34 files changed, 270 insertions, 92 deletions

diff --git a/.clang-format b/.clang-format
index 56822c116b..611ab4750b 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,4 +1,8 @@
-# Defaults
+# This file is an example configuration for clang-format 5.0.
+#
+# Note that this style definition should only be understood as a hint
+# for writing new code. The rules are still work-in-progress and does
+# not yet exactly match the style we have in the existing code.
 
 # Use tabs whenever we need to fill whitespace that spans at least from one tab
 # stop to the next one.
diff --git a/Documentation/RelNotes/2.15.0.txt b/Documentation/RelNotes/2.15.0.txt
index face5e0b02..1be62c9e27 100644
--- a/Documentation/RelNotes/2.15.0.txt
+++ b/Documentation/RelNotes/2.15.0.txt
@@ -219,6 +219,9 @@ Performance, Internal Implementation, Development Support etc.
    pre-parse everything, and an access to a single ref in the
    packed-refs does not touch majority of irrelevant refs, either.
 
+ * Add comment to clarify that the style file is meant to be used with
+   clang-5 and the rules are still work in progress.
+
 Also contains various documentation updates and code clean-ups.
 
 
@@ -442,6 +445,16 @@ Fixes since v2.14
    correctly, which has been corrected.
    (merge a6304fa4c2 bc/rev-parse-parseopt-fix later to maint).
 
+ * The checkpoint command "git fast-import" did not flush updates to
+   refs and marks unless at least one object was created since the
+   last checkpoint, which has been corrected, as these things can
+   happen without any new object getting created.
+   (merge 30e215a65c er/fast-import-dump-refs-on-checkpoint later to maint).
+
+ * Spell the name of our system as "Git" in the output from
+   request-pull script.
+   (merge e66d7c37a5 ar/request-pull-phrasofix later to maint).
+
  * Other minor doc, test and build updates and code cleanups.
    (merge f094b89a4d ma/parse-maybe-bool later to maint).
    (merge 39b00fa4d4 jk/drop-sha1-entry-pos later to maint).
@@ -465,3 +478,6 @@ Fixes since v2.14
    (merge 0bca165fdb jk/validate-headref-fix later to maint).
    (merge 93dbefb389 mr/doc-negative-pathspec later to maint).
    (merge 5e633326e4 ad/doc-markup-fix later to maint).
+   (merge 9ca356fa8b rs/cocci-de-paren-call-params later to maint).
+   (merge 7099153e8d rs/tag-null-pointer-arith-fix later to maint).
+   (merge 0e187d758c rs/run-command-use-alloc-array later to maint).
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index 75beb2e775..ab04c977be 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.14.GIT
+DEF_VER=v2.15.0-rc0
 
 LF='
 '
diff --git a/builtin/branch.c b/builtin/branch.c
index b998e16d0c..d7a876cca3 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -217,7 +217,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		if (!head_rev)
 			die(_("Couldn't look up commit object for HEAD"));
 	}
-	for (i = 0; i < argc; i++, strbuf_release(&bname)) {
+	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
 		char *target = NULL;
 		int flags = 0;
 
@@ -282,8 +282,9 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 	}
 
 	free(name);
+	strbuf_release(&bname);
 
-	return(ret);
+	return ret;
 }
 
 static int calc_maxwidth(struct ref_array *refs, int remote_bonus)
@@ -353,7 +354,7 @@ static char *build_format(struct ref_filter *filter, int maxwidth, const char *r
 			strbuf_addf(&obname, "%%(objectname:short=%d)", filter->abbrev);
 
 		strbuf_addf(&local, "%%(align:%d,left)%%(refname:lstrip=2)%%(end)", maxwidth);
-		strbuf_addf(&local, "%s", branch_get_color(BRANCH_COLOR_RESET));
+		strbuf_addstr(&local, branch_get_color(BRANCH_COLOR_RESET));
 		strbuf_addf(&local, " %s ", obname.buf);
 
 		if (filter->verbose > 1)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 3345a0d16f..fc4f8fd2ea 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1124,9 +1124,8 @@ static int checkout_branch(struct checkout_opts *opts,
 
 	if (new->path && !opts->force_detach && !opts->new_branch &&
 	    !opts->ignore_other_worktrees) {
-		struct object_id oid;
 		int flag;
-		char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
+		char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
 		if (head_ref &&
 		    (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
 			die_if_checked_out(new->path, 1);
@@ -1298,6 +1297,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		strbuf_release(&buf);
 	}
 
