--- a/mercurial/context.py Thu Nov 21 23:25:08 2019 +0100
+++ b/mercurial/context.py Thu Nov 21 23:46:51 2019 +0100
@@ -1161,7 +1161,9 @@
# use linkrev to find the first changeset where self appeared
base = self.introfilectx()
if getattr(base, '_ancestrycontext', None) is None:
- cl = self._repo.changelog
+ # it is safe to use an unfiltered repository here because we are
+ # walking ancestors only.
+ cl = self._repo.unfiltered().changelog
if base.rev() is None:
# wctx is not inclusive, but works because _ancestrycontext
# is used to test filelog revisions