--- a/hgext/convert/cvsps.py	Tue Oct 06 21:06:18 2020 -0700
+++ b/hgext/convert/cvsps.py	Thu Oct 08 15:35:44 2020 -0700
@@ -559,7 +559,7 @@
                     pass  # try next encoding
                 except LookupError as inst:  # unknown encoding, maybe
                     raise error.Abort(
-                        inst,
+                        pycompat.bytestr(inst),
                         hint=_(
                             b'check convert.cvsps.logencoding configuration'
                         ),