+	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr)
 		return checkout_paths(&opts, new.name);
 	else
diff --git a/builtin/diff-index.c b/builtin/diff-index.c
index 9d772f8f27..522f4fdffd 100644
--- a/builtin/diff-index.c
+++ b/builtin/diff-index.c
@@ -56,5 +56,6 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
 		return -1;
 	}
 	result = run_diff_index(&rev, cached);
+	UNLEAK(rev);
 	return diff_result_code(&rev.diffopt, result);
 }
diff --git a/builtin/diff.c b/builtin/diff.c
index 7e3ebcea38..f5bbd4d757 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -464,5 +464,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	result = diff_result_code(&rev.diffopt, result);
 	if (1 < rev.diffopt.skip_stat_unmatch)
 		refresh_index_quietly();
+	UNLEAK(rev);
+	UNLEAK(ent);
+	UNLEAK(blob);
 	return result;
 }
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 598da6c8bc..9e088ebd11 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -494,5 +494,6 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 				  always, allow_undefined, data.name_only);
 	}
 
+	UNLEAK(revs);
 	return 0;
 }
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 29a0f3b75f..cc48767405 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1458,7 +1458,6 @@ static void execute_commands(struct command *commands,
 {
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	struct command *cmd;
-	struct object_id oid;
 	struct iterate_data data;
 	struct async muxer;
 	int err_fd = 0;
@@ -1515,7 +1514,7 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", 0, oid.hash, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", 0, NULL, NULL);
 
 	if (use_atomic)
 		execute_commands_atomic(commands, si);
diff --git a/builtin/tag.c b/builtin/tag.c
index 12dbbc56d9..695cb0778e 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -553,9 +553,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (force && !is_null_oid(&prev) && oidcmp(&prev, &object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev.hash, DEFAULT_ABBREV));
 
-	strbuf_release(&err);
-	strbuf_release(&buf);
-	strbuf_release(&ref);
-	strbuf_release(&reflog_msg);
+	UNLEAK(buf);
+	UNLEAK(ref);
+	UNLEAK(reflog_msg);
+	UNLEAK(msg);
+	UNLEAK(err);
 	return 0;
 }
diff --git a/compat/poll/poll.c b/compat/poll/poll.c
index b10adc780f..ae03b74a6f 100644
--- a/compat/poll/poll.c
+++ b/compat/poll/poll.c
@@ -438,6 +438,10 @@ poll (struct pollfd *pfd, nfds_t nfd, int timeout)
 	    pfd[i].revents = happened;
 	    rc++;
 	  }
+	else
+	  {
+	    pfd[i].revents = 0;
+	  }
       }
 
   return rc;
diff --git a/contrib/coccinelle/array.cocci b/contrib/coccinelle/array.cocci
index c61d1ca8dc..01586821dc 100644
--- a/contrib/coccinelle/array.cocci
+++ b/contrib/coccinelle/array.cocci
@@ -4,7 +4,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(*dst));
+- memcpy(dst, src, (n) * sizeof(*dst));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -13,7 +13,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(*src));
+- memcpy(dst, src, (n) * sizeof(*src));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -22,7 +22,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(T));
+- memcpy(dst, src, (n) * sizeof(T));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -47,7 +47,7 @@ type T;
 T *ptr;
 expression n;
 @@
-- ptr = xmalloc(n * sizeof(*ptr));
+- ptr = xmalloc((n) * sizeof(*ptr));
 + ALLOC_ARRAY(ptr, n);
 
 @@
@@ -55,5 +55,5 @@ type T;
 T *ptr;
 expression n;
 @@
-- ptr = xmalloc(n * sizeof(T));
+- ptr = xmalloc((n) * sizeof(T));
 + ALLOC_ARRAY(ptr, n);
diff --git a/fast-import.c b/fast-import.c
index 35bf671f12..d5e4cf0bad 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -3189,10 +3189,10 @@ static void checkpoint(void)
 	checkpoint_requested = 0;
 	if (object_count) {
 		cycle_packfile();
-		dump_branches();
-		dump_tags();
-		dump_marks();
 	}
+	dump_branches();
+	dump_tags();
+	dump_marks();
 }
 
 static void parse_checkpoint(void)
diff --git a/git-request-pull.sh b/git-request-pull.sh
index eebd33276d..13c172bd94 100755
--- a/git-request-pull.sh
+++ b/git-request-pull.sh
@@ -128,7 +128,7 @@ git show -s --format='The following changes since commit %H:
 
