add default nix formatter and its corresponding Github action

.github/workflows/nix-fmt-checks.yaml

@@ -0,0 +1,17 @@
+name: Nix formatter checks
+
+on:
+  pull_request:
+
+jobs:
+  lockfile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v18
+
+      - name: Run nix formatter tool
+        run: nix fmt . -- --check

checks.nix

@@ -2,158 +2,172 @@
   system,
   packages,
   pkgs,
-}:
-
-let
+}: let
   phpPackages = builtins.filter (name: builtins.match "php[0-9]+" name != null) (builtins.attrNames packages);
 
   checks = {
     php = {
       description = "Build PHP";
-      drv = { php, ... }: php;
+      drv = {php, ...}: php;
     };
 
     imagick = {
       description = "Build Imagick extension";
-      drv = { php, ... }: php.extensions.imagick;
+      drv = {php, ...}: php.extensions.imagick;
     };
 
     redis = {
       description = "Build Redis extension";
-      drv = { php, ... }: php.extensions.redis;
+      drv = {php, ...}: php.extensions.redis;
     };
 
     redis3 = {
       description = "Build Redis 3 extension";
-      enabled = { php, lib, ... }: lib.versionOlder php.version "8";
-      drv = { php, ... }: php.extensions.redis3;
+      enabled = {
+        php,
+        lib,
+        ...
+      }:
+        lib.versionOlder php.version "8";
+      drv = {php, ...}: php.extensions.redis3;
     };
 
     mysql = {
       description = "Build MySQL extension";
-      enabled = { php, lib, ... }: lib.versionOlder php.version "7";
-      drv = { php, ... }: php.extensions.mysql;
+      enabled = {
+        php,
+        lib,
+        ...
+      }:
+        lib.versionOlder php.version "7";
+      drv = {php, ...}: php.extensions.mysql;
     };
 
     xdebug = {
       description = "Build Xdebug extension";
-      drv = { php, ... }: php.extensions.xdebug;
+      drv = {php, ...}: php.extensions.xdebug;
     };
 
     tidy = {
       description = "Build Tidy extension";
-      drv = { php, ... }: php.extensions.tidy;
+      drv = {php, ...}: php.extensions.tidy;
     };
 
     composer-phar = {
       description = "Check that composer PHAR works";
-      drv =
-        { pkgs, php, ... }:
+      drv = {
+        pkgs,
+        php,
+        ...
+      }:
         pkgs.runCommand
-          "composer-phar-check"
-          {
-            buildInputs = [
-              php.packages.composer
-            ];
-          }
-          ''
-            composer --version
-            touch "$out"
-          '';
+        "composer-phar-check"
+        {
+          buildInputs = [
+            php.packages.composer
+          ];
+        }
+        ''
+          composer --version
+          touch "$out"
+        '';
     };
 
     mysqli-socket-path = {
       description = "Validate php.extensions.mysqli default unix socket path";
-      drv =
-        { pkgs, php, ... }:
+      drv = {
+        pkgs,
+        php,
+        ...
+      }:
         pkgs.runCommand
-          "mysqli-socket-path-check"
-          {
-            buildInputs = [
-              (php.withExtensions ({ all, ... }: [
-                all.mysqli
-              ]))
-            ];
-          }
-          ''
-            php -r "echo ini_get('mysqli.default_socket') . PHP_EOL;" | grep /run/mysqld/mysqld.sock
-            touch "$out"
-          '';
+        "mysqli-socket-path-check"
+        {
+          buildInputs = [
+            (php.withExtensions ({all, ...}: [
+              all.mysqli
+            ]))
+          ];
+        }
+        ''
+          php -r "echo ini_get('mysqli.default_socket') . PHP_EOL;" | grep /run/mysqld/mysqld.sock
+          touch "$out"
+        '';
     };
 
     pdo_mysql-socket-path = {
       description = "Validate php.extensions.pdo_mysql default unix socket path";
-      drv =
-        { pkgs, php, ... }:
+      drv = {
+        pkgs,
+        php,
+        ...
+      }:
         pkgs.runCommand
-          "pdo_mysql-socket-path-check"
-          {
-            buildInputs = [
-              (php.withExtensions ({ all, ... }: [
-                all.pdo_mysql
-              ]))
-            ];
-          }
-          ''
-            php -r "echo ini_get('pdo_mysql.default_socket') . PHP_EOL;" | grep /run/mysqld/mysqld.sock
-            touch "$out"
-          '';
+        "pdo_mysql-socket-path-check"
+        {
+          buildInputs = [
+            (php.withExtensions ({all, ...}: [
+              all.pdo_mysql
+            ]))
+          ];
+        }
+        ''
+          php -r "echo ini_get('pdo_mysql.default_socket') . PHP_EOL;" | grep /run/mysqld/mysqld.sock
+          touch "$out"
+        '';
     };
   };
 
   inherit (pkgs) lib;
 
