Bump flake inputs and tools

[amesgen]

• Update flake inputs
• Update HLS to 2.5
• Use upstream scriv as Add support for cabal files nedbat/scriv#91 was merged and released in 1.4.0 (latest is 1.5.1 already).

[amesgen]

Can a non-Nix user confirm that installing scriv like this works and yields a version >=1.4.0?

[fraser-iohk]

yup, pip3 install scriv on mac installs scriv-1.5.1 👍

[jasagredo]

pip3 install scriv --break-system-packages in Ubuntu also installs scriv-1.5.1

[RenateEilers]

I have no idea what I'm talking about, but just in case: should the version here match the update in shell.nix, i.e. hls-2.5 instead of hls-2.4?

[amesgen]

This file is the Nix flake lock file, which contains the exact pins (eg git commit hashes + further integrity hashes) of everything external used by our flake here, and also all inputs used transitively by flakes we use etc. In this case, hls-2.4 is not a direct input of our flake, but rather a transitive input via haskell.nix.¹

We don't use this input ourselves currently (we use HLS 2.5 from Hackage)², so there is no need to adapt anything to stay in sync with our declared version 2.5.0.0 in shell.nix. The flake lock file is usually updated automatically by commands like nix flake update which I ran for this PR, which updated haskell.nix and hence also this transitive flake input, which is why it shows up in the diff.

Hope that makes a bit of sense 😃

Footnotes

1. You can explore the flake graph interactively with eg nix-melt. ↩

2. Motivation why haskell.nix has this input: In the past, HLS didn't compile if you didn't use its own cabal.project (which you don't get if you compile it from Hackage as we do ATM), so haskell.nix pinned HLS from GitHub which contains the cabal.project. ↩

[RenateEilers]

Thank you for explaining!