Merge branch 'cc/trailers-corner-case-fix'

The "interpret-trailers" helper mistook a multi-paragraph title of
a commit log message with a colon in it as the end of the trailer
block.

* cc/trailers-corner-case-fix:
  trailer: support multiline title

Author: gitster

t/t7513-interpret-trailers.sh

@@ -112,6 +112,20 @@ test_expect_success 'with only a title in the message' '
 	test_cmp expected actual
 '
 
+test_expect_success 'with multiline title in the message' '
+	cat >expected <<-\EOF &&
+		place of
+		code: change
+
+		Reviewed-by: Peff
+		Acked-by: Johan
+	EOF
+	printf "%s\n" "place of" "code: change" |
+	git interpret-trailers --trailer "Reviewed-by: Peff" \
+		--trailer "Acked-by: Johan" >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'with config setup' '
 	git config trailer.ack.key "Acked-by: " &&
 	cat >expected <<-\EOF &&

trailer.c

@@ -735,15 +735,22 @@ static int find_patch_start(struct strbuf **lines, int count)
  */
 static int find_trailer_start(struct strbuf **lines, int count)
 {
-	int start, only_spaces = 1;
+	int start, end_of_title, only_spaces = 1;
+
+	/* The first paragraph is the title and cannot be trailers */
+	for (start = 0; start < count; start++) {
+		if (lines[start]->buf[0] == comment_line_char)
+			continue;
+		if (contains_only_spaces(lines[start]->buf))
+			break;
+	}
+	end_of_title = start;
 
 	/*
 	 * Get the start of the trailers by looking starting from the end
 	 * for a line with only spaces before lines with one separator.
-	 * The first line must not be analyzed as the others as it
-	 * should be either the message title or a blank line.
 	 */
-	for (start = count - 1; start >= 1; start--) {
+	for (start = count - 1; start >= end_of_title; start--) {
 		if (lines[start]->buf[0] == comment_line_char)
 			continue;
 		if (contains_only_spaces(lines[start]->buf)) {