[Python-Dev] 'hasattr' is broken by design

[Benjamin Peterson]

2010/8/23 Raymond Hettinger <raymond.hettinger at gmail.com>:
> I don't have a specific proposal in mind.  My main questions are
> * Is there anything that hasattr(obj, key) can or should do that
>   can't already be done with getattr(obj, key, None)?
>   If not, do we really need to change anything?

For one, it's annoying when "key" can be None.

> * Why do people typically use hasattr() instead getattr()?
>    Aren't they are really trying to just determine
>    whether a key exists somewhere in the MRO?
>    If so, then doing anything more than that is probably a surprise.

It's generally more convenient that getattr(obj, "blah", None) is not None.

>
> P.S.  The current behavior seems to be deeply embedded:

Well, that's what happens when a behavior is added in 1990. :)



-- 
Regards,
Benjamin