Issue #2502195 by vijaycs85, larowlan: \Drupal\Core\StringTranslation\Translator\CustomStrings should be serializable, but contain \Drupal\Core\Site\Settings which is not

core/lib/Drupal/Core/StringTranslation/Translator/CustomStrings.php

@@ -3,6 +3,7 @@
 namespace Drupal\Core\StringTranslation\Translator;
 
 use Drupal\Core\Site\Settings;
+use Drupal\Core\DependencyInjection\DependencySerializationTrait;
 
 /**
  * String translator using overrides from variables.
@@ -12,6 +13,8 @@ use Drupal\Core\Site\Settings;
  */
 class CustomStrings extends StaticTranslation {
 
+  use DependencySerializationTrait;
+
   /**
    * The settings read only object.
    *

core/modules/datetime/tests/src/Kernel/DateTimeFormInjectionTest.php

@@ -0,0 +1,113 @@
+<?php
+
+namespace Drupal\Tests\datetime\Kernel;
+
+use Drupal\Core\Datetime\DrupalDateTime;
+use Drupal\Core\DependencyInjection\DependencySerializationTrait;
+use Drupal\Core\Form\FormInterface;
+use Drupal\Core\Form\FormState;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests serializing a form with an injected datetime instance.
+ *
+ * @group datetime
+ */
+class DateTimeFormInjectionTest extends KernelTestBase implements FormInterface {
+
+  use DependencySerializationTrait;
+
+  /**
+   * A Dblog logger instance.
+   *
+   * @var \Psr\Log\LoggerInterface
+   */
+  protected $logger;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = ['system', 'datetime'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installSchema('system', ['key_value_expire', 'sequences']);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'datetime_test_injection_form';
+  }
+
+  /**
+   * Process callback.
+   *
+   * @param array $element
+   *   Form element.
+   *
+   * @return array
+   *   Processed element.
+   */
+  public function process($element) {
+    return $element;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['datelist_element'] = [
+      '#title' => 'datelist test',
+      '#type' => 'datelist',
+      '#default_value' => new DrupalDateTime('2000-01-01 00:00:00'),
+      '#date_part_order' => [
+        'month',
+        'day',
+        'year',
+        'hour',
+        'minute', 'ampm',
+      ],
+      '#date_text_parts' => ['year'],
+      '#date_year_range' => '2010:2020',
+      '#date_increment' => 15,
+    ];
+    $form['#process'][] = [$this, 'process'];
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {}
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $this->assertTrue(TRUE);
+    $form_state->setRebuild();
+  }
+
+  /**
+   * Tests custom string injection serialization.
+   */
+  public function testDatetimeSerialization() {
+    $form_state = new FormState();
+    $form_state->setRequestMethod('POST');
+    $form_state->setCached();
+    $form_builder = $this->container->get('form_builder');
+    $form_id = $form_builder->getFormId($this, $form_state);
+    $form = $form_builder->retrieveForm($form_id, $form_state);
+    $form_builder->prepareForm($form_id, $form, $form_state);
+    $form_builder->processForm($form_id, $form, $form_state);
+  }
+
+}