Make uv venv use the python version listed in .python-version if no --python is provided

[jfcherng]

As the title. People can list multiple versions in the .python-version file too. The first matched one should be used.

E.g., with the following .python-version, 3.12 is preferred but 3.11 is fine as well.

3.12
3.11

---

It looks like uv project uses .python-versions (there is a trailing s somehow). pyenv uses .python-version.

[zanieb]

HI! That file is for internal development purposes – we need multiple specific Python versions to test this project.

We don't support .python-version markers at all. We definitely can consider it though.

[liiight]

+1 for this.
I have a use case where different branches are currently using different python version as part of a transition so using a versioned file to specify this would be great.

Thank you for this wonderful project!

[Spenhouet]

This becomes especially interesting in combination with #2607

[konstin]

Implemented in #4335

[jfcherng]

Just leave a note here the command is: uv venv --preview

Update: now --preview is not needed as of v0.3.0.