esc = 'f'; break;
+		case '\r': esc = 'r'; break;
+		default: esc = 0; break;
+		}
+		if (esc) {
+			putc('\\', stdout);
+			putc(esc, stdout);
+		} else {
+			printf("\\%03o", (unsigned char)ch);
+		}
 	} else {
 		if (ch == '\\' || ch == quote)
 			putc('\\', stdout);
diff --git a/trailer.c b/trailer.c
index 911a81ed993ec6..ca8abd18826bf2 100644
--- a/trailer.c
+++ b/trailer.c
@@ -7,8 +7,11 @@
 #include "string-list.h"
 #include "run-command.h"
 #include "commit.h"
+#include "strvec.h"
 #include "trailer.h"
 #include "list.h"
+#include "tempfile.h"
+
 /*
  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  */
@@ -772,6 +775,35 @@ void parse_trailers_from_command_line_args(struct list_head *arg_head,
 	free(cl_separators);
 }
 
+int validate_trailer_args(const struct strvec *cli_args)
+{
+	char *cl_separators;
+	int ret = 0;
+
+	trailer_config_init();
+
+	cl_separators = xstrfmt("=%s", separators);
+
+	for (size_t i = 0; i < cli_args->nr; i++) {
+		const char *txt = cli_args->v[i];
+		ssize_t separator_pos;
+
+		if (!*txt) {
+			ret = error(_("empty --trailer argument"));
+			goto out;
+		}
+		separator_pos = find_separator(txt, cl_separators);
+		if (separator_pos == 0) {
+			ret = error(_("invalid trailer '%s': missing key before separator"),
+				    txt);
+			goto out;
+		}
+	}
+out:
+	free(cl_separators);
+	return ret;
+}
+
 static const char *next_line(const char *str)
 {
 	const char *nl = strchrnul(str, '\n');
@@ -1224,14 +1256,146 @@ void trailer_iterator_release(struct trailer_iterator *iter)
 	strbuf_release(&iter->key);
 }
 
