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I think this technique would not work with the limited API: https://docs.python.org/3/c-api/stable.html#limited-c-api https://docs.python.org/3/c-api/stable.htm

I think this technique would not work with the limited API: https://docs.python.org/3/c-api/stable.html#limited-c-api https://docs.python.org/3/c-api/stable.html#limited-c-api The Limited API has a nice benefit of letting you build artifacts that are compatible with a wide range of Python versions. The technique described in this article tightly couples the extension code to the interpreter internals.

nickelpro 3y ago
It doesn't work with any version of the public API, Limited, Stable, or Unstable, because this is not a part of the API. It's more of an application of Hyrum's Law[1]. That said, assuming the structures themselves exist on the versions of Python you're targeting in a format compatible with whatever hacking you're doing on them, it's very easy to compile for lots of Python versions using cibuildwheel[2] and the rest of the PyPA ecosystem. I don't think the Limited API is very useful, as a practical matter for the common distribution methods you need the wheel to be built with the target Python version. [1]: https://www.hyrumslaw.com/ https://www.hyrumslaw.com/ [2]: https://github.com/pypa/cibuildwheel https://github.com/pypa/cibuildwheel
- haberman 3y ago
  > I don't think the Limited API is very useful, as a practical matter for the common distribution methods you need the wheel to be built with the target Python version. The limited API provides ABI stability, which allows building a single artifact that will work across Python versions. We use this for the Protobuf PyPI package. A single artifact like protobuf-4.25.1-cp37-abi3-manylinux2014_x86_64.whl can be used with any Python version >= 3.7.
  - nickelpro 3y ago
    Ya, but so what? It's zero engineering effort to build the wheels for all the compatible versions. You don't win anything with the limited API.
    - haberman 3y ago
      You suggested it wasn't possible (or practical), so it seemed worth clearing up that it is indeed possible. It is nice to cut the number of distributed artifacts by a factor of four. Also, depending on third-party repositories full of build infrastructure increases your risk of supply chain attacks.

nickelpro 3y ago

It doesn't work with any version of the public API, Limited, Stable, or Unstable, because this is not a part of the API. It's more of an application of Hyrum's Law[1]. That said, assuming the structures themselves exist on the versions of Python you're targeting in a format compatible with whatever hacking you're doing on them, it's very easy to compile for lots of Python versions using cibuildwheel[2] and the rest of the PyPA ecosystem. I don't think the Limited API is very useful, as a practical matter for the common distribution methods you need the wheel to be built with the target Python version. [1]: https://www.hyrumslaw.com/ https://www.hyrumslaw.com/ [2]: https://github.com/pypa/cibuildwheel https://github.com/pypa/cibuildwheel

haberman 3y ago
> I don't think the Limited API is very useful, as a practical matter for the common distribution methods you need the wheel to be built with the target Python version. The limited API provides ABI stability, which allows building a single artifact that will work across Python versions. We use this for the Protobuf PyPI package. A single artifact like protobuf-4.25.1-cp37-abi3-manylinux2014_x86_64.whl can be used with any Python version >= 3.7.
- nickelpro 3y ago
  Ya, but so what? It's zero engineering effort to build the wheels for all the compatible versions. You don't win anything with the limited API.
  - haberman 3y ago
    You suggested it wasn't possible (or practical), so it seemed worth clearing up that it is indeed possible. It is nice to cut the number of distributed artifacts by a factor of four. Also, depending on third-party repositories full of build infrastructure increases your risk of supply chain attacks.