object-refs: avoid division by zero

Currently, we don't check refs_hash_size size and happily call
lookup_object_refs() even if refs_hash_size is zero which leads to
a division by zero in hash_obj().

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/object-refs.c b/object-refs.c
index 8afa2276fbe9e79bba700b99b1ef345bb6d7f5e8..a7d49c60d7176fbc90635e07dc2ce658125edafc 100644 (file)
--- a/object-refs.c
+++ b/object-refs.c
@@ -127,6 +127,9 @@ void mark_reachable(struct object *obj, unsigned int mask)
 
        if (!track_object_refs)
                die("cannot do reachability with object refs turned off");
+       /* nothing to lookup */
+       if (!refs_hash_size)
+               return;
        /* If we've been here already, don't bother */
        if (obj->flags & mask)
                return;