diff -r 4fcee38d71d6 -r 04c971850183 src/topic/__init__.py
--- a/src/topic/__init__.py	Fri Dec 11 12:56:23 2015 -0500
+++ b/src/topic/__init__.py	Fri Dec 11 12:53:38 2015 -0500
@@ -131,7 +131,6 @@
                    del fixedextra[constants.extrakey]
                else:
                    fixedextra[constants.extrakey] = topic
-               c.parents()
                ui.debug('changing topic of %s from %s to %s\n' % (
                    c, oldtopic, newtopic))
                ui.debug('fixedextra: %r\n' % fixedextra)