symfony
diff --git a/‎src/Symfony/Component/DomCrawler/Crawler.php
Lines changed: 7 additions & 6 deletions b/‎src/Symfony/Component/DomCrawler/Crawler.php
Lines changed: 7 additions & 6 deletions
@@ -34,9 +34,9 @@ class Crawler implements \Countable, \IteratorAggregate
     private $namespaces = [];
 
     /**
-     * @var array A map of cached namespaces
+     * @var \ArrayIterator A map of cached namespaces
      */
-    private $cachedNamespaces = [];
+    private $cachedNamespaces;
 
     /**
      * @var string The base href value
@@ -73,6 +73,7 @@ public function __construct($node = null, string $uri = null, string $baseHref =
         $this->uri = $uri;
         $this->baseHref = $baseHref ?: $uri;
         $this->html5Parser = class_exists(HTML5::class) ? new HTML5(['disable_html_ns' => true]) : null;
+        $this->cachedNamespaces = new \ArrayIterator();
 
         $this->add($node);
     }
@@ -104,7 +105,7 @@ public function clear()
     {
         $this->nodes = [];
         $this->document = null;
-        $this->cachedNamespaces = [];
+        $this->cachedNamespaces = new \ArrayIterator();
     }
 
     /**
@@ -1258,15 +1259,15 @@ private function discoverNamespace(\DOMXPath $domxpath, string $prefix): ?string
             return $this->namespaces[$prefix];
         }
 
-        if (\array_key_exists($prefix, $this->cachedNamespaces)) {
-            return $this->cachedNamespaces[$prefix];
+        if ($this->cachedNamespaces->offsetExists($prefix)) {
+            return $this->cachedNamespaces->offsetGet($prefix);
         }
 
         // ask for one namespace, otherwise we'd get a collection with an item for each node
         $namespaces = $domxpath->query(sprintf('(//namespace::*[name()="%s"])[last()]', $this->defaultNamespacePrefix === $prefix ? '' : $prefix));
 
         $namespace = ($node = $namespaces->item(0)) ? $node->nodeValue : null;
-        $this->cachedNamespaces[$prefix] = $namespace;
+        $this->cachedNamespaces->offsetSet($prefix, $namespace);
 
         return $namespace;
     }