--- a/mercurial/merge.py	Sat Jun 16 08:22:10 2018 +0530
+++ b/mercurial/merge.py	Sun Jun 17 22:13:41 2018 -0700
@@ -1785,7 +1785,7 @@
         actions[ACTION_MERGE] = [a for a in actions[ACTION_MERGE]
                                  if a[0] in mfiles]
 
-    progress.update(None)
+    progress.complete()
     return updateresult(updated, merged, removed, unresolved)
 
 def recordupdates(repo, actions, branchmerge):