uv python pin should support writing to a uv.toml or pyproject.toml

[zanieb]

We need to design the schema for this data. Probably at uv.python-version or uv.python.default-version.

[T-256]

Then, should it also be top-level command uv pin? since it tries to manage project/workspace directly.

[zanieb]

That's a reasonable question. I'm not sure. I don't love it at the top-level since it's not obvious what we're pinning.

[zanieb]

I duped myself, #4359 covers reading from the configuration file.

[charliermarsh]

(At least figure out the rough design prior to the release.)

[edmorley]

I'm slightly concerned this will lead to more fragmentation of where third party ecosystems (such as Heroku, GHA setup-python, Dependabot, ...) will need to check for Python versions when bootstrapping an environment.

If there was a field in pyproject.toml that was guaranteed in the upstream spec to be a single Python version (either X.Y.Z or X.Y) rather than a multiple major version range, then I'd be fine with the ecosystem consolidating around that, but as-is the existing pyproject.toml requires-python field isn't suitable for bootstrapping purposes, and so the .python-version file is the next best thing available - and pretty widely accepted at this point.

[zanieb]

... as-is the existing pyproject.toml requires-python field isn't suitable for bootstrapping purposes, and so the .python-version file is the next best thing available - and pretty widely accepted at this point.

Agreed. That's why we've delayed implementing this. Unfortunately, we're getting quite a bit of confusion from users. I'm not sure how we'll address that.