MAGETWO-97680: Issue with Email template preview

Author: DianaRusin

lib/internal/Magento/Framework/Filter/Template.php

@@ -367,7 +367,10 @@ protected function getVariable($value, $default = '{no_value_defined}')
                     }
                 }
                 $last = $i;
-            } elseif (isset($stackVars[$i - 1]['variable']) && $stackVars[$i]['type'] == 'method') {
+            } elseif (isset($stackVars[$i - 1]['variable'])
+                && is_object($stackVars[$i - 1]['variable'])
+                && $stackVars[$i]['type'] == 'method'
+            ) {
                 // Calling object methods
                 $object = $stackVars[$i - 1]['variable'];
                 $method = $stackVars[$i]['name'];

lib/internal/Magento/Framework/Filter/Test/Unit/TemplateTest.php

@@ -216,4 +216,18 @@ public function testInappropriateCallbacks()
         $this->templateFilter->setVariables(['filter' => $this->templateFilter]);
         $this->templateFilter->filter('Test {{var filter.addAfterFilterCallback(\'mb_strtolower\')}}');
     }
+
+    /**
+     * Check that if calling a method of an object fails expected result is returned.
+     *
+     * @return void
+     */
+    public function testInvalidMethodCall()
+    {
+        $this->templateFilter->setVariables(['dateTime' => '\DateTime']);
+        $this->assertEquals(
+            '\DateTime',
+            $this->templateFilter->filter('{{var dateTime.createFromFormat(\'d\',\'1548201468\')}}')
+        );
+    }
 }