1 files changed, 246 insertions, 138 deletions

diff --git a/builtin/commit.c b/builtin/commit.c
index 243b0c3300..cda74e9a68 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -6,6 +6,7 @@
  */
 
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "color.h"
 #include "dir.h"
@@ -42,7 +43,20 @@ static const char * const builtin_status_usage[] = {
 	NULL
 };
 
-static const char implicit_ident_advice[] =
+static const char implicit_ident_advice_noconfig[] =
+N_("Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly. Run the\n"
+"following command and follow the instructions in your editor to edit\n"
+"your configuration file:\n"
+"\n"
+"    git config --global --edit\n"
+"\n"
+"After doing this, you may fix the identity used for this commit with:\n"
+"\n"
+"    git commit --amend --reset-author\n");
+
+static const char implicit_ident_advice_config[] =
 N_("Your name and email address were configured automatically based\n"
 "on your username and hostname. Please check that they are accurate.\n"
 "You can suppress this message by setting them explicitly:\n"
@@ -302,8 +316,8 @@ static void refresh_cache_or_die(int refresh_flags)
 		die_resolve_conflict("commit");
 }
 
-static char *prepare_index(int argc, const char **argv, const char *prefix,
-			   const struct commit *current_head, int is_status)
+static const char *prepare_index(int argc, const char **argv, const char *prefix,
+				 const struct commit *current_head, int is_status)
 {
 	struct string_list partial;
 	struct pathspec pathspec;
@@ -328,7 +342,7 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 			die(_("unable to create temporary index"));
 
 		old_index_env = getenv(INDEX_ENVIRONMENT);
-		setenv(INDEX_ENVIRONMENT, index_lock.filename, 1);
+		setenv(INDEX_ENVIRONMENT, index_lock.filename.buf, 1);
 
 		if (interactive_add(argc, argv, prefix, patch_interactive) != 0)
 			die(_("interactive add failed"));
@@ -339,10 +353,17 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 			unsetenv(INDEX_ENVIRONMENT);
 
 		discard_cache();
-		read_cache_from(index_lock.filename);
+		read_cache_from(index_lock.filename.buf);
+		if (update_main_cache_tree(WRITE_TREE_SILENT) == 0) {
+			if (reopen_lock_file(&index_lock) < 0)
+				die(_("unable to write index file"));
+			if (write_locked_index(&the_index, &index_lock, CLOSE_LOCK))
+				die(_("unable to update temporary index"));
+		} else
+			warning(_("Failed to update main cache tree"));
 
 		commit_style = COMMIT_NORMAL;
-		return index_lock.filename;
+		return index_lock.filename.buf;
 	}
 
 	/*
@@ -365,7 +386,7 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 		if (write_locked_index(&the_index, &index_lock, CLOSE_LOCK))
 			die(_("unable to write new_index file"));
 		commit_style = COMMIT_NORMAL;
-		return index_lock.filename;
+		return index_lock.filename.buf;
 	}
 
 	/*
@@ -380,8 +401,12 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 	if (!only && !pathspec.nr) {
 		hold_locked_index(&index_lock, 1);
 		refresh_cache_or_die(refresh_flags);
-		if (active_cache_changed) {
+		if (active_cache_changed
+		    || !cache_tree_fully_valid(active_cache_tree)) {
 			update_main_cache_tree(WRITE_TREE_SILENT);
+			active_cache_changed = 1;
+		}
+		if (active_cache_changed) {
 			if (write_locked_index(&the_index, &index_lock,
 					       COMMIT_LOCK))
 				die(_("unable to write new_index file"));
@@ -420,8 +445,7 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 			die(_("cannot do a partial commit during a cherry-pick."));
 	}
 
-	memset(&partial, 0, sizeof(partial));
-	partial.strdup_strings = 1;
+	string_list_init(&partial, 1);
 	if (list_paths(&partial, !current_head ? NULL : "HEAD", prefix, &pathspec))
 		exit(1);
 
@@ -432,6 +456,7 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 	hold_locked_index(&index_lock, 1);
 	add_remove_files(&partial);
 	refresh_cache(REFRESH_QUIET);
+	update_main_cache_tree(WRITE_TREE_SILENT);
 	if (write_locked_index(&the_index, &index_lock, CLOSE_LOCK))
 		die(_("unable to write new_index file"));
 
