deref_tag: handle tag->tagged = NULL

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/tag.c b/tag.c
index 38bf9134f97c18973fe189c8703438f5e1135e49..990134fe7ab14043d40b97230571ffea109b9129 100644 (file)
--- a/tag.c
+++ b/tag.c
@@ -9,7 +9,10 @@ const char *tag_type = "tag";
 struct object *deref_tag(struct object *o, const char *warn, int warnlen)
 {
        while (o && o->type == OBJ_TAG)
-               o = parse_object(((struct tag *)o)->tagged->sha1);
+               if (((struct tag *)o)->tagged)
+                       o = parse_object(((struct tag *)o)->tagged->sha1);
+               else
+                       o = NULL;
        if (!o && warn) {
                if (!warnlen)
                        warnlen = strlen(warn);