fsck: treat a NUL in a tag header as an error

We check the return value of verify_header() for commits already, so do
the same for tags as well.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>

fsck.c

@@ -711,7 +711,8 @@ static int fsck_tag_buffer(struct tag *tag, const char *data,
 		}
 	}
 
-	if (verify_headers(buffer, size, &tag->object, options))
+	ret = verify_headers(buffer, size, &tag->object, options);
+	if (ret)
 		goto done;
 
 	if (!skip_prefix(buffer, "object ", &buffer)) {

t/t1450-fsck.sh

@@ -288,7 +288,7 @@ test_expect_success 'tag with bad tagger' '
 	grep "error in tag .*: invalid author/committer" out
 '
 
-test_expect_failure 'tag with NUL in header' '
+test_expect_success 'tag with NUL in header' '
 	sha=$(git rev-parse HEAD) &&
 	q_to_nul >tag-NUL-header <<-EOF &&
 	object $sha