diff --git a/mercurial/wireprotoserver.py b/mercurial/wireprotoserver.py
--- a/mercurial/wireprotoserver.py
+++ b/mercurial/wireprotoserver.py
@@ -91,7 +91,6 @@
 class webproto(abstractserverproto):
     def __init__(self, req, ui):
         self.req = req
-        self.response = ''
         self.ui = ui
         self.name = 'http'