PIP_ROOT_USER_ACTION=ignore ignored: pip still issues error messages about running it as root

[RoFz]

Description:
setup-action@v5 and python-version: 3.11 leads to pip's warnings about running as root, which should have been suppressed by the install script on self-hosted runner and GHES 3.12.8.

Action version:
@v5

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:
python 3.11 (3.11.9)

Repro steps:

1. job running under an ubuntu:jammy container image, as root (without 'options: --user ...)
2. setup-python step like so:

      - name: Set up python
        uses: actions/setup-python@v5
        with:
          python-version: '3.11'

Expected behavior:
No warnings, since the the install script seems to properly export PIP_ROOT_USER_ACTION=ignore.

Actual behavior:
pip throws the known errors (warnings?) about running it as root:

Error: WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behavior with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
  Error: WARNING: The directory '/github/home/.cache/pip' or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you should use sudo's -H flag.

This is related to #513, which, although initially opened as a feature request and closed as such, is still receiving updates from people impacted by the same problem.

[RoFz]

Additional note: also tried with setup-python@v4 and specific python versions 3.11.9 and 3.11.8.

[priyagupta108]

Hello @RoFz 👋,
Thank you for reporting this issue. We will investigate it and get back to you as soon as we have some feedback.