[Pyobjc-dev] Doc, it hurts when I say +isKindOfClass...

[Steven D. M. <sd...@mi...>]

In the following code, the classes in skiplist will all
generate objective-c runtime exceptions if they are touched:

----
from pyobjc import runtime,lookup_class

_Pool = runtime.NSAutoreleasePool()

skiplist = [ 'NSConcreteProtocolChecker', 'NSDistantObject',
        'NSInvocationBuilder', 'NSMutableStringProxy', 'NSProtocolChecker'
,
        'NSProxy' , '_NSZombie' ]

for x in runtime.__objc_classes__:
        if x not in skiplist:
                print x
                print lookup_class(x)
----


All of the exceptions happens in ObjCObject_new().


#   NSConcreteProtocolChecker
#   NSDistantObject
#   NSMutableStringProxy
#   NSProtocolChecker
#   NSProxy
# Apr 05 23:54:51 python[2259] *** Uncaught exception:
<NSInvalidArgumentException> *** -[NSProxy forwardInvocation:] called!
#
# caused by: [obj isKindOfClass: [NSAutoreleasePool class]]
#
#
#   NSInvocationBuilder
# Apr 05 23:54:41 python[2256] *** Uncaught exception:
<NSInvalidArgumentException> target does not implement method
#
# caused by: [obj respondsToSelector:@selector (count)]
#
#
#   _NSZombie           Bus error
 (seems to be somewhere close to the one above)

I'm quite willing to believe that whatever "_NSZombie" is, it
probably shouln't be touched. Most likely all of the classes
with a leading underscore in their names are not meant to be
exposed and should be removed from the Python-Objc runtime.

NSInvocationBuilder is undocumented (not even in the header
files) and I'm even unable to see it in the Class Introspector.

All of the first bunch, except for NSProxy are all subclasses of NSProxy.
NSProxy is another root class that is independent of NSObject.
Looking at NSProxy with the Class Introspector, I can see that indeed,
there is no class method for isKindOfClass: as there is in NSObject.
( NSObject has both a Class and an Instance isKindOfClass: )


I was looking at this problem too see if it was related to some of
the delegation bugs I've run into, but I'm now pretty convinced they
are probably unrelated. I'm not sure if there is any likey case in
which those classes would need to be called from Python -- perhaps
they should all be removed from the runtime.

For now, I'm going to leave them alone with just this warning:
 don't try to access any of those classes from python.

Does anyone know:
Is there a reason that +[NSProxy isKindOfClass:] is not implemented
or is it just an oversight (bug) ?

-- Steve Majewski