@@ -448,9 +473,9 @@ static char *prepare_index(int argc, const char **argv, const char *prefix,
 		die(_("unable to write temporary index file"));
 
 	discard_cache();
-	read_cache_from(false_lock.filename);
+	read_cache_from(false_lock.filename.buf);
 
-	return false_lock.filename;
+	return false_lock.filename.buf;
 }
 
 static int run_status(FILE *fp, const char *index_file, const char *prefix, int nowarn,
@@ -521,56 +546,82 @@ static int sane_ident_split(struct ident_split *person)
 	return 1;
 }
 
+static int parse_force_date(const char *in, struct strbuf *out)
+{
+	strbuf_addch(out, '@');
+
+	if (parse_date(in, out) < 0) {
+		int errors = 0;
+		unsigned long t = approxidate_careful(in, &errors);
+		if (errors)
+			return -1;
+		strbuf_addf(out, "%lu", t);
+	}
+
+	return 0;
+}
+
+static void set_ident_var(char **buf, char *val)
+{
+	free(*buf);
+	*buf = val;
+}
+
+static char *envdup(const char *var)
+{
+	const char *val = getenv(var);
+	return val ? xstrdup(val) : NULL;
+}
+
 static void determine_author_info(struct strbuf *author_ident)
 {
 	char *name, *email, *date;
 	struct ident_split author;
 
-	name = getenv("GIT_AUTHOR_NAME");
-	email = getenv("GIT_AUTHOR_EMAIL");
-	date = getenv("GIT_AUTHOR_DATE");
+	name = envdup("GIT_AUTHOR_NAME");
+	email = envdup("GIT_AUTHOR_EMAIL");
+	date = envdup("GIT_AUTHOR_DATE");
 
 	if (author_message) {
-		const char *a, *lb, *rb, *eol;
+		struct ident_split ident;
 		size_t len;
+		const char *a;
 
-		a = strstr(author_message_buffer, "\nauthor ");
+		a = find_commit_header(author_message_buffer, "author", &len);
 		if (!a)
-			die(_("invalid commit: %s"), author_message);
-
-		lb = strchrnul(a + strlen("\nauthor "), '<');
-		rb = strchrnul(lb, '>');
-		eol = strchrnul(rb, '\n');
-		if (!*lb || !*rb || !*eol)
-			die(_("invalid commit: %s"), author_message);
-
-		if (lb == a + strlen("\nauthor "))
-			/* \nauthor <foo@example.com> */
-			name = xcalloc(1, 1);
-		else
-			name = xmemdupz(a + strlen("\nauthor "),
-					(lb - strlen(" ") -
-					 (a + strlen("\nauthor "))));
-		email = xmemdupz(lb + strlen("<"), rb - (lb + strlen("<")));
-		len = eol - (rb + strlen("> "));
-		date = xmalloc(len + 2);
-		*date = '@';
-		memcpy(date + 1, rb + strlen("> "), len);
-		date[len + 1] = '\0';
+			die(_("commit '%s' lacks author header"), author_message);
+		if (split_ident_line(&ident, a, len) < 0)
+			die(_("commit '%s' has malformed author line"), author_message);
+
+		set_ident_var(&name, xmemdupz(ident.name_begin, ident.name_end - ident.name_begin));
+		set_ident_var(&email, xmemdupz(ident.mail_begin, ident.mail_end - ident.mail_begin));
+
+		if (ident.date_begin) {
+			struct strbuf date_buf = STRBUF_INIT;
+			strbuf_addch(&date_buf, '@');
+			strbuf_add(&date_buf, ident.date_begin, ident.date_end - ident.date_begin);
+			strbuf_addch(&date_buf, ' ');
+			strbuf_add(&date_buf, ident.tz_begin, ident.tz_end - ident.tz_begin);
+			set_ident_var(&date, strbuf_detach(&date_buf, NULL));
+		}
 	}
 
 	if (force_author) {
-		const char *lb = strstr(force_author, " <");
-		const char *rb = strchr(force_author, '>');
+		struct ident_split ident;
 
