From c57bc30e675a697a2fb0ad295e3236b252086c35 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@netways.de>
Date: Thu, 30 Jul 2015 16:00:04 +0200
Subject: [PATCH] AuthBackendPage: Don't crash while validating an external
 backend's config

---
 modules/setup/application/forms/AuthBackendPage.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/modules/setup/application/forms/AuthBackendPage.php b/modules/setup/application/forms/AuthBackendPage.php
index 01cd7176d..24ca72b8d 100644
--- a/modules/setup/application/forms/AuthBackendPage.php
+++ b/modules/setup/application/forms/AuthBackendPage.php
@@ -171,7 +171,10 @@ class AuthBackendPage extends Form
     {
         if (isset($formData['backend_validation']) && parent::isValid($formData)) {
             $self = clone $this;
-            $self->getSubForm('backend_form')->getElement('resource')->setIgnore(false);
+            if (($resourceElement = $self->getSubForm('backend_form')->getElement('resource')) !== null) {
+                $resourceElement->setIgnore(false);
+            }
+
             $inspection = UserBackendConfigForm::inspectUserBackend($self);
             if ($inspection !== null) {
                 $join = function ($e) use (& $join) {