Issue 3449678: fix block placement filter format not found

Closes #3449678

src/Plugin/Block/TocFilterBlock.php

@@ -3,6 +3,7 @@
 namespace Drupal\toc_filter\Plugin\Block;
 
 use Drupal\Core\Access\AccessResult;
+use Drupal\filter\Entity\FilterFormat;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\toc_api\Plugin\Block\TocBlockBase;
 
@@ -31,15 +32,19 @@ class TocFilterBlock extends TocBlockBase {
 
     // Node should have [toc] token or filter should have auto enabled.
     $format_id = $node->body->format;
+    if ($format_id !== NULL){
     $format = FilterFormat::load($format_id);
-    if ($format && $format->filters('toc_filter')) {
-      $toc_filter_config = $format->filters('toc_filter')->getConfiguration();
-      // If auto is disabled, and there is no [toc token, don't display block.
-      if (!$toc_filter_config['settings']['auto'] && stripos($node->body->value, '[toc') === FALSE) {
-        return AccessResult::forbidden();
+      if ( $format && $format->filters('toc_filter')) {
+        $toc_filter_config = $format->filters('toc_filter')->getConfiguration();
+        // If auto is disabled, and there is no [toc token, don't display block.
+        if (!$toc_filter_config['settings']['auto'] && stripos($node->body->value, '[toc') === FALSE) {
+          return AccessResult::forbidden();
+        }
       }
+    } else {
+      return AccessResult::forbidden();
     }
-
+    
     // Since entities (ie node) are cached we need to pass the current node's
     // body through it's filters and see if a TOC is being generated and
     // displayed in this block.