Difference between env.pythonLocation on macOS in Python 3.11+

Description:

I'm encountering a strange issue related to caching the Python installation. I'm using actions/setup-python@v5.0.0 to install Python, then actions/cache@v4.0.0 to cache the env.pythonLocation directory, similar to this blog.

This works fantastically, except on macOS in Python 3.11 and 3.12, and I have no idea why. For some reason, the cache is empty, but only for those specific versions. Did anything change in the installation layout or env.pythonLocation variable that could explain this?

Action version:

5.0.0

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:

Python 3.11, 3.12

Repro steps:

The full workflow can be seen here.

Expected behavior:

I would expect this to work for all platforms/Python versions and cache the installed Python packages.

Actual behavior:

The cache is empty. See https://github.com/actions/cache/issues/1176 for the cross-referenced bug report.

Start with the referenced .github/workflows/tests.yaml workflow and compare env.pythonLocation and cache contents for macOS with Python 3.11 and 3.12. Read the cross-referenced actions/cache issue 1176 alongside this report; done means the platform/version-specific behavior is explained and the affected caching behavior has a verified resolution.