-int amend_file_with_trailers(const char *path, const struct strvec *trailer_args)
+struct tempfile *trailer_create_in_place_tempfile(const char *file)
+{
+	struct tempfile *tempfile = NULL;
+	struct stat st;
+	struct strbuf filename_template = STRBUF_INIT;
+	const char *tail;
+
+	if (stat(file, &st)) {
+		error_errno(_("could not stat %s"), file);
+		return NULL;
+	}
+	if (!S_ISREG(st.st_mode)) {
+		error(_("file %s is not a regular file"), file);
+		return NULL;
+	}
+	if (!(st.st_mode & S_IWUSR)) {
+		error(_("file %s is not writable by user"), file);
+		return NULL;
+	}
+	/* Create temporary file in the same directory as the original */
+	tail = find_last_dir_sep(file);
+	if (tail)
+		strbuf_add(&filename_template, file, tail - file + 1);
+	strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
+
+	tempfile = mks_tempfile_m(filename_template.buf, st.st_mode);
+
+	strbuf_release(&filename_template);
+
+	return tempfile;
+}
+
+int amend_strbuf_with_trailers(struct strbuf *buf,
+				const struct strvec *trailer_args)
 {
-	struct child_process run_trailer = CHILD_PROCESS_INIT;
-
-	run_trailer.git_cmd = 1;
-	strvec_pushl(&run_trailer.args, "interpret-trailers",
-		     "--in-place", "--no-divider",
-		     path, NULL);
-	strvec_pushv(&run_trailer.args, trailer_args->v);
-	return run_command(&run_trailer);
+	struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
+	LIST_HEAD(new_trailer_head);
+	struct strbuf out = STRBUF_INIT;
+	size_t i;
+	int ret = 0;
+
+	opts.no_divider = 1;
+
+	for (i = 0; i < trailer_args->nr; i++) {
+		const char *text = trailer_args->v[i];
+		struct new_trailer_item *item;
+
+		if (!*text) {
+			ret = error(_("empty --trailer argument"));
+			goto out;
+		}
+		item = xcalloc(1, sizeof(*item));
+		item->text = xstrdup(text);
+		list_add_tail(&item->list, &new_trailer_head);
+	}
+
+	process_trailers(&opts, &new_trailer_head, buf, &out);
+
+	strbuf_swap(buf, &out);
+out:
+	strbuf_release(&out);
+	free_trailers(&new_trailer_head);
+
+	return ret;
+}
+
+static int write_file_in_place(const char *path, const struct strbuf *buf)
+{
+	struct tempfile *tempfile = trailer_create_in_place_tempfile(path);
+	if (!tempfile)
+		return -1;
+
+	if (write_in_full(tempfile->fd, buf->buf, buf->len) < 0)
+		return error_errno(_("could not write to temporary file"));
+
+	if (rename_tempfile(&tempfile, path))
+		return error_errno(_("could not rename temporary file to %s"), path);
+
+	return 0;
+}
+
+int amend_file_with_trailers(const char *path,
+			     const struct strvec *trailer_args)
+{
+	struct strbuf buf = STRBUF_INIT;
+	int ret = 0;
+
+	if (!trailer_args)
+		BUG("amend_file_with_trailers called with NULL trailer_args");
+	if (!trailer_args->nr)
+		return 0;
+
+	if (validate_trailer_args(trailer_args)) {
+		ret = -1;
+		goto out;
+	}
+	if (strbuf_read_file(&buf, path, 0) < 0)
+		ret = error_errno(_("could not read '%s'"), path);
+	else
+		amend_strbuf_with_trailers(&buf, trailer_args);
+
+	if (!ret)
+		ret = write_file_in_place(path, &buf);
+out:
+	strbuf_release(&buf);
+	return ret;
+}
+
+void process_trailers(const struct process_trailer_options *opts,
+		      struct list_head *new_trailer_head,
+		      struct strbuf *input, struct strbuf *out)
+{
+	LIST_HEAD(head);
+	struct trailer_block *trailer_block;
+
+	trailer_block = parse_trailers(opts, input->buf, &head);
+
+	/* Print the lines before the trailer block */
+	if (!opts->only_trailers)
+		strbuf_add(out, input->buf, trailer_block_start(trailer_block));
+
+	if (!opts->only_trailers && !blank_line_before_trailer_block(trailer_block))
+		strbuf_addch(out, '\n');
+
+	if (!opts->only_input) {
+		LIST_HEAD(config_head);
+		LIST_HEAD(arg_head);
+		parse_trailers_from_config(&config_head);
+		parse_trailers_from_command_line_args(&arg_head, new_trailer_head);
+		list_splice(&config_head, &arg_head);
+		process_trailers_lists(&head, &arg_head);
+	}
+
+	/* Print trailer block. */
+	format_trailers(opts, &head, out);
+	free_trailers(&head);
+
+	/* Print the lines after the trailer block as is. */
+	if (!opts->only_trailers)
+		strbuf_add(out, input->buf + trailer_block_end(trailer_block),
+			   input->len - trailer_block_end(trailer_block));
+	trailer_block_release(trailer_block);
 }
diff --git a/trailer.h b/trailer.h
index 4740549586a8e5..b49338858c482a 100644
--- a/trailer.h
+++ b/trailer.h
@@ -68,6 +68,8 @@ void parse_trailers_from_config(struct list_head *config_head);
 void parse_trailers_from_command_line_args(struct list_head *arg_head,
 					   struct list_head *new_trailer_head);
 
+int validate_trailer_args(const struct strvec *cli_args);
+
 void process_trailers_lists(struct list_head *head,
 			    struct list_head *arg_head);
 
@@ -196,10 +198,38 @@ int trailer_iterator_advance(struct trailer_iterator *iter);
 void trailer_iterator_release(struct trailer_iterator *iter);
 
