[Twisted-Python] Traceback on loseConnection

[Werner Thie]

Hi all

My users are complaining that they get the odd disconnect while using my 
  site built with nevow/athena on FreeBSD 7.1 with the poll reactor. I 
recently switched to twisted 8.2 release and am now observing 199 
'Unhandled Error' out of 298436 logged requests with the following 
traceback.

Any clues?

TIA, Werner

2009-02-04 05:21:29+0100 [ProxyClient,client] Unhandled Error
         Traceback (most recent call last):
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/application/app.py", 
line 348, in runReactorWithLogging
             reactor.run()
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/base.py", 
line 1148, in run
             self.mainLoop()
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/base.py", 
line 1160, in mainLoop
             self.doIteration(t)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/pollreactor.py", 
line 165, in doPoll
             log.callWithLogger(selectable, _drdw, selectable, fd, event)
         --- <exception caught here> ---
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/python/log.py", 
line 84, in callWithLogger
             return callWithContext({"system": lp}, func, *args, **kw)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/python/log.py", 
line 69, in callWithContext
             return context.call({ILogContext: newCtx}, func, *args, **kw)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/python/context.py", 
line 59, in callWithContext
             return self.currentContext().callWithContext(ctx, func, 
*args, **kw)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/python/context.py", 
line 37, in callWithContext
             return func(*args,**kw)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/pollreactor.py", 
line 189, in _doReadOrWrite
             self._disconnectSelectable(selectable, why, inRead)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/posixbase.py", 
line 194, in _disconnectSelectable
             selectable.connectionLost(failure.Failure(why))
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/tcp.py", 
line 676, in connectionLost
             Connection.connectionLost(self, reason)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/internet/tcp.py", 
line 518, in connectionLost
             protocol.connectionLost(reason)
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/web/http.py", 
line 426, in connectionLost
             self.handleResponseEnd()
           File 
"/usr/local/lib/python2.5/site-packages/Twisted-8.2.0_r26128-py2.5-freebsd-7.1-RELEASE-amd64.egg/twisted/web/proxy.py", 
line 79, in handleResponseEnd
             self.father.channel.transport.loseConnection()
         exceptions.AttributeError: 'NoneType' object has no attribute 
'transport'