Let's get rid of the stable ABI, but keep the limited API

[tiran (Christian Heimes)]

@tekknolagi

HPy seems to have this in their design already. With their universal mode, you get ABI compatibility, and with their non-universal mode you get runtime-specific performance features.

That’s not abi3, isn’t it? I’m pretty sure HPy has its own abi that is incompatible with abi3.

@markshannon Would it help you if we would to relax PEP 384 and introduce a new stable ABI? PEP 384 promise that abi3 will be supported throughout the entire life cycle of Python 3. The PEP is from 2009 and targets Python 3.2. Back then we did not anticipate that Python 3 will ever have two digit minor release.

We could consider to introduce a new stable ABI that would be valid for another 5 to 10 years.