[Python-Dev] why different between staticmethod and classmethod on non-callable object?

Brett Cannon brett at python.org
Wed Sep 2 00:13:20 CEST 2009


On Tue, Sep 1, 2009 at 14:54, Benjamin Peterson<benjamin at python.org> wrote:
> 2009/9/1 Brett Cannon <brett at python.org>:
>> On Tue, Sep 1, 2009 at 07:21, Benjamin Peterson<benjamin at python.org> wrote:
>>> 2009/8/31 xiaobing jiang <s7v7nislands at gmail.com>:
>>>> My idea is: here, the two functions (or maybe classes) should have the
>>>> same behavior).
>>>> so is this a bug or something I missing ?
>>>
>>> I think they should both not check their arguments in __init__ to
>>> allow for duck typing.
>>
>> But what is the point of wrapping something with classmethod or
>> staticmethod that can't be called? It isn't like it is checking
>> explicitly for a function or method, just that it can be called which
>> seems reasonable to me (unless PyCallable_Check() is as off as
>> callable() was).
>
> Well, if checking if tp_call is not NULL is as bad as callable, then yes.
>
> I don't see any reason to use staticmethod or classmethod with a
> non-callable, but to be consistent, I would, given the choice between
> removing code and adding another type check, perfer to remove a type
> check.

Fine by me. I guess it will just fail later with a slightly more
cryptic exception.

-Brett


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