diff -r fe37721aa0d9 -r e10ebc58926e hgext3rd/topic/stack.py
--- a/hgext3rd/topic/stack.py	Thu Mar 07 10:51:48 2019 +0100
+++ b/hgext3rd/topic/stack.py	Wed Mar 06 16:56:25 2019 +0800
@@ -5,7 +5,6 @@
 from mercurial.i18n import _
 from mercurial import (
     destutil,
-    context,
     error,
     node,
     phases,
@@ -20,14 +19,6 @@
 
 short = node.short
 
-# TODO: compat
-
-if not util.safehasattr(context.basectx, 'orphan'):
-    context.basectx.orphan = context.basectx.unstable
-
-if not util.safehasattr(context.basectx, 'isunstable'):
-    context.basectx.isunstable = context.basectx.troubled
-
 def parseusername(user):
     """parses the ctx user and returns the username without email ID if
     possible, otherwise returns the mail address from that"""