   %s (%ci)
 
-are available in the git repository at:
+are available in the Git repository at:
 ' $merge_base &&
 echo "  $url $pretty_remote" &&
 git show -s --format='
diff --git a/graph.c b/graph.c
index e7e20650da..e1f6d3bddb 100644
--- a/graph.c
+++ b/graph.c
@@ -696,12 +696,8 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
 	 * This way, fields printed to the right of the graph will remain
 	 * aligned for the entire commit.
 	 */
-	int extra;
-	if (chars_written >= graph->width)
-		return;
-
-	extra = graph->width - chars_written;
-	strbuf_addf(sb, "%*s", (int) extra, "");
+	if (chars_written < graph->width)
+		strbuf_addchars(sb, ' ', graph->width - chars_written);
 }
 
 static void graph_output_padding_line(struct git_graph *graph,
@@ -787,7 +783,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 		if (col->commit == graph->commit) {
 			seen_this = 1;
 			strbuf_write_column(sb, col, '|');
-			strbuf_addf(sb, "%*s", graph->expansion_row, "");
+			strbuf_addchars(sb, ' ', graph->expansion_row);
 			chars_written += 1 + graph->expansion_row;
 		} else if (seen_this && (graph->expansion_row == 0)) {
 			/*
diff --git a/http-push.c b/http-push.c
index d860c477c6..493ee7d719 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1018,7 +1018,7 @@ static int get_oid_hex_from_objpath(const char *path, struct object_id *oid)
 	memcpy(hex, path, 2);
 	path += 2;
 	path++; /* skip '/' */
-	memcpy(hex, path, GIT_SHA1_HEXSZ - 2);
+	memcpy(hex + 2, path, GIT_SHA1_HEXSZ - 2);
 
 	return get_oid_hex(hex, oid);
 }
diff --git a/path.c b/path.c
index 5aa9244eb2..2e09a7bce0 100644
--- a/path.c
+++ b/path.c
@@ -34,11 +34,10 @@ static struct strbuf *get_pathname(void)
 	return sb;
 }
 
-static char *cleanup_path(char *path)
+static const char *cleanup_path(const char *path)
 {
 	/* Clean it up */
-	if (!memcmp(path, "./", 2)) {
-		path += 2;
+	if (skip_prefix(path, "./", &path)) {
 		while (*path == '/')
 			path++;
 	}
@@ -47,7 +46,7 @@ static char *cleanup_path(char *path)
 
 static void strbuf_cleanup_path(struct strbuf *sb)
 {
-	char *path = cleanup_path(sb->buf);
+	const char *path = cleanup_path(sb->buf);
 	if (path > sb->buf)
 		strbuf_remove(sb, 0, path - sb->buf);
 }
@@ -64,7 +63,7 @@ char *mksnpath(char *buf, size_t n, const char *fmt, ...)
 		strlcpy(buf, bad_path, n);
 		return buf;
 	}
-	return cleanup_path(buf);
+	return (char *)cleanup_path(buf);
 }
 
 static int dir_prefix(const char *buf, const char *dir)
@@ -718,7 +717,7 @@ char *expand_user_path(const char *path, int real_home)
 			if (!home)
 				goto return_null;
 			if (real_home)
-				strbuf_addstr(&user_path, real_path(home));
+				strbuf_add_real_path(&user_path, home);
 			else
 				strbuf_addstr(&user_path, home);
 #ifdef GIT_WINDOWS_NATIVE
diff --git a/pretty.c b/pretty.c
index 94eab5c89e..2f6b0ae6c1 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1056,6 +1056,24 @@ static size_t parse_padding_placeholder(struct strbuf *sb,
 	return 0;
 }
 
