- Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.30, 8.2.0 - 8.2.25, 8.3.0 - 8.3.13
- bool(true)
<?php
function is_cyclic(array &$array) {
json_encode($array);
return json_last_error() === JSON_ERROR_RECURSION;
}
$array = [1, [2, 3]];
$array[1][1] = &$array;
var_dump(is_cyclic($array));