sparse-checkout: detect short patterns

In cone mode, the shortest pattern the sparse-checkout command will
write into the sparse-checkout file is "/*". This is handled carefully
in add_pattern_to_hashsets(), so warn if any other pattern is this
short. This will assist future pattern checks by allowing us to assume
there are at least three characters in the pattern.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/dir.c b/dir.c
index 40fed73a94..c2e585607e 100644
--- a/dir.c
+++ b/dir.c
@@ -651,7 +651,8 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern
 		return;
 	}
 
-	if (strstr(given->pattern, "**")) {
+	if (given->patternlen <= 2 ||
+	    strstr(given->pattern, "**")) {
 		/* Not a cone pattern. */
 		warning(_("unrecognized pattern: '%s'"), given->pattern);
 		goto clear_hashmaps;