From 86032de8e54a0a8567dd8c503aa75ff38efbfa5c Mon Sep 17 00:00:00 2001
From: David <d.fecke@wunderbit.de>
Date: Fri, 6 Oct 2017 10:25:04 +0200
Subject: [PATCH] Use strict comparision instead of is_null

---
 lib/internal/Magento/Framework/View/Model/Layout/Merge.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/Magento/Framework/View/Model/Layout/Merge.php b/lib/internal/Magento/Framework/View/Model/Layout/Merge.php
index 1bae54e8728d9..4d611c830e91a 100644
--- a/lib/internal/Magento/Framework/View/Model/Layout/Merge.php
+++ b/lib/internal/Magento/Framework/View/Model/Layout/Merge.php
@@ -799,7 +799,7 @@ private function getXmlErrors($libXmlErrors)
     protected function _getPhysicalTheme(\Magento\Framework\View\Design\ThemeInterface $theme)
     {
         $result = $theme;
-        while (!is_null($result) && $result->getId() && !$result->isPhysical()) {
+        while ($result !== null && $result->getId() && !$result->isPhysical()) {
             $result = $result->getParentTheme();
         }
         if (!$result) {