[Python-Dev] PEP 580 and PEP 590 comparison.
On 2019-04-27 11:26, Mark Shannon wrote:
> Specifically, and this is important, PEP 580 cannot implement efficient
> calls to class objects without breaking the ABI.
First of all, the layout of PyTypeObject isn't actually part of the
stable ABI (see PEP 384). So, we wouldn't be breaking anything by
Second, even if you don't buy this argument and you really think that we
should guarantee ABI-compatibility, we can still solve that in PEP 580
by special-casing instances of "type". Sure, that's an annoyance but
it's not a fundamental obstruction.