 /*
- * Augment a file to add trailers to it by running git-interpret-trailers.
- * This calls run_command() and its return value is the same (i.e. 0 for
- * success, various non-zero for other errors). See run-command.h.
+ * Append trailers specified in trailer_args to buf in-place.
+ *
+ * Each element of trailer_args should be in the same format as the value
+ * accepted by --trailer=<trailer> (i.e., without the --trailer= prefix).
+ */
+int amend_strbuf_with_trailers(struct strbuf *buf,
+				const struct strvec *trailer_args);
+
+/*
+ * Augment a file by appending trailers specified in trailer_args.
+ *
+ * Each element of trailer_args should be in the same format as the value
+ * accepted by --trailer=<trailer> (i.e., without the --trailer= prefix).
+ *
+ * Returns 0 on success or a non-zero error code on failure.
  */
 int amend_file_with_trailers(const char *path, const struct strvec *trailer_args);
 
+/*
+ * Create a tempfile ""git-interpret-trailers-XXXXXX" in the same
+ * directory as file.
+ */
+struct tempfile *trailer_create_in_place_tempfile(const char *file);
+
+/*
+ * Rewrite the contents of input by processing its trailer block according to
+ * opts and (optionally) appending trailers from new_trailer_head.
+ *
+ * The rewritten message is appended to out (callers should strbuf_reset()
+ * first if needed).
+ */
+void process_trailers(const struct process_trailer_options *opts,
+		      struct list_head *new_trailer_head,
+		      struct strbuf *input, struct strbuf *out);
 #endif /* TRAILER_H */
diff --git a/transport.c b/transport.c
index 107f4fa5dce96a..259e9d7b701121 100644
--- a/transport.c
+++ b/transport.c
@@ -29,6 +29,7 @@
 #include "object-name.h"
 #include "color.h"
 #include "bundle-uri.h"
+#include "sideband.h"
 
 static enum git_colorbool transport_use_color = GIT_COLOR_UNKNOWN;
 static char transport_colors[][COLOR_MAXLEN] = {
@@ -1246,6 +1247,8 @@ struct transport *transport_get(struct remote *remote, const char *url)
 
 	ret->hash_algo = &hash_algos[GIT_HASH_SHA1_LEGACY];
 
+	sideband_apply_url_config(ret->url);
+
 	return ret;
 }
 
diff --git a/worktree.c b/worktree.c
index e9ff6e6ef2eb58..56732f8f3312bf 100644
--- a/worktree.c
+++ b/worktree.c
@@ -445,7 +445,7 @@ void update_worktree_location(struct worktree *wt, const char *path_,
 	strbuf_realpath(&path, path_, 1);
 	strbuf_addf(&dotgit, "%s/.git", path.buf);
 	if (fspathcmp(wt->path, path.buf)) {
-		write_worktree_linking_files(dotgit, gitdir, use_relative_paths);
+		write_worktree_linking_files(dotgit.buf, gitdir.buf, use_relative_paths);
 
 		free(wt->path);
 		wt->path = strbuf_detach(&path, NULL);
@@ -673,7 +673,8 @@ static void repair_gitfile(struct worktree *wt,
 		}
 	}
 
-	if (err == READ_GITFILE_ERR_NOT_A_FILE)
+	if (err == READ_GITFILE_ERR_NOT_A_FILE ||
+		err == READ_GITFILE_ERR_IS_A_DIR)
 		fn(1, wt->path, _(".git is not a file"), cb_data);
 	else if (err)
 		repair = _(".git file broken");
@@ -684,7 +685,7 @@ static void repair_gitfile(struct worktree *wt,
 
 	if (repair) {
 		fn(0, wt->path, repair, cb_data);
-		write_worktree_linking_files(dotgit, gitdir, use_relative_paths);
+		write_worktree_linking_files(dotgit.buf, gitdir.buf, use_relative_paths);
 	}
 
 done:
@@ -742,7 +743,7 @@ void repair_worktree_after_gitdir_move(struct worktree *wt, const char *old_path
 	if (!file_exists(dotgit.buf))
 		goto done;
 
