AC-3160: Fix possible deprecation issues with 8.1

Author: karyna-t

lib/internal/Magento/Framework/View/Element/Template/File/Validator.php

@@ -9,15 +9,12 @@
 use Magento\Framework\Component\ComponentRegistrar;
 use \Magento\Framework\Filesystem\Driver\File as FileDriver;
 
-/**
- * Class Validator
- */
 class Validator
 {
     /**
      * Config path to 'Allow Symlinks' template settings
      */
-    const XML_PATH_TEMPLATE_ALLOW_SYMLINK = 'dev/template/allow_symlink';
+    public const XML_PATH_TEMPLATE_ALLOW_SYMLINK = 'dev/template/allow_symlink';
 
     /**
      * Template files map
@@ -140,7 +137,7 @@ protected function isPathInDirectories($path, $directories)
         }
         $realPath = $this->fileDriver->getRealPath($path);
         foreach ($directories as $directory) {
-            if (0 === strpos($realPath, $directory)) {
+            if ($directory !== null && 0 === strpos($realPath, $directory)) {
                 return true;
             }
         }

lib/internal/Magento/Framework/View/Element/UiComponent/Config/DomMerger.php

@@ -8,15 +8,12 @@
 use Magento\Framework\Config\Dom;
 use Magento\Framework\Config\ValidationStateInterface;
 
-/**
- * Class DomMerger
- */
 class DomMerger implements DomMergerInterface
 {
     /**
      * Format of items in errors array to be used by default. Available placeholders - fields of \LibXMLError.
      */
-    const ERROR_FORMAT_DEFAULT = "Message: %message%\nLine: %line%\n";
+    public const ERROR_FORMAT_DEFAULT = "Message: %message%\nLine: %line%\n";
 
     /**
      * @var \Magento\Framework\Config\ValidationStateInterface
@@ -45,15 +42,11 @@ class DomMerger implements DomMergerInterface
     protected $idAttributes = [];
 
     /**
-     * Context XPath
-     *
      * @var array
      */
     protected $contextXPath = [];
 
     /**
-     * Is merge simple XML Element
-     *
      * @var bool
      */
     protected $isMergeSimpleXMLElement;
@@ -152,7 +145,7 @@ protected function mergeAttributes(\DOMElement $baseNode, \DOMNode $mergeNode)
     protected function createXPath(\DOMNode $node)
     {
         $parentXPath = '';
-        $currentXPath = $node->getNodePath();
+        $currentXPath = $node->getNodePath() ?? '';
         if ($node->parentNode !== null && !$node->isSameNode($node->parentNode)) {
             $parentXPath = $this->createXPath($node->parentNode);
             $pathParts = explode('/', $currentXPath);
@@ -187,6 +180,7 @@ protected function createXPath(\DOMNode $node)
      *
      * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      * @SuppressWarnings(PHPMD.NPathComplexity)
+     * phpcs:disable Generic.Metrics.NestingLevel
      */
     protected function nestedMerge(\DOMXPath $rootDomXPath, \DOMNodeList $insertedNodes, \DOMNode $contextNode)
     {
@@ -236,6 +230,7 @@ protected function nestedMerge(\DOMXPath $rootDomXPath, \DOMNodeList $insertedNo
             }
         }
     }
+    // phpcs:enable Generic.Metrics.NestingLevel
 
     /**
      * Append child node

lib/internal/Magento/Framework/View/FileSystem.php

@@ -171,7 +171,7 @@ public function getEmailTemplateFileName($fileId, array $params, $module)
      */
     public static function normalizePath($path)
     {
-        $parts = explode('/', $path);
+        $parts = $path !== null ? explode('/', $path) : [];
         $result = [];
 
         foreach ($parts as $part) {

lib/internal/Magento/Framework/View/Layout/Data/Structure.php

@@ -77,7 +77,7 @@ public function createStructuralElement($name, $type, $class)
      */
     protected function _generateAnonymousName($class)
     {
-        $position = strpos($class, '\\Block\\');
+        $position = $class !== null ? strpos($class, '\\Block\\') : '';
         $key = $position !== false ? substr($class, $position + 7) : $class;
         $key = strtolower(trim($key, '_'));