<?php
var_dump([
$original_set = [ 'arrayobject' => new arrayobject( [3] ), 'reference?' => [5] ],
$original_serialized = serialize( $original_set ),
$original_unserialized = unserialize( $original_serialized ),
$withreference_serialized = preg_replace( '/a:1:{i:0;i:5;}}/', 'R:4;}', $original_serialized ),
$withreference_unserialized = unserialize( $withreference_serialized ),
$withreference_unserialized['reference?'][9] = 8,
$referenced_arrayobject = & $withreference_unserialized['arrayobject'],
$reference_array = & $withreference_unserialized['reference?'],
$withreference_unserialized,
( ( $referenced_arrayobject[9] ) === ( $reference_array[9] ) )
? 'looks like a reference' : 'does not look like a reference' ,
]) ;
preferences:
67.68 ms | 402 KiB | 5 Q