Issue using uv with nox: uv insists using .venv instead of the nox-managed virtualenv

[sfermigier]

I have trouble integrating uv with nox.

Here is what I would like to work:

nox.options.default_venv_backend = "uv|virtualenv"

@nox.session
def lint(session: nox.Session) -> None:
    session.run("uv", "sync", "--no-dev")
    session.run("uv", "pip", "install", "pyright")
    session.run("uv", "run", "pyright")

If fails, because uv ignores the virtualenv supplied by nox:

warning: `VIRTUAL_ENV=.nox/lint` does not match the project environment path `.venv` and will be ignored

Here's a workaround:

nox.options.default_venv_backend = "uv|virtualenv"

@nox.session
def lint(session: nox.Session) -> None:
    session.run("rm", "-rf", ".venv", external=True)
    session.run("ln", "-s", ".nox/lint", ".venv", external=True)
    session.run("uv", "sync", "--no-dev")
    session.run("uv", "pip", "install", "abilian-devtools")
    session.run("just", "lint", external=True)

Here's a successful run:

nox -e lint -r
nox > Running session lint
nox > Creating virtual environment (uv) using python in .nox/lint
nox > rm -rf .venv
nox > ln -s .nox/lint .venv
nox > uv sync --no-dev
...

However, at the end of the run, I have to run uv sync to recreate my .venv to keep working.

I have eventually found another workaround, but anyway, I still think the use case of running "uv sync" from a virtualenv created by something else (e.g. tox or nox) could be useful.

Another thing that breaks is if I have a Makefile or Justfile that calls uv run make something, then uv will use .venv and not .nox/whatever and this breaks.

Version infos:

❯ nox --version
2024.10.9
❯ uv --version
uv 0.5.1 (Homebrew 2024-11-08)

[zanieb]

Please see #6834 and the discussions linked there.