nox fails in CI even when nox.options.error_on_missing_interpreters = False

[johnthagen]

Current Behavior

This PR makes CI fail if there are missing Python interpreters:

• Missing interpreters now error the session on CI by default #567

There was an exception for --no-error-on-missing-interpreters to override this behavior, but setting this in the noxfile.py itself does not work:

nox.options.error_on_missing_interpreters = False

In CI:

nox > Session test-3.9 was successful.
nox > Running session test-3.10
nox > Session test-3.10 failed: Python interpreter 3.10 not found.
nox > Ran multiple sessions:
nox > * test-3.9: success
nox > * test-3.10: failed

Expected Behavior

When nox.options.error_on_missing_interpreters = False is set, missing interpreters should not fail in CI.

Steps To Reproduce

Create a noxfile.py with

import nox

nox.options.error_on_missing_interpreters = False

@session(python=["3.9", "3.10"])
def test(s: Session) -> None:
    ...

Run this in a python:3.9 Docker image in GitLab CI.

nox > Session test-3.9 was successful.
nox > Running session test-3.10
nox > Session test-3.10 failed: Python interpreter 3.10 not found.
nox > Ran multiple sessions:
nox > * test-3.9: success
nox > * test-3.10: failed

Environment

- OS: `python:3.9` DockerHub image running on GitLab CI
- Python: 3.9
- Nox: 2022.8.7

Anything else?

tox allows this to be set in their configuration file:

• https://tox.wiki/en/latest/config.html#conf-skip_missing_interpreters

[q0w]

its because of flag_pair_merge_func where

    noxfile_value = getattr(noxfile_args, enable_name) # False
    command_value = getattr(command_args, enable_name) # True
    disable_value = getattr(command_args, disable_name) # None
    return (command_value or noxfile_value) and not disable_value #(False or True) and not None

noxfile_value should take precedence over command_value

[johnthagen]

Fixed in

• Allow override via noxfile of nox.options.error_on_missing_interpreters #725