[Python-Dev] Can we improve support for abstract base classes with desciptors

Darren Dale dsdale24 at gmail.com
Thu Jun 9 13:45:57 CEST 2011

On Wed, Jun 8, 2011 at 10:01 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Thu, Jun 9, 2011 at 8:51 AM, Darren Dale <dsdale24 at gmail.com> wrote:
>>>       for base in bases:
>>>           for name in getattr(base, "__abstractmethods__", ()):
>>>               # CHANGE 4: Using rpartition better tolerates weird
>>> naming in the metaclass
>>>               # (weird naming in descriptors will still blow up in
>>> the earlier search for abstract names)
>> Could you provide an example of weird naming?
>>>> class C(object):
> ...   pass
> ...
>>>> setattr(C, 'weird.name', staticmethod(int))

> This is definitely something that could legitimately be dismissed as
> "well, don't do that then" (particularly since similarly weird names
> on the descriptors will still break). However, I also prefer the way
> partition based code reads over split-based code, so I still like the
> modified version.

Yes, I like your modified version as well. I just wanted to understand
your concern, since it had never occurred to me to try something like
"setattr(C, 'pathological.name', ...)".

> Full tolerance for weird naming would require storing 2-tuples in
> __abstractmethods__ which would cause a whole new set of problems and
> isn't worth the hassle.

I'm glad you feel that way.

I'll work on a patch that includes docs and unit tests and post it at
http://bugs.python.org/issue11610. What do you think about deprecating
abstractproperty, or removing it from the documentation?


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