[Python-3000] Minor problem with ABCMeta?

[Nick Coghlan]

Andrew McNamara wrote:
> The __subclasscheck__ method of ABCMeta contains the following code:
> 
>         # Check if it's a subclass of a registered class (recursive)
>         for rcls in cls._abc_registry:
>             if issubclass(subclass, rcls):
>                 cls._abc_registry.add(subclass)
>                 return True
> 
> It looks to me like this code will result in an unnecessary call to
> cls._abc_registry.add() in the case that "subclass" is already in
> cls._abc_registry. It looks like the code should be preceded with
> something like:
> 
>         if subclass in cls._abc_registry:
>             return True

Actually, it looks to me like the subclass is getting added to the wrong
set - it should be going into the _abc_cache, not the _abc_registry.

Tracker item with the 2-line patch here if someone would care to give it
the necessary post-beta review:
http://bugs.python.org/issue3747

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
---------------------------------------------------------------
            http://www.boredomandlaziness.org