Merge branch '3.3' into 3.4

* 3.3:
  include file and line number in deprecation
  parse merge keys with PARSE_OBJECT_FOR_MAP flag

Author: xabbuh

Mapping/Loader/YamlFileLoader.php

@@ -115,10 +115,18 @@ protected function parseNodes(array $nodes)
      */
     private function parseFile($path)
     {
+        $prevErrorHandler = set_error_handler(function ($level, $message, $script, $line) use ($path, &$prevErrorHandler) {
+            $message = E_USER_DEPRECATED === $level ? preg_replace('/ on line \d+/', ' in "'.$path.'"$0', $message) : $message;
+
+            return $prevErrorHandler ? $prevErrorHandler($level, $message, $script, $line) : false;
+        });
+
         try {
             $classes = $this->yamlParser->parseFile($path, Yaml::PARSE_CONSTANT);
         } catch (ParseException $e) {
             throw new \InvalidArgumentException(sprintf('The file "%s" does not contain valid YAML.', $path), 0, $e);
+        } finally {
+            restore_error_handler();
         }
 
         // empty file