👷 Update setup-python action in tests to use new caching feature

[zanieb]

Updates the "Test" GitHub Actions workflow to use the cache feature on the setup-python action instead of the separate cache action.

This should resolve libffi problems failing builds right now e.g. https://github.com/tiangolo/fastapi/actions/runs/3531449114/jobs/5924630998 and simplify future maintenance.

Unfortunately there is not yet upstream support for caching based on the dependency section of a pyproject.toml and there will be a cache miss if unrelated metadata changes. See actions/setup-python#529.

[github-actions]

📝 Docs preview for commit 30ec2d7 at: https://637e7a79cb2392410df8af2c--fastapi.netlify.app

[tiangolo]

Ha! I didn't know about this new cache. Thank you! 🙇 🍰

[tiangolo]

It seems this only caches the files downloaded by pip, but not the installation in the environment. 😔 actions/setup-python#330

So, the normal cache is still needed. I'll add that back in another PR.

[zanieb]

:( @tiangolo sorry about that! Where I've used it elsewhere, we don't skip the installation step based on a cache hit because we want to ensure we're testing against the latest versions of libraries and the cache is just used to speed installation time.

Seems likely that the corrupted cache issue that prompted this can be resolved by just changing the version suffix you had on the cache key in your original implementation. (edit: for future reference, this was done in #5696)

[tiangolo]

Ah! I get it! Makes sense. And no worries! It's working now.

Also the docs for that weren't obvious to me, I thought they meant what I was thinking. 😅

But anyway, it's solved now. 🤓☕

[Avasam]

Unfortunately there is not yet upstream support for caching based on the dependency section of a pyproject.toml

Hi! I just saw this issue link and would like to offer you a workaround: After checkout, but before the python action step, you can read your pyproject.toml dependency section (I use the SebRollen/toml-action) and output it to a new file. Then you'll have a file to use as the cache-key.