patch_parse: handle patches without extended headers

Extended header lines (especially the "index <hash>..<hash> <mode>") are
not required by "git apply" so it import patches. So we allow the
from-file/to-file lines (--- a/file\n+++ b/file) to directly follow the
git diff header.

This fixes #5267.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/diff/parse.c b/tests/diff/parse.c
index 7d9f4b2e5..b004d1e23 100644
--- a/tests/diff/parse.c
+++ b/tests/diff/parse.c
@@ -98,6 +98,16 @@ void test_diff_parse__empty_file(void)
 	git_diff_free(diff);
 }
 
+void test_diff_parse__no_extended_headers(void)
+{
+	const char *content = PATCH_NO_EXTENDED_HEADERS;
+	git_diff *diff;
+
+	cl_git_pass(git_diff_from_buffer(
+		&diff, content, strlen(content)));
+	git_diff_free(diff);
+}
+
 void test_diff_parse__invalid_patches_fails(void)
 {
 	test_parse_invalid_diff(PATCH_CORRUPT_MISSING_NEW_FILE);