ModuleNotFoundError: No module named '_pytest.scope'

TL;DR

Upgrade pytest to 8.x: python -m pip install -U pytest. The _pytest.scope module was added in pytest 8.0, so any plugin or tool importing it (like newer anyio) breaks on pytest 7.x and older with this exact error.

ModuleNotFoundError: No module named '_pytest.scope'

Fix it

1. Check your pytest version. Run pytest --version or python -m pip show pytest.

• Expected: you will see pytest 7.x or older.

1. Upgrade pytest. Run python -m pip install -U pytest.

• Expected: Successfully installed pytest-8.x.x.

1. Re-run your tests. The importing plugin (often anyio's pytest plugin) should now load cleanly.

• Expected: no ModuleNotFoundError, tests collect normally.

1. If you cannot upgrade pytest, pin the plugin to a version that supports your pytest. For anyio, that means staying on anyio 3.x with pytest 7.x.

When this applies

• The traceback shows a plugin (anyio, or similar) doing from _pytest.scope import ... or import _pytest.scope.
• You recently upgraded a pytest plugin but not pytest itself.

When it does not apply

• If the missing module is pytest itself (not _pytest.scope), pytest is simply not installed.
• If the error names a hook (like pytest_namespace), that is a plugin validation error, a different problem.

Tool compatibility

pytest 8.0+ provides _pytest.scope. anyio 4.x requires it. Python 3.8+.

Why it happens

_pytest.scope is an internal pytest module introduced in pytest 8.0. Plugins written against pytest 8 import it at load time. If your environment pins pytest 7.x (common in CI images or libraries with upper bounds), the import fails even though everything else works.

Edge cases

• Some distributions pin pytest via constraints files; check pip freeze | grep -i pytest and any constraints files.
• If you must stay on pytest 7, downgrade the plugin instead: pip install "anyio<4".