diff -r 1df7e7b8558e -r 04c319a07c7b mercurial/localrepo.py
--- a/mercurial/localrepo.py	Sun Feb 25 22:30:14 2018 -0500
+++ b/mercurial/localrepo.py	Sun Feb 25 23:08:41 2018 -0500
@@ -259,7 +259,8 @@
                     bundle2.processbundle(self._repo, b)
                 raise
         except error.PushRaced as exc:
-            raise error.ResponseError(_('push failed:'), str(exc))
+            raise error.ResponseError(_('push failed:'),
+                                      util.forcebytestr(exc))
 
     # End of _basewirecommands interface.