diff -r 3efadf2317c7 -r e9e61fbac787 mercurial/hook.py
--- a/mercurial/hook.py	Sun Jun 24 01:13:09 2018 -0400
+++ b/mercurial/hook.py	Sun Jul 02 00:32:09 2017 -0400
@@ -120,8 +120,6 @@
     return r, False
 
 def _exthook(ui, repo, htype, name, cmd, args, throw):
-    ui.note(_("running hook %s: %s\n") % (name, cmd))
-
     starttime = util.timer()
     env = {}
 
@@ -141,6 +139,12 @@
             v = stringutil.pprint(v)
         env['HG_' + k.upper()] = v
 
+    if pycompat.iswindows:
+        environ = procutil.shellenviron(env)
+        cmd = util.platform.shelltocmdexe(cmd, environ)
+
+    ui.note(_("running hook %s: %s\n") % (name, cmd))
+
     if repo:
         cwd = repo.root
     else: