Updating pyproject.toml with maximum Python version

[bprobert97]

Raised in #367.

At the time of writing, labthings-fastapi supports Python 3.10, 3.11, 3.11 and 3.12. We mention this in the installation instructions updated in #367 but we do not enforce a maximum python version on the pyproject.toml. We only enforce the minimum version of >= 3.10. The only limitation on python 3.14 or greater is our current version of pydatic core, which only supports up to python 3.13.

This may require discussion as this is a stricter limitation and one that may require more frequent updates.

[rwb27]

Doing a little reading, I see a couple of articles that suggest this is a bad idea:

https://iscinumpy.dev/post/bound-version-constraints/#pinning-the-python-version-is-special

As the only reason we don't support 3.14 is an upstream problem, I think we are probably better declaring it in docs (which you've done) but not adding a hard cap in our metadata. That way, when pydantic is fixed, we don't have to do anything.

@bprobert97 are you happy to close this.

[bprobert97]

Yeah that makes sense, less work for the future is always a good thing too. I think we are planning on updating pydantic soon(?) so that also makes this less of a long term issue

[rwb27]

Thinking some more, while I think we don't want to cap the Python version, we probably do want to specify the supported minor versions in metadata. I propose using classifiers to do this.

Using classifiers is purely informational - it creates none of the pip problems that requires-python gets into. It does, however, show up in PyPI and make it very obvious what we do and don't support. I'll make a PR.

[rwb27]

pydantic isn't pinned, we are awaiting a new release I think. I don't know when they will support 3.14 but when they do, I think all we'd need to do is add 3.14 to the CI matrix :)