Thread (1 message) 1 message, 1 author, 2021-04-14

Re: What's cooking (draft for #4's issue this month)

From: Junio C Hamano <hidden>
Date: 2021-04-14 21:32:10

Patrick Steinhardt [off-list ref] writes:
The other breakages I see are caused by hn/reftable, where all tests in
t0031-reftables.sh cause segfaults. The root cause seems to be that
reading refs via the reftable backend doesn't initialize the `algo`
field of the OID, which is fixed via the following patch.
OK.  On 'master' without bc/hash-transition-interop-part-1,
hashcpy() and oidread() both use the size from the_hash_algo
but with the topic, oidread() becomes the way to declare that
the given oid uses the_hash_algo.

static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
{
	memcpy(sha_dst, sha_src, the_hash_algo->rawsz);
}

static inline void oidread(struct object_id *oid, const unsigned char *hash)
{
	size_t rawsz = the_hash_algo->rawsz;
	memcpy(oid->hash, hash, rawsz);
	memset(oid->hash + rawsz, 0, GIT_MAX_RAWSZ - rawsz);
	oid->algo = hash_algo_by_ptr(the_hash_algo);
}

So the patch makes sense to directly squashed into hn/reftable topic
to (1) be a benign no-op in the master and to (2) fix an expected
semantic conflict with bc/hash-transition-interop-part-1 topic.

Thanks.


quoted hunk
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 130fd90e45..35fb7dd0a2 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -251,10 +251,10 @@ static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator)
 		ri->base.flags = 0;
 		switch (ri->ref.value_type) {
 		case REFTABLE_REF_VAL1:
-			hashcpy(ri->oid.hash, ri->ref.value.val1);
+			oidread(&ri->oid, ri->ref.value.val1);
 			break;
 		case REFTABLE_REF_VAL2:
-			hashcpy(ri->oid.hash, ri->ref.value.val2.value);
+			oidread(&ri->oid, ri->ref.value.val2.value);
 			break;
 		case REFTABLE_REF_SYMREF: {
 			int out_flags = 0;
@@ -299,7 +299,7 @@ static int reftable_ref_iterator_peel(struct ref_iterator *ref_iterator,
 	struct git_reftable_iterator *ri =
 		(struct git_reftable_iterator *)ref_iterator;
 	if (ri->ref.value_type == REFTABLE_REF_VAL2) {
-		hashcpy(peeled->hash, ri->ref.value.val2.target_value);
+		oidread(peeled, ri->ref.value.val2.target_value);
 		return 0;
 	}
@@ -977,7 +977,7 @@ git_reftable_reflog_ref_iterator_advance(struct ref_iterator *ref_iterator)

 		free(ri->last_name);
 		ri->last_name = xstrdup(ri->log.refname);
-		hashcpy(ri->oid.hash, ri->log.update.new_hash);
+		oidread(&ri->oid, ri->log.update.new_hash);
 		return ITER_OK;
 	}
 }
@@ -1090,8 +1090,8 @@ static int git_reftable_for_each_reflog_ent_newest_first(
 			break;
 		}

-		hashcpy(old_oid.hash, log.update.old_hash);
-		hashcpy(new_oid.hash, log.update.new_hash);
+		oidread(&old_oid, log.update.old_hash);
+		oidread(&new_oid, log.update.new_hash);

 		full_committer = fmt_ident(log.update.name, log.update.email,
 					   WANT_COMMITTER_IDENT,
@@ -1157,8 +1157,8 @@ static int git_reftable_for_each_reflog_ent_oldest_first(
 		struct object_id new_oid;
 		const char *full_committer = "";

-		hashcpy(old_oid.hash, log->update.old_hash);
-		hashcpy(new_oid.hash, log->update.new_hash);
+		oidread(&old_oid, log->update.old_hash);
+		oidread(&new_oid, log->update.new_hash);

 		full_committer = fmt_ident(log->update.name, log->update.email,
 					   WANT_COMMITTER_IDENT, NULL,
@@ -1330,8 +1330,8 @@ git_reftable_reflog_expire(struct ref_store *ref_store, const char *refname,
 		if (err > 0 || strcmp(log.refname, refname)) {
 			break;
 		}
-		hashcpy(ooid.hash, log.update.old_hash);
-		hashcpy(noid.hash, log.update.new_hash);
+		oidread(&ooid, log.update.old_hash);
+		oidread(&noid, log.update.new_hash);

 		if (should_prune_fn(&ooid, &noid, log.update.email,
 				    (timestamp_t)log.update.time,
@@ -1410,7 +1410,7 @@ static int git_reftable_read_raw_ref(struct ref_store *ref_store,
 		strbuf_addstr(referent, ref.value.symref);
 		*type |= REF_ISSYMREF;
 	} else if (reftable_ref_record_val1(&ref) != NULL) {
-		hashcpy(oid->hash, reftable_ref_record_val1(&ref));
+		oidread(oid, reftable_ref_record_val1(&ref));
 	} else {
 		*type |= REF_ISBROKEN;
 		errno = EINVAL;

Patrick
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