Thanks for clarifying. On Tue, Jul 19, 2016 at 10:34 AM Nick Coghlan <ncoghlan@gmail.com> wrote:
Yes, I see what you're saying. However, I don't understand why __init_subclass__ (defined on some class C) cannot be used to implement
On 19 July 2016 at 16:41, Neil Girdhar <mistersheik@gmail.com> wrote: the
checks required by @abstractmethod instead of doing it in ABCMeta. This would prevent metaclass conflicts since you could use @abstractmethod with any metaclass or no metaclass at all provided you inherit from C.
ABCMeta also changes how __isinstance__ and __issubclass__ work and adds additional methods (like register()), so enabling the use of @abstractmethod without otherwise making the type an ABC would be very confusing behaviour that we wouldn't enable by default.
But yes, this change does make it possible to write a mixin class that implements the "@abstractmethod instances must all be overridden to allow instances to to be created" logic from ABCMeta without otherwise turning the class into an ABC instance.
Cheers, Nick.
-- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia