Rule Definition
The structure include_once include and check the specified file during the script execution. The functionality is similar to include with the difference that in the case of include_once a verification is done to be sure that the file has been included only once. For this reason include_once is more costly than include statement. Sometimes it's necessary, but you should default to include() in most situations.

Remediation
Try and reduce the use of include_once

Violation Code Sample

<?php
include_once "a.php"; // VIOLATION
include_once "B.php"; // VIOLATION
?>

Fixed Code Sample

<?php
include "a.php"; // CORRECTED
include "B.php"; // CORRECTED
?>