--- a/mercurial/scmutil.py Mon Mar 11 09:42:29 2019 -0700
+++ b/mercurial/scmutil.py Mon Mar 11 14:04:48 2019 -0700
@@ -1255,7 +1255,12 @@
wctx.copy(origsrc, dst)
def movedirstate(repo, newctx, match=None):
- """Move the dirstate to newctx and adjust it as necessary."""
+ """Move the dirstate to newctx and adjust it as necessary.
+
+ A matcher can be provided as an optimization. It is probably a bug to pass
+ a matcher that doesn't match all the differences between the parent of the
+ working copy and newctx.
+ """
oldctx = repo['.']
ds = repo.dirstate
ds.setparents(newctx.node(), nullid)