[Feature request] Respect VIRTUAL_ENV env var when running uv venv without an arg

[dwreeves]

Running uv venv does not respect the VIRTUAL_ENV env var, even though it feels like it should.

Example

$ mkdir testproject && cd testproject
$ uv --version
uv 0.1.5
$ VIRTUAL_ENV=customvenv uv venv --verbose
 uv_interpreter::python_query::find_default_python platform=Platform { os: Macos { major: 14, minor: 1 }, arch: X86_64 }, cache=Cache { root: "~/Library/Caches/uv", refresh: None, _temp_dir_drop: None }
      0.004652s   2ms DEBUG uv_interpreter::interpreter Using cached markers for: ~/.pyenv/versions/3.12.0/bin/python3.12
Using Python 3.12.0 interpreter at ~/.pyenv/versions/3.12.0/bin/python3.12
Creating virtualenv at: .venv

With the above, I expected that it would create a venv at customvenv, not at .venv.

[zanieb]

Hm we generally use a VIRTUAL_ENV path to find the Python interpreter to use. It seems like it'd be pretty surprising to use it for a name here?

Related:

• Support custom virtual environment directory names #1422

[dwreeves]

Sounds good.

I'm not sure that this is surprising behavior per se, as setting the VIRTUAL_ENV variable shows intent to use it for the purposes of a venv. (I ran into this when trying to rely on VIRTUAL_ENV to do uv venv && uv pip install.)

That said, VIRTUAL_ENV is a bit of a hack, and this isn't a big deal in any event.

Want me to close this issue?

[zanieb]

Yeah I'd say VIRTUAL_ENV is actually intended to use an existing environment elsewhere on the system.

Thanks for the feedback though. Hopefully we can tackle this more holistically.