Add pre-commit

Author: zmrocze

.gitignore

@@ -12,3 +12,5 @@ result*
 
 # local files created by the cluster
 local-cluster-info.json
+
+.pre-commit-config.yaml

flake.lock

@@ -30,11 +30,12 @@
       url = "github:edolstra/flake-compat";
       flake = false;
     };
-
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    pre-commit-hooks-nix.url = "github:cachix/pre-commit-hooks.nix";
   };
 
   outputs =
-    { self, nixpkgs, haskell-nix, CHaP, iohk-nix, cardano-node, ... }:
+    inputs@{ self, nixpkgs, haskell-nix, CHaP, iohk-nix, cardano-node, flake-parts, ... }:
     let
       defaultSystems = [ "x86_64-linux" "x86_64-darwin" ];
 
@@ -130,64 +131,51 @@
 
           modules = haskellModules system;
         };
+
+        project = perSystem projectFor;
+        flake = perSystem (system: (projectFor system).flake { });
     in
-    {
-      project = perSystem projectFor;
-      flake = perSystem (system: (projectFor system).flake { });
-
-      defaultPackage = perSystem (system:
-        let lib = "plutip-core:lib:plutip-core";
-        in self.flake.${system}.packages.${lib});
-
-      packages = perSystem (system: self.flake.${system}.packages);
-
-      apps = perSystem (system: self.flake.${system}.apps);
-
-      devShell = perSystem (system: self.flake.${system}.devShell);
-
-      # This will build all of the project's executables and the tests
-      check = perSystem
-        (system:
-          (nixpkgsFor system).runCommand "combined-check"
-            {
-              nativeBuildInputs = builtins.attrValues self.checks.${system}
-                ++ builtins.attrValues self.flake.${system}.packages;
-            } ''mkdir $out''
-        );
-
-      checks = perSystem (system:
-        self.flake.${system}.checks // {
-          formatting = (nixpkgsFor system).runCommand "formatting-check"
-            {
-              nativeBuildInputs = [
-                self.devShell.${system}.inputDerivation
-                self.devShell.${system}.nativeBuildInputs
-              ];
-            }
-            ''
-              cd ${self}
-              export LC_CTYPE=C.UTF-8
-              export LC_ALL=C.UTF-8
-              export LANG=C.UTF-8
-              export IN_NIX_SHELL='pure'
-              # this check is temporarily skipped in CI due to a bug in
-              # fourmolu:
-              #
-              # ```
-              # Formatting is not idempotent:
-              #   src/Plutip/Launch/Cluster.hs<rendered>:753:19
-              #   before: "       sgs\n         "
-              #   after:  "       sgs{ Ledger.s"
-              # Please, consider reporting the bug.
-              # ```
-              # make format_check cabalfmt_check nixpkgsfmt_check lint
-              mkdir $out
-            '';
-        });
-
-      haskellModules = perSystem haskellModules;
-
-      # Instruction for the Hercules CI to build on x86_64-linux only, to avoid errors about systems without agents.
-      herculesCI.ciSystems = [ "x86_64-linux" ];
+      flake-parts.lib.mkFlake { inherit inputs; } {
+        imports = [
+          ./pre-commit.nix
+        ];
+        flake = {
+          inherit project flake;
+
+          # This will build all of the project's executables and the tests
+          check = perSystem
+            (system:
+              (nixpkgsFor system).runCommand "combined-check"
+                {
+                  nativeBuildInputs = builtins.attrValues self.checks.${system}
+                    ++ builtins.attrValues self.flake.${system}.packages;
+                } ''mkdir $out''
+            );
+
+          haskellModules = perSystem haskellModules;
+
+          # Instruction for the Hercules CI to build on x86_64-linux only, to avoid errors about systems without agents.
+          herculesCI.ciSystems = [ "x86_64-linux" ];
+        };
+        systems = defaultSystems;
+        perSystem = { system, config, pkgs, ... }: {
+          packages = flake.${system}.packages 
+            // {
+              default = config.packages."plutip-core:lib:plutip-core";
+            };
+
+          apps = flake.${system}.apps;
+
+          devShells = {
+            # Adds pre-commit packages and shell hook to the haskell shell
+            default = pkgs.mkShell {
+              inputsFrom = [ config.devShells.haskell config.devShells.dev-pre-commit ];
+              shellHook = config.devShells.haskell.shellHook + config.devShells.dev-pre-commit.shellHook;
+            };
+            haskell = flake.${system}.devShell;
+          };
+
+          checks = flake.${system}.checks;
+        };
     };
 }

flake.nix

@@ -0,0 +1,34 @@
+{ inputs, ... }: {
+  imports = [
+    inputs.pre-commit-hooks-nix.flakeModule
+  ];
+  perSystem = { pkgs, system, config, ... }:
+    {
+      devShells.dev-pre-commit = config.pre-commit.devShell;
+      # devShells.default = config.pre-commit.devShell;
+
+      pre-commit = {
+        settings = {
+          excludes = [
+            "cluster-data/"
+            "src/Plutip/Launch/"
+          ];
+
+          hooks = {
+            nixpkgs-fmt.enable = true;
+            deadnix.enable = true;
+            cabal-fmt.enable = true;
+            fourmolu.enable = true;
+            shellcheck.enable = true;
+            hlint.enable = true;
+            typos.enable = true;
+            markdownlint.enable = true;
+          };
+
+          settings = {
+            ormolu.cabalDefaultExtensions = true;
+          };
+        };
+      };
+    };
+}