-  /* AttrSet<phpName, AttrSet<checkName, checkDrv>> */
-  checksPerVersion =
-    lib.listToAttrs (
-      builtins.map
-        (phpName:
-          let
-            php = packages.${phpName};
-            phpVersion = lib.versions.majorMinor php.version;
-            args = { inherit lib php pkgs system; };
-            supportedChecks = lib.filterAttrs (_name: { enabled ? lib.const true, ... }: enabled args) checks;
-          in
-          {
-            name = phpName;
-            value =
-              lib.mapAttrs
-                (
-                  _name:
-                  {
-                    description,
-                    drv,
-                    ...
-                  }:
-
-                  let
-                    check = drv args;
-                  in
-                  check // {
-                    passthru = check.passthru or { } // {
-                      description = "PHP ${phpVersion} – ${description}";
-                    };
-                  }
-                )
-                supportedChecks;
-          }
-        )
-        phpPackages
-    );
+  # AttrSet<phpName, AttrSet<checkName, checkDrv>>
+  checksPerVersion = lib.listToAttrs (
+    builtins.map
+    (
+      phpName: let
+        php = packages.${phpName};
+        phpVersion = lib.versions.majorMinor php.version;
+        args = {inherit lib php pkgs system;};
+        supportedChecks = lib.filterAttrs (_name: {enabled ? lib.const true, ...}: enabled args) checks;
+      in {
+        name = phpName;
+        value =
+          lib.mapAttrs
+          (
+            _name: {
+              description,
+              drv,
+              ...
+            }: let
+              check = drv args;
+            in
+              check
+              // {
+                passthru =
+                  check.passthru
+                  or {}
+                  // {
+                    description = "PHP ${phpVersion} – ${description}";
+                  };
+              }
+          )
+          supportedChecks;
+      }
+    )
+    phpPackages
+  );
 in
-lib.foldAttrs
+  lib.foldAttrs
   lib.mergeAttrs
   {}
   (
     lib.mapAttrsToList
     (
       phpName:
-
-      lib.mapAttrs'
+        lib.mapAttrs'
         (
           name:
-
-          lib.nameValuePair "${phpName}-${name}"
+            lib.nameValuePair "${phpName}-${name}"
         )
     )
     checksPerVersion

default.nix

@@ -1,9 +1,12 @@
 (import (
-  let
-    lock = builtins.fromJSON (builtins.readFile ./flake.lock);
-  in fetchTarball {
-    url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-    sha256 = lock.nodes.flake-compat.locked.narHash; }
-) {
-  src =  ./.;
-}).defaultNix
+    let
+      lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    in
+      fetchTarball {
+        url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+        sha256 = lock.nodes.flake-compat.locked.narHash;
+      }
+  ) {
+    src = ./.;
+  })
+.defaultNix

flake.nix

@@ -13,10 +13,15 @@
     utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, flake-compat, nixpkgs, utils }:
-    # For each supported platform,
-    utils.lib.eachDefaultSystem (system:
-      let
+  outputs = {
+    self,
+    flake-compat,
+    nixpkgs,
+    utils,
+  }:
+  # For each supported platform,
+    utils.lib.eachDefaultSystem (
+      system: let
         # Let’s merge the package set from Nixpkgs with our custom PHP versions.
         pkgs = import nixpkgs.outPath {
           config = {
@@ -28,6 +33,8 @@
           ];
         };
       in rec {
+        formatter = pkgs.alejandra;
+
         packages = {
           inherit (pkgs) php php56 php70 php71 php72 php73 php74 php80 php81 php82;
         };
@@ -36,7 +43,8 @@
           inherit packages pkgs system;
         };
       }
-    ) // {
+    )
+    // {
       overlays.default = import ./pkgs/phps.nix nixpkgs.outPath;
     };
 }