[Python-Dev] super() bug (?)

[Samuele Pedroni]

From: "Guido van Rossum" <guido@python.org>
> [Samuele]
> > >>> class C(object):
> > ...  def f(self): pass
> > ...
> > >>> class D(C): pass
> > ...
> > >>> D.f
> > <unbound method D.f>
> > >>> super(D,D).f
> > <bound method D.f of <class '__main__.D'>>
> >
> > I think this should produce the same thing as D.f,
>
> Really?  It makes no sense either way though.

It was sloppy phrased, super(D,D).f should return the same value as C.f, that
means an unbound method like D.f.

> super(D, D) only makes
> sense from inside a class method; there the first argument should be
> the current class and the second should be the cls argument to the
> class method, e.g.:
>
>   class C(object):
>     def cm(cls): pass
>     cm = classmethod(cm)
>
>   class D(C):
>     def cm(cls):
>       super(D, cls).cm() # ~Same as C.cm(cls)

you mean C.cm()


> And this works.
>
> I should also mention that super() should really only be used to call
> a method with the same name as the currently called method -- I see
> no use case for using super() with another method.

>
> It shouldn't be terribly hard to detect this situation and fix it
> (somewhere in super_init()) but unless you have a use case I'd
> rather consider this as a "don't care" situation.
>

no, but passing D,D even to classmethods __get__ is working but conceptually
bogus,

btw the clarifying example Python impl for super semantics at

http://www.python.org/2.2.2/descrintro.html#cooperation

is broken wrt to classmethods.