Fix ref_newer() in send-pack.

When more than two references need to be checked with
ref_newer() function, the second and later calls did not work
correctly.  This was because the later calls found commits
retained by the "struct object" layer that still had smudges
made by earlier calls.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

send-pack.c

@@ -105,12 +105,23 @@ static int pack_objects(int fd, struct ref *refs)
 	return 0;
 }
 
+static void unmark_and_free(struct commit_list *list, unsigned int mark)
+{
+	while (list) {
+		struct commit_list *temp = list;
+		temp->item->object.flags &= ~mark;
+		list = temp->next;
+		free(temp);
+	}
+}
+
 static int ref_newer(const unsigned char *new_sha1,
 		     const unsigned char *old_sha1)
 {
 	struct object *o;
 	struct commit *old, *new;
-	struct commit_list *list;
+	struct commit_list *list, *used;
+	int found = 0;
 
 	/* Both new and old must be commit-ish and new is descendant of
 	 * old.  Otherwise we require --force.
@@ -127,14 +138,20 @@ static int ref_newer(const unsigned char *new_sha1,
 
 	if (parse_commit(new) < 0)
 		return 0;
-	list = NULL;
+
+	used = list = NULL;
 	commit_list_insert(new, &list);
 	while (list) {
 		new = pop_most_recent_commit(&list, 1);
-		if (new == old)
-			return 1;
+		commit_list_insert(new, &used);
+		if (new == old) {
+			found = 1;
+			break;
+		}
 	}
-	return 0;
+	unmark_and_free(list, 1);
+	unmark_and_free(used, 1);
+	return found;
 }
 
 static struct ref *local_refs, **local_tail;