This is the significant semantic changes that we're talking about wrt to the API when the `GIT_STATUS_XYZ_RENAMED` flags come into play - namely, that they will be combined with MODIFIED as a quick check for whether the OIDs have changed or not. For tree-to-index comparison, this is essentially free. As you will see below, for the index-to-workdir side of the compare, this is not totally free because we need to know the workdir OID definitively and there are many code paths that may have avoided calculating it before now.