Fix $this->namespaces to $this->itemInstances

Author: hammermaps

src/phpFastCache/Drivers/Zendshm/Driver.php

@@ -133,14 +133,14 @@ public function getStats()
         if(function_exists('zend_shm_cache_info')) {
             $stats = (array)zend_shm_cache_info();
             return (new driverStatistic())
-                ->setData(implode(', ', array_keys($this->namespaces)))
+                ->setData(implode(', ', array_keys($this->itemInstances)))
                 ->setInfo(sprintf("The Zend memory have %d item(s) in cache.\n For more information see RawData.", $stats['items_total']))
                 ->setRawData($stats)
                 ->setSize($stats['memory_total']);
         } else {
             /** zend_shm_cache_info supported V8 or higher */
             return (new driverStatistic())
-                ->setData(implode(', ', array_keys($this->namespaces)))
+                ->setData(implode(', ', array_keys($this->itemInstances)))
                 ->setInfo("The Zend memory statistics is only supported by ZendServer V8 or higher")
                 ->setRawData(null)
                 ->setSize(0);