guard against new pathspec magic in pathspec matching code

GUARD_PATHSPEC() marks pathspec-sensitive code, basically all those
that touch anything in 'struct pathspec' except fields "nr" and
"original". GUARD_PATHSPEC() is not supposed to fail. It's mainly to
help the designers catch unsupported codepaths.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/tree-diff.c b/tree-diff.c
index 826512e84d..5a876148bb 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -198,6 +198,25 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
 	const char *paths[1];
 	int i;
 
+	/*
+	 * follow-rename code is very specific, we need exactly one
+	 * path. Magic that matches more than one path is not
+	 * supported.
+	 */
+	GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP);
+#if 0
+	/*
+	 * We should reject wildcards as well. Unfortunately we
+	 * haven't got a reliable way to detect that 'foo\*bar' in
+	 * fact has no wildcards. nowildcard_len is merely a hint for
+	 * optimization. Let it slip for now until wildmatch is taught
+	 * about dry-run mode and returns wildcard info.
+	 */
+	if (opt->pathspec.has_wildcard)
+		die("BUG:%s:%d: wildcards are not supported",
+		    __FILE__, __LINE__);
+#endif
+
 	/* Remove the file creation entry from the diff queue, and remember it */
 	choice = q->queue[0];
 	q->nr = 0;