zendframework/zendframework#6366 - session data is backed up and merg…

…ed back into `$_SESSION` after `session_start()` (when not empty)

Signed-off-by: Marco Pivetta <ocramius@gmail.com>

src/SessionManager.php

@@ -10,6 +10,7 @@
 namespace Zend\Session;
 
 use Zend\EventManager\EventManagerInterface;
+use Zend\Stdlib\ArrayUtils;
 
 /**
  * Session ManagerInterface implementation utilizing ext/session
@@ -92,8 +93,16 @@ public function start($preserveStorage = false)
             $this->registerSaveHandler($saveHandler);
         }
 
+        $oldSessionData = $_SESSION;
+
         session_start();
 
+        if ($oldSessionData instanceof \Traversable
+            || (! empty($oldSessionData) && is_array($oldSessionData))
+        ) {
+            $_SESSION = ArrayUtils::merge($oldSessionData, $_SESSION, true);
+        }
+
         $storage = $this->getStorage();
 
         // Since session is starting, we need to potentially repopulate our