[PATCH v2 2/2] trailer: support multiline title

[Christian Couder <christian.couder@gmail.com>]

We currently ignore the first line passed to `git interpret-trailers`,
when looking for the beginning of the trailers.

Unfortunately this does not work well when a commit is created with a
line break in the title, using for example the following command:

git commit -m 'place of
code: change we made'

In this special case, it is best to look at the first line and if it
does not contain only spaces, consider that the second line is not a
trailer.
---
 t/t7513-interpret-trailers.sh | 14 ++++++++++++++
 trailer.c                     |  8 +++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/t/t7513-interpret-trailers.sh b/t/t7513-interpret-trailers.sh
index 9577b4e..56efe88 100755
--- a/t/t7513-interpret-trailers.sh
+++ b/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%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 &&
diff --git a/trailer.c b/trailer.c
index b808868..9a54449 100644
--- a/trailer.c
+++ b/trailer.c
@@ -759,7 +759,13 @@ static int find_trailer_start(struct strbuf **lines, int count)
 		return count;
 	}
 
-	return only_spaces ? count : 0;
+	if (only_spaces)
+		return count;
+
+	if (contains_only_spaces(lines[0]->buf))
+		return 1;
+
+	return count;
 }
 
 /* Get the index of the end of the trailers */
-- 
2.5.0.401.g009ef9b.dirty