--- a/mercurial/localrepo.py	Tue May 02 18:56:07 2017 +0200
+++ b/mercurial/localrepo.py	Tue May 02 22:27:44 2017 +0200
@@ -1246,6 +1246,7 @@
 
         if tr is None or tr.changes['revs']:
             # updating the unfiltered branchmap should refresh all the others,
+            self.ui.debug('updating the branch cache\n')
             branchmap.updatecache(self.filtered('served'))
 
     def invalidatecaches(self):