-		if (!lb || !rb)
+		if (split_ident_line(&ident, force_author, strlen(force_author)) < 0)
 			die(_("malformed --author parameter"));
-		name = xstrndup(force_author, lb - force_author);
-		email = xstrndup(lb + 2, rb - (lb + 2));
+		set_ident_var(&name, xmemdupz(ident.name_begin, ident.name_end - ident.name_begin));
+		set_ident_var(&email, xmemdupz(ident.mail_begin, ident.mail_end - ident.mail_begin));
+	}
+
+	if (force_date) {
+		struct strbuf date_buf = STRBUF_INIT;
+		if (parse_force_date(force_date, &date_buf))
+			die(_("invalid date format: %s"), force_date);
+		set_ident_var(&date, strbuf_detach(&date_buf, NULL));
 	}
 
-	if (force_date)
-		date = force_date;
 	strbuf_addstr(author_ident, fmt_ident(name, email, date, IDENT_STRICT));
 	if (!split_ident_line(&author, author_ident->buf, author_ident->len) &&
 	    sane_ident_split(&author)) {
@@ -578,15 +629,52 @@ static void determine_author_info(struct strbuf *author_ident)
 		export_one("GIT_AUTHOR_EMAIL", author.mail_begin, author.mail_end, 0);
 		export_one("GIT_AUTHOR_DATE", author.date_begin, author.tz_end, '@');
 	}
+
+	free(name);
+	free(email);
+	free(date);
+}
+
+static void split_ident_or_die(struct ident_split *id, const struct strbuf *buf)
+{
+	if (split_ident_line(id, buf->buf, buf->len) ||
+	    !sane_ident_split(id))
+		die(_("Malformed ident string: '%s'"), buf->buf);
+}
+
+static int author_date_is_interesting(void)
+{
+	return author_message || force_date;
 }
 
-static char *cut_ident_timestamp_part(char *string)
+static void adjust_comment_line_char(const struct strbuf *sb)
 {
-	char *ket = strrchr(string, '>');
-	if (!ket || ket[1] != ' ')
-		die(_("Malformed ident string: '%s'"), string);
-	*++ket = '\0';
-	return ket;
+	char candidates[] = "#;@!$%^&|:";
+	char *candidate;
+	const char *p;
+
+	comment_line_char = candidates[0];
+	if (!memchr(sb->buf, comment_line_char, sb->len))
+		return;
+
+	p = sb->buf;
+	candidate = strchr(candidates, *p);
+	if (candidate)
+		*candidate = ' ';
+	for (p = sb->buf; *p; p++) {
+		if ((p[0] == '\n' || p[0] == '\r') && p[1]) {
+			candidate = strchr(candidates, p[1]);
+			if (candidate)
+				*candidate = ' ';
+		}
+	}
+
+	for (p = candidates; *p == ' '; p++)
+		;
+	if (!*p)
+		die(_("unable to select a comment character that is not used\n"
+		      "in the current commit message"));
+	comment_line_char = *p;
 }
 
 static int prepare_to_commit(const char *index_file, const char *prefix,
@@ -645,9 +733,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	} else if (use_message) {
 		char *buffer;
 		buffer = strstr(use_message_buffer, "\n\n");
-		if (!use_editor && (!buffer || buffer[2] == '\0'))
-			die(_("commit has empty message"));
-		strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
+		if (buffer)
+			strbuf_addstr(&sb, buffer + 2);
 		hook_arg1 = "commit";
 		hook_arg2 = use_message;
 	} else if (fixup_message) {
@@ -713,36 +800,14 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	if (clean_message_contents)
 		stripspace(&sb, 0);
 
-	if (signoff) {
-		/*
-		 * See if we have a Conflicts: block at the end. If yes, count
-		 * its size, so we can ignore it.
-		 */
-		int ignore_footer = 0;
-		int i, eol, previous = 0;
-		const char *nl;
-
-		for (i = 0; i < sb.len; i++) {
-			nl = memchr(sb.buf + i, '\n', sb.len - i);
-			if (nl)
-				eol = nl - sb.buf;
-			else
-				eol = sb.len;
-			if (starts_with(sb.buf + previous, "\nConflicts:\n")) {
-				ignore_footer = sb.len - previous;
-				break;
-			}
-			while (i < eol)
-				i++;
-			previous = eol;
-		}
-
-		append_signoff(&sb, ignore_footer, 0);
-	}
+	if (signoff)
+		append_signoff(&sb, ignore_non_trailer(&sb), 0);
 
 	if (fwrite(sb.buf, 1, sb.len, s->fp) < sb.len)
 		die_errno(_("could not write commit template"));
 
