Do we really need this? I'm not sure every possible thing you can set on a platform needs its own package set, and I especially don't think we need Hydra to build every single-change stdenv.

We can drop it before merging but for the purposes of testing this PR, I added it in.

I think this sort of thing is useful to have. For what it's worth. I don't think its existence needs to promise that it will work, much the same as for pkgsStatic and friends as well. It is quite powerful to have a simple name for this thing to reach for from the shell.

The problem is that these things also make it way too easy to use them within Nixpkgs, and then we end up with a layering violation where a single package is going through a whole distinct package set out of convenience.

But that's a general problem that needs to be solved, by making these inaccessible from within Nixpkgs while still being a convenience layer on top, so if this is really useful it can stay. I think there's no justification for building this set on Hydra, though.

The problem is that these things also make it way too easy to use them within Nixpkgs, and then we end up with a layering violation where a single package is going through a whole distinct package set out of convenience.

We can add in a config option similar to the aliases one which enables the subsets. Then have it disabled in Hydra / CI.

But that's a general problem that needs to be solved, by making these inaccessible from within Nixpkgs while still being a convenience layer on top, so if this is really useful it can stay. I think there's no justification for building this set on Hydra, though.

I kinda agree but its also good to ensure things work.

The problem is that these things also make it way too easy to use them within Nixpkgs, and then we end up with a layering violation where a single package is going through a whole distinct package set out of convenience.

We can add in a config option similar to the aliases one which enables the subsets. Then have it disabled in Hydra / CI.

Oh that's not a bad idea!

This is done in #400351

Unresolved this thread, because "We can drop it before merging" should still be taken care of eventually. (Or via the variants stuff, but not the current form)

I thought it was resolved because it sounded like Alyssa agreed to the variants overlay.

I still don't really like adding new ones, but not enough to really object if it can't be used within Nixpkgs.

Use replaceVars instead, see #395275.

Done

Unresolved this thread, because "We can drop it before merging" should still be taken care of eventually. (Or via the variants stuff, but not the current form)

Doesn't mkDerivation do this?

Idk, I couldn't get the hook to appear for whatever reason.

I wonder if there's a more precise verb than "use" that would work better here…

Not sure