PytestAssertRewriteWarning when installing a plugin in editable mode #10230
Description
Create an empty plugin (pytest-plugin) as follows:
pyproject.toml
[build-system]
requires = ['setuptools']
build-backend = 'setuptools.build_meta'
[project]
name = 'pytest-plugin'
version = '0.0.1'
[project.entry-points.pytest11]
plugin = 'pytest_plugin.main'
requirements.txt
pip==22.2.2
pytest==7.1.2
pytest_plugin/main.py
"""
An empty plugin.
"""
Install the plugin in editable mode:
> pip install -e .
Run pytest:
> pytest
=== test session starts ===
platform linux -- Python 3.8.10, pytest-7.1.2, pluggy-1.0.0
rootdir: .../pytest-plugin
plugins: plugin-0.0.1
collected 0 items
=== warnings summary ===
.../pytest-plugin/lib/python3.8/site-packages/_pytest/config/__init__.py:1129
.../pytest-plugin/lib/python3.8/site-packages/_pytest/config/__init__.py:1129: PytestAssertRewriteWarning: Module already imported so cannot be rewritten: __editable___pytest_plugin_0_0_1_finder
self._mark_plugins_for_rewrite(hook)
-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
=== 1 warning in 0.02s ===
The issue seems to be that pytest tries re-writing the module under site-packages/__editable___pytest_plugin_0_0_1_finder.py which I think is created by pip. Note that a new mechanism for pyproject.toml-based editable builds was introduced in https://pip.pypa.io/en/stable/news/#v21-3, which I believe doesn't use the egg-based editable mechanism anymore.
It might be that it would be enough to update https://github.com/pytest-dev/pytest/blob/main/src/_pytest/config/__init__.py#L799 to exclude the editable installation finder modules (similar to how setup.py files are excluded).
> pip list
Package Version Editable project location
------------- ------- --------------------------------------------
attrs 22.1.0
iniconfig 1.1.1
packaging 21.3
pip 22.2.2
pkg_resources 0.0.0
pluggy 1.0.0
py 1.11.0
pyparsing 3.0.9
pytest 7.1.2
pytest-plugin 0.0.1 .../pytest-plugin
setuptools 44.0.0
tomli 2.0.1
> uname -a
Linux flux 5.15.0-46-generic #49~20.04.1-Ubuntu SMP Thu Aug 4 19:15:44 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
- a detailed description of the bug or problem you are having
- output of
pip listfrom the virtual environment you are using - pytest and operating system versions
- minimal example if possible