ISTWCMS-4943: adding check to ensure that we get a node object on a revisions page

uw_fdsu_theme_resp.theme

@@ -9,6 +9,7 @@ use Drupal\Core\Url;
 use Drupal\file\Plugin\Field\FieldType\FileFieldItemList;
 use Drupal\image\Plugin\Field\FieldType\ImageItem;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\node\Entity\Node;
 
 /**
  * @file
@@ -395,6 +396,14 @@ function uw_fdsu_theme_resp_preprocess_block(&$variables) {
     // Load the node.
     $node = \Drupal::routeMatch()->getParameter('node');
 
+    // ISTWCMS-4943: ensure that we get a node object.
+    // If node is not object by this point, probably on
+    // a revision page where node is an integer, so load
+    // the node.
+    if (!is_object($node)) {
+      $node = Node::load($node);
+    }
+
     // If there is a node, check that it has a featured image.
     if ($node) {