How would this feature be useful?

With the acceptance of PEP 621 and a number of tools supporting it now, it might be a good idea to move Nox to the standard. The more high profile projects we have adopting it, (hopefully) the wider it will spread.

It will also enable us to switch build backends with relative ease should the need (or desire) ever arise.

Our current build backend (setuptools) has (currently experimental) support for PEP 621 from setuptools>=61.0.0.

Describe the solution you'd like

Nox to adopt the PEP 621 standard and put project metadata in pyproject.toml.

Note that we'll still need either a setup.py or setup.cfg present in order to enable editable installs with setuptools.

I have a working implementation in my fork here: https://github.com/FollowTheProcess/nox/blob/build/pep-621/pyproject.toml that's passing the check-manifest pre-commit hook and I've verified the contents of the sdist after running pyproject-build --sdist --wheel.

Describe alternatives you've considered

Just stay as it is, but I think projects like Nox can be the leaders here and help kick the community at large into adoption 🙂

Anything else?

Edit: Thought I'd just confirm that doing this won't break things like pipx (it doesn't) and I actually discovered that pipx itself has adopted PEP 621! (using the hatchlings build backend): https://github.com/pypa/pipx/blob/main/pyproject.toml