Flake ghc 92

[guibou]

This is (partial) flake support for GHC 9.2.

This is in a limited state, especially:

• I have not repaired the support for a few plugins.
• nix develop .#....-dev target is not working, it pulls a few dependencies which are not overiden. I'll give another pass soon.

But the cool thing is that it allows to build haskell-language-server from flake in another project. I've just updated my work project to GHC 9.2 and I'm enjoying HLS thank to this flake.

Tell me if you prefer to merge "partial" support or if I need to work on the currently broken tasks. I cannot guarantee that I'll allocate time to this soon.

However, users can find this MR and point their flake to this commit and immediately get HLS in their project.

[guibou]

For reference, here is the command I used in my project to upgrade HLS, where hls is the name of my flake input:

nix flake lock --override-input hls github:guibou/haskell-language-server/flake_ghc_92

And obviously:

        hls = inputs.hls.packages.${system}."haskell-language-server-921";

somwhere.

[guibou]

/cc @teto

[michaelpj]

Are you interested in maintaining these going forwards?

[teto]

that may be the problem you are referring to, but putting it there just in case, since it's an area that is under active development in nix: With nix 2.6.0pre20211217_6e6e998

nix develop .#haskell-language-server-921-dev          
AWS error 'RequestTimeTooSkewed' (The difference between the request time and the current time is too large.), will retry in 0 ms
error: cannot fetch input 'path:./flake_hackage?narHash=sha256-gVzFEW0y%2fuPHJaGJ6w7VZc3QDhH6latvmYHJuzaXDa0=' because it uses a relative path
(use '--show-trace' to show detailed location information)

Cool work o/

[michaelpj]

Ah, that's a good point. Do flakes at relative paths work reliably? I remember there being issues with that.

[guibou]

Ah, that's a good point. Do flakes at relative paths work reliably? I remember there being issues with that.

Initially I moved everything to a relative path flake because I wanted to have a flake only for the hackage dependencies and remove boilerplate, I tried that;

Unfortunately, it does not work, because flake does not "evaluate" nix language in the input section.

So actually, we can move everything back in the main flake.nix file. Let me do that tomorrow.

Are you interested in maintaining these going forwards?

Yes sure.

[michaelpj]

I added you to the CODEOWNERS in #2619.

[smunix]

@guibou - I'm seeing this issue with the flake use at a relative path; is it possibly related to this fix?

/e/nixos (main ± u+4) ∫ sudo nixos-rebuild test --cores 10 --max-jobs 5                                             [21:08:41] 
building the system configuration...
warning: Git tree '/etc/nixos' is dirty
error: cannot fetch input 'path:./flake_hackage?narHash=sha256-%2fF3itZJSZDnaxRGpkTffHDkxC7PloYqxVTW%2f%2fbP3i20=' because it uses a relative path
(use '--show-trace' to show detailed location information)

I use flake with home-manager and that used to work before, but it no longer does.

[guibou]

@smunix yes, that's unfortunately an issue. I'm working on a fix right now. Sorry for the inconvenience.