diff -r c8e9a3636abe -r 888bd39ed555 mercurial/changegroup.py
--- a/mercurial/changegroup.py	Fri Nov 22 11:08:59 2019 -0800
+++ b/mercurial/changegroup.py	Tue Nov 19 18:38:17 2019 -0800
@@ -436,7 +436,7 @@
 
             if changesets > 0:
 
-                def runhooks():
+                def runhooks(unused_success):
                     # These hooks run when the lock releases, not when the
                     # transaction closes. So it's possible for the changelog
                     # to have changed since we last saw it.