X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=sha1_name.c;h=d67de18ba5f5aa1f5b3dd1c5c81e75618d12e330;hb=5b5d4d9e1b31997b3179e6a253d47b7eea03d0fa;hp=fa85d8a88d31219cef5bed195044327459f9162b;hpb=2d310d8a018ca1a8d3e4c8a52f60ae5f57f34b31;p=git.git

diff --git a/sha1_name.c b/sha1_name.c
index fa85d8a8..d67de18b 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -186,16 +186,18 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 
 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
-	int status;
+	int status, is_null;
 	static char hex[41];
 
+	is_null = !memcmp(sha1, null_sha1, 20);
 	memcpy(hex, sha1_to_hex(sha1), 40);
 	if (len == 40)
 		return hex;
 	while (len < 40) {
 		unsigned char sha1_ret[20];
 		status = get_short_sha1(hex, len, sha1_ret, 1);
-		if (!status) {
+		if (!status ||
+		    (is_null && status != SHORT_NAME_AMBIGUOUS)) {
 			hex[len] = 0;
 			return hex;
 		}