Online PHP editor | output for mLGPa

<?php $x = 4; if($x == 1){ class X{} session_start(); $_SESSION["x"] = new X(); $_SESSION["y"] = "5"; echo session_encode(); // x|O:1:"X":0:{}y|s:1:"5"; } elseif($x == 2){ session_start(); session_decode('x|O:1:"X":0:{}y|s:1:"5";'); $_SESSION["y"] = 6; echo session_encode(); die(); print_r($_SESSION); /* Array ( [x] => __PHP_Incomplete_Class Object ( [__PHP_Incomplete_Class_Name] => X ) [y] => 5 ) */ } elseif($x == 3){ enum Y{ case Y; } session_start(); $_SESSION["x"] = Y::Y; $_SESSION["y"] = "5"; echo session_encode(); // x|E:3:"Y:Y";y|s:1:"5"; } elseif($x == 4){ session_start(); session_decode('x|E:3:"Y:Y";y|s:1:"5";'); print_r($_SESSION); /* Warning: session_decode(): Class 'Y' not found in /in/1IEIF on line 36 Warning: session_decode(): Failed to decode session object. Session has been destroyed in /in/1IEIF on line 36 Array ( ) */ }