I am traveling and have no keyboard right now, but it looks like this thread is confusing the slots that a type gives to its *instances* and extra slots in the type object itself. Only the latter are a problem.
I also would like to hear more about the problem this is trying to solve, when th real-world examples. (E.g. from pydantic?) On Tue, Apr 26, 2022 at 11:57 Larry Hastings <la...@hastings.org> wrote: > > On 4/25/22 23:56, Ronald Oussoren wrote: > > A problem with this trick is that you don’t know how large a class object > can get because a subclass of type might add new slots. This is currently > not possible to do in Python code (non-empty ``__slots__`` in a type > subclass is rejected at runtime), but you can do this in C code. > > Dang it! __slots__! Always there to ruin your best-laid plans. *shakes > fist at heavens* > > I admit I don't know how __slots__ is currently implemented, so I wasn't > aware of this. However! The first part of my proto-PEP already proposes > changing the implementation of __slots__, to allow adding __slots__ after > the class is created but before it's instantiated. Since this is so > late-binding, it means the slots wouldn't be allocated at the same time as > the type, so happily we'd sidestep this problem. On the other hand, this > raises the concern that we may need to change the C interface for creating > __slots__, which might break C extensions that use it. (Maybe we can find > a way to support the old API while permitting the new late-binding > behavior, though from your description of the problem I'm kind of doubtful.) > > > Cheers, > > > */arry* > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/YU3PJKPMJZNWKLZUG3JCJFGFOKGMV2GI/ > Code of Conduct: http://python.org/psf/codeofconduct/ > -- --Guido (mobile)
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