Change RLock from factory function to actual type, remove dead Python RLock implementation

Feature or enhancement

Proposal:

Currently in CPython threading.RLock is a factory function that returns a new RLock instance. It either returns an instance of _CRLock, if it's defined, otherwise it returns an instance of _PyRLock. I'm kidding--in practice, it never returns _PyRLock. You'd have to do something silly (threading._CRLock = None) in order to get it to return an instance of _PyRLock, because these days _CRLock is always defined.

I haven't gone reading through old versions / git blame / etc, but my guess is that CPython used to support platforms that didn't have a native RLock, or the C implementation of RLock was unsuitable for some reason on some platforms. Here in 2025 I find the C implementation of RLock is unguarded by any #if / #ifdef statement. All platforms currently supported by CPython must support threading, the C version of RLock (_thread.RLock) is always defined, and the threading.RLock factory function always returns an instance of that object (unless you do something silly).

Assuming I'm right about all that:

• The Python implementation of RLock (class _RLock) in Lib/threading.py is dead code and should be removed.
• There's no longer any point in making threading.RLock a factory function. (Was there ever a point?) threading.RLock should simply be an alias for the RLock implementation in C (_thread.RLock).

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-141462
• gh-142977

Commencez par Lib/threading.py et le point d’entrée _thread.RLock, puis examinez les discussions des PR associés avant d’apporter des modifications. Vérifiez que l’alias et la suppression proposés sont compatibles avec les plateformes prises en charge et le comportement existant de threading ; le travail est terminé lorsque l’implémentation _RLock obsolète est supprimée et que threading.RLock fait directement référence à l’implémentation C.