mercurial/hook.py

--- a/mercurial/hook.py	Thu Jun 01 02:14:26 2017 +0530
+++ b/mercurial/hook.py	Fri Jun 02 10:35:21 2017 +0530
@@ -13,6 +13,7 @@
 from .i18n import _
 from . import (
     demandimport,
+    encoding,
     error,
     extensions,
     pycompat,
@@ -97,7 +98,7 @@
                          (hname, exc.args[0]))
         else:
             ui.warn(_('error: %s hook raised an exception: '
-                           '%s\n') % (hname, exc))
+                      '%s\n') % (hname, encoding.strtolocal(str(exc))))
         if throw:
             raise
         if not ui.tracebackflag: