Re: [Pyobjc-dev] Exceptions on calling super

[Ronald O. <ron...@ma...>]

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
>
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