AttributeError: module 'py' has no attribute 'io' for tox for python

AttributeError: module 'py' has no attribute 'io'

Steps:

1. clone Pytest

   git clone https://github.com/pytest-dev/pytest.git

2. Run tox:

   tox

Result:

AttributeError: module 'py' has no attribute 'io'

everything else is working fine. What am I do wrong?

The py module used to have py.io but in py>=1.12.0 it was removed. Some parts of the pytest source code or plugins still rely on py.io, especially in older clones or test setups.

Try:

1: Pin the py version

Edit the tox.ini or requirements.txt (depending on your setup) and add a version pin for py:

[deps]

py<1.12.0

Or you can manually install the compatible version:

pip install 'py<1.12.0'

Then run tox again.

2: Update your clone

If you're cloning pytest's own repo, make sure you're on the latest commit:

git pull origin main

They may have already patched this issue in recent commits. Then re-run:

tox

3: Use a virtualenv and pip install editable

Sometimes cloning and testing a package like pytest is easier with a manual virtualenv setup:

python -m venv .venv

source .venv/bin/activate

pip install -e .[testing]

pytest