clone_error.php

<?php

function method($cache) {
  $prepared = clone $cache;
  $prepared->data = unserialize($prepared->data);
  return $prepared;
}

$cache = new stdClass();
$cache->data = serialize(['foo' => 'bar']);

for ($i = 0; $i < 5; ++$i) {
  echo "$i\n";
  method($cache);
}