-	write_worktree_linking_files(dotgit, gitdir, is_relative_path);
+	write_worktree_linking_files(dotgit.buf, gitdir.buf, is_relative_path);
 done:
 	strbuf_release(&gitdir);
 	strbuf_release(&dotgit);
@@ -853,7 +854,8 @@ void repair_worktree_at_path(const char *path,
 			strbuf_addstr(&backlink, dotgit_contents);
 			strbuf_realpath_forgiving(&backlink, backlink.buf, 0);
 		}
-	} else if (err == READ_GITFILE_ERR_NOT_A_FILE) {
+	} else if (err == READ_GITFILE_ERR_NOT_A_FILE ||
+			err == READ_GITFILE_ERR_IS_A_DIR) {
 		fn(1, dotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
 		goto done;
 	} else if (err == READ_GITFILE_ERR_NOT_A_REPO) {
@@ -913,7 +915,7 @@ void repair_worktree_at_path(const char *path,
 
 	if (repair) {
 		fn(0, gitdir.buf, repair, cb_data);
-		write_worktree_linking_files(dotgit, gitdir, use_relative_paths);
+		write_worktree_linking_files(dotgit.buf, gitdir.buf, use_relative_paths);
 	}
 done:
 	free(dotgit_contents);
@@ -1087,17 +1089,17 @@ int init_worktree_config(struct repository *r)
 	return res;
 }
 
-void write_worktree_linking_files(struct strbuf dotgit, struct strbuf gitdir,
+void write_worktree_linking_files(const char *dotgit, const char *gitdir,
 				  int use_relative_paths)
 {
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf repo = STRBUF_INIT;
 	struct strbuf tmp = STRBUF_INIT;
 
-	strbuf_addbuf(&path, &dotgit);
+	strbuf_addstr(&path, dotgit);
 	strbuf_strip_suffix(&path, "/.git");
 	strbuf_realpath(&path, path.buf, 1);
-	strbuf_addbuf(&repo, &gitdir);
+	strbuf_addstr(&repo, gitdir);
 	strbuf_strip_suffix(&repo, "/gitdir");
 	strbuf_realpath(&repo, repo.buf, 1);
 
@@ -1110,11 +1112,11 @@ void write_worktree_linking_files(struct strbuf dotgit, struct strbuf gitdir,
 	}
 
 	if (use_relative_paths) {
-		write_file(gitdir.buf, "%s/.git", relative_path(path.buf, repo.buf, &tmp));
-		write_file(dotgit.buf, "gitdir: %s", relative_path(repo.buf, path.buf, &tmp));
+		write_file(gitdir, "%s/.git", relative_path(path.buf, repo.buf, &tmp));
+		write_file(dotgit, "gitdir: %s", relative_path(repo.buf, path.buf, &tmp));
 	} else {
-		write_file(gitdir.buf, "%s/.git", path.buf);
-		write_file(dotgit.buf, "gitdir: %s", repo.buf);
+		write_file(gitdir, "%s/.git", path.buf);
+		write_file(dotgit, "gitdir: %s", repo.buf);
 	}
 
 	strbuf_release(&path);
diff --git a/worktree.h b/worktree.h
index e450d1a3317e23..026ef303e81f5a 100644
--- a/worktree.h
+++ b/worktree.h
@@ -240,7 +240,7 @@ int init_worktree_config(struct repository *r);
  *  dotgit: "/path/to/foo/.git"
  *  gitdir: "/path/to/repo/worktrees/foo/gitdir"
  */
-void write_worktree_linking_files(struct strbuf dotgit, struct strbuf gitdir,
+void write_worktree_linking_files(const char *dotgit, const char *gitdir,
 				  int use_relative_paths);
 
