Make it possible to mark Argument Clinic args as unused #104389

For base classes, it is not unusual to create stubs for interface methods, and let those stubs simply raise an exception. It would be nice to be able to mark the arguments with Py_UNUSED in those cases.

Implementing this is straight-forward in clinic.py. CConverter get's a new keyword argument unused which defaults to False, and we can write code like this:

/*[clinic input]
_io._TextIOBase.read
    cls: defining_class
    size: int(unused=True) = -1
[clinic start generated code]*/

Linked PRs

• gh-104389: Add 'unused' keyword to Argument Clinic C converters #104390