Merge branch '5.4' into 6.3

* 5.4:
  [DotEnv] Mention the `overrideExistingVars` parameter of `DotEnv`
  simplify compiler pass example

Author: javiereguiluz

configuration.rst

@@ -885,6 +885,25 @@ the env files ending in ``.local`` (``.env.local`` and ``.env.<environment>.loca
 **should not be committed** because only you will use them. In fact, the
 ``.gitignore`` file that comes with Symfony prevents them from being committed.
 
+Overriding Environment Variables Defined By The System
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you need to override an environment variable defined by the system, use the
+``overrideExistingVars`` parameter defined by the
+:method:`Symfony\\Component\\Dotenv\\Dotenv::loadEnv`,
+:method:`Symfony\\Component\\Dotenv\\Dotenv::bootEnv`, and
+:method:`Symfony\\Component\\Dotenv\\Dotenv::populate` methods::
+
+    use Symfony\Component\Dotenv\Dotenv;
+
+    $dotenv = new Dotenv();
+    $dotenv->loadEnv(__DIR__.'/.env', null, 'dev', ['test'], true);
+
+    // ...
+
+This will override environment variables defined by the system but it **won't**
+override environment variables defined in ``.env`` files.
+
 .. _configuration-env-var-in-prod:
 
 Configuring Environment Variables in Production

testing.rst

@@ -599,32 +599,27 @@ to remove the ``kernel.reset`` tag from some services in your test environment::
     // src/Kernel.php
     namespace App;
 
-    use App\DependencyInjection\Compiler\CustomPass;
     use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
+    use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
     use Symfony\Component\DependencyInjection\ContainerBuilder;
     use Symfony\Component\HttpKernel\Kernel as BaseKernel;
 
-    class Kernel extends BaseKernel
+    class Kernel extends BaseKernel implements CompilerPassInterface
     {
         use MicroKernelTrait;
 
         // ...
 
-        protected function build(ContainerBuilder $container): void
+        protected function process(ContainerBuilder $container): void
         {
             if ('test' === $this->environment) {
-                $container->addCompilerPass(new class() implements CompilerPassInterface {
-                    public function process(ContainerBuilder $container): void
-                    {
-                        // prevents the security token to be cleared
-                        $container->getDefinition('security.token_storage')->clearTag('kernel.reset');
-
-                        // prevents Doctrine entities to be detached
-                        $container->getDefinition('doctrine')->clearTag('kernel.reset');
-
-                        // ...
-                    }
-                });
+                // prevents the security token to be cleared
+                $container->getDefinition('security.token_storage')->clearTag('kernel.reset');
+
+                // prevents Doctrine entities to be detached
+                $container->getDefinition('doctrine')->clearTag('kernel.reset');
+
+                // ...
             }
         }
     }