 #endif
diff --git a/wt-status.c b/wt-status.c
index 543000311fd615..479ccc3304bc33 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -150,11 +150,11 @@ void wt_status_prepare(struct repository *r, struct wt_status *s)
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = GIT_COLOR_UNKNOWN;
 	s->relative_paths = 1;
-	s->branch = refs_resolve_refdup(get_main_ref_store(the_repository),
+	s->branch = refs_resolve_refdup(get_main_ref_store(r),
 					"HEAD", 0, NULL, NULL);
 	s->reference = "HEAD";
 	s->fp = stdout;
-	s->index_file = repo_get_index_file(the_repository);
+	s->index_file = repo_get_index_file(r);
 	s->change.strdup_strings = 1;
 	s->untracked.strdup_strings = 1;
 	s->ignored.strdup_strings = 1;
@@ -670,7 +670,7 @@ static void wt_status_collect_changes_index(struct wt_status *s)
 
 	repo_init_revisions(s->repo, &rev, NULL);
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? empty_tree_oid_hex(the_repository->hash_algo) : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex(s->repo->hash_algo) : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.flags.override_submodule_config = 1;
@@ -1008,17 +1008,17 @@ static int stash_count_refs(const char *refname UNUSED,
 	return 0;
 }
 
-static int count_stash_entries(void)
+static int count_stash_entries(struct repository *r)
 {
 	int n = 0;
-	refs_for_each_reflog_ent(get_main_ref_store(the_repository),
+	refs_for_each_reflog_ent(get_main_ref_store(r),
 				 "refs/stash", stash_count_refs, &n);
 	return n;
 }
 
 static void wt_longstatus_print_stash_summary(struct wt_status *s)
 {
-	int stash_count = count_stash_entries();
+	int stash_count = count_stash_entries(s->repo);
 
 	if (stash_count > 0)
 		status_printf_ln(s, GIT_COLOR_NORMAL,
@@ -1170,7 +1170,7 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	rev.diffopt.ita_invisible_in_index = 1;
 
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? empty_tree_oid_hex(the_repository->hash_algo) : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex(s->repo->hash_algo) : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
@@ -1311,10 +1311,10 @@ static void show_am_in_progress(struct wt_status *s,
 	wt_longstatus_print_trailer(s);
 }
 
-static char *read_line_from_git_path(const char *filename)
+static char *read_line_from_git_path(struct repository *r, const char *filename)
 {
 	struct strbuf buf = STRBUF_INIT;
-	FILE *fp = fopen_or_warn(repo_git_path_append(the_repository, &buf,
+	FILE *fp = fopen_or_warn(repo_git_path_append(r, &buf,
 						      "%s", filename), "r");
 
 	if (!fp) {
@@ -1341,16 +1341,16 @@ static int split_commit_in_progress(struct wt_status *s)
 	    !s->branch || strcmp(s->branch, "HEAD"))
 		return 0;
 
-	if (refs_read_ref_full(get_main_ref_store(the_repository), "HEAD", RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+	if (refs_read_ref_full(get_main_ref_store(s->repo), "HEAD", RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
 			       &head_oid, &head_flags) ||
-	    refs_read_ref_full(get_main_ref_store(the_repository), "ORIG_HEAD", RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+	    refs_read_ref_full(get_main_ref_store(s->repo), "ORIG_HEAD", RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
 			       &orig_head_oid, &orig_head_flags))
 		return 0;
 	if (head_flags & REF_ISSYMREF || orig_head_flags & REF_ISSYMREF)
 		return 0;
 
