From 6ee58c0d259c6eebe5e62e6211c1b7c7d377e6a9 Mon Sep 17 00:00:00 2001
From: Daniel Firth <daniel.firth@iohk.io>
Date: Wed, 14 Feb 2024 09:49:40 +0000
Subject: [PATCH] Replace hlint shell job with check derivation.

---
 .github/workflows/formatting.yaml |  2 +-
 flake.lock                        | 38 +++++++++++++++++++++++++++++++
 flake.nix                         | 13 ++++++++++-
 nix/hydra/shell.nix               |  6 ++---
 4 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/formatting.yaml b/.github/workflows/formatting.yaml
index 2af62a4951d..025bf949257 100644
--- a/.github/workflows/formatting.yaml
+++ b/.github/workflows/formatting.yaml
@@ -30,4 +30,4 @@ jobs:
 
     - name: 📐 Check hlint
       run: |
-        nix develop .#fmt --command hlint .
+        nix build .#checks.x86_64-linux.hlint
diff --git a/flake.lock b/flake.lock
index db27a0dc816..c36941b8467 100644
--- a/flake.lock
+++ b/flake.lock
@@ -791,6 +791,21 @@
         "type": "github"
       }
     },
+    "flake-utils_8": {
+      "locked": {
+        "lastModified": 1644229661,
+        "narHash": "sha256-1YdnJAsNy69bpcjuoKdOYQX0YxZBiCYZo4Twxerqv7k=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "3cecb5b042f7f209c56ffd8371b2711a290ec797",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "ghc-8.6.5-iohk": {
       "flake": false,
       "locked": {
@@ -1498,6 +1513,28 @@
         "url": "https://gitlab.haskell.org/hamishmack/iserv-proxy.git"
       }
     },
+    "lint-utils": {
+      "inputs": {
+        "flake-utils": "flake-utils_8",
+        "nixpkgs": [
+          "haskellNix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1707777931,
+        "narHash": "sha256-PsPb5xMBZ9dPDP04o9vqKEUIEG80Z84/74fPuOMs0ZI=",
+        "owner": "homotopic",
+        "repo": "lint-utils",
+        "rev": "5f11e3e51d8f1aa4ed62a89e90f05953931e105a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "homotopic",
+        "repo": "lint-utils",
+        "type": "github"
+      }
+    },
     "lowdown-src": {
       "flake": false,
       "locked": {
@@ -2550,6 +2587,7 @@
         "haskellNix": "haskellNix_2",
         "hls": "hls",
         "iohk-nix": "iohk-nix",
+        "lint-utils": "lint-utils",
         "mithril": "mithril",
         "nixpkgs": [
           "haskellNix",
diff --git a/flake.nix b/flake.nix
index 5ff471df347..8393389d7c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,6 +4,10 @@
     haskellNix.url = "github:input-output-hk/haskell.nix";
     iohk-nix.url = "github:input-output-hk/iohk-nix";
     flake-utils.url = "github:numtide/flake-utils";
+    lint-utils = {
+      url = "github:homotopic/lint-utils";
+      inputs.nixpkgs.follows = "haskellNix/nixpkgs";
+    };
     CHaP = {
       url = "github:input-output-hk/cardano-haskell-packages?ref=repo";
       flake = false;
@@ -33,6 +37,9 @@
       (system:
       let
         pkgs = import inputs.nixpkgs { inherit system; };
+        tools = {
+          hlint = hydraProject.pkgs.haskell-nix.tool hydraProject.compiler "hlint" "3.8";
+        };
         hydraProject = import ./nix/hydra/project.nix {
           inherit (inputs) haskellNix iohk-nix CHaP;
           inherit system nixpkgs;
@@ -58,8 +65,12 @@
             spec = import ./spec { inherit pkgs; };
           };
 
+        checks = let lu = inputs.lint-utils.linters.${system}; in {
+          hlint = lu.hlint { src = self; hlint = tools.hlint; };
+        };
+
         devShells = (import ./nix/hydra/shell.nix {
-          inherit inputs hydraProject system;
+          inherit inputs hydraProject tools system;
         }) // {
           ci = (import ./nix/hydra/shell.nix {
             inherit inputs hydraProject system;
diff --git a/nix/hydra/shell.nix b/nix/hydra/shell.nix
index ffa692fc252..322e90a5eec 100644
--- a/nix/hydra/shell.nix
+++ b/nix/hydra/shell.nix
@@ -7,6 +7,7 @@
   withoutDevTools ? false
 , hydraProject
 , inputs
+, tools
 , system ? builtins.currentSystem
 }:
 let
@@ -16,7 +17,6 @@ let
 
   fourmolu = pkgs.haskell-nix.tool compiler "fourmolu" "0.14.0.0";
   cabal-fmt = pkgs.haskell-nix.tool compiler "cabal-fmt" "0.1.9";
-  hlint = pkgs.haskell-nix.tool compiler "hlint" "3.8";
   apply-refact = pkgs.haskell-nix.tool compiler "apply-refact" "0.14.0.0";
 
   # Build HLS form our fork (see flake.nix)
@@ -47,7 +47,7 @@ let
     fourmolu
     cabal-fmt
     pkgs.nixpkgs-fmt
-    hlint
+    tools.hlint
     apply-refact
     # For validating JSON instances against a pre-defined schema
     pkgs.check-jsonschema
@@ -159,7 +159,7 @@ let
       fourmolu
       cabal-fmt
       pkgs.nixpkgs-fmt
-      hlint
+      tools.hlint
       apply-refact
     ];
   };