tasks/eval/nixpkgs: build the nixos manual / options to verify them

[cole-h]

Just evaluating them isn't enough anymore, now that the docs are lazy.

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Maybe we should keep the instantiate step but add the build step? idk

[cole-h]

There's a NixOS option that will allow us to go back to the old way and keep checking at eval-time: documentation.nixos.options.splitBuild = false (thanks pennae!)

Now just need to set that somehow.

[Artturin]

There's a NixOS option that will allow us to go back to the old way and keep checking at eval-time: documentation.nixos.options.splitBuild = false (thanks pennae!)

Now just need to set that somehow.

maybe this but the drv still contains lazy-options.json

nix-instantiate --arg configuration '{ ... }: { documentation.nixos.options.splitBuild = false; }' ./nixos/release.nix -A options

[ncfavier]

Is this really needed? The GitHub workflow already builds the NixOS manual whenever a file in nixos/ is modified.

[cole-h]

Well, we have two options: 1) make this actually build the manual / don't be lazy when instantiating it; or 2) disable the functionality in ofborg, since we do have GHA setup for that. This is assuming the GHA workflow does indeed catch issues with the manual (I don't know).

[ncfavier]

This is assuming the GHA workflow does indeed catch issues with the manual

It does.

I think we can go with 2, unless there's a need to do this in ofborg? GHA are a bit nicer, and they're already working.

[lheckemann]

Given the discussion linked above (GHA doesn't run on backport PRs), I think it would be good to introduce this if it's feasible.