-	rebase_amend = read_line_from_git_path("rebase-merge/amend");
-	rebase_orig_head = read_line_from_git_path("rebase-merge/orig-head");
+	rebase_amend = read_line_from_git_path(s->repo, "rebase-merge/amend");
+	rebase_orig_head = read_line_from_git_path(s->repo, "rebase-merge/orig-head");
 
 	if (!rebase_amend || !rebase_orig_head)
 		; /* fall through, no split in progress */
@@ -1374,7 +1374,7 @@ static int split_commit_in_progress(struct wt_status *s)
  * The function assumes that the line does not contain useless spaces
  * before or after the command.
  */
-static void abbrev_oid_in_line(struct strbuf *line)
+static void abbrev_oid_in_line(struct repository *r, struct strbuf *line)
 {
 	struct string_list split = STRING_LIST_INIT_DUP;
 	struct object_id oid;
@@ -1386,7 +1386,7 @@ static void abbrev_oid_in_line(struct strbuf *line)
 		return;
 
 	if ((2 <= string_list_split(&split, line->buf, " ", 2)) &&
-	    !repo_get_oid(the_repository, split.items[1].string, &oid)) {
+	    !repo_get_oid(r, split.items[1].string, &oid)) {
 		strbuf_reset(line);
 		strbuf_addf(line, "%s ", split.items[0].string);
 		strbuf_add_unique_abbrev(line, &oid, DEFAULT_ABBREV);
@@ -1396,10 +1396,10 @@ static void abbrev_oid_in_line(struct strbuf *line)
 	string_list_clear(&split, 0);
 }
 
-static int read_rebase_todolist(const char *fname, struct string_list *lines)
+static int read_rebase_todolist(struct repository *r, const char *fname, struct string_list *lines)
 {
 	struct strbuf buf = STRBUF_INIT;
-	FILE *f = fopen(repo_git_path_append(the_repository, &buf, "%s", fname), "r");
+	FILE *f = fopen(repo_git_path_append(r, &buf, "%s", fname), "r");
 	int ret;
 
 	if (!f) {
@@ -1408,7 +1408,7 @@ static int read_rebase_todolist(const char *fname, struct string_list *lines)
 			goto out;
 		}
 		die_errno("Could not open file %s for reading",
-			  repo_git_path_replace(the_repository, &buf, "%s", fname));
+			  repo_git_path_replace(r, &buf, "%s", fname));
 	}
 	while (!strbuf_getline_lf(&buf, f)) {
 		if (starts_with(buf.buf, comment_line_str))
@@ -1416,7 +1416,7 @@ static int read_rebase_todolist(const char *fname, struct string_list *lines)
 		strbuf_trim(&buf);
 		if (!buf.len)
 			continue;
-		abbrev_oid_in_line(&buf);
+		abbrev_oid_in_line(r, &buf);
 		string_list_append(lines, buf.buf);
 	}
 	fclose(f);
@@ -1437,8 +1437,8 @@ static void show_rebase_information(struct wt_status *s,
 		struct string_list have_done = STRING_LIST_INIT_DUP;
 		struct string_list yet_to_do = STRING_LIST_INIT_DUP;
 
-		read_rebase_todolist("rebase-merge/done", &have_done);
-		if (read_rebase_todolist("rebase-merge/git-rebase-todo",
+		read_rebase_todolist(s->repo, "rebase-merge/done", &have_done);
+		if (read_rebase_todolist(s->repo, "rebase-merge/git-rebase-todo",
 					 &yet_to_do))
 			status_printf_ln(s, color,
 				_("git-rebase-todo is missing."));
@@ -1456,7 +1456,7 @@ static void show_rebase_information(struct wt_status *s,
 				i++)
 				status_printf_ln(s, color, "   %s", have_done.items[i].string);
 			if (have_done.nr > nr_lines_to_show && s->hints) {
-				char *path = repo_git_path(the_repository, "rebase-merge/done");
+				char *path = repo_git_path(s->repo, "rebase-merge/done");
 				status_printf_ln(s, color,
 					_("  (see more in file %s)"), path);
 				free(path);
@@ -1558,7 +1558,7 @@ static void show_cherry_pick_in_progress(struct wt_status *s,
 	else
 		status_printf_ln(s, color,
 			_("You are currently cherry-picking commit %s."),
-			repo_find_unique_abbrev(the_repository, &s->state.cherry_pick_head_oid,
+			repo_find_unique_abbrev(s->repo, &s->state.cherry_pick_head_oid,
 						DEFAULT_ABBREV));
 
