Replacing create_function in validation loop

You can replace the create_function with a closure like this:

if( is_array($s) ) {

    $c = count($s);
    $a = 0;

    while( $a < $c ) {

        if( isset($s[$a]['validate_callback']) ) {

            $this->create_function[] = $s[$a]['id'];
            $s[$a]['validate_callback'] = '';

            $file = addslashes(WC_XSI_SETTINGS . 'validate-' . $s[$a]['id'] . '.php');

            // Replace create_function with a closure
            $s[$a]['validate_callback'] = function($fields) use ($s, $a) {
                do_action("wc_xsi_settings_validate", $fields);
                do_action("wc_xsi_settings_validate_" . $s[$a]['id'], $fields);
            };
        }

        $a++;
    }
}

Explanation of Changes: Anonymous Function (Closure):

• The create_function() has been replaced by an anonymous function (function($fields) use ($s, $a)), which is a much safer and modern way to define inline functions in PHP. use ($s, $a):

• The use keyword is necessary to bring variables from the outer scope ($s and $a) into the closure, as they are required inside the anonymous function for the callbacks. No More String-based Code:

• The anonymous function avoids the need for string-based function creation, making the code easier to read, maintain, and much safer from potential injection vulnerabilities.