PEP 704 - Require virtual environments by default for package installers

This is not a good idea. Virtualenvs on top of conda envs do not work well (worse that pip-installing into a conda env). It’s also not necessary and treating conda envs like system envs is conceptually not quite right. Conda envs are like system envs in terms of what they are able to contain, but much more like virtualenvs than like real system envs in terms of their most important characteristics: they need activation, you can have multiple of them, they have their own lock/requirements files, they’re ephemeral (destroy/recreate rather than updating them often is recommended).

If you want to include conda environments in your picture here, then you could:

  • rely on the externally managed designator for installers (good idea for the base env at least, and there’s an active discussion on that),
  • treat non-base conda envs like virtualenvs rather than like system envs, either by special-casing conda envs or by generalizing whatever you do to “user-activated environments” (I’d quite like the latter),
  • or leave things as they are.

All those options are better than what you are suggesting here.