--- a/mercurial/merge.py	Sun Oct 06 16:55:18 2019 -0400
+++ b/mercurial/merge.py	Sun Oct 06 16:58:55 2019 -0400
@@ -23,6 +23,7 @@
     nullid,
     nullrev,
 )
+from .pycompat import delattr
 from .thirdparty import attr
 from . import (
     copies,