Add alternative approach for multiple versions of the compiler

.github/workflows/build.yml

@@ -24,10 +24,15 @@ jobs:
         with:
           extra-conf: accept-flake-config = true
       - uses: DeterminateSystems/magic-nix-cache-action@v7
-      - name: Compile code
-        run: nix build .#test
-      - name: Run tests
-        run: nix run .#test
+      # TODO: improve with matrix
+      - name: Compile code ghc8107
+        run: nix build .#test-ghc8107
+      - name: Run tests ghc8107
+        run: nix run .#test-ghc8107
+      - name: Compile code ghc902
+        run: nix build .#test-ghc902
+      - name: Run tests ghc902
+        run: nix run .#test-ghc902
 
   docker:
     uses: ./.github/workflows/reusable-docker.yml

flake.nix

@@ -18,8 +18,8 @@
   };
 
   outputs = inputs@{ self, flake-utils, haskellNix, nixpkgs }:
-    let
-      buildWithGhc = ghcVersion: system:
+    # https://input-output-hk.github.io/haskell.nix/tutorials/getting-started-flakes.html
+    flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs {
           inherit system;
@@ -27,29 +27,53 @@
           overlays = [
             haskellNix.overlay
             (final: prev: {
-                hapistrano = final.haskell-nix.cabalProject' {
+              hapistrano-ghc8107 = final.haskell-nix.cabalProject' {
                 src = final.haskell-nix.haskellLib.cleanGit {
                   name = "hapistrano";
                   src = ./.;
                 };
-                  compiler-nix-name = ghcVersion;
+                compiler-nix-name = "ghc8107";
+              };
+              hapistrano-ghc902 = final.haskell-nix.cabalProject' {
+                src = final.haskell-nix.haskellLib.cleanGit {
+                  name = "hapistrano";
+                  src = ./.;
+                };
+                compiler-nix-name = "ghc902";
               };
             })
           ];
         };
-          flake = pkgs.hapistrano.flake { };
+        flake-ghc8107 = pkgs.hapistrano-ghc8107.flake { };
+        flake-ghc902 = pkgs.hapistrano-ghc902.flake { };
       in
-        flake // rec {
+      flake-ghc8107 // flake-ghc902 // rec {
         apps = {
-            test = {
+          test-ghc8107 = {
             type = "app";
-              program = "${packages.test}/bin/test";
+            program = "${packages.test-ghc8107}/bin/test";
+          };
+          test-ghc902 = {
+            type = "app";
+            program = "${packages.test-ghc902}/bin/test";
           };
         };
         legacyPackages = pkgs;
         packages = {
-            default = flake.packages."hapistrano:exe:hap";
-            test = flake.packages."hapistrano:test:test".overrideAttrs (_: {
+          default = flake-ghc8107.packages."hapistrano:exe:hap";
+          test-ghc8107 = flake-ghc8107.packages."hapistrano:test:test".overrideAttrs (_: {
+            postFixup = ''
+              wrapProgram $out/bin/test \
+                --set PATH ${pkgs.lib.makeBinPath [
+                  pkgs.bash
+                  pkgs.coreutils
+                  pkgs.findutils
+                  pkgs.git
+                  pkgs.zsh
+                ]}
+            '';
+          });
+          test-ghc902 = flake-ghc902.packages."hapistrano:test:test".overrideAttrs (_: {
             postFixup = ''
               wrapProgram $out/bin/test \
                 --set PATH ${pkgs.lib.makeBinPath [
@@ -62,8 +86,5 @@
             '';
           });
         };
-        };
-    in
-    flake-utils.lib.eachDefaultSystem (buildWithGhc "ghc902") // 
-    flake-utils.lib.eachDefaultSystem (buildWithGhc "ghc8107");
+      });
 }