Re: [Pyobjc-dev] Exceptions on calling super

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

Hi Ronald,

I recently moved our app to PyObjC HEAD / Python 2.6.2 (from the dmg  
installer from python.org) on Leopard and have not seen these  
exceptions since, so I'm also pretty sure the underlying issue is fixed.

Before making this move I've tried to isolate the issue but had no  
luck in figuring out a way to consistently reproduce it.  If I ever  
run into it again on a recent revision of PyObjC, I'll let you know.

thx,
- Dirk

On Sep 29, 2009, at 10:36 PM, Ronald Oussoren wrote:

> Dirk,
>
> I cannot reproduce this with Python 2.6 and PyObjC HEAD, or with / 
> usr/bin/python on SL with its version of PyObjC.
>
> I've used the following scriptlet to test:
>
> #BEGIN
> from Cocoa import *
>
> NSApplication.sharedApplication()
>
> class SFWindow(NSWindow):
>    def initWithContentRect_styleMask_backing_defer_(self,
>            contentRect, styleMask, backing, defer):
>        print "init"
>        self = super(SFWindow,  
> self).initWithContentRect_styleMask_backing_defer_(
>                contentRect,  styleMask, backing, defer)
>        if self:
>            pass # do stuff
>        return self
>
> v = SFWindow.alloc().init()
> # EOF
>
> This prints "init" when run.
>
> Ronald
>
> On 20 Sep, 2009, at 13:16, Dirk Stoop wrote:
>
>>>> We recently moved our app from PyObjC 1.4 to 2.2 and now get a  
>>>> lot of
>>>> exceptions like this:
>>>>
>>>> TypeError??: super(type, obj): obj must be an instance or subtype  
>>>> of
>>>> type
>>>>
>>>> These happen in any Python subclass of a Cocoa superclass, but only
>>>> occasionally.  I'm not completely clear how to reproduce the issue,
>>>> but it only happens when we override an initializer and have a call
>>>> to:
>>>>
>>>> super(classNameOfOurSubClass, self).init() # or any other
>>>> initializer.
>>>>
>>>> Does anyone have a clue what might be going on?
>>>
>>> That message pretty clearly means that a classic class is getting
>>> injected somehow.  Consider this::
>>>
>>>  class C:
>>>      def foo(self):
>>>          super(C, self)
>>>
>>>  C().foo()
>>>
>>> Which version of Python?
>>
>>
>> Thanks for your reply :)
>>
>> We're using Python 2.5.4 and we don't have classic classes anywhere  
>> in
>> our app.
>>
>> The error message I get from the example you wrote is also different
>> from the one we're getting..
>>
>> TypeError: super() argument 1 must be type, not classobj
>>
>> The one I get seems to explicitely state that the second argument is
>> not the type or a subtype of the first argument, yet the one I get
>> when I run your example just tells me that the second type can't be
>> 'the' old-style classobj.
>>
>> To get our app to stop crashing on this, I'll replace e.g.
>>
>> class SFWindow(NSWindow):
>>    def initWithContentRect_styleMask_backing_defer_(self,
>> contentRect, styleMask, backing, defer):
>>        self = super(SFWindow,
>> self).initWithContentRect_styleMask_backing_defer_(contentRect,
>> styleMask, backing, defer)
>>        if self:
>>            pass # do stuff
>>        return self
>>
>> with:
>>
>> class SFWindow(NSWindow):
>>    def initWithContentRect_styleMask_backing_defer_(self,
>> contentRect, styleMask, backing, defer):
>>        self =
>> NSWindow.initWithContentRect_styleMask_backing_defer_(self,
>> contentRect, styleMask, backing, defer)
>>        if self:
>>            pass # do stuff
>>        return self
>> 	
>> for now.  I'm not planning on changing the superclasses of any of
>> these classes anyway, so the extra burden of maintaining this code is
>> well worth getting rid of these occasional crashes.
>>
>> Still very weird that this happens, I've tried to isolate the issue  
>> to
>> a particular situation, but all my efforts so far have failed and I
>> don't have time now to do more research.  I'll post again here if/ 
>> when
>> I've figured out the exact regression of this problem.
>>
>> - Dirk
>>
>> ------------------------------------------------------------------------------
>> Come build with us! The BlackBerry&reg; Developer Conference in SF,  
>> CA
>> is the only developer event you need to attend this year. Jumpstart  
>> your
>> developing skills, take BlackBerry mobile applications to market  
>> and stay
>> ahead of the curve. Join us from November 9&#45;12, 2009. Register  
>> now&#33;
>> http://p.sf.net/sfu/devconf
>> _______________________________________________
>> Pyobjc-dev mailing list
>> Pyo...@li...
>> https://lists.sourceforge.net/lists/listinfo/pyobjc-dev
>