HLS is broken on 9.4 with a recent stack; passing flags while configuring tools

[abarbu]

HLS has build problems because of a version bump in some without coordination with dependent-sum: haskell/haskell-language-server#2969

This results in a build failure with the latest stackage nightly on GHC 9.4.

To reproduce:
Init a new repo nix flake init --template templates#haskell-nix --impure

Replace flake.nix with the file below

{
  description = "A very basic flake";
  inputs.haskellNix.url = "github:input-output-hk/haskell.nix";
  inputs.nixpkgs.follows = "haskellNix/nixpkgs-unstable";
  inputs.flake-utils.url = "github:numtide/flake-utils";
  outputs = { self, nixpkgs, flake-utils, haskellNix }:
    flake-utils.lib.eachSystem [ "x86_64-linux" "x86_64-darwin" ] (system:
    let
      overlays = [ haskellNix.overlay
        (final: prev: {
          helloProject =
            final.haskell-nix.project' {
              src = ./.;
              compiler-nix-name = "ghc943";
              projectFileName = "stack.yaml";
              shell.tools = {
                cabal = {};
                hlint = {};
                haskell-language-server = {};
              };
              shell.buildInputs = with pkgs; [
                nixpkgs-fmt
                pkgs.zlib
              ];
            };
        })
      ];
      pkgs = import nixpkgs { inherit system overlays; inherit (haskellNix) config; };
      flake = pkgs.helloProject.flake {
      };
    in flake // {
      defaultPackage = flake.packages."hello:exe:hello";
    });
}

Add stack.yaml

resolver: nightly-2022-12-09

nix:
  enable: true

allow-newer: true

I can see 3 solutions but I can't seem to get any of them to work:

1. Override some to the older some-1.0.3 instead of some-1.0.4.1. I tried to do this but stack.yaml doesn't seem to affect the tools.
2. Pass -allow-newer when building HLS. Doesn't seem like anything I try ends up affecting the configureFlags while building HLS.
3. Change the snapshot used. Even if I set the resolver to one where some-1.0.3 is available, like nightly-2022-11-11, this doesn't seem to affect how HLS is built.

How can I build HLS against 9.4? Preferably with option 1?

[abarbu]

Just for reference this is what the problem looks like when you run nix develop

Error: cabal: Could not resolve dependencies:
[__0] trying: haskell-language-server-1.8.0.0 (user goal)
[__1] trying: lsp-types-1.6.0.0 (dependency of haskell-language-server)
[__2] trying: some-1.0.4.1 (dependency of lsp-types)
[__3] trying: hls-plugin-api-1.5.0.0 (dependency of haskell-language-server)
[__4] next goal: dependent-sum (dependency of hls-plugin-api)
[__4] rejecting: dependent-sum-0.7.1.1 (conflict: some==1.0.4.1, dependent-sum
=> some>=1.0.1 && <1.0.3)
[__4] skipping: dependent-sum-0.7.1.0, dependent-sum-0.7.0.0 (has the same
characteristics that caused the previous version to fail: excludes 'some'
version 1.0.4.1)
[__4] rejecting: dependent-sum-0.6.2.0, dependent-sum-0.5, dependent-sum-0.4,
dependent-sum-0.3.2.2, dependent-sum-0.3.2.1, dependent-sum-0.3.2.0,
dependent-sum-0.3.1.0, dependent-sum-0.2.1.0, dependent-sum-0.2.0.2,
dependent-sum-0.2.0.1, dependent-sum-0.2, dependent-sum-0.1,
dependent-sum-0.6.2.2, dependent-sum-0.6.1, dependent-sum-0.6 (constraint from
project config /build/tmp.N5BGsK03ju/cabal.project requires >=0.7.1.0)
[__4] fail (backjumping, conflict set: dependent-sum, hls-plugin-api, some)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: base, dependent-sum,
haskell-language-server, some, hls-plugin-api, lsp-types
Try running with --minimize-conflict-set to improve the error message.

