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

[P.J. Eby]

At 12:47 PM 8/23/2010 -0700, Raymond Hettinger wrote:
>As your example shows, property() defeats this intent by actually executing
>the code.   A better behavior would not run the code at all.  It would check
>the dictionaries along the MRO but not execute any descriptors associated
>with a given key.

That just introduces a new class of error when the descriptor can 
raise AttributeError (e.g. __slots__ descriptors).  And of course, it 
ignoress __getattr__ and __getattribute__.