所需文件不起作用，但所需文件存在

我遇到了一些麻烦，我制作了一个动态requires函数，并在同一目录下的两个php文件中使用它，名为database_controller.php和Login.php。事实是，当我在登录文件中调用require函数时，它在测试后告诉我该文件存在，但测试后的require没有接收该文件。在我的文件database_controller上，当我调用requires函数时，它工作起来没有问题

所需的登录文件测试

require "./Utils/require.php";
if (file_exists(requires(intval($rows["role"])))) {
    echo "exist";
    require requires(intval($rows["role"]));
    echo "loaded";
    //doing something with the dynamic require
}
else {
    echo requires(intval($rows["role"]));
    exit;
}

当我运行登录时，我得到了错误500内部服务器错误，登录文件的响应只是"存在"

这是的内容/Utils/require.php

/**
 * @function requires
 * @param $userType
 * @return int|string
 */
function requires($userType) {
    switch($userType) {
        case 0:
            if (file_exists("Path to required file for user type 0")) {
                return "Path to required file for user type 0";
            }
        else
            return 0;
        case 1:
            if (file_exists("Path to required file for user type 1")) {
                return "Path to required file for user type 1";
            }
            else
                return 0;
        case 2:
            if (file_exists("Path to required file for user type 2")) {
                return "Path to required file for user type 2";
            }
            else
                return 0;
    }
}

这是我在数据库控制器上做的，具有相同功能

require_once "./Utils/require.php";
require_once "./error.php";
/*
 * Post request method for packers
 */
if ($UserType == 0) {
    if (requires($UserType)) {
        require requires($UserType);
        //doing something with the dynamic required file
    }
}
/*
 * Post request method for supervisors
 */
elseif ($UserType == 1) {
    if (requires($UserType)) {
        require requires($UserType);
        //doing something with the dynamic required file
    }
}
/*
 * Post request method for admins
 */
elseif ($UserType == 2) {
     if (requires($UserType)) {
         require requires($UserType);
        //doing something with the dynamic required file
    }
}

这里我没有500内部服务器错误，我有200 ok，我有显示的具体表格