--- a/mercurial/ui.py	Sat Feb 03 00:01:57 2018 -0500
+++ b/mercurial/ui.py	Sat Jan 27 13:09:49 2018 +0900
@@ -1508,11 +1508,7 @@
                                ''.join(exconly))
             else:
                 output = traceback.format_exception(exc[0], exc[1], exc[2])
-                data = r''.join(output)
-                if pycompat.ispy3:
-                    enc = pycompat.sysstr(encoding.encoding)
-                    data = data.encode(enc, errors=r'replace')
-                self.write_err(data)
+                self.write_err(encoding.strtolocal(r''.join(output)))
         return self.tracebackflag or force
 
     def geteditor(self):