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<?php function is_cyclic(&$array) { $isRecursive = false; set_error_handler(function ($errno, $errstr) use (&$isRecursive) { $isRecursive = $errno === E_WARNING && mb_stripos($errstr, 'recursion'); }); try { count($array, COUNT_RECURSIVE); } finally { restore_error_handler(); } return $isRecursive; } $array = [1, [2, 3]]; $array[1][1] = &$array; var_dump(is_cyclic($array));
Output for 7.3.0 - 7.3.26, 7.4.0 - 7.4.14, 8.0.0 - 8.0.3
bool(true)