+static int match_placeholder_arg(const char *to_parse, const char *candidate,
+				 const char **end)
+{
+	const char *p;
+
+	if (!(skip_prefix(to_parse, candidate, &p)))
+		return 0;
+	if (*p == ',') {
+		*end = p + 1;
+		return 1;
+	}
+	if (*p == ')') {
+		*end = p;
+		return 1;
+	}
+	return 0;
+}
+
 static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 				const char *placeholder,
 				void *context)
@@ -1285,11 +1303,16 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 
 	if (skip_prefix(placeholder, "(trailers", &arg)) {
 		struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
-		while (*arg == ':') {
-			if (skip_prefix(arg, ":only", &arg))
-				opts.only_trailers = 1;
-			else if (skip_prefix(arg, ":unfold", &arg))
-				opts.unfold = 1;
+		if (*arg == ':') {
+			arg++;
+			for (;;) {
+				if (match_placeholder_arg(arg, "only", &arg))
+					opts.only_trailers = 1;
+				else if (match_placeholder_arg(arg, "unfold", &arg))
+					opts.unfold = 1;
+				else
+					break;
+			}
 		}
 		if (*arg == ')') {
 			format_trailers_from_commit(sb, msg + c->subject_off, &opts);
diff --git a/ref-filter.c b/ref-filter.c
index bc591f4f3d..55323620ab 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -295,9 +295,7 @@ static void if_atom_parser(const struct ref_format *format, struct used_atom *at
 
 static void head_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
 {
-	struct object_id unused;
-
-	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, unused.hash, NULL);
+	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 }
 
 static struct {
@@ -1317,9 +1315,8 @@ static void populate_value(struct ref_array_item *ref)
 	ref->value = xcalloc(used_atom_cnt, sizeof(struct atom_value));
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
-		struct object_id unused1;
 		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
-					     unused1.hash, NULL);
+					     NULL, NULL);
 		if (!ref->symref)
 			ref->symref = "";
 	}
diff --git a/reflog-walk.c b/reflog-walk.c
index 74ebe5148f..842b2f77dc 100644
--- a/reflog-walk.c
+++ b/reflog-walk.c
@@ -61,11 +61,10 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 	reflogs->ref = xstrdup(ref);
 	for_each_reflog_ent(ref, read_one_reflog, reflogs);
 	if (reflogs->nr == 0) {
-		struct object_id oid;
 		const char *name;
 		void *name_to_free;
 		name = name_to_free = resolve_refdup(ref, RESOLVE_REF_READING,
-						     oid.hash, NULL);
+						     NULL, NULL);
 		if (name) {
 			for_each_reflog_ent(name, read_one_reflog, reflogs);
 			free(name_to_free);
@@ -151,9 +150,8 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 		reflogs = item->util;
 	else {
 		if (*branch == '\0') {
-			struct object_id oid;
 			free(branch);
-			branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
+			branch = resolve_refdup("HEAD", 0, NULL, NULL);
 			if (!branch)
 				die ("No current branch");
 
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 1b6141e718..014dabb0bf 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2494,7 +2494,6 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 	char *head_ref = NULL;
 	int head_type;
-	struct object_id head_oid;
 	struct files_transaction_backend_data *backend_data;
 	struct ref_transaction *packed_transaction = NULL;
 
@@ -2551,7 +2550,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 	 */
 	head_ref = refs_resolve_refdup(ref_store, "HEAD",
 				       RESOLVE_REF_NO_RECURSE,
-				       head_oid.hash, &head_type);
+				       NULL, &head_type);
 
 	if (head_ref && !(head_type & REF_ISSYMREF)) {
 		FREE_AND_NULL(head_ref);
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 6e85b0bf0b..3279d42c5a 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1233,8 +1233,8 @@ static int write_with_updates(struct packed_ref_store *refs,
 	}
 
 	if (ok != ITER_DONE) {
-		strbuf_addf(err, "unable to write packed-refs file: "
-			    "error iterating over old contents");
+		strbuf_addstr(err, "unable to write packed-refs file: "
+			      "error iterating over old contents");
 		goto error;
 	}
 
diff --git a/repository.c b/repository.c
index 97c732bd48..bb2fae5446 100644
--- a/repository.c
+++ b/repository.c
@@ -200,25 +200,17 @@ out:
 
