[IronPython] object lifecycle issues

[Dino Viehland]

The first 2 things that occur to me is that either there's an exception
happening when we run WeakRefTracker's finalizer (it swallows exceptions)
or the object simply isn't being collected.

But it definitely sounds like we're creating the object which will
ultimately call __del__ when it gets finalized.

Have you tried windbg + SOS and done a !DumpHeap to see if the object
could still be alive?  Another thought would be to look at the finalizer
queue and make sure it's not blocked on something (like a transition
into an STA).


> -----Original Message-----
> From: users-bounces at lists.ironpython.com [mailto:users-
> bounces at lists.ironpython.com] On Behalf Of William Reade
> Sent: Tuesday, July 21, 2009 9:20 AM
> To: Discussion of IronPython
> Subject: Re: [IronPython] object lifecycle issues
>
> Dino Viehland wrote:
> > #2 I'd guess could be either that for some reason we're failing to
> > detect the presence of __del__ or that when we run the finalizer
> cleanup
> > that we believe it's part of cyclic trash and don't think we should
> cleanup.
> > Of those I'd think it'd be the cyclic trash detection that'd be most
> > likely to go wrong.
> >
> > I'd suggest putting a break point or some logging in
> > PythonOps.InitializeForFinalization and in WeakRefTracker's finalizer
> > and see what's happening there.
> >
>
> In PythonOps.InitializeForFinalization, I see 2 InstanceFinalizers
> created for each object; one after the stub __new__, and one after the
> real __new__. Each IF creates a WeakRefTracker as expected; in both
> cases, the second WRT (and only the second one) is subsequently
> GC.SuppressFinalized in SetFinalizerWorker. However, in the broken
> cases, the WRT finalizer just never gets called.
>
> I'll keep hunting, but it seemed worth posting this in case it rang any
> bells.
>
> Cheers
> william
>
>
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