[DependencyInjection] Prepend extension config with ContainerConfigurator

Author: alexandre-daubois

bundles/prepend_extension.rst

@@ -186,6 +186,34 @@ method::
 
     The ``prependExtension()`` method, like ``prepend()``, is called only at compile time.
 
+Alternatively, you can use the ``prepend`` parameter of the
+:method:`Symfony\\Component\\DependencyInjection\\Loader\\ContainerConfigurator::extension`
+method::
+
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+    use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
+    use Symfony\Component\HttpKernel\Bundle\AbstractBundle;
+
+    class FooBundle extends AbstractBundle
+    {
+        public function prependExtension(ContainerConfigurator $containerConfigurator, ContainerBuilder $containerBuilder): void
+        {
+            // ...
+
+            $containerConfigurator->extension('framework', [
+                'cache' => ['prefix_seed' => 'foo/bar'],
+            ], prepend: true);
+
+            // ...
+        }
+    }
+
+.. versionadded:: 7.1
+
+    The ``prepend`` parameter of the
+    :method:`Symfony\\Component\\DependencyInjection\\Loader\\ContainerConfigurator::extension`
+    method was added in Symfony 7.1.
+
 More than one Bundle using PrependExtensionInterface
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