Re: [Pyobjc-dev] crasher demo app

[Ronald O. <ous...@ci...>]

On 26-mrt-04, at 0:03, Bob Ippolito wrote:

>
> On Mar 25, 2004, at 4:23 PM, Ronald Oussoren wrote:
>
>>
>> On 25-mrt-04, at 22:08, Burris T. Ewell wrote:
>>
>>> First off, I appreciate all of the help here...
>>>
>>> On Mar 25, 2004, at 12:19 PM, Ronald Oussoren wrote:
>>>> If I remove those calls the application runs longer, e.g. it didn't 
>>>> crash yet :-)
>>>
>>> I don't think that's it...  I tried that, holding a reference to the 
>>> cell, and also retaining the application delegate that holds 
>>> references to the controller objects.  Still, inside the cell, the 
>>> controller attribute disappears inside drawInteriorWithFrame.  Here 
>>> is a traceback from the full application, which is pretty much the 
>>> same as the demonstration.  This shouldn't be possible since the 
>>> cell sets self.controller inside of init() and nowhere else is the 
>>> attribute removed.
>>
>> Hmm, doesn't NSTableView use -copy? That might explain why 
>> self.controller disappears.
>>
>> There's definitly something fishy going on,
>
> There's fishy things with threads in PyObjC in general.. try this, for 
> example (I just ran into this bug today):
>
> http://undefined.org/~bob/PyURLProtocol_broken.tgz
>
> My guess is that it doesn't release the GIL when doing the call, so 
> when it gets the callback it can't acquire the GIL and deadlocks.

Yup, we don't release the GIL when calling into Objective-C, and we get 
a callback on another thread here.

This won't be completely solved before the 1.1 release, I'd prefer to 
get that out soon (we should have released that long ago). Doing a 90% 
solution should be possible by releasing the GIL when calling ffi_call 
(libffi_support.m).

That won't solve the problems with mcfoo.

Ronald
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