Merge branch 'js/find-commit-subject-ignore-leading-blanks' into maint

A helper function that takes the contents of a commit object and
finds its subject line did not ignore leading blank lines, as is
commonly done by other codepaths.  Make it ignore leading blank
lines to match.

* js/find-commit-subject-ignore-leading-blanks:
  reset --hard: skip blank lines when reporting the commit subject
  sequencer: use skip_blank_lines() to find the commit subject
  commit -C: skip blank lines at the beginning of the message
  commit.c: make find_commit_subject() more robust
  pretty: make the skip_blank_lines() function public

builtin/commit.c

@@ -714,7 +714,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		char *buffer;
 		buffer = strstr(use_message_buffer, "\n\n");
 		if (buffer)
-			strbuf_addstr(&sb, buffer + 2);
+			strbuf_addstr(&sb, skip_blank_lines(buffer + 2));
 		hook_arg1 = "commit";
 		hook_arg2 = use_message;
 	} else if (fixup_message) {

builtin/reset.c

@@ -103,7 +103,7 @@ static void print_new_head_line(struct commit *commit)
 	if (body) {
 		const char *eol;
 		size_t len;
-		body += 2;
+		body = skip_blank_lines(body + 2);
 		eol = strchr(body, '\n');
 		len = eol ? eol - body : strlen(body);
 		printf(" %.*s\n", (int) len, body);

commit.c

@@ -414,7 +414,7 @@ int find_commit_subject(const char *commit_buffer, const char **subject)
 	while (*p && (*p != '\n' || p[1] != '\n'))
 		p++;
 	if (*p) {
-		p += 2;
+		p = skip_blank_lines(p + 2);
 		for (eol = p; *eol && *eol != '\n'; eol++)
 			; /* do nothing */
 	} else

commit.h

@@ -178,6 +178,7 @@ extern const char *format_subject(struct strbuf *sb, const char *msg,
 				  const char *line_separator);
 extern void userformat_find_requirements(const char *fmt, struct userformat_want *w);
 extern int commit_format_is_empty(enum cmit_fmt);
+extern const char *skip_blank_lines(const char *msg);
 extern void format_commit_message(const struct commit *commit,
 				  const char *format, struct strbuf *sb,
 				  const struct pretty_print_context *context);

pretty.c

@@ -507,7 +507,7 @@ void pp_user_info(struct pretty_print_context *pp,
 	}
 }
 
-static int is_empty_line(const char *line, int *len_p)
+static int is_blank_line(const char *line, int *len_p)
 {
 	int len = *len_p;
 	while (len && isspace(line[len - 1]))
@@ -516,14 +516,14 @@ static int is_empty_line(const char *line, int *len_p)
 	return !len;
 }
 
-static const char *skip_empty_lines(const char *msg)
+const char *skip_blank_lines(const char *msg)
 {
 	for (;;) {
 		int linelen = get_one_line(msg);
 		int ll = linelen;
 		if (!linelen)
 			break;
-		if (!is_empty_line(msg, &ll))
+		if (!is_blank_line(msg, &ll))
 			break;
 		msg += linelen;
 	}
@@ -875,7 +875,7 @@ const char *format_subject(struct strbuf *sb, const char *msg,
 		int linelen = get_one_line(line);
 
 		msg += linelen;
-		if (!linelen || is_empty_line(line, &linelen))
+		if (!linelen || is_blank_line(line, &linelen))
 			break;
 
 		if (!sb)
@@ -894,11 +894,11 @@ static void parse_commit_message(struct format_commit_context *c)
 	const char *msg = c->message + c->message_off;
 	const char *start = c->message;
 
-	msg = skip_empty_lines(msg);
+	msg = skip_blank_lines(msg);
 	c->subject_off = msg - start;
 
 	msg = format_subject(NULL, msg, NULL);
-	msg = skip_empty_lines(msg);
+	msg = skip_blank_lines(msg);
 	c->body_off = msg - start;
 
 	c->commit_message_parsed = 1;
@@ -1718,7 +1718,7 @@ void pp_remainder(struct pretty_print_context *pp,
 		if (!linelen)
 			break;
 
-		if (is_empty_line(line, &linelen)) {
+		if (is_blank_line(line, &linelen)) {
 			if (first)
 				continue;
 			if (pp->fmt == CMIT_FMT_SHORT)
@@ -1789,7 +1789,7 @@ void pretty_print_commit(struct pretty_print_context *pp,
 	}
 
 	/* Skip excess blank lines at the beginning of body, if any... */
-	msg = skip_empty_lines(msg);
+	msg = skip_blank_lines(msg);
 
 	/* These formats treat the title line specially. */
 	if (pp->fmt == CMIT_FMT_ONELINE || pp->fmt == CMIT_FMT_EMAIL)

sequencer.c

@@ -544,10 +544,8 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 		 * information followed by "\n\n".
 		 */
 		p = strstr(msg.message, "\n\n");
-		if (p) {
-			p += 2;
-			strbuf_addstr(&msgbuf, p);
-		}
+		if (p)
+			strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
 
 		if (opts->record_origin) {
 			if (!has_conforming_footer(&msgbuf, NULL, 0))

t/t8008-blame-formats.sh

@@ -87,4 +87,21 @@ test_expect_success 'blame --line-porcelain output' '
 	test_cmp expect actual
 '
 
+test_expect_success '--porcelain detects first non-blank line as subject' '
+	(
+		GIT_INDEX_FILE=.git/tmp-index &&
+		export GIT_INDEX_FILE &&
+		echo "This is it" >single-file &&
+		git add single-file &&
+		tree=$(git write-tree) &&
+		commit=$(printf "%s\n%s\n%s\n\n\n  \noneline\n\nbody\n" \
+			"tree $tree" \
+			"author A <a@b.c> 123456789 +0000" \
+			"committer C <c@d.e> 123456789 +0000" |
+		git hash-object -w -t commit --stdin) &&
+		git blame --porcelain $commit -- single-file >output &&
+		grep "^summary oneline$" output
+	)
+'
+
 test_done