--- a/hgext3rd/topic/destination.py	Wed Aug 29 18:59:07 2018 +0200
+++ b/hgext3rd/topic/destination.py	Tue Aug 28 21:28:41 2018 +0800
@@ -59,7 +59,10 @@
     """decide on an update destination from current topic"""
     movemark = node = None
     topic = repo.currenttopic
-    revs = repo.revs('.::topic("%s")' % topic)
+    if topic:
+        revs = repo.revs('.::topic(%s)', topic)
+    else:
+        revs = []
     if not revs:
         return None, None, None
     node = revs.last()