--- a/hgext3rd/topic/discovery.py	Thu Apr 18 13:02:06 2019 +0200
+++ b/hgext3rd/topic/discovery.py	Thu Apr 18 13:02:44 2019 +0200
@@ -154,7 +154,7 @@
 def handlecheckheads(orig, op, inpart):
     """This is used to check for new heads when publishing changeset"""
     orig(op, inpart)
-    if op.repo.publishing():
+    if not common.hastopicext(op.repo) or op.repo.publishing():
         return
     tr = op.gettransaction()
     if tr.hookargs['source'] not in ('push', 'serve'): # not a push