Just a comment regarding the change to "PyCode_NewWithPosOnlyArgs()". As Pablo mentioned, this has happened before. And that's OK! Exactly because this has happened before, it's clearly not a part of the API that is meant to be stable.

I can easily adapt Cython to make this work in the next patch-level release of CPython 3.11 (or the current one, since alpha-1 seems not so close), but any adaptation will be patch-level dependent. Meaning, for each such change, there will be a couple of weeks or months until the C preprocessor makes the code compile again. And during that time, people won't be able to test their code to report issues.

So, I'd rather have compatibility broken and stay that way, than going one way now and changing it back later, thus going through the same adaptation period twice.

That being said, any such change means that maintainers will have to rebuild their packages with a new Cython release to adapt them to Py3.11. Many will, but some won't, for whatever reason.