--- a/mercurial/ui.py	Sun Oct 06 13:17:19 2019 -0400
+++ b/mercurial/ui.py	Sun Oct 06 13:28:56 2019 -0400
@@ -22,6 +22,7 @@
 
 from .i18n import _
 from .node import hex
+from .pycompat import open
 
 from . import (
     color,