Issue #2875987 by raman.b, smustgrave, ericgsmith, anushrikumari, Lendude: Form alter hook called twice for views forms without view arguments

core/modules/views/src/Form/ViewsForm.php

@@ -148,8 +148,11 @@ class ViewsForm implements FormInterface, ContainerInjectionInterface {
     }
     $form_state->set(['step_controller', 'views_form_views_form'], 'Drupal\views\Form\ViewsFormMainForm');
 
-    // Add the base form ID.
-    $form_state->addBuildInfo('base_form_id', $this->getBaseFormId());
+    // Views forms without view arguments return the same Base Form ID and
+    // Form ID. Base form ID should only be added when different.
+    if ($this->getBaseFormId() !== $this->getFormId()) {
+      $form_state->addBuildInfo('base_form_id', $this->getBaseFormId());
+    }
 
     $form = [];
 

core/modules/views/tests/modules/views_form_test/views_form_test.info.yml

@@ -0,0 +1,8 @@
+name: 'Views Form Test'
+type: module
+description: 'Provides hook to alter views form for testing purposes.'
+package: Testing
+version: VERSION
+dependencies:
+  - drupal:views
+  - drupal:media

core/modules/views/tests/modules/views_form_test/views_form_test.module

@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * @file
+ * Hook implementations for this module.
+ */
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Implements hook_form_BASE_FORM_ID_alter().
+ */
+function views_form_test_form_views_form_media_media_page_list_alter(&$form, FormStateInterface $form_state, $form_id) {
+  $state = \Drupal::state();
+  $count = $state->get('hook_form_BASE_FORM_ID_alter_count', 0);
+  $state->set('hook_form_BASE_FORM_ID_alter_count', $count + 1);
+}

core/modules/views/tests/src/Functional/ViewsFormAlterTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Drupal\Tests\views\Functional;
+
+/**
+ * Tests hook_form_BASE_FORM_ID_alter for a ViewsForm.
+ *
+ * @group views
+ */
+class ViewsFormAlterTest extends ViewTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['views_form_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests hook_form_BASE_FORM_ID_alter for a ViewsForm.
+   */
+  public function testViewsFormAlter() {
+    $this->drupalLogin($this->createUser(['access media overview']));
+    $this->drupalGet('admin/content/media');
+    $count = $this->container->get('state')->get('hook_form_BASE_FORM_ID_alter_count');
+    $this->assertEquals(1, $count, 'hook_form_BASE_FORM_ID_alter was invoked only once');
+  }
+
+}