send-pack: do not send out single-level refs such as refs/stash

Since no version of receive-pack accepts these "funny refs", we should
mirror the check when considering the list of refs to send. IOW, don't
even make them eligible for matching or mirroring.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-send-pack.c

@@ -132,7 +132,13 @@ static struct ref *remote_refs, **remote_tail;
 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 {
 	struct ref *ref;
-	int len = strlen(refname) + 1;
+	int len;
+
+	/* we already know it starts with refs/ to get here */
+	if (check_ref_format(refname + 5))
+		return 0;
+
+	len = strlen(refname) + 1;
 	ref = xcalloc(1, sizeof(*ref) + len);
 	hashcpy(ref->new_sha1, sha1);
 	memcpy(ref->name, refname, len);