+	if (auto_comment_line_char)
+		adjust_comment_line_char(&sb);
 	strbuf_release(&sb);
 
 	/* This checks if committer ident is explicitly given */
@@ -750,7 +815,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	if (use_editor && include_status) {
 		int ident_shown = 0;
 		int saved_color_setting;
-		char *ai_tmp, *ci_tmp;
+		struct ident_split ci, ai;
+
 		if (whence != FROM_COMMIT) {
 			if (cleanup_mode == CLEANUP_SCISSORS)
 				wt_status_add_cut_line(s->fp);
@@ -790,32 +856,39 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 					"%s", only_include_assumed);
 
-		ai_tmp = cut_ident_timestamp_part(author_ident->buf);
-		ci_tmp = cut_ident_timestamp_part(committer_ident.buf);
-		if (strcmp(author_ident->buf, committer_ident.buf))
+		split_ident_or_die(&ai, author_ident);
+		split_ident_or_die(&ci, &committer_ident);
+
+		if (ident_cmp(&ai, &ci))
+			status_printf_ln(s, GIT_COLOR_NORMAL,
+				_("%s"
+				"Author:    %.*s <%.*s>"),
+				ident_shown++ ? "" : "\n",
+				(int)(ai.name_end - ai.name_begin), ai.name_begin,
+				(int)(ai.mail_end - ai.mail_begin), ai.mail_begin);
+
+		if (author_date_is_interesting())
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 				_("%s"
-				"Author:    %s"),
+				"Date:      %s"),
 				ident_shown++ ? "" : "\n",
-				author_ident->buf);
+				show_ident_date(&ai, DATE_NORMAL));
 
 		if (!committer_ident_sufficiently_given())
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 				_("%s"
-				"Committer: %s"),
+				"Committer: %.*s <%.*s>"),
 				ident_shown++ ? "" : "\n",
-				committer_ident.buf);
+				(int)(ci.name_end - ci.name_begin), ci.name_begin,
+				(int)(ci.mail_end - ci.mail_begin), ci.mail_begin);
 
 		if (ident_shown)
-			status_printf_ln(s, GIT_COLOR_NORMAL, "");
+			status_printf_ln(s, GIT_COLOR_NORMAL, "%s", "");
 
 		saved_color_setting = s->use_color;
 		s->use_color = 0;
 		commitable = run_status(s->fp, index_file, prefix, 1, s);
 		s->use_color = saved_color_setting;
-
-		*ai_tmp = ' ';
-		*ci_tmp = ' ';
 	} else {
 		unsigned char sha1[20];
 		const char *parent = "HEAD";
@@ -828,8 +901,22 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 
 		if (get_sha1(parent, sha1))
 			commitable = !!active_nr;
-		else
-			commitable = index_differs_from(parent, 0);
+		else {
+			/*
+			 * Unless the user did explicitly request a submodule
+			 * ignore mode by passing a command line option we do
+			 * not ignore any changed submodule SHA-1s when
+			 * comparing index and parent, no matter what is
+			 * configured. Otherwise we won't commit any
+			 * submodules which were manually staged, which would
+			 * be really confusing.
+			 */
+			int diff_flags = DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG;
+			if (ignore_submodule_arg &&
+			    !strcmp(ignore_submodule_arg, "all"))
+				diff_flags |= DIFF_OPT_IGNORE_SUBMODULES;
+			commitable = index_differs_from(parent, diff_flags);
+		}
 	}
 	strbuf_release(&committer_ident);
 
@@ -936,7 +1023,7 @@ static int message_is_empty(struct strbuf *sb)
 static int template_untouched(struct strbuf *sb)
 {
 	struct strbuf tmpl = STRBUF_INIT;
-	char *start;
+	const char *start;
 
 	if (cleanup_mode == CLEANUP_NONE && sb->len)
 		return 0;
@@ -945,8 +1032,7 @@ static int template_untouched(struct strbuf *sb)
 		return 0;
 
 	stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
-	start = (char *)skip_prefix(sb->buf, tmpl.buf);
-	if (!start)
+	if (!skip_prefix(sb->buf, tmpl.buf, &start))
 		start = sb->buf;
 	strbuf_release(&tmpl);
 	return rest_is_empty(sb, start - sb->buf);
@@ -971,7 +1057,8 @@ static const char *find_author_by_nickname(const char *name)
 	revs.mailmap = &mailmap;
 	read_mailmap(revs.mailmap, NULL);
 