 	if (s->hints) {
@@ -1588,7 +1588,7 @@ static void show_revert_in_progress(struct wt_status *s,
 	else
 		status_printf_ln(s, color,
 			_("You are currently reverting commit %s."),
-			repo_find_unique_abbrev(the_repository, &s->state.revert_head_oid,
+			repo_find_unique_abbrev(s->repo, &s->state.revert_head_oid,
 						DEFAULT_ABBREV));
 	if (s->hints) {
 		if (has_unmerged(s))
@@ -1715,7 +1715,7 @@ static void wt_status_get_detached_from(struct repository *r,
 	char *ref = NULL;
 
 	strbuf_init(&cb.buf, 0);
-	if (refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository), "HEAD", grab_1st_switch, &cb) <= 0) {
+	if (refs_for_each_reflog_ent_reverse(get_main_ref_store(r), "HEAD", grab_1st_switch, &cb) <= 0) {
 		strbuf_release(&cb.buf);
 		return;
 	}
@@ -1848,10 +1848,10 @@ void wt_status_get_state(struct repository *r,
 	if (!sequencer_get_last_command(r, &action)) {
 		if (action == REPLAY_PICK && !state->cherry_pick_in_progress) {
 			state->cherry_pick_in_progress = 1;
-			oidcpy(&state->cherry_pick_head_oid, null_oid(the_hash_algo));
+			oidcpy(&state->cherry_pick_head_oid, null_oid(r->hash_algo));
 		} else if (action == REPLAY_REVERT && !state->revert_in_progress) {
 			state->revert_in_progress = 1;
-			oidcpy(&state->revert_head_oid, null_oid(the_hash_algo));
+			oidcpy(&state->revert_head_oid, null_oid(r->hash_algo));
 		}
 	}
 	if (get_detached_from)
@@ -2134,7 +2134,7 @@ static void wt_shortstatus_print_tracking(struct wt_status *s)
 		upstream_is_gone = 1;
 	}
 
-	short_base = refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
+	short_base = refs_shorten_unambiguous_ref(get_main_ref_store(s->repo),
 						  base, 0);
 	color_fprintf(s->fp, header_color, "...");
 	color_fprintf(s->fp, branch_color_remote, "%s", short_base);
@@ -2268,7 +2268,7 @@ static void wt_porcelain_v2_print_tracking(struct wt_status *s)
 		ab_info = stat_tracking_info(branch, &nr_ahead, &nr_behind,
 					     &base, 0, s->ahead_behind_flags);
 		if (base) {
-			base = refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
+			base = refs_shorten_unambiguous_ref(get_main_ref_store(s->repo),
 							    base, 0);
 			fprintf(s->fp, "# branch.upstream %s%c", base, eol);
 			free((char *)base);
@@ -2294,7 +2294,7 @@ static void wt_porcelain_v2_print_tracking(struct wt_status *s)
  */
 static void wt_porcelain_v2_print_stash(struct wt_status *s)
 {
-	int stash_count = count_stash_entries();
+	int stash_count = count_stash_entries(s->repo);
 	char eol = s->null_termination ? '\0' : '\n';
 
 	if (stash_count > 0)
@@ -2665,7 +2665,7 @@ int has_uncommitted_changes(struct repository *r,
 		 * We have no head (or it's corrupt); use the empty tree,
 		 * which will complain if the index is non-empty.
 		 */
-		struct tree *tree = lookup_tree(r, the_hash_algo->empty_tree);
+		struct tree *tree = lookup_tree(r, r->hash_algo->empty_tree);
 		add_pending_object(&rev_info, &tree->object, "");
 	}