`TypeError: IdMaker.__init__() takes 7 positional arguments but 8 were given` with pytest 9.1.0

[TomAugspurger]

pytest 9.1.0 was released a couple days ago (https://pypi.org/project/pytest/#history).

Here's a MRE:

import pytest


@pytest.fixture(params=[1, 2])
def lower(request):
    return request.param


@pytest.fixture(params=[10, 20])
def upper(request):
    return request.param * 10


def test_plain_pytest(lower, upper):
    """Sanity check: would pass if pytest-cases could load."""
    assert lower in (1, 2)
    assert upper in (10, 20)

which fails during collection with

❯ pytest -vs test_mre.py
Traceback (most recent call last):
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/bin/pytest", line 10, in <module>
    sys.exit(_console_main())
             ~~~~~~~~~~~~~^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/config/__init__.py", line 253, in _console_main
    code = _main(prog=_get_prog_name(sys.argv))
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/config/__init__.py", line 223, in _main
    config = _prepareconfig(new_args, plugins, prog=prog)
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/config/__init__.py", line 410, in _prepareconfig
    config: Config = pluginmanager.hook.pytest_cmdline_parse(
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        pluginmanager=pluginmanager, args=args
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_hooks.py", line 512, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_callers.py", line 167, in _multicall
    raise exception
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_callers.py", line 139, in _multicall
    teardown.throw(exception)
    ~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/helpconfig.py", line 124, in pytest_cmdline_parse
    config = yield
             ^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_callers.py", line 121, in _multicall
    res = hook_impl.function(*args)
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/config/__init__.py", line 1232, in pytest_cmdline_parse
    self.parse(args)
    ~~~~~~~~~~^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/config/__init__.py", line 1583, in parse
    self.pluginmanager.load_setuptools_entrypoints("pytest11")
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pluggy/_manager.py", line 416, in load_setuptools_entrypoints
    plugin = ep.load()
  File "/home/nfs/toaugspurger/.local/share/uv/python/cpython-3.13.3-linux-x86_64-gnu/lib/python3.13/importlib/metadata/__init__.py", line 179, in load
    module = import_module(match.group('module'))
  File "/home/nfs/toaugspurger/.local/share/uv/python/cpython-3.13.3-linux-x86_64-gnu/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/assertion/rewrite.py", line 188, in exec_module
    exec(co, module.__dict__)
    ~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pytest_cases/__init__.py", line 8, in <module>
    from .fixture_core1_unions import fixture_union, NOT_USED, unpack_fixture, ignore_unused
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/assertion/rewrite.py", line 188, in exec_module
    exec(co, module.__dict__)
    ~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pytest_cases/fixture_core1_unions.py", line 40, in <module>
    from .common_pytest import get_fixture_name, is_marked_parameter_value, get_marked_parameter_values, pytest_fixture, \
        extract_parameterset_info, get_param_argnames_as_list, get_fixture_scope, resolve_ids
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/_pytest/assertion/rewrite.py", line 188, in exec_module
    exec(co, module.__dict__)
    ~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/raid/toaugspurger/envs/gh/rapidsai/cudf/lib/python3.13/site-packages/pytest_cases/common_pytest.py", line 644, in <module>
    _idval = IdMaker([], [], None, None, None, None, None)._idval
             ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: IdMaker.__init__() takes 7 positional arguments but 8 were given

Presumably, we could add another pytest version check there and pass one fewer None.

[dtczest]

Running into this same issue.