--- a/hgext3rd/topic/__init__.py	Thu Apr 18 11:12:58 2019 +0200
+++ b/hgext3rd/topic/__init__.py	Thu Apr 18 11:13:14 2019 +0200
@@ -565,6 +565,8 @@
 
 def wrapinit(orig, self, repo, *args, **kwargs):
     orig(self, repo, *args, **kwargs)
+    if not hastopicext(repo):
+        return
     if constants.extrakey not in self._extra:
         if getattr(repo, 'currenttopic', ''):
             self._extra[constants.extrakey] = repo.currenttopic