nox.options.keywords unexpected behaviour

[Kamforka]

Current Behavior

The nox.options.keywords configuration option makes the nox command to error out when specified in noxfile.py

Expected Behavior

The noxfile.py's nox.options.keywords option should behave the same as the -k command line flag.

Steps To Reproduce

1. With this noxfile.py:

import nox

nox.options.keywords = ["ci and not test"]


@nox.session(tags=["ci", "lint"])
def style(session: nox.Session):
    """Run style checks."""
    print("running style checks...")


@nox.session(tags=["ci", "test"])
def test(session: nox.Session):
    """Run integration tests with pytest."""
    print("running tests...")

2. Run:
   nox -l
3. See error:

Traceback (most recent call last):
  File "/home/ubuntu/projects/mypkg/venv/bin/nox", line 8, in <module>
    sys.exit(main())
             ~~~~^^
  File "/home/ubuntu/projects/mypkg/venv/lib/python3.13/site-packages/nox/_cli.py", line 219, in main
    exit_code = execute_workflow(args)
  File "/home/ubuntu/projects/mypkg/venv/lib/python3.13/site-packages/nox/_cli.py", line 53, in execute_workflow
    return workflow.execute(
           ~~~~~~~~~~~~~~~~^
        global_config=args,
        ^^^^^^^^^^^^^^^^^^^
    ...<10 lines>...
        ),
        ^^
    )
    ^
  File "/home/ubuntu/projects/mypkg/venv/lib/python3.13/site-packages/nox/workflow.py", line 61, in execute
    return_value = function_(*args, **kwargs)
  File "/home/ubuntu/projects/mypkg/venv/lib/python3.13/site-packages/nox/tasks.py", line 231, in filter_manifest
    ast.parse(global_config.keywords, mode="eval")
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/.pyenv/versions/3.13.3/lib/python3.13/ast.py", line 54, in parse
    return compile(source, filename, mode, flags,
                   _feature_version=feature_version, optimize=optimize)
TypeError: compile() arg 1 must be a string, bytes or AST object

Environment

- OS: Ubuntu 20.04
- Python: 3.13.3
- Nox: 2025.5.1

Anything else?

On the other hand the command nox -l -k "ci and not test" works as expected and outputs the below:

Sessions defined in /home/ubuntu/projects/mypkg/noxfile.py:

* style -> Run style checks.
- test -> Run integration tests with pytest.

sessions marked with * are selected, sessions marked with - are skipped.

Additionally in the noxfile.py I other values:

nox.options.keywords = "ci and not test"  # fails with: ValueError: ("not_ validator child '<instance_of validator for type <class 'str'>>' did not raise a captured error", Attribute(name='keywords', default=NOTHING, validator=<optional validator for <deep_iterable validator for <not_ validator wrapping <instance_of validator for type <class 'str'>>, capturing (<class 'ValueError'>, <class 'TypeError'>)> iterables of <instance_of validator for type <class 'str'>>> or None>, repr=True, eq=True, eq_key=None, order=True, order_key=None, hash=None, init=True, metadata=mappingproxy({}), type='None | Sequence[str]', converter=None, kw_only=True, inherited=False, on_setattr=None, alias='keywords'), <instance_of validator for type <class 'str'>>, 'ci and not test', (<class 'ValueError'>, <class 'TypeError'>))
nox.options.keywords = ["ci", "and", "not", "test"]  # fails with: TypeError: compile() arg 1 must be a string, bytes or AST object