Fix NULL $extender breaks PageHeaderBlock

src/Plugin/Block/PageHeaderBlock.php

@@ -18,6 +18,7 @@
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
+use Drupal\localgov_core\Plugin\views\display_extender\PageHeaderDisplayExtender;
 
 /**
  * Provides a 'PageHeaderBlock' block.
@@ -260,14 +261,18 @@ protected function getLede() {
     if ($this->view instanceof ViewExecutable) {
       $extender = $this->view->getDisplay()->getExtenders()['localgov_page_header_display_extender'] ?? NULL;
 
-      // Need to render view to apply tokens.
-      $this->view->render();
-      $lede = $extender->getLede();
-      return [
-        '#type' => 'html_tag',
-        '#tag' => 'p',
-        '#value' => $lede,
-      ];
+      // Only return a view lede if the Page Header Display extender is found.
+      if ($extender instanceof PageHeaderDisplayExtender) {
+
+        // Need to render view to apply tokens.
+        $this->view->render();
+        $lede = $extender->getLede();
+        return [
+          '#type' => 'html_tag',
+          '#tag' => 'p',
+          '#value' => $lede,
+        ];
+      }
     }
 
     return NULL;

tests/src/Functional/ViewsPageExtenderTest.php

@@ -6,6 +6,7 @@
 use Drupal\Tests\node\Traits\NodeCreationTrait;
 use Drupal\Tests\taxonomy\Traits\TaxonomyTestTrait;
 use Drupal\node\NodeInterface;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Functional tests for LocalGovDrupal install profile.
@@ -38,7 +39,7 @@ protected function setUp(): void {
   }
 
   /**
-   * Test block display.
+   * Test view with the page header extender displays correctly.
    */
   public function testViewWithPageHeadeExtender(): void {
 
@@ -67,4 +68,26 @@ public function testViewWithPageHeadeExtender(): void {
 
   }
 
+  /**
+   * Test a view page displays even when the display extender is disabled.
+   */
+  public function testViewWithoutPageExtenderInstalled(): void {
+
+    // Disable the pageHeaderExtender.
+    $config = \Drupal::service('config.factory')->getEditable('views.settings');
+    $display_extenders = $config->get('display_extenders') ?: [];
+    $display_extenders = array_filter($display_extenders, function ($item) {
+      return $item != 'localgov_page_header_display_extender' ? TRUE : FALSE;
+    });
+    $config->set('display_extenders', $display_extenders);
+    $config->save();
+
+    // Try to access the test view.
+    $this->drupalGet('/recent-content');
+
+    // Test view page should still display without the extender enabled.
+    // @See https://github.com/localgovdrupal/localgov_core/issues/270
+    $this->assertSession()->statusCodeEquals(Response::HTTP_OK);
+  }
+
 }