Issue #3084030 by hchonov, jibran: route node.add should be defined through...

Issue #3084030 by hchonov, jibran: route node.add should be defined through _entity_form instead through _controller

core/modules/node/node.routing.yml

@@ -27,7 +27,7 @@ node.add_page:
 node.add:
   path: '/node/add/{node_type}'
   defaults:
-    _controller: '\Drupal\node\Controller\NodeController::add'
+    _entity_form: 'node.default'
     _title_callback: '\Drupal\node\Controller\NodeController::addPageTitle'
   requirements:
     _node_add_access: 'node:{node_type}'
@@ -35,6 +35,7 @@ node.add:
     _node_operation_route: TRUE
     parameters:
       node_type:
+        type: entity:node_type
         with_config_overrides: TRUE
 
 entity.node.preview:

core/modules/node/src/Controller/NodeController.php

@@ -121,8 +121,13 @@ public function addPage() {
    *
    * @return array
    *   A node submission form.
+   *
+   * @deprecated in Drupal 8.8.0 and will be removed before Drupal 9.0.0. Define
+   *   entity form routes through the _entity_form instead through the
+   *   _controller directive.
    */
   public function add(NodeTypeInterface $node_type) {
+    @trigger_error(__METHOD__ . ' is deprecated in drupal:8.8.0 and is removed from drupal:9.0.0. Define entity form routes through the _entity_form instead through the _controller directive. See https://www.drupal.org/node/3084856', E_USER_DEPRECATED);
     $node = $this->entityTypeManager()->getStorage('node')->create([
       'type' => $node_type->id(),
     ]);