[sekunho]

I have a similar looking error with HLS 1.9 for GHC 9.2.5

Using index-state 2023-01-05T00:00:00Z
Warning: The package list for 'hackage.haskell.org-at-2023-01-05T000000Z' is
19362 days old.
Run 'cabal update' to get the latest list of available packages.
Resolving dependencies...
Error: cabal: Could not resolve dependencies:
[__0] trying: haskell-language-server-1.9.0.0 (user goal)
[__1] trying: haskell-language-server:+callhierarchy
[__2] trying: hls-call-hierarchy-plugin-1.1.0.0 (dependency of
haskell-language-server +callhierarchy)
[__3] next goal: hls-plugin-api (dependency of haskell-language-server)
[__3] rejecting: hls-plugin-api-1.6.0.0 (conflict: hls-call-hierarchy-plugin
=> hls-plugin-api^>=1.5)
[__3] rejecting: hls-plugin-api-1.5.0.0 (conflict: haskell-language-server =>
hls-plugin-api^>=1.6)
[__3] skipping: hls-plugin-api-1.4.0.0, hls-plugin-api-1.3.0.0,
hls-plugin-api-1.2.0.2, hls-plugin-api-1.2.0.1, hls-plugin-api-1.2.0.0,
hls-plugin-api-1.1.0.2, hls-plugin-api-1.1.0.1, hls-plugin-api-1.1.0.0,
hls-plugin-api-1.0.0.0, hls-plugin-api-0.7.1.0, hls-plugin-api-0.7.0.0,
hls-plugin-api-0.6.0.0, hls-plugin-api-0.5.0.1, hls-plugin-api-0.5.0.0,
hls-plugin-api-0.4.1.0, hls-plugin-api-0.4.0.0 (has the same characteristics
that caused the previous version to fail: excluded by constraint '^>=1.6' from
'haskell-language-server')
[__3] fail (backjumping, conflict set: haskell-language-server,
hls-call-hierarchy-plugin, hls-plugin-api)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: haskell-language-server,
hls-plugin-api, hls-call-hierarchy-plugin,
haskell-language-server:callhierarchy
Try running with --minimize-conflict-set to improve the error message.

• Updated input 'haskellNix':
    'github:input-output-hk/haskell.nix/2f3ec7bbf2e790122ca276a4ab038bf2749c6c93' (2022-12-22)
  → 'github:input-output-hk/haskell.nix/895435f1893db0ff3666f25ed7d6c92c78673322' (2023-01-05)
• Updated input 'haskellNix/hackage':
    'github:input-output-hk/hackage.nix/2f24c038122b94e1d1dcf24c0eee11f05bdcb414' (2022-12-22)
  → 'github:input-output-hk/hackage.nix/d07ba13b6bf6197ec96c7e912cb1184eaf005928' (2023-01-05)
• Updated input 'haskellNix/stackage':
    'github:input-output-hk/stackage.nix/b482b18e4e619ce7a7e5db3f96865b6b1d25ee41' (2022-12-22)
  → 'github:input-output-hk/stackage.nix/5c1a68f2f6642fe7419c5c1c5f4d6668786f8bf7' (2023-01-04)

[michaelpj]

Upstream issue, recently resolved: haskell/haskell-language-server#3427

[abarbu]

This specific issue was, but the problem of how to pass flags to tools hasn't been resolved.

The old solution of doing:

                shell = {
                  tools = {
                    cabal = {};
                    hlint = {};
                    haskell-language-server = {
                      version = "latest";
                      compiler-nix-name = "ghc943";
                      modules = [{
                        packages.haskell-language-server.flags.callHierarchy = false;

No longer works. The flag is ignored now.

@sekunho This works for me now

                shell = {
                  tools = {
                    cabal = {};
                    hlint = {};
                    haskell-language-server = {
                      version = "latest";
                      cabalProject = ''
                        packages: .
                        package haskell-language-server
                           flags: -callHierarchy
                      '';
                      compiler-nix-name = "ghc943";
                      modules = [{
                        packages.haskell-language-server.flags.callHierarchy = false;

Although note that you will want to add reinstallableLibGhc and nonReinstallablePkgs to the tools modules and modules for your project as in #1809 After that HLS works with 9.4.

[hamishmack]

For now we have given up on making HLS compile from hackage. Instead we are now building it from the GitHub repo. To help with this we have added a pin for the current version to haskell-nix.sources. You can use it like this:

tools.haskell-language-server = { src = pkgs.haskell-nix.sources."hls-1.10"; };

It works better because there is a cabal.project in the GitHub repo with workarounds that would be difficult to add to hackage.

It should be in cache.zw3rk.com for the most recent GHC releases (8.10.7, 9.0.2, 9.2.8, 9.4.5). The code that includes it in the cache is

haskell.nix/build.nix

Lines 58 to 63 in 4835f2b

	} // pkgs.lib.optionalAttrs (__compareVersions haskell.compiler.${compiler-nix-name}.version "9.6" < 0) {
	hls-latest = tool compiler-nix-name "haskell-language-server" {
	inherit evalPackages;
	src = pkgs.haskell-nix.sources."hls-1.10";
	};
	})

[dhess]

We've had to do the same, so it's nice to see that we can replace our hacky version with yours. Thanks!