Re: [Pyobjc-dev] DeprecationWarning: Not all Objective-C arguments are present in the Python argument-list

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

On 20 Feb, 2008, at 7:00, James R Eagan wrote:

> I've been using the following decorator in PyObjC 1.4 without  
> problems, but now PyObjC 2.0 gives me a nice DeprecationWarning.  Am  
> I doing something naughty and/or dangerous?  If so, is there a safer  
> way to accomplish the same thing in PyObjC2?

The DeprecationWarning is bogus here. What this is trying to  
accomplish is warn about mismatches between the Python signature and  
Objective-C signature of a method, but this is giving false positives  
on some occassions. In your case you get the warning because the  
decorated function has a variable number of arguments.

I guess it is time to start working on a set of unittests for this  
feature to find all types of false positives.

Ronald

>
>
> First, the decorator:
>
> def trap_exceptions(func):
>   ''' Trap exceptions and prevent them from being passed along to  
> the ObjC runtime. '''
>   def trapper(self, *args, **kwargs):
>       try:
>           return func(self, *args, **kwargs)
>       except:
>           sys.stderr.write('Exception in %s: ' % (func.__name__))
>           traceback.print_exception(*sys.exc_info())
>   return trapper
>
> Typical usage is on an Objective-C entrypoint.  e.g.:
>
>   @trap_exceptions
>   def performDragOperation_(self, sender):
>       if self.delegate is not None \
>               and  
> self.delegate.respondsToSelector_('performDragOperation:'):
>           return self.delegate.performDragOperation_(sender)
>       return False
>
> This worked fine pre-Leopard.  When an exception was thrown  
> somewhere in (e.g.) performDragOperation_, I'd get a stack trace on  
> the console and everything would carry along as if nothing  
> happened.  In PyObjC2, the decorator appears to behave as expected,  
> but I also get this warning for every @trap_exceptions'ed method (at  
> NIB load time):
>
> /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/ 
> python/PyObjC/PyObjCTools/NibClassBuilder.py:219:  
> DeprecationWarning: Not all Objective-C arguments are present in the  
> Python argument-list of <unbound selector  
> observeValueForKeyPath:ofObject:change:context: of CBIconView at  
> 0x4f1fef0>
> return metaClass(name, bases, methods)
>
> Thanks!
> James
>
> PS:  Thanks for all the work you've done on PyObjC 2.0.  There are  
> lots of wonderful improvements here!  I'm very much looking forward  
> to the Tiger backport. :-)
>
> --
> Doctors are sadists who like to play God and watch lesser people  
> scream
> 			-- Bren MacGuff in "Juno"
>
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