 void repo_clear(struct repository *repo)
 {
-	free(repo->gitdir);
-	repo->gitdir = NULL;
-	free(repo->commondir);
-	repo->commondir = NULL;
-	free(repo->objectdir);
-	repo->objectdir = NULL;
-	free(repo->graft_file);
-	repo->graft_file = NULL;
-	free(repo->index_file);
-	repo->index_file = NULL;
-	free(repo->worktree);
-	repo->worktree = NULL;
-	free(repo->submodule_prefix);
-	repo->submodule_prefix = NULL;
+	FREE_AND_NULL(repo->gitdir);
+	FREE_AND_NULL(repo->commondir);
+	FREE_AND_NULL(repo->objectdir);
+	FREE_AND_NULL(repo->graft_file);
+	FREE_AND_NULL(repo->index_file);
+	FREE_AND_NULL(repo->worktree);
+	FREE_AND_NULL(repo->submodule_prefix);
 
 	if (repo->config) {
 		git_configset_clear(repo->config);
-		free(repo->config);
-		repo->config = NULL;
+		FREE_AND_NULL(repo->config);
 	}
 
 	if (repo->submodule_cache) {
@@ -228,8 +220,7 @@ void repo_clear(struct repository *repo)
 
 	if (repo->index) {
 		discard_index(repo->index);
-		free(repo->index);
-		repo->index = NULL;
+		FREE_AND_NULL(repo->index);
 	}
 }
 
diff --git a/run-command.c b/run-command.c
index b5e6eb37c0..014b2165b5 100644
--- a/run-command.c
+++ b/run-command.c
@@ -452,7 +452,7 @@ static char **prep_childenv(const char *const *deltaenv)
 	}
 
 	/* Create an array of 'char *' to be used as the childenv */
-	childenv = xmalloc((env.nr + 1) * sizeof(char *));
+	ALLOC_ARRAY(childenv, env.nr + 1);
 	for (i = 0; i < env.nr; i++)
 		childenv[i] = env.items[i].util;
 	childenv[env.nr] = NULL;
diff --git a/sequencer.c b/sequencer.c
index b8c1e876fa..7886e2269e 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -204,7 +204,7 @@ int sequencer_remove_state(struct replay_opts *opts)
 		free(opts->xopts[i]);
 	free(opts->xopts);
 
-	strbuf_addf(&dir, "%s", get_dir(opts));
+	strbuf_addstr(&dir, get_dir(opts));
 	remove_dir_recursively(&dir, 0);
 	strbuf_release(&dir);
 
diff --git a/strbuf.h b/strbuf.h
index 7496cb8ec5..0a74acb236 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -82,8 +82,12 @@ extern char strbuf_slopbuf[];
 extern void strbuf_init(struct strbuf *, size_t);
 
 /**
- * Release a string buffer and the memory it used. You should not use the
- * string buffer after using this function, unless you initialize it again.
+ * Release a string buffer and the memory it used. After this call, the
+ * strbuf points to an empty string that does not need to be free()ed, as
+ * if it had been set to `STRBUF_INIT` and never modified.
+ *
+ * To clear a strbuf in preparation for further use without the overhead
+ * of free()ing and malloc()ing again, use strbuf_reset() instead.
  */
 extern void strbuf_release(struct strbuf *);
 
@@ -91,6 +95,9 @@ extern void strbuf_release(struct strbuf *);
  * Detach the string from the strbuf and returns it; you now own the
  * storage the string occupies and it is your responsibility from then on
  * to release it with `free(3)` when you are done with it.
+ *
+ * The strbuf that previously held the string is reset to `STRBUF_INIT` so
+ * it can be reused after calling this function.
  */
 extern char *strbuf_detach(struct strbuf *, size_t *);
 
diff --git a/sub-process.c b/sub-process.c
index 6dde5062be..8d2a1707cf 100644
--- a/sub-process.c
+++ b/sub-process.c
@@ -77,13 +77,12 @@ int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, co
 {
 	int err;
 	struct child_process *process;
-	const char *argv[] = { cmd, NULL };
 
 	entry->cmd = cmd;
 	process = &entry->process;
 
