Merge pull request #2450 from nowackipawel/patch-76

CRITICAL when $_SESSION is null / Argument 2 passed to dot_array_search() must be []

system/Session/Session.php

@@ -497,7 +497,7 @@ public function set($data, $value = null)
 	 */
 	public function get(string $key = null)
 	{
-		if (! empty($key) && ! is_null($value = dot_array_search($key, $_SESSION)))
+		if (! empty($key) && ! is_null($value = dot_array_search($key, $_SESSION??[])))
 		{
 			return $value;
 		}