getattr() woes

[Aahz]

In article <87hdm5hnet.fsf at thomas.local>,
Thomas Rast  <foo.bar at freesurf.ch.invalid> wrote:
>
>I've found out about a fundamental problem of attribute lookup, the
>hard way.

Maybe.

>asyncore.py uses the following code:
>
>class dispatcher:
>    # ...
>    def __getattr__(self, attr):
>        return getattr(self.socket, attr)
>
>Now suppose that I'm asking for some attribute not provided by
>dispatcher: The lookup mechanism will apparently try to find it
>directly and fail, generating an AttributeError; next it will call
>__getattr__ to find the attribute.  So far, no problems.
>
>But I used a property much like this:
>
>>>> import asyncore
>>>> class Peer(asyncore.dispatcher):
>...     def _get_foo(self):
>...         # caused by a bug, several stack levels deeper
>...         raise AttributeError('hidden!')
>...     foo = property(_get_foo)
>...

You're not supposed to use properties with classic classes.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

"19. A language that doesn't affect the way you think about programming,
is not worth knowing."  --Alan Perlis