--- a/hgext3rd/topic/__init__.py	Fri Aug 26 16:52:02 2016 +0000
+++ b/hgext3rd/topic/__init__.py	Fri Aug 26 16:57:45 2016 +0000
@@ -84,6 +84,8 @@
             msg = _('cannot resolve "%s": topic "%s" has only %d changesets')
             raise error.Abort(msg % (name, topic, len(revs)))
         return [repo[r].node()]
+    if not name in repo.topics:
+        return []
     return [ctx.node() for ctx in
             repo.set('not public() and extra(topic, %s)', name)]