--- a/mercurial/hook.py	Sun Dec 10 04:46:39 2017 +0530
+++ b/mercurial/hook.py	Sun Dec 10 04:46:50 2017 +0530
@@ -91,7 +91,7 @@
     starttime = util.timer()
 
     try:
-        r = obj(ui=ui, repo=repo, hooktype=htype, **args)
+        r = obj(ui=ui, repo=repo, hooktype=htype, **pycompat.strkwargs(args))
     except Exception as exc:
         if isinstance(exc, error.Abort):
             ui.warn(_('error: %s hook failed: %s\n') %