Will third-party C code be broken if they don't make these same changes?

I don't like this. This makes the user code cluttered. The public API should use PyObject*, other types are implementation details. While _PyTuple_ITEMS is not in a public API, PyTuple_GET_ITEM and PyTuple_GET_SIZE are, and they should be called with the PyObject* argument.

Sorry, I shouldn't have posted a public PR for this change. I wasn't sure if it was a good idea or not. But sometimes, seeing the diff in GitHub helps me :-)

Will third-party C code be broken if they don't make these same changes?

The C API must not be modified, so third-party code doesn't have to be modified.

Note: _PyTuple_ITEMS() function is part of the internal API. I introduced it very recently, so no third-party C extensions don't use and cannot use it :-)

Honestly, I'm not sure that this change is worth it. I wasn't sure if the compiler might benefit of it, but when I looked at the machine code, the compiler is always smarter than me and doesn't need my help :-)

I abandon this change in favor of the minimum enhancement of _PyTuple_CAST(): PR #10712.

PyTuple_GET_ITEM and PyTuple_GET_SIZE are, and they should be called with the PyObject* argument.

Right. I mostly wrote this PR to ask myself if there is any benefit of passing directly the right type. I don't see any obvious advantage, so _Py*_CAST() macros are here to stay :-)

But sometimes, seeing the diff in GitHub helps me :-)

Tip: you can create PRs for your own fork.

Tip: you can create PRs for your own fork.

Aha, I will try next time. Thanks for the tip :-)