.github: fix outdated dependencies and prevent disk filling up by splitting attributes across multiple jobs

.github/workflows/nixpkgs-ci.yml

@@ -1,18 +1,46 @@
 name: "nixpkgs CI"
 
 on:
+  workflow_dispatch:
   push:
     branches: [ master ]
   pull_request:
     branches: [ master ]
 
 jobs:
+  get-ghc-versions:
+    name: Determine GHC versions to test
+    runs-on: ubuntu-latest
+    outputs:
+      versions: ${{ steps.get-ghc-versions-step.outputs.versions }}
+
+    steps:
+      - uses: actions/checkout@v4.2.2
+      - uses: cachix/install-nix-action@v30
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - name: Get GHC Versions from ci.nix
+        id: get-ghc-versions-step
+        run: |
+          echo -n "versions=" >> "$GITHUB_OUTPUT"
+          nix-instantiate --eval --strict --json -E "builtins.attrNames (import ./ci.nix { })" >> "$GITHUB_OUTPUT"
+
   nix-build:
     runs-on: ubuntu-latest
+    needs:
+      - get-ghc-versions
+
+    strategy:
+      matrix:
+        version: ${{ fromJSON(needs.get-ghc-versions.outputs.versions) }}
+
     steps:
-    - uses: actions/checkout@v3.3.0
-    - uses: cachix/install-nix-action@v19
-      with:
-        nix_path: nixpkgs=channel:nixos-unstable
-    - name: ci.nix
-      run: nix-build ci.nix
+      - uses: actions/checkout@v4.2.2
+      - uses: cachix/install-nix-action@v30
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - name: nix-build ci.nix -A ${{ matrix.version }}
+        env:
+          ATTR: ${{ matrix.version }}
+        run: |
+          nix-build ci.nix -A "$ATTR"

ci.nix

@@ -5,6 +5,21 @@ let
   inherit (pkgs) lib haskell;
   inherit (haskell.lib.compose) buildFromSdist overrideCabal;
 
+  expr =
+    { mkDerivation, base, Cabal, Cabal-syntax, lib }:
+    mkDerivation {
+      pname = "jailbreak-cabal";
+      version = "unstable-unknown";
+      src = ./.;
+      isLibrary = false;
+      isExecutable = true;
+      executableHaskellDepends = [ base Cabal Cabal-syntax ];
+      homepage = "https://github.com/NixOS/jailbreak-cabal";
+      description = "Strip version restrictions from Cabal files";
+      license = lib.licenses.bsd3;
+      mainProgram = "jailbreak-cabal";
+    };
+
   # All non-binary GHC package sets
   eligible = lib.filterAttrs
     (name: _:
@@ -18,11 +33,11 @@ lib.mapAttrs
   (_: hpkgs:
     # cabal-install is not cached for all package sets, so we'll rely on Setup.hs
     lib.pipe
-      (hpkgs.callCabal2nix "jailbreak-cabal-ghc-${hpkgs.ghc.version}.nix" ./. {})
+      (hpkgs.callPackage expr { })
       [
         # Check for packaging bugs
         buildFromSdist
         # To better identify build failures
-        (overrideCabal { pname = "jailbreak-cabal-ghc-${hpkgs.ghc.version}"; })
+        (overrideCabal (old: { version = "${old.version}+ghc-${hpkgs.ghc.version}"; }))
       ])
   eligible