diff --git a/hash.h b/hash.h
index 615ae0691d..e064807c17 100644
--- a/hash.h
+++ b/hash.h
@@ -73,10 +73,15 @@ static inline void oidclr(struct object_id *oid)
 	oid->algo = hash_algo_by_ptr(the_hash_algo);
 }
 
+static inline void oidread_algop(struct object_id *oid, const unsigned char *hash, const struct git_hash_algo *algop)
+{
+	memcpy(oid->hash, hash, algop->rawsz);
+	oid->algo = hash_algo_by_ptr(algop);
+}
+
 static inline void oidread(struct object_id *oid, const unsigned char *hash)
 {
-	memcpy(oid->hash, hash, the_hash_algo->rawsz);
-	oid->algo = hash_algo_by_ptr(the_hash_algo);
+	oidread_algop(oid, hash, the_hash_algo);
 }
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)