Make GILOnceCell<Py<PyType>>'s get_or_try_init_type_ref public

[glevco]

Hi!

Is there any reason why GILOnceCell<Py<PyType>>'s get_or_try_init_type_ref() is not public API? It's a useful function and it looks like it should be the default way of importing Python modules. I would be happy to open a PR changing it and updating the docs accordingly, if it makes sense.

Thanks in advance!

[davidhewitt]

Hey, thanks for the request. There's a couple of different factors at play here:

• eventually, we should probably use "module state" for extension modules to store things like imports. This is still a way off but I think the way the CPython team wants us to do things instead of using GILOnceCell.
• There is also some debate about the immediate future for GILOnceCell. The python 3.13 freethreaded build removes the ability to synchronize using the GIL, so we are exploring solutions like make GILOnceCell threadsafe #4512 and add OnceLockExt extension trait to help initialize OnceLock #4513

So overall, it's not the best time to be expanding the GILOnceCell API until we are more sure of its future direction.

[davidhewitt]

That said, we just merged #4511 so maybe it's fine to make this public for the short term. PR would be accepted.

[glevco]

Ok, thanks! I'll work on it.

[glevco]

@davidhewitt Done in #4542, can you please review it?