From bfab343d32c3d4e00a7d9e5d205e99c073b38a7b Mon Sep 17 00:00:00 2001
From: Seth Shaw <seth.shaw@unlv.edu>
Date: Wed, 22 Jul 2020 12:25:46 -0700
Subject: [PATCH] verify entity before walking breadcrumb (#786)

---
 .../islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php   | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/modules/islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php b/modules/islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php
index c58e7006..86090ff1 100644
--- a/modules/islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php
+++ b/modules/islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php
@@ -107,7 +107,8 @@ class IslandoraBreadcrumbBuilder implements BreadcrumbBuilderInterface {
 
     // Find the next in the chain, if there are any.
     if ($entity->hasField($this->config->get('referenceField')) &&
-      !$entity->get($this->config->get('referenceField'))->isEmpty()) {
+      !$entity->get($this->config->get('referenceField'))->isEmpty() &&
+      $entity->get($this->config->get('referenceField'))->entity instanceof EntityInterface) {
       $this->walkMembership($entity->get($this->config->get('referenceField'))->entity, $crumbs);
     }
   }