Simplify Stack usage in Nix

.github/workflows/bundle-ucm.yaml

@@ -40,7 +40,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       - name: build
         run: |

.github/workflows/ci.yaml

@@ -110,7 +110,7 @@ jobs:
         if: steps.cache-ucm-binaries.outputs.cache-hit != 'true'
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       # Build deps, then build local code. Splitting it into two steps just allows us to see how much time each step
       # takes.

.github/workflows/haddocks.yaml

@@ -28,7 +28,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       - name: build with haddocks
         working-directory: unison

.github/workflows/update-transcripts.yaml

@@ -23,7 +23,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       # One of the transcripts fails if the user's git name hasn't been set.
       - name: set git user info

.vscode/settings.json

@@ -1,7 +1,7 @@
 {
   "haskell.toolchain": {
     "cabal": "3.10.3.0",
-    "hls": "2.8.0.0",
+    "hls": "2.9.0.0",
     "stack": "2.15.7"
   }
 }

flake.nix

@@ -7,53 +7,49 @@
   };
 
   inputs = {
-    haskellNix.url = "github:input-output-hk/haskell.nix";
-    nixpkgs-haskellNix.follows = "haskellNix/nixpkgs-unstable";
-    nixpkgs-release.url = "github:NixOS/nixpkgs/release-24.05";
     flake-utils.url = "github:numtide/flake-utils";
+    haskellNix.url = "github:input-output-hk/haskell.nix";
+    nixpkgs.follows = "haskellNix/nixpkgs-2405";
+    systems.follows = "flake-utils/systems";
   };
 
   outputs = {
-    self,
-    haskellNix,
-    nixpkgs-haskellNix,
-    nixpkgs-release,
     flake-utils,
+    haskellNix,
+    nixpkgs,
+    self,
+    systems,
   }:
-    flake-utils.lib.eachSystem [
-      "x86_64-linux"
-      "x86_64-darwin"
-      "aarch64-darwin"
-    ]
+    flake-utils.lib.eachSystem (import systems)
     (system: let
       ## It’s much easier to read from a JSON file than to have JSON import from some other file, so we extract some
       ## configuration from the VS Code settings to avoid duplication.
-      vscodeSettings = nixpkgs-release.lib.importJSON ./.vscode/settings.json;
+      vscodeSettings = nixpkgs.lib.importJSON ./.vscode/settings.json;
       versions =
         vscodeSettings."haskell.toolchain"
         ## There are some things we want to pin that the VS Code Haskell extension doesn’t let us control.
         // {
-        hpack = "0.35.2";
-        ormolu = "0.7.2.0";
-      };
-      pkgs = import nixpkgs-haskellNix {
+          hpack = "0.36.0";
+          ormolu = "0.7.2.0";
+        };
+      pkgs = import nixpkgs {
         inherit system;
         inherit (haskellNix) config;
         overlays = [
           haskellNix.overlay
-          (import ./nix/dependencies.nix {inherit nixpkgs-release;})
+          (import ./nix/dependencies.nix)
         ];
       };
       unison-project = import ./nix/unison-project.nix {
-        inherit (nixpkgs-haskellNix) lib;
+        inherit (nixpkgs) lib;
         inherit (pkgs) haskell-nix;
       };
       haskell-nix-flake = import ./nix/haskell-nix-flake.nix {
         inherit pkgs unison-project versions;
-        inherit (nixpkgs-haskellNix) lib;
+        inherit (nixpkgs) lib;
       };
       renameAttrs = fn:
-        nixpkgs-haskellNix.lib.mapAttrs' (name: value: {
+        nixpkgs.lib.mapAttrs' (name: value: {
           inherit value;
           name = fn name;
         });
@@ -71,11 +67,10 @@
             all = pkgs.symlinkJoin {
               name = "all";
               paths = let
-                all-other-packages =
-                  builtins.attrValues (builtins.removeAttrs self.packages."${system}" [
-                    "all"
-                    "docker-ucm" # this package doesn’t produce a directory
-                  ]);
+                all-other-packages = builtins.attrValues (builtins.removeAttrs self.packages."${system}" [
+                  "all"
+                  "docker-ucm" # this package doesn’t produce a directory
+                ]);
                 devshell-inputs =
                   builtins.concatMap
                   (devShell: devShell.buildInputs ++ devShell.nativeBuildInputs)

nix/dependencies.nix

@@ -1,21 +1,13 @@
-{nixpkgs-release}: final: prev: let
-  pinned-pkgs = import nixpkgs-release {inherit (final) system;};
-in {
-  stack = pinned-pkgs.stack;
-
+final: prev: {
   ## See https://docs.haskellstack.org/en/stable/nix_integration/#supporting-both-nix-and-non-nix-developers for an
-  ## explanation of this package.
-  stack-wrapped = final.symlinkJoin {
-    name = "stack"; # will be available as the usual `stack` in terminal
-    paths = [final.stack];
+  ## explanation of this derivation.
+  stack = final.symlinkJoin {
+    inherit (prev.stack) version;
+    name = "stack";
+    paths = [prev.stack];
     buildInputs = [final.makeWrapper];
     postBuild = ''
-      wrapProgram $out/bin/stack \
-        --add-flags "\
-          --no-nix \
-          --system-ghc \
-          --no-install-ghc \
-        "
+      wrapProgram $out/bin/stack --add-flags "--no-nix --system-ghc --no-install-ghc"
     '';
   };
 }