448
448
if self._merge_sorted_revisions_cache is None:
449
449
last_revision = self.last_revision()
453
452
self._merge_sorted_revisions_cache = known_graph.merge_sort(
455
454
filtered = self._filter_merge_sorted_revisions(
456
455
self._merge_sorted_revisions_cache, start_revision_id,
457
456
stop_revision_id, stop_rule)