Issue #2479449 by sudiptadas19, smustgrave, akashkumar07, rithesh bk, rpayanm,...

Issue #2479449 by sudiptadas19, smustgrave, akashkumar07, rithesh bk, rpayanm, pradhumanjain2311, tstoeckler, mrinalini9, tatisilva, larowlan, andypost, dawehner, xjm, yesct: contact_menu_local_tasks_alter() should check whether ['tabs'][0] is set

core/modules/contact/contact.module

@@ -98,7 +98,7 @@ function contact_entity_extra_field_info() {
  * email address configured.
  */
 function contact_menu_local_tasks_alter(&$data, $route_name) {
-  if ($route_name == 'entity.user.canonical') {
+  if ($route_name == 'entity.user.canonical' && isset($data['tabs'][0])) {
     foreach ($data['tabs'][0] as $href => $tab_data) {
       if ($href == 'entity.user.contact_form') {
         $link_params = $tab_data['#link']['url']->getRouteParameters();

core/modules/contact/tests/src/Unit/ContactTest.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\contact\Unit;
+
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @group contact
+ */
+class ContactTest extends UnitTestCase {
+
+  /**
+   * Test contact_menu_local_tasks_alter doesn't throw warnings.
+   */
+  public function testLocalTasksAlter(): void {
+    require_once $this->root . '/core/modules/contact/contact.module';
+    $data = [];
+    \contact_menu_local_tasks_alter($data, 'entity.user.canonical');
+    $this->assertTrue(TRUE, 'No warning thrown');
+  }
+
+}