-	prepare_revision_walk(&revs);
+	if (prepare_revision_walk(&revs))
+		die(_("revision walk setup failed"));
 	commit = get_revision(&revs);
 	if (commit) {
 		struct pretty_print_context ctx = {0};
@@ -1161,22 +1248,21 @@ static int dry_run_commit(int argc, const char **argv, const char *prefix,
 	return commitable ? 0 : 1;
 }
 
-static int parse_status_slot(const char *var, int offset)
+static int parse_status_slot(const char *slot)
 {
-	if (!strcasecmp(var+offset, "header"))
+	if (!strcasecmp(slot, "header"))
 		return WT_STATUS_HEADER;
-	if (!strcasecmp(var+offset, "branch"))
+	if (!strcasecmp(slot, "branch"))
 		return WT_STATUS_ONBRANCH;
-	if (!strcasecmp(var+offset, "updated")
-		|| !strcasecmp(var+offset, "added"))
+	if (!strcasecmp(slot, "updated") || !strcasecmp(slot, "added"))
 		return WT_STATUS_UPDATED;
-	if (!strcasecmp(var+offset, "changed"))
+	if (!strcasecmp(slot, "changed"))
 		return WT_STATUS_CHANGED;
-	if (!strcasecmp(var+offset, "untracked"))
+	if (!strcasecmp(slot, "untracked"))
 		return WT_STATUS_UNTRACKED;
-	if (!strcasecmp(var+offset, "nobranch"))
+	if (!strcasecmp(slot, "nobranch"))
 		return WT_STATUS_NOBRANCH;
-	if (!strcasecmp(var+offset, "unmerged"))
+	if (!strcasecmp(slot, "unmerged"))
 		return WT_STATUS_UNMERGED;
 	return -1;
 }
@@ -1184,6 +1270,7 @@ static int parse_status_slot(const char *var, int offset)
 static int git_status_config(const char *k, const char *v, void *cb)
 {
 	struct wt_status *s = cb;
+	const char *slot_name;
 
 	if (starts_with(k, "column."))
 		return git_column_config(k, v, "status", &s->colopts);
@@ -1213,14 +1300,14 @@ static int git_status_config(const char *k, const char *v, void *cb)
 		s->display_comment_prefix = git_config_bool(k, v);
 		return 0;
 	}
-	if (starts_with(k, "status.color.") || starts_with(k, "color.status.")) {
-		int slot = parse_status_slot(k, 13);
+	if (skip_prefix(k, "status.color.", &slot_name) ||
+	    skip_prefix(k, "color.status.", &slot_name)) {
+		int slot = parse_status_slot(slot_name);
 		if (slot < 0)
 			return 0;
 		if (!v)
 			return config_error_nonbool(k);
-		color_parse(v, k, s->color_palette[slot]);
-		return 0;
+		return color_parse(v, s->color_palette[slot]);
 	}
 	if (!strcmp(k, "status.relativepaths")) {
 		s->relative_paths = git_config_bool(k, v);
@@ -1325,6 +1412,24 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static const char *implicit_ident_advice(void)
+{
+	char *user_config = NULL;
+	char *xdg_config = NULL;
+	int config_exists;
+
+	home_config_paths(&user_config, &xdg_config, "config");
+	config_exists = file_exists(user_config) || file_exists(xdg_config);
+	free(user_config);
+	free(xdg_config);
+
+	if (config_exists)
+		return _(implicit_ident_advice_config);
+	else
+		return _(implicit_ident_advice_noconfig);
+
+}
+
 static void print_summary(const char *prefix, const unsigned char *sha1,
 			  int initial_commit)
 {
@@ -1351,12 +1456,19 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 		strbuf_addstr(&format, "\n Author: ");
 		strbuf_addbuf_percentquote(&format, &author_ident);
 	}
+	if (author_date_is_interesting()) {
+		struct strbuf date = STRBUF_INIT;
+		format_commit_message(commit, "%ad", &date, &pctx);
+		strbuf_addstr(&format, "\n Date: ");
+		strbuf_addbuf_percentquote(&format, &date);
+		strbuf_release(&date);
+	}
 	if (!committer_ident_sufficiently_given()) {
 		strbuf_addstr(&format, "\n Committer: ");
 		strbuf_addbuf_percentquote(&format, &committer_ident);
 		if (advice_implicit_identity) {
 			strbuf_addch(&format, '\n');
-			strbuf_addstr(&format, _(implicit_ident_advice));
+			strbuf_addstr(&format, implicit_ident_advice());
 		}
 	}
 	strbuf_release(&author_ident);
@@ -1377,14 +1489,12 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
-	printf("[%s%s ",
-		starts_with(head, "refs/heads/") ?
-			head + 11 :
-			!strcmp(head, "HEAD") ?
-				_("detached HEAD") :
-				head,
-		initial_commit ? _(" (root-commit)") : "");
+	head = resolve_ref_unsafe("HEAD", 0, junk_sha1, NULL);
+	if (!strcmp(head, "HEAD"))
+		head = _("detached HEAD");
+	else
+		skip_prefix(head, "refs/heads/", &head);
+	printf("[%s%s ", head, initial_commit ? _(" (root-commit)") : "");
 
