X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=sha1_name.c;h=faac158b16ca978914696ed5d2801770a122cce2;hb=8bf14d6ef9245f3b81d24cb7725a868f62343277;hp=be1755a70b2c53fc102db41a62e6099fa0adac1b;hpb=3eeb419968c1f8f0a762a7127db770e9d9c8037d;p=git.git

diff --git a/sha1_name.c b/sha1_name.c
index be1755a7..faac158b 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -236,6 +236,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 		NULL
 	};
 	const char **p;
+	int found = 0;
 
 	if (len == 40 && !get_sha1_hex(str, sha1))
 		return 0;
@@ -246,10 +247,20 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 
 	for (p = prefix; *p; p++) {
 		char *pathname = git_path("%s/%.*s", *p, len, str);
-		if (!read_ref(pathname, sha1))
-			return 0;
+		if (!read_ref(pathname, sha1)) {
+			/* Must be unique; i.e. when heads/foo and
+			 * tags/foo are both present, reject "foo".
+			 * Note that read_ref() eventually calls
+			 * get_sha1_hex() which can smudge initial
+			 * part of the buffer even if what is read
+			 * is found to be invalid halfway.
+			 */
+			if (1 < found++)
+				return -1;
+		}
 	}
-
+	if (found == 1)
+		return 0;
 	return -1;
 }