Nix-based xmonad-contrib hacking: this needs to be recorded somewhere

[geekosaur]

[27 20:07:27] <wisconsin> hi, is there a walkthrough somewhere explaining how to build and test xmonad and xmonad-contrib using nix?
[27 20:08:54] <wisconsin> i have some minor improvements i'd like to submit to xmonad-contrib, but im unfamiliar with haskell's + nix tooling, and no longer have access to a simpler arch setup.
[27 20:17:07] <Lears> wisconsin: Not that I'm aware of, but you can pretty much just `nix develop .` in your xmonad-contrib clone then use cabal like normal.
[27 21:26:22] <wisconsin> Lears: Thanks, I had gotten that far, but then had some trouble with cabal. what's the cabal workflow?
[27 21:28:37] <geekosaur> mine is `cabal build` until it seems to be ready, then build my config against it to test, but I have a fully cabalized config (https://github.com/geekosaur/xmonad.hs)
[27 21:29:35] <geekosaur> I suspect it won't help much with a Nix setup since it's all very cabal + git
[27 21:31:33] <Lears> There isn't really one workflow. I mostly just let `ghcid -a` rebuild with cabal when I write changes. When I'm ready to test, I point the flake's NixOS module at the local branch and rebuild my system.
[27 21:32:45] <Lears> Rather, I point my system flake at the local branch's.
[27 21:33:31] <wisconsin> Lears: yes, i had done that with other WMs, pointing to locally patched branches, i'll see if can do that too.
[27 21:34:40] <Lears> wisconsin: If you're on NixOS, see https://github.com/xmonad/xmonad-contrib/blob/master/NIX.md for an intro to using the the flake.
[27 22:28:03] <wisconsin> Lears: thanks, and how do i test my xmonad-contrib in nixos once its building?
[27 22:36:12] <Lears> wisconsin: By using it with the xmonad-contrib flake, as the link above details, with the system flake input like: `xmonad-contrib = { type = "git"; url = "file:///path/to/xmonad-contrib"; ref = "your-pr-branch" };
[27 22:45:04] <wisconsin> Lears: thanks, im a bit confused about the last part as my system is not yet in flake form, just traditional. I only use flakes for dev envs. i'll try to see if i can figure it out.

One thing this needs, aside from some cleaning up, is expansion to non-NixOS (and, as the last line says, to non-flake-based systems).