--- a/mercurial/hgweb/hgweb_mod.py	Wed Jan 31 16:43:46 2018 -0800
+++ b/mercurial/hgweb/hgweb_mod.py	Wed Jan 31 17:34:45 2018 -0800
@@ -369,18 +369,7 @@
                 if cmd in perms:
                     self.check_perm(rctx, req, perms[cmd])
             except ErrorResponse as inst:
-                # A client that sends unbundle without 100-continue will
-                # break if we respond early.
-                if (cmd == 'unbundle' and
-                    (req.env.get('HTTP_EXPECT',
-                                 '').lower() != '100-continue') or
-                    req.env.get('X-HgHttp2', '')):
-                    req.drain()
-                else:
-                    req.headers.append((r'Connection', r'Close'))
-                req.respond(inst, wireprotoserver.HGTYPE,
-                            body='0\n%s\n' % inst)
-                return ''
+                return protohandler['handleerror'](inst)
 
             return protohandler['dispatch']()