Allow overriding PHP and WordPress versions

To override, you must set env vars like
PHP_PACKAGE=php84
or WORDPRESS_PACKAGE=wordpress_6_8_1
and run a command with --impure. E.g.,
PHP_PACKAGE=php84 nix flake check --impure

Author: john-shaffer

dev/flake.nix

@@ -15,24 +15,22 @@
       perSystem = { self', pkgs, config, lib, system, ... }:
         with pkgs;
         let
+          getEnv = name: default:
+            (if "" == builtins.getEnv name then
+              default
+            else
+              builtins.getEnv name);
           dbName = "wordpress";
           dbPort = 3306;
           dbUserName = "wordpress";
           dbUserPass = "8BVMm2jqDE6iADNyfaVCxoCzr3eBY6Ep";
           serverPort = 8888;
-          phpVersions = {
-            php81 = php81;
-            php82 = php82;
-            php83 = php83;
-            php84 = php84;
-          };
-          phpBins = lib.attrsets.mapAttrsToList (name: phpPkg:
-            pkgs.writeShellScriptBin name ''${phpPkg}/bin/php "$@"'')
-            phpVersions;
-          php = php84.buildEnv {
+          phpPackage = getEnv "PHP_PACKAGE" "php";
+          php = pkgs.${phpPackage}.buildEnv {
             extensions = { enabled, all }:
               enabled ++ (with all; [ imagick memcached ]);
           };
+          wordpressPackage = getEnv "WORDPRESS_PACKAGE" "default";
           wp2staticLib = inputs.wp2static.lib.${system};
           wp2staticPkgs = inputs.wp2static.packages.${system};
           wp2static = wp2staticPkgs.plugin;
@@ -150,6 +148,8 @@
                 }).format { };
               update-wordpress =
                 inputs.wordpress-flake.packages.${system}.update-wordpress;
+              wordpress =
+                inputs.wordpress-flake.packages.${system}.${wordpressPackage};
               wpConfig = inputs.wordpress-flake.lib.${system}.mkWPConfig {
                 inherit pkgs lib;
                 name = "wp-config.php";
@@ -208,7 +208,7 @@
                 mkdir -p ./data/wordpress1
                 chmod ug+w ./data/wordpress1/wp-config.php || true
                 cp "${wpConfig}" "./data/wordpress1/wp-config.php"
-                ${update-wordpress}/bin/update-wordpress ./data/wordpress1
+                ${update-wordpress}/bin/update-wordpress ./data/wordpress1 ${wordpress}
                 cd ./data/wordpress1
                 ${pkgs.wp-cli}/bin/wp core install --url="https://example.com" --title=WordPress --admin_user=user --admin_email="user@example.com" --admin_password=pass
                 ${pkgs.wp-cli}/bin/wp option update permalink_structure "/%postname%/"
@@ -220,8 +220,7 @@
 
           devShells.default = pkgs.mkShell {
             buildInputs =
-              [ omnix php phpunit phpPackages.composer shellcheck wp-cli ]
-              ++ phpBins;
+              [ omnix php phpunit phpPackages.composer shellcheck wp-cli ];
             inputsFrom =
               [ config.process-compose."default".services.outputs.devShell ];
           };