Request: adding `py.typed` for type checkers

[jamesbraza]

Currently with torchtune==0.5.0 and mypy=1.14.1 I get import-untyped:

error: Skipping analyzing "torchtune": module is installed, but missing library stubs or py.typed marker  [import-untyped]
    from torchtune import generation
    ^
error: Skipping analyzing "torchtune.data": module is installed, but missing library stubs or py.typed marker  [import-untyped]
    from torchtune.data import Message as TorchTuneMessage
    ^

It would be nice to add a py.typed to torchtune so type checkers like mypy can inspect torchtune.

[krammnic]

Interesting point about mypy! @joecummings Actually, probably there are several points related to modern python related techniques(uv for example) that might improve our CI/CD. Is this really relevant for us?

[joecummings]

torchtune tries to be as complete as possible in it's typing but we aren't perfect, hence why we are hesitant to provide a py.typed file ATM. We're working on this and any type-hints you see missing in our code, we'd love to accept a PR!

I'm definitely interested in looking into modernizing our Python stack as much as possible, but since we are PyTorch we have to support all the way down to Python 3.9 until all of PyTorch upgrades.