GroupContentController::addPage and its access checks now support a base plugin ID, gnode module extensions removed

You may now present the user with a page of entities you can add to a group that is specific to a base plugin ID. This can be useful when you have a plugin with derivatives per bundle, so that you can present an add/create page with only node types, group types, or whatever bundleable entity you have enabled.

As a result, GroupNodeController and GroupNodeRouteProvider have been removed as the same functionality can now be achieved by a simple route subscriber cloning the original routes and adding a base_plugin_id default.

See the example from the gnode module below:

namespace Drupal\gnode\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

/**
 * Subscriber for Group Node routes.
 */
class RouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  protected function alterRoutes(RouteCollection $collection) {
    if ($route = $collection->get('entity.group_content.create_page')) {
      $copy = clone $route;
      $copy->setPath('group/{group}/node/create');
      $copy->setDefault('base_plugin_id', 'group_node');
      $collection->add('entity.group_content.group_node_create_page', $copy);
    }

    if ($route = $collection->get('entity.group_content.add_page')) {
      $copy = clone $route;
      $copy->setPath('group/{group}/node/add');
      $copy->setDefault('base_plugin_id', 'group_node');
      $collection->add('entity.group_content.group_node_add_page', $copy);
    }
  }

}