Guido van Rossum schrieb am 02.02.22 um 01:43:
Yes. HPy is certainly far from ready for anything real, but even for the
Limited API, it's still unclear whether it's actually complete enough to
cover Cython's needs. Basically, the API that Cython uses must really to be
able to implement CPython on top of itself. And at the same time interact
not with the reimplementation but with the underlying original, at the C
level. The C-API, and especially the Limited API, were never really meant
for that.
Undoubtedly.
My question for you is if you're willing to write up a list of things in CPython that you depend on. Or is this just something you're not willing to commit to? It would be nice to know which it is, just so the CPython team knows what we're up against. And if you just want to retain the freedom to use any and all CPython internals you can gain access to, maybe (a) Cython users should be told, so they can be prepared for the consequences, and (b) you should probably just #define the C preprocessor symbols that let you #include the truly internal headers so you can do what you want.