nix: add outputs for each supported ocaml version

[Alizter]

This let's us do nix build .#fiber_4_09. CI PR will follow this one.

Flakes unfortunately have this somewhat artificial restriction of only allowing "flake-like" values as inputs, meaning we can't parameterize the flake by arbitrary values. One way to get around that restriction is to create some local flakes for each OCaml version. I just opted for the simpler solution of adding the appropriate flake outputs.

Not all of them build however, as there are issues in the test suite for 4.09 for example. We can investigate that (and others) after this PR.

[Alizter]

Due to the way the devShell was setup, all the packages were being added as buildInputs. I've now restricted it to the two packages it was before.

[rgrinberg]

Can you include the CI here? I don't know how to use any of this stuff so the only value is the CI

[Alizter]

Here is the CI commits. Some further questions:

1. Do you want a different GH job for each version?
2. Do you want to restrict which versions we test? We are currently testing each version 4.08-5.1.
3. This won't be ready to merge until we fix some tests that don't work on <4.11. Should I ignore those versions?

[anmonteiro]

I believe an overlay approach would be a bit more lightweight ocaml/ocaml-lsp#1231

[rgrinberg]

Sure, doing it with overlays sounds good to me. Could you send a PR?

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On Mar 30, 2024, at 10:59 PM, Antonio Nuno Monteiro ***@***.***> wrote: I believe an overlay approach would be a bit more lightweight ocaml/ocaml-lsp#1231 <ocaml/ocaml-lsp#1231> — Reply to this email directly, view it on GitHub <#34 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABB56ZBPLWWBFEMU7A5MKLY247UXAVCNFSM6AAAAABACDFRAKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDAMRYGQ4DSMZTGQ>. You are receiving this because you commented.