Re: [Pyobjc-dev] crasher demo app

[Bob I. <bo...@re...>]

On Mar 26, 2004, at 1:54 AM, Ronald Oussoren wrote:

>
> 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.

I spent a few minutes playing with that, but it gets complicated really 
fast and about 24 of the tests start crashing or deadlocking ;)

-bob