diff --git a/src/pack-objects.c b/src/pack-objects.c
index 0afa28e62..5d9c09dd7 100644
--- a/src/pack-objects.c
+++ b/src/pack-objects.c
@@ -850,9 +850,11 @@ static int try_delta(git_packbuilder *pb, struct unpacked *trg,
 
 		git_packbuilder__cache_unlock(pb);
 
-		if (overflow ||
-			!(trg_object->delta_data = git__realloc(delta_buf, delta_size)))
+		if (overflow)
 			return -1;
+
+		trg_object->delta_data = git__realloc(delta_buf, delta_size);
+		GITERR_CHECK_ALLOC(trg_object->delta_data);
 	} else {
 		/* create delta when writing the pack */
 		git_packbuilder__cache_unlock(pb);