if (pbvh == NULL) {
  /* It is possible to have SculptSession without PBVH. Happes, for example, when toggling
   * objetc mode to sculpt them to edit mode.
   * <Can even give more details about overlays> */
  return;
}

if (!pbvh_has_mask(pbvh) && !pbvh_has_face_sets(pbvh)) {
  /* <explanation why the cache is only populated for mask and face sets, as it is not
   * obviously clear why generic sounding function only handles these two cases> */
  return;
}