Nox does not raise an error when wrong option is set: reuse_venv

[smarie]

Current Behavior

I was giving a training today and I wanted to show how nox can be configured to reuse existing virtual environments.
This is what I wrote in noxfile.py :

nox.options.reuse_venv = True

Unfortunately nox does not raise any error and continues to run ! I did not realize it but if you look carefully it actually tells us that it (re)creates the env :

This is the correct way to tell nox to reuse virtual environments for all sessions :

nox.options.reuse_existing_virtualenvs = True

And we can check it that way

Expected Behavior

I would expect that an unsupported option in noxfile.py

nox.options.reuse_venv = True

would raise an error when running nox

Steps To Reproduce

see above

Environment

- OS: Windows 10
- Python: 3.11.4
- Nox: 2024.4.15

Anything else?

See #488 for related recent PR

[henryiii]

reuse_venv is actually a valid nox.options value. You are correct, though, that any invalid assignment is ignored - this has bugged me before. I've opened a PR.

In your case, reuse_venv takes a string: no, yes, never, and always. A second followup (more invasive, though) could be to validate these, say using attrs. A simpler fix just for this one would be to error if it's not set to one of those four strings.