id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
147	NoneType is not callable error in RemoteReferenceTracker	bgranger		"Brian,

A few months ago, I emailed you about this. I said I would file a ticket, but lost track of it.  Here is the report.

I hope things are going well. I am seeing a very odd error in foolscap occasionally.  Here is what I see:

{{{
Exception exceptions.TypeError: ""'NoneType' object is not callable"" in <bound
method RemoteReferenceTracker._refLost of
<RemoteReferenceTracker(clid=1,url=pb://ahrpv6rtya6exuk75h2quxaubdkdubst@10.0.1.163:55071,127.0.0.1:55071/quegnf6enammggq33rgwiq3sgdt4dhh5)>>
ignored
}}}

This happens sometimes when my foolscap using process *ends*.  I looked at RemoteRemoteReferenceTracker:


{{{
    def _refLost(self, wref):
        # don't do anything right now, we could be in the middle of all sorts
        # of weird code. both __del__ and weakref callbacks can fire at any
        # time. Almost as bad as threads..

        # instead, do stuff later.
        eventually(self._handleRefLost)

    def _handleRefLost(self):
        if self.ref() is None:
            count, self.received_count = self.received_count, 0
            if count == 0:
                return
            self.broker.freeYourReference(self, count)
        # otherwise our RemoteReference is actually still alive, resurrected
        # between the call to _refLost and the eventual call to
        # _handleRefLost. In this case, don't decref anything.
}}}


I suspect the problem is in _handleRefLost, when it does if self.ref() is None.  For some reason
self.ref is None so calling it gives the TypeError.  Should this be protected by a ""if self.ref is None""?

Your response:

Yeah, please file a bug on that one. Your analysis sounds correct, but
I'd need to walk through the code to find where .ref is being
manipulated, and a bug will help me not forget about it. (it'll be
mid-week before I get a chance to look at it).

Thanks,

Brian Granger
"	defect	new	major	eventually	unknown	0.4.1