hash: provide per-algorithm null OIDs
Up until recently, object IDs did not have an algorithm member, only a
hash. Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms. Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.
Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/reset.c b/reset.c
index 2f4fbd0..4bea758 100644
--- a/reset.c
+++ b/reset.c
@@ -128,7 +128,7 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
}
if (run_hook)
run_hook_le(NULL, "post-checkout",
- oid_to_hex(orig ? orig : &null_oid),
+ oid_to_hex(orig ? orig : null_oid()),
oid_to_hex(oid), "1", NULL);
leave_reset_head:
