--- a/mercurial/hgweb/hgweb_mod.py	Sat Feb 17 01:09:56 2018 -0500
+++ b/mercurial/hgweb/hgweb_mod.py	Sat Feb 17 01:11:48 2018 -0500
@@ -443,20 +443,20 @@
 
         except (error.LookupError, error.RepoLookupError) as err:
             req.respond(HTTP_NOT_FOUND, ctype)
-            msg = str(err)
+            msg = pycompat.bytestr(err)
             if (util.safehasattr(err, 'name') and
                 not isinstance(err,  error.ManifestLookupError)):
                 msg = 'revision not found: %s' % err.name
             return tmpl('error', error=msg)
         except (error.RepoError, error.RevlogError) as inst:
             req.respond(HTTP_SERVER_ERROR, ctype)
-            return tmpl('error', error=str(inst))
+            return tmpl('error', error=pycompat.bytestr(inst))
         except ErrorResponse as inst:
             req.respond(inst, ctype)
             if inst.code == HTTP_NOT_MODIFIED:
                 # Not allowed to return a body on a 304
                 return ['']
-            return tmpl('error', error=str(inst))
+            return tmpl('error', error=pycompat.bytestr(inst))
 
     def check_perm(self, rctx, req, op):
         for permhook in permhooks: