ENGCOM-5474: Fix for PHP_CodeSniffer error after app:config:dump #23787

Author: sivaschenko

lib/internal/Magento/Framework/App/DeploymentConfig/Writer/PhpFormatter.php

@@ -18,10 +18,11 @@ class PhpFormatter implements FormatterInterface
 
     /**
      * Format deployment configuration.
+     *
      * If $comments is present, each item will be added
      * as comment to the corresponding section
      *
-     * {@inheritdoc}
+     * @inheritdoc
      */
     public function format($data, array $comments = [])
     {
@@ -71,6 +72,8 @@ private function formatData($data, $comments = [], $prefix = '    ')
     }
 
     /**
+     * Format generated config files using the short array syntax.
+     *
      * If variable to export is an array, format with the php >= 5.4 short array syntax. Otherwise use
      * default var_export functionality.
      *
@@ -80,7 +83,9 @@ private function formatData($data, $comments = [], $prefix = '    ')
      */
     private function varExportShort($var, int $depth = 0)
     {
-        if (!is_array($var)) {
+        if (null === $var) {
+            return 'null';
+        } elseif (!is_array($var)) {
             return var_export($var, true);
         }