--- a/mercurial/localrepo.py Mon May 13 14:19:36 2019 -0400
+++ b/mercurial/localrepo.py Tue Apr 23 13:29:13 2019 -0700
@@ -2650,6 +2650,14 @@
mn = p1.manifestnode()
files = []
+ if writecopiesto == 'changeset-only':
+ # If writing only to changeset extras, use None to indicate that
+ # no entry should be written. If writing to both, write an empty
+ # entry to prevent the reader from falling back to reading
+ # filelogs.
+ p1copies = p1copies or None
+ p2copies = p2copies or None
+
# update changelog
self.ui.note(_("committing changelog\n"))
self.changelog.delayupdate(tr)