[Python-Dev] getstate() not inherited when slots present (original) (raw)

Greg Ward gward@python.net
Sun, 8 Dec 2002 18:09:41 -0500

If a class and its superclass both define slots, it appears that getstate() is not inherited from the superclass. Example:

""" class Base (object): slots = []

def __getstate__ (self):
    return tuple([getattr(self, attr) for attr in self.__slots__])

class Thing (Base): slots = ['a', 'b']

def __init__ (self):
    self.a = 42
    self.b = "boo!"

abstract = Base() thing = Thing()

print abstract.getstate print thing.getstate """

When I run this with a not-quite-current CVS Python:

<bound method Base.__getstate__ of <__main__.Base object at 0x401f73b8>>

The upshot of this is that I can't just define one getstate() in the superclass of a bunch of slots-using classes -- I guess I'll have to set getstate manually for each class. ;-( If this is a feature, is it documented anywhere?

(BTW, I see the same behaviour with Python 2.2.2.)

    Greg

-- Greg Ward <gward@python.net> http://www.gerg.ca/ "Very funny, Scotty. Now beam my clothes down."