--- a/hgext3rd/topic/__init__.py	Sat Sep 30 11:11:04 2017 +0100
+++ b/hgext3rd/topic/__init__.py	Mon Oct 09 17:42:30 2017 +0200
@@ -322,14 +322,14 @@
             ct = self.currenttopic
             if not ct:
                 return tr
-            ctwasempty = stack.stackdata(self, topic=ct)['changesetcount'] == 0
+            ctwasempty = stack.stack(self, topic=ct).changesetcount == 0
 
             reporef = weakref.ref(self)
 
             def currenttopicempty(tr):
                 # check active topic emptyness
                 repo = reporef()
-                csetcount = stack.stackdata(repo, topic=ct)['changesetcount']
+                csetcount = stack.stack(repo, topic=ct).changesetcount
                 empty = csetcount == 0
                 if empty and not ctwasempty:
                     ui.status('active topic %r is now empty\n' % ct)
@@ -480,7 +480,7 @@
 
     ct = repo.currenttopic
     if clear:
-        empty = stack.stackdata(repo, topic=ct)['changesetcount'] == 0
+        empty = stack.stack(repo, topic=ct).changesetcount == 0
         if empty:
             if ct:
                 ui.status(_('clearing empty topic "%s"\n') % ct)
@@ -917,7 +917,7 @@
         # rebased commit. We have explicitly stored in config if rebase is
         # running.
         ot = repo.currenttopic
-        empty = stack.stackdata(repo, topic=ot)['changesetcount'] == 0
+        empty = stack.stack(repo, topic=ot).changesetcount == 0
         if repo.ui.hasconfig('experimental', 'topicrebase'):
             isrebase = True
         if repo.ui.configbool('_internal', 'keep-topic'):