 	child_process_init(process);
-	process->argv = argv;
+	argv_array_push(&process->args, cmd);
 	process->use_shell = 1;
 	process->in = -1;
 	process->out = -1;
diff --git a/t/helper/test-string-list.c b/t/helper/test-string-list.c
index c502fa16d3..829ec3d7d2 100644
--- a/t/helper/test-string-list.c
+++ b/t/helper/test-string-list.c
@@ -108,7 +108,7 @@ int cmd_main(int argc, const char **argv)
 		 * Split by newline, but don't create a string_list item
 		 * for the empty string after the last separator.
 		 */
-		if (sb.buf[sb.len - 1] == '\n')
+		if (sb.len && sb.buf[sb.len - 1] == '\n')
 			strbuf_setlen(&sb, sb.len - 1);
 		string_list_split_in_place(&list, sb.buf, '\n', -1);
 
diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index ec5f530102..977472f539 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -588,8 +588,8 @@ test_expect_success '%(trailers:unfold) unfolds trailers' '
 '
 
 test_expect_success ':only and :unfold work together' '
-	git log --no-walk --pretty="%(trailers:only:unfold)" >actual &&
-	git log --no-walk --pretty="%(trailers:unfold:only)" >reverse &&
+	git log --no-walk --pretty="%(trailers:only,unfold)" >actual &&
+	git log --no-walk --pretty="%(trailers:unfold,only)" >reverse &&
 	test_cmp actual reverse &&
 	{
 		grep -v patch.description <trailers | unfold &&
diff --git a/t/t5150-request-pull.sh b/t/t5150-request-pull.sh
index 82c33b88e7..08c210f035 100755
--- a/t/t5150-request-pull.sh
+++ b/t/t5150-request-pull.sh
@@ -68,7 +68,7 @@ test_expect_success 'setup: two scripts for reading pull requests' '
 	cat <<-\EOT >read-request.sed &&
 	#!/bin/sed -nf
 	# Note that a request could ask for "tag $tagname"
-	/ in the git repository at:$/!d
+	/ in the Git repository at:$/!d
 	n
 	/^$/ n
 	s/ tag \([^ ]*\)$/ tag--\1/
@@ -192,7 +192,7 @@ test_expect_success 'pull request format' '
 
 	  SUBJECT (DATE)
 
-	are available in the git repository at:
+	are available in the Git repository at:
 
 	  URL BRANCH
 
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 67b8c50a5a..d47560b634 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -3120,4 +3120,146 @@ test_expect_success 'U: validate root delete result' '
 	compare_diff_raw expect actual
 '
 
