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/sequencer.c b/sequencer.c
index fd183b5..dbee779 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -524,7 +524,7 @@ static int fast_forward_to(struct repository *r,
if (!transaction ||
ref_transaction_update(transaction, "HEAD",
to, unborn && !is_rebase_i(opts) ?
- &null_oid : from,
+ null_oid() : from,
0, sb.buf, &err) ||
ref_transaction_commit(transaction, &err)) {
ref_transaction_free(transaction);
@@ -1131,7 +1131,7 @@ int update_head_with_reflog(const struct commit *old_head,
transaction = ref_transaction_begin(err);
if (!transaction ||
ref_transaction_update(transaction, "HEAD", new_head,
- old_head ? &old_head->object.oid : &null_oid,
+ old_head ? &old_head->object.oid : null_oid(),
0, sb.buf, err) ||
ref_transaction_commit(transaction, err)) {
ret = -1;
