[DI] Document PHP-DSL service_closure() function

Author: HypeMC

service_container/service_closures.rst

@@ -4,6 +4,9 @@
 Service Closures
 ================
 
+.. versionadded:: 5.4
+    The ``service_closure()`` function was introduced in Symfony 5.4.
+
 This feature wraps the injected service into a closure allowing it to be
 lazily loaded when and if needed.
 This is useful if the service being injected is a bit heavy to instantiate
@@ -70,17 +73,37 @@ argument of type ``service_closure``:
         namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
         use App\Service\MyService;
-        use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
-        use Symfony\Component\DependencyInjection\Reference;
 
         return function (ContainerConfigurator $configurator) {
             $services = $configurator->services();
 
             $services->set(MyService::class)
-                ->args([new ServiceClosureArgument(new Reference('mailer'))]);
+                ->args([service_closure('mailer')]);
+
+            // In case the dependency is optional
+            // $services->set(MyService::class)
+            //     ->args([service_closure('mailer')->ignoreOnInvalid()]);
         };
 
 .. seealso::
 
     Another way to inject services lazily is via a
     :doc:`service locators </service_container/service_subscribers_locators>`.
+
+Using a Service Closures in a Compiler Pass
+-------------------------------------------
+
+In :doc:`compiler passes </service_container/compiler_passes>` you can create
+a service closure by wrapping the service reference into an instance of
+:class:`Symfony\\Component\\DependencyInjection\\Argument\\ServiceClosureArgument`::
+
+    use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+    use Symfony\Component\DependencyInjection\Reference;
+
+    public function process(ContainerBuilder $container): void
+    {
+        // ...
+
+        $myService->addArgument(new ServiceClosureArgument(new Reference('mailer')));
+    }