--- a/hgext3rd/topic/discovery.py	Thu Oct 25 10:01:58 2018 +0200
+++ b/hgext3rd/topic/discovery.py	Thu Oct 25 12:49:48 2018 +0200
@@ -81,8 +81,11 @@
 
         def revbranchcache(self):
             rbc = super(repocls, self).revbranchcache()
+            localchangelog = self.changelog
 
             def branchinfo(rev, changelog=None):
+                if changelog is None:
+                    changelog = localchangelog
                 branch, close = changelog.branchinfo(rev)
                 if rev in publishedset:
                     return branch, close