--- a/mercurial/hook.py	Fri Feb 12 11:42:18 2016 -0800
+++ b/mercurial/hook.py	Fri Feb 12 11:44:35 2016 -0800
@@ -106,6 +106,8 @@
                            '%s\n') % (hname, exc))
         if throw:
             raise
+        if not ui.tracebackflag:
+            ui.warn(_('(run with --traceback for stack trace)\n'))
         ui.traceback()
         return True, True
     finally: