CodeIgniter3启用CSRF保护触发CI_Controller未找到致命错误

问题背景 #

我基于CodeIgniter 3开发系统，需要为登录和注册表单启用CSRF保护，于是在配置文件中做了如下设置：

$config['csrf_protection'] = FALSE;
if (isset($_SERVER["REQUEST_URI"])) {
    if (stripos($_SERVER["REQUEST_URI"], '/login') !== FALSE || stripos($_SERVER["REQUEST_URI"], '/register') !== FALSE ) {
        $config['csrf_protection'] = TRUE;
    }
}

但一旦将csrf_protection配置项设为true，错误处理器就触发函数不存在的提示——该函数实际存在于MY_url_helper中，真正的问题是CI_Controller未被找到，尽管回溯信息显示CodeIgniter已加载：

Array
(
    [0] => Array
        (
            [file] => path\to\system\core\Exceptions.php
            [line] => 268
            [function] => include
        )

    [1] => Array
        (
            [file] => path\to\system\core\Common.php
            [line] => 627
            [function] => show_php_error
            [class] => CI_Exceptions
            [object] => CI_Exceptions Object
                (
                    [ob_level] => 1
                    [levels] => Array
                        (
                            [1] => Error
                            [2] => Warning
                            [4] => Parsing Error
                            [8] => Notice
                            [16] => Core Error
                            [32] => Core Warning
                            [64] => Compile Error
                            [128] => Compile Warning
                            [256] => User Error
                            [512] => User Warning
                            [1024] => User Notice
                            [2048] => Runtime Notice
                        )

                )

            [type] => ->
            [args] => Array
                (
                    [0] => Error
                    [1] => Uncaught Error: Class "CI_Controller" not found in path\to\system\core\CodeIgniter.php:369
Stack trace:
#0 path\to\app\core\MY_Exceptions.php(54): get_instance()
#1 path\to\system\core\Common.php(195): MY_Exceptions->__construct()
#2 path\to\system\core\Common.php(656): load_class('Exceptions', 'core')
#3 [internal function]: _exception_handler(Object(Error))
#4 {main}
thrown
                    [2] => core/CodeIgniter.php
                    [3] => 369
                )

        )

    [2] => Array
        (
            [file] => path\to\system\core\Common.php
            [line] => 693
            [function] => _error_handler
            [args] => Array
                (
                    [0] => 1
                    [1] => Uncaught Error: Class "CI_Controller" not found in path\to\system\core\CodeIgniter.php:369
Stack trace:
#0 path\to\app\core\MY_Exceptions.php(54): get_instance()
#1 path\to\system\core\Common.php(195): MY_Exceptions->__construct()
#2 path\to\system\core\Common.php(656): load_class('Exceptions', 'core')
#3 [internal function]: _exception_handler(Object(Error))
#4 {main}
thrown
                    [2] => path\to\system\core\CodeIgniter.php
                    [3] => 369
                )

        )

    [3] => Array
        (
            [function] => _shutdown_handler
            [args] => Array
                (
                )

        )

)

代码库扩展了CI_Exceptions类，测试用构造函数如下：

class MY_Exceptions extends CI_Exceptions
{
    public function __construct() {
        parent::__construct();
        die('Error is showing');
        $this->CI =& get_instance();
        die('Error not showing');
    }
}

可以看到，执行到$this->CI =& get_instance();时触发异常。我已查看相关问题，但无法采用现有解决方案。将CI错误日志级别设为4后，日志未显示任何错误：

INFO - 2023-10-06 13:47:57 --> Config Class Initialized
INFO - 2023-10-06 13:47:57 --> Hooks Class Initialized
DEBUG - 2023-10-06 13:47:57 --> UTF-8 Support Enabled
INFO - 2023-10-06 13:47:57 --> Utf8 Class Initialized
INFO - 2023-10-06 13:47:57 --> URI Class Initialized
INFO - 2023-10-06 13:47:57 --> Router Class Initialized
INFO - 2023-10-06 13:47:57 --> Output Class Initialized
INFO - 2023-10-06 13:47:57 --> Security Class Initialized
DEBUG - 2023-10-06 13:47:57 --> Global POST, GET and COOKIE data sanitized

求助解决思路 #

内容的提问来源于stack exchange，提问作者Kobus Myburgh