Ticket #21155: 21155.diff

wp-includes/category-template.php

@@ -73 +73 @@
  */
 function get_the_category( $id = false ) {
         $categories = get_the_terms( $id, 'category' );
-        if ( ! $categories )
+        if ( ! $categories || is_wp_error( $categories ) )
                 $categories = array();
 
         $categories = array_values( $categories );