 	if (!log_tree_commit(&rev, commit)) {
 		rev.always_show_header = 1;
@@ -1424,7 +1534,7 @@ static int run_rewrite_hook(const unsigned char *oldsha1,
 {
 	/* oldsha1 SP newsha1 LF NUL */
 	static char buf[2*40 + 3];
-	struct child_process proc;
+	struct child_process proc = CHILD_PROCESS_INIT;
 	const char *argv[3];
 	int code;
 	size_t n;
@@ -1436,7 +1546,6 @@ static int run_rewrite_hook(const unsigned char *oldsha1,
 	argv[1] = "amend";
 	argv[2] = NULL;
 
-	memset(&proc, 0, sizeof(proc));
 	proc.argv = argv;
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
@@ -1536,11 +1645,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	const char *index_file, *reflog_msg;
 	char *nl;
 	unsigned char sha1[20];
-	struct ref_lock *ref_lock;
 	struct commit_list *parents = NULL, **pptr = &parents;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
 	struct commit_extra_header *extra = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_commit_usage, builtin_commit_options);
@@ -1654,20 +1764,14 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		append_merge_tag_headers(parents, &tail);
 	}
 
-	if (commit_tree_extended(&sb, active_cache_tree->sha1, parents, sha1,
-				 author_ident.buf, sign_commit, extra)) {
+	if (commit_tree_extended(sb.buf, sb.len, active_cache_tree->sha1,
+			 parents, sha1, author_ident.buf, sign_commit, extra)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
 	}
 	strbuf_release(&author_ident);
 	free_commit_extra_headers(extra);
 
-	ref_lock = lock_any_ref_for_update("HEAD",
-					   !current_head
-					   ? NULL
-					   : current_head->object.sha1,
-					   0, NULL);
-
 	nl = strchr(sb.buf, '\n');
 	if (nl)
 		strbuf_setlen(&sb, nl + 1 - sb.buf);
@@ -1676,14 +1780,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
 	strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
 
-	if (!ref_lock) {
-		rollback_index_files();
-		die(_("cannot lock HEAD ref"));
-	}
-	if (write_ref_sha1(ref_lock, sha1, sb.buf) < 0) {
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", sha1,
+				   current_head
+				   ? current_head->object.sha1 : NULL,
+				   0, !!current_head, sb.buf, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		rollback_index_files();
-		die(_("cannot update HEAD ref"));
+		die("%s", err.buf);
 	}
+	ref_transaction_free(transaction);
 
 	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("REVERT_HEAD"));
@@ -1694,7 +1801,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	if (commit_index_files())
 		die (_("Repository has been updated, but unable to write\n"
-		     "new_index file. Check that disk is not full or quota is\n"
+		     "new_index file. Check that disk is not full and quota is\n"
 		     "not exceeded, and then \"git reset HEAD\" to recover."));
 
 	rerere(0);
@@ -1712,5 +1819,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	if (!quiet)
 		print_summary(prefix, sha1, !current_head);
 
+	strbuf_release(&err);
 	return 0;
 }