Leverage array_is_list

Author: jderusse

Dumper/XmlDumper.php

@@ -268,7 +268,7 @@ private function addServices(\DOMElement $parent)
 
     private function convertParameters(array $parameters, string $type, \DOMElement $parent, string $keyAttribute = 'key')
     {
-        $withKeys = array_keys($parameters) !== range(0, \count($parameters) - 1);
+        $withKeys = !array_is_list($parameters);
         foreach ($parameters as $key => $value) {
             $element = $this->document->createElement($type);
             if ($withKeys) {

composer.json

@@ -20,6 +20,7 @@
         "psr/container": "^1.1.1",
         "symfony/deprecation-contracts": "^2.1",
         "symfony/polyfill-php80": "^1.16",
+        "symfony/polyfill-php81": "^1.22",
         "symfony/service-contracts": "^1.1.6|^2"
     },
     "require-dev": {