Issue #83: Listen to ConfgEvents::SAVE to detect changes instead of f…

…orm API.

oe_authentication.services.yml

@@ -14,3 +14,8 @@ services:
     tags:
       - { name: event_subscriber }
     arguments: ['@config.factory', '@messenger']
+  oe_authentication.config_subscriber:
+    class: Drupal\oe_authentication\Event\UserRegisterRouteRedirectConfigSubscriber
+    arguments: ['@router.builder']
+    tags:
+      - { name: event_subscriber }

src/Event/UserRegisterRouteRedirectConfigSubscriber.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\oe_authentication\Event;
+
+use Drupal\Core\Config\ConfigCrudEvent;
+use Drupal\Core\Config\ConfigEvents;
+use Drupal\Core\Routing\RouteBuilderInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Acts when oe_authentication.settings:redirect_user_register_route changes.
+ */
+class UserRegisterRouteRedirectConfigSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The route builder service.
+   *
+   * @var \Drupal\Core\Routing\RouteBuilderInterface
+   */
+  protected $routeBuilder;
+
+  /**
+   * Constructs a new event subscriber instance.
+   *
+   * @param \Drupal\Core\Routing\RouteBuilderInterface $route_builder
+   *   The route builder service.
+   */
+  public function __construct(RouteBuilderInterface $route_builder) {
+    $this->routeBuilder = $route_builder;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents(): array {
+    return [
+      ConfigEvents::SAVE => 'onConfigSave',
+    ];
+  }
+
+  /**
+   * Acts when oe_authentication.settings:redirect_user_register_route changes.
+   *
+   * @param \Drupal\Core\Config\ConfigCrudEvent $event
+   *   The config CRUD event.
+   */
+  public function onConfigSave(ConfigCrudEvent $event): void {
+    if ($event->getConfig()->getName() === 'oe_authentication.settings') {
+      if ($event->isChanged('redirect_user_register_route')) {
+        $this->routeBuilder->rebuild();
+      }
+    }
+  }
+
+}

src/Form/AuthenticationSettingsForm.php

@@ -98,9 +98,6 @@ public function buildForm(array $form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
-    $original_redirect_user_register_route = $this->config(static::CONFIG_NAME)
-      ->get('redirect_user_register_route');
-
     $this->config(static::CONFIG_NAME)
       ->set('protocol', $form_state->getValue('protocol'))
       ->set('register_path', $form_state->getValue('register_path'))
@@ -110,11 +107,6 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
       ->set('redirect_user_register_route', $form_state->getValue('redirect_user_register_route'))
       ->save();
     parent::submitForm($form, $form_state);
-
-    // Rebuild the routes if the redirect user register config has changed.
-    if ($original_redirect_user_register_route != $form_state->getValue('redirect_user_register_route')) {
-      $this->routeBuilder->rebuild();
-    }
   }
 
   /**