was raised in.
     * @param int $line the line number the error was raised at.
     * @return bool whether the normal error handler continues.
     *
     * @throws ErrorException
     */
    public function handleError($code, $message, $file, $line)
    {
        if (error_reporting() & $code) {
            // load ErrorException manually here because autoloading them will not work
            // when error occurs while autoloading a class
            if (!class_exists('yii\\base\\ErrorException', false)) {
                require_once __DIR__ . '/ErrorException.php';
            }
            $exception = new ErrorException($message, $code, $code, $file, $line);

            if (PHP_VERSION_ID < 70400) {
                // prior to PHP 7.4 we can't throw exceptions inside of __toString() - it will result a fatal error
                $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
                array_shift($trace);
                foreach ($trace as $frame) {
                    if ($frame['function'] === '__toString') {
                        $this->handleException($exception);
                        if (defined('HHVM_VERSION')) {
                            flush();
                        }
                        exit(1);
                    }
                }
            }

            throw $exception;
        }

        return false;
    }

    /**
     * Handles fatal PHP errors.
     */
    public function handleFatalError()
    {
        $this->_memoryReserve = null;

        if (!empty($this->_workingDirectory)) {
            // fix working directory for some Web servers e.g. Apache
            chdir($this->_workingDirectory);
            // flush memory
            $this->_workingDirectory = null;
        }

        $error = error_get_last();
        if ($error === null) {
            return;
        }

        // load ErrorException manually here because autoloading them will not work
        // when error occurs while autoloading a class
        if (!class_exists('yii\\base\\ErrorException', false)) {
            require_once __DIR__ . '/ErrorException.php';
        }
        if (!ErrorException::isFatalError($error)) {
            return;
        }

        if (!empty($this->_hhvmException)) {
            $this->exception = $this->_hhvmException;
        } else {
            $this->exception = new ErrorException(
                $error['message'],
                $error['type'],
                $error['type'],
                $error['file'],
                $error['line']
            );
        }
        unset($error);

        $this->logException($this->exception);

        if ($this->discardExistingOutput) {
            $this->clearOutput();
        }
        $this->renderException($this->exception);

        // need to explicitly flush logs because exit() next will terminate the app immediately
        Yii::getLogger()->flush(true);
        if (defined('HHVM_VERSION')) {
            flush();
        }

        $this->trigger(static::EVENT_SHUTDOWN);

        // ensure it is called after user-defined shutdown functions
        register_shutdown_function(function () {
            exit(1);
        });
    }

    /**
     * Renders the exception.
     * @param \Throwable $exception the exception to be rendered.
     */
    abstract protected function renderException($exception);

    /**
     * Logs the given exception.
     * @param \Throwable $exception the exception to be logged
     * @since 2.0.3 this method is now public.
     */
    public function logException($exception)
    {
        $category = get_class($exception);
        if ($exception instanceof HttpException) {
            $category = 'yii\\web\\HttpException:' . $exception->statusCode;
        } elseif ($exception instanceof \ErrorException) {
            $category .= ':' . $exception->getSeverity();
        }
        Yii::error($exception, $category);
    }

    /**
     * Removes all output echoed before calling this method.
     */
    public function clearOutput()
    {
        // the following manual level counting is to deal with zlib.output_compression set to On
        for ($level = ob_get_level(); $level > 0; --$level) {
            if (!@ob_end_clean()) {
                ob_clean();
            }
        }
    }

    /**
     * Converts an exception into a PHP error.
     *
     * This method can be used to convert exceptions inside of methods like `__toString()`
     * to PHP errors because exceptions cannot be thrown inside of them.
     * @param \Throwable $exception the exception to convert to a PHP error.
     * @return never
     */
    public static function convertExceptionToError($exception)
    {
        trigger_error(static::convertExceptionToString($exception), E_USER_ERROR);
    }

    /**
     * Converts an exception into a simple string.
     * @param \Throwable $exception the exception being converted
     * @return string the string representation of the exception.
     */
    public static function convertExceptionToString($exception)
    {
        if ($exception instanceof UserException) {
            return "{$exception->getName()}: {$exception->getMessage()}";
        }

        if (YII_DEBUG) {
            return static::convertExceptionToVerboseString($exception);
        }

        return 'An internal server error occurred.';
    }

    /**
     * Converts an exception into a string that has verbose information about the exception and its trace.
     * @param \Throwable $exception the exception being converted
     * @return string the string representation of the exception.
     *
     * @since 2.0.14
     */
    public static function convertExceptionToVerboseString($exception)
    {
        if ($exception instanceof Exception) {
            $message = "Exception ({$exception->getName()})";
        } elseif ($exception instanceof ErrorException) {
            $message = (string)$exception->getName();
        } else {
            $message = 'Exception';
        }
        $message .= " '" . get_class($exception) . "' with message '{$exception->getMessage()}' \n\nin "
            . $exception->getFile() . ':' . $exception->getLine() . "\n\n"
            . "Stack trace:\n" . $exception->getTraceAsString();

        return $message;
    }
}