attempt to use local actions

[geekosaur]

Extremely experimental, and with all the limitations and restrictions I keep finding in GitHub Actions it'll probably fail in the messiest way it can.

At present this is incomplete but sufficient to see if this has any chance of working to begin with. If it somehow does, I'll look into abstracting out the other sub-jobs, then making an overnight validate for Tier 2 platforms and probably a prerelease job (which would fix the recently revealed problem where if there is no need to rebase on merge, no prerelease is made).

Template B: This PR does not modify behaviour or interface

E.g. the PR only touches documentation or tests, does refactorings, etc.

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Is this a PR that fixes CI? If so, it will need to be backported to older cabal release branches (ask maintainers for directions). (No point in backporting, as even the LTS prerelease part has to live on master.)

[ulysses4ever]

Amazing, thanks!

[ulysses4ever]

But in a follow-up, we really need to sweep the less-relevant comments (like # look familiar?): They make the reader not want to read the comments at all because of the low signal/noise.

[geekosaur]

They're not entirely pointless: they mark the (IMO unnecessary except that GHA is stupid) duplications.

[ulysses4ever]

well, it's too subtle. I'd appreciate something less playful and more direct. E.g. for the matrix, duplicate matrix yet again see [Note: matrix duplication].

[geekosaur]

At this point I do not recommend merging this unless you have someone, preferably several someones, who understand it; otherwise your bus factor situation is looking pretty dire. If necessary I can expand the prerelease jobs out to full form and submit those separately, as they're the most urgent part of this and I don't want to leave you in a bad situation.

[Kleidukos]

Let's put this PR away for the moment

[9999years]

At this point I do not recommend merging this unless you have someone, preferably several someones, who understand it; otherwise your bus factor situation is looking pretty dire.

Ehhh, GitHub Actions stuff is kinda always like that. It's usually not too miserable to make small tweaks to, but changes in design goals require rearchitecting, as I think you're running into with this!

I haven't read over this with eagle eyes but it looks largely fine to me. A couple notes:

• Try running over this with actionlint and see if it catches anything.
• It might be worth porting some of the logic to Haskell, like cabal-validate; then, it's easier to test more of the logic locally, and you can cut down on the scary GitHub Actions shell-scripts-templated-YAML stuff. (In this design, the actions ideally become fairly thin wrappers that set up some inputs and then call the relevant script with the relevant arguments.)

[geekosaur]

Dammit, GitHub, this validate.yml is essentially unrelated to master. Quit whining about "conflicts" that are pretty much you trying to rewrite it into the one on master!

[geekosaur]

Installed actionlint and fixed a number of things CI wouldn't have caught for various reasons.

[geekosaur]

Sigh. NTS: GitHub's insistence on turning validate.yml back into the one on master means it will include messing up validate.sh in cabal-setup in the process; remember to fix it after rebasing.

[geekosaur]

The tests suddenly aren't finding the caches from the build step. This could be really bad.

[geekosaur]

GitHub has started aggressively pruning caches; we went from around 300GB in use to 25GB, which means they can't be used as shared state between the build and test stages any more. Will rewrite to use artifacts to pass the important parts around, but that will have its own limits and may have its own problems.