Fix intersphinx cache handling

[picnixz]

This one is based on top of #12083.

This is the actual implementation (and bugfix) of #11466. I open it so that I can track more easily (and don't forget about it) but don't review it until the aforementioned PR is merged (and this one is rebased).

[AA-Turner]

@picnixz on the tests, please could you move everything new to a new test_ext_intersphinx_cache.py file? That would allow you to define the constants and classes as module globals and avoid nested class/function definitions.

If you're able to add more comments / explanation of what's being tested and which invariants we expect to hold etc, that would be great. (though optional)

A

[picnixz]

on the tests, please could you move everything new to a new test_ext_intersphinx_cache.py file? That would allow you to define the constants and classes as module globals and avoid nested class/function definitions.

Yes I can (I thought about it because I was like "mmmh this file becomes huge...")

[picnixz]

Do you want me to fix the tests now? or are you working on it now?

[picnixz]

I'll take care of fixing the CI/CD

[AA-Turner]

Do you want me to fix the tests now?

That'd be great, thank you! I've no more changes for now.

[jayaddison]

Do you want me to fix the tests now? or are you working on it now?

@AA-Turner @picnixz one more observation: during those test failures, tests on Windows succeeded. And on all the others, an Intersphinx cache key eviction failure occurred. Could the reason that only Windows passed -- and also perhaps the reason why it tends to take longer than other CI pipelines -- be that it is rebuilding from fresh every time?

[jayaddison]

I would personally still prefer to see the itemgetter usage removed and replaced with named attributes.

However, I'm comfortable enough with the state of the changeset to approve it 👍

[picnixz]

I split the test into 3 actually:

• One test for checking that it works correctly the first time.
• One test for checking 'build -> update -> build'.
• One test for checking 'build -> update -> build -> revert -> build'

I'm going offline now.

[AA-Turner]

Thanks for the mammoth effort @picnixz

[picnixz]

You're welcome! (the effort wasn't that much and it was fun). I plan, at some point, to refactor the tests in general so that we can have helper classes but I cannot find time for that...