+###
+### series V (checkpoint)
+###
+
+# The commands in input_file should not produce any output on the file
+# descriptor set with --cat-blob-fd (or stdout if unspecified).
+#
+# To make sure you're observing the side effects of checkpoint *before*
+# fast-import terminates (and thus writes out its state), check that the
+# fast-import process is still running using background_import_still_running
+# *after* evaluating the test conditions.
+background_import_then_checkpoint () {
+	options=$1
+	input_file=$2
+
+	mkfifo V.input
+	exec 8<>V.input
+	rm V.input
+
+	mkfifo V.output
+	exec 9<>V.output
+	rm V.output
+
+	git fast-import $options <&8 >&9 &
+	echo $! >V.pid
+	# We don't mind if fast-import has already died by the time the test
+	# ends.
+	test_when_finished "exec 8>&-; exec 9>&-; kill $(cat V.pid) || true"
+
+	# Start in the background to ensure we adhere strictly to (blocking)
+	# pipes writing sequence. We want to assume that the write below could
+	# block, e.g. if fast-import blocks writing its own output to &9
+	# because there is no reader on &9 yet.
+	(
+		cat "$input_file"
+		echo "checkpoint"
+		echo "progress checkpoint"
+	) >&8 &
+
+	error=1 ;# assume the worst
+	while read output <&9
+	do
+		if test "$output" = "progress checkpoint"
+		then
+			error=0
+			break
+		fi
+		# otherwise ignore cruft
+		echo >&2 "cruft: $output"
+	done
+
+	if test $error -eq 1
+	then
+		false
+	fi
+}
+
+background_import_still_running () {
+	if ! kill -0 "$(cat V.pid)"
+	then
+		echo >&2 "background fast-import terminated too early"
+		false
+	fi
+}
+
+test_expect_success PIPE 'V: checkpoint helper does not get stuck with extra output' '
+	cat >input <<-INPUT_END &&
+	progress foo
+	progress bar
+
+	INPUT_END
+
+	background_import_then_checkpoint "" input &&
+	background_import_still_running
+'
+
+test_expect_success PIPE 'V: checkpoint updates refs after reset' '
+	cat >input <<-\INPUT_END &&
+	reset refs/heads/V
+	from refs/heads/U
+
+	INPUT_END
+
+	background_import_then_checkpoint "" input &&
+	test "$(git rev-parse --verify V)" = "$(git rev-parse --verify U)" &&
+	background_import_still_running
+'
+
+test_expect_success PIPE 'V: checkpoint updates refs and marks after commit' '
+	cat >input <<-INPUT_END &&
+	commit refs/heads/V
+	mark :1
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data 0
+	from refs/heads/U
+
+	INPUT_END
+
+	background_import_then_checkpoint "--export-marks=marks.actual" input &&
+
+	echo ":1 $(git rev-parse --verify V)" >marks.expected &&
+
+	test "$(git rev-parse --verify V^)" = "$(git rev-parse --verify U)" &&
+	test_cmp marks.expected marks.actual &&
+	background_import_still_running
+'
+
+# Re-create the exact same commit, but on a different branch: no new object is
+# created in the database, but the refs and marks still need to be updated.
+test_expect_success PIPE 'V: checkpoint updates refs and marks after commit (no new objects)' '
+	cat >input <<-INPUT_END &&
+	commit refs/heads/V2
+	mark :2
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data 0
+	from refs/heads/U
+
+	INPUT_END
+
+	background_import_then_checkpoint "--export-marks=marks.actual" input &&
+
+	echo ":2 $(git rev-parse --verify V2)" >marks.expected &&
+
+	test "$(git rev-parse --verify V2)" = "$(git rev-parse --verify V)" &&
+	test_cmp marks.expected marks.actual &&
+	background_import_still_running
+'
+
+test_expect_success PIPE 'V: checkpoint updates tags after tag' '
+	cat >input <<-INPUT_END &&
+	tag Vtag
+	from refs/heads/V
+	tagger $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data 0
+
+	INPUT_END
+
+	background_import_then_checkpoint "" input &&
+	git show-ref -d Vtag &&
+	background_import_still_running
+'
+
 test_done
diff --git a/tag.c b/tag.c
index 7e10acfb6e..fcbe012f7a 100644
--- a/tag.c
+++ b/tag.c
@@ -142,13 +142,13 @@ int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
 	bufptr = nl + 1;
 
 	if (!strcmp(type, blob_type)) {
-		item->tagged = &lookup_blob(&oid)->object;
+		item->tagged = (struct object *)lookup_blob(&oid);
 	} else if (!strcmp(type, tree_type)) {
-		item->tagged = &lookup_tree(&oid)->object;
+		item->tagged = (struct object *)lookup_tree(&oid);
 	} else if (!strcmp(type, commit_type)) {
-		item->tagged = &lookup_commit(&oid)->object;
+		item->tagged = (struct object *)lookup_commit(&oid);
 	} else if (!strcmp(type, tag_type)) {
-		item->tagged = &lookup_tag(&oid)->object;
+		item->tagged = (struct object *)lookup_tag(&oid);
 	} else {
 		error("Unknown type %s", type);
 		item->tagged = NULL;
diff --git a/transport.c b/transport.c
index fb8c01e57a..f1e2f61991 100644
--- a/transport.c
+++ b/transport.c
@@ -471,11 +471,10 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 {
 	struct ref *ref;
 	int n = 0;
-	struct object_id head_oid;
 	char *head;
 	int summary_width = transport_summary_width(refs);
 
-	head = resolve_refdup("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 
 	if (verbose) {
 		for (ref = refs; ref; ref = ref->next)
diff --git a/wt-status.c b/wt-status.c
index 6f730ee8f2..29bc64cc02 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -121,15 +121,13 @@ static void status_printf_more(struct wt_status *s, const char *color,
 
 void wt_status_prepare(struct wt_status *s)
 {
-	struct object_id oid;
-
 	memset(s, 0, sizeof(*s));
 	memcpy(s->color_palette, default_wt_status_colors,
 	       sizeof(default_wt_status_colors));
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = -1;
 	s->relative_paths = 1;
-	s->branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
+	s->branch = resolve_refdup("HEAD", 0, NULL, NULL);
 	s->reference = "HEAD";
 	s->fp = stdout;
 	s->index_file = get_index_file();