Issue #2787025 by vidorado, vivek panicker, danmer, dfletcher, smustgrave:...

Issue #2787025 by vidorado, vivek panicker, danmer, dfletcher, smustgrave: Setting #resizable on a textarea has no effect

core/includes/form.inc

@@ -391,7 +391,11 @@ function template_preprocess_textarea(&$variables): void {
   $variables['wrapper_attributes'] = new Attribute();
   $variables['attributes'] = new Attribute($element['#attributes']);
   $variables['value'] = $element['#value'];
-  $variables['resizable'] = !empty($element['#resizable']) ? $element['#resizable'] : NULL;
+  $resizable = !empty($element['#resizable']) ? $element['#resizable'] : NULL;
+  $variables['resizable'] = $resizable;
+  if ($resizable) {
+    $variables['attributes']->addClass('resize-' . $resizable);
+  }
   $variables['required'] = !empty($element['#required']) ? $element['#required'] : NULL;
 }
 

core/modules/system/tests/modules/form_test/form_test.routing.yml

@@ -574,6 +574,15 @@ form_test.incorrect_config_target:
   requirements:
     _access: 'TRUE'
 
+form_test.textarea:
+  path: '/form-test/textarea'
+  defaults:
+    _form: '\Drupal\form_test\Form\FormTestTextareaForm'
+  options:
+    _admin_route: TRUE
+  requirements:
+    _access: 'TRUE'
+
 form_test.recipe_input:
   path: '/form-test/recipe-input'
   defaults:

core/modules/system/tests/modules/form_test/src/Form/FormTestTextareaForm.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\form_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Symfony\Component\HttpFoundation\JsonResponse;
+
+/**
+ * Form for testing textarea.
+ *
+ * @internal
+ */
+class FormTestTextareaForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return '_test_textarea_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+
+    foreach (['vertical', 'horizontal', 'both', 'none'] as $resizableMode) {
+      $id = 'textarea_resizable_' . $resizableMode;
+      $form[$id] = [
+        '#type' => 'textarea',
+        '#title' => $id,
+        '#resizable' => $resizableMode,
+      ];
+    }
+
+    $form['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Submit'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state): void {
+    $form_state->setResponse(new JsonResponse($form_state->getValues()));
+  }
+
+}

core/modules/system/tests/src/Functional/Form/TextareaTest.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\system\Functional\Form;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests the form API textarea element.
+ *
+ * @group Form
+ */
+class TextareaTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['form_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the textarea element #resizable property.
+   */
+  public function testFormTextareaResizable(): void {
+    $this->drupalGet('form-test/textarea');
+    $this->assertNotEmpty($this->cssSelect('#edit-textarea-resizable-vertical.resize-vertical'));
+    $this->assertNotEmpty($this->cssSelect('#edit-textarea-resizable-horizontal.resize-horizontal'));
+    $this->assertNotEmpty($this->cssSelect('#edit-textarea-resizable-both.resize-both'));
+    $this->assertNotEmpty($this->cssSelect('#edit-textarea-resizable-none.resize-none'));
+  }
+
+}

core/profiles/standard/tests/src/FunctionalJavascript/StandardPerformanceTest.php

@@ -142,8 +142,8 @@ protected function testAnonymous(): void {
       ],
       'CacheSetCount' => 45,
       'CacheDeleteCount' => 0,
-      'CacheTagChecksumCount' => 37,
-      'CacheTagIsValidCount' => 42,
+      'CacheTagChecksumCount' => 38,
+      'CacheTagIsValidCount' => 43,
       'CacheTagInvalidationCount' => 0,
       'CacheTagLookupQueryCount' => 21,
       'CacheTagGroupedLookups' => [