PytestRemovedIn10Warning for base_url with pytest 9.2.0 and pytest-playwright 0.10.0 without pytest-base-url #341

With pytest 9.2.0 and pytest-playwright 0.10.0 without pytest-base-url, a test using page passes with 1 PytestRemovedIn10Warning naming the base_url fixture, and reports ERROR at setup of test_page_fixture[chromium] when that warning is an error. I saw the same warning with pytest-playwright-asyncio 0.10.0. I did not see it with pytest 9.1.1, with pytest-base-url 2.1.0 installed, or with pytest-playwright 0.9.0, which requires pytest-base-url.

Version

pytest-playwright 0.10.0, pytest 9.2.0, playwright 1.64.1. PyPI listed pytest-playwright 0.10.0 and pytest 9.2.0 as latest at 2026-10-30T19:43:53Z.

Steps to reproduce

test_repro.py:

def test_page_fixture(page):
    page.goto("about:blank")

python -m pip install pytest==9.2.0 pytest-playwright==0.10.0
python -m pytest -q -p no:cacheprovider
python -m pytest -q -p no:cacheprovider -W error::pytest.PytestRemovedIn10Warning

Chromium builds chromium-1248 and chromium_headless_shell-1248 were already installed. Each row below is a fresh venv:

The asyncio row used a separate file, test_repro_async.py:

import pytest


@pytest.mark.asyncio(loop_scope="session")
async def test_page_fixture(page):
    await page.goto("about:blank")

Every row used Python 3.14.10 and playwright 1.64.1. pytest-asyncio 1.4.1 was also installed in the asyncio row.

Evidence: repro/run_all.zsh, repro/run_scenario.zsh and the six scenarios in ledger.md, in the attached bundle.zip. The commands above leave out the venv path, --quiet --disable-pip-version-check and 2>&1 | tail -2 on the install, and, on the pytest runs, PYTHONDONTWRITEBYTECODE=1, the cd into the case directory, and the 2>&1, sed and tail output handling. Result cells leave out the duration. Each scenario prints hashes of its installed _pytest/fixtures.py and plugin file.

Actual behavior

test_repro.py::test_page_fixture[chromium]
  <venv>/lib/python3.14/site-packages/_pytest/fixtures.py:1392: PytestRemovedIn10Warning: Session-scoped fixtures defined as instance methods are deprecated.
  Instance attributes set in the 'base_url' fixture will NOT be visible to test methods,
  as each test gets a new instance while the fixture runs only once per class.
  Use a @classmethod decorator below @pytest.fixture and set attributes on cls instead.
  See https://docs.pytest.org/en/stable/deprecations.html#class-scoped-fixture-as-instance-method
    fixturefunc = resolve_fixture_function(fixturedef, request)

With the warning as an error, adding --tb=short:

________________ ERROR at setup of test_page_fixture[chromium] _________________
[...]
ERROR test_repro.py::test_page_fixture[chromium] - pytest.PytestRemovedIn10Wa...
1 error in 1.09s

Evidence: excerpts of scenario A and of the --tb=short run of scenario B in ledger.md. <venv> replaces the temporary venv path. [...] replaces the traceback lines, the E lines and the short test summary info rule.

Additional context

The plugin file pointers without a stated version are at v0.10.0 (80d7569). The _BaseUrlFallback registration and fixture lines, sync and asyncio, are identical at main (f71b92f).

Downstream PRs mentioning _BaseUrlFallback:

• fix(tests): Install pytest-base-url to avoid pytest 9.2's base_url warning posit-dev/py-shiny#2591
• fix: install pytest-base-url so browser tests use real base_url fixture tkoyama010/pyvista-js#749

Not examined: Python versions other than 3.14.10; Linux and Windows; Firefox and WebKit; pytest-playwright built from main; unreleased pytest.

Evidence: commands and output are in ledger.md in the attached bundle.zip, with scenario output limited to the last 14 lines per run except the --tb=short run.

Environment

- Operating System: macOS 27.2
- CPU: arm64
- Browser: Chromium
- Python Version: 3.14.10
- Other info: uv 0.13.6 created the venvs

bundle.zip