Symfony / Process失败，但有例外

Question

我尝试使用Symfony / Process组件为linux执行独立的chromedriver。这是项目的文件夹结构：

 .
 ├── bin
 │   └── chromedriver-linux
 ├── composer.json
 ├── index.php
 └── vendor

在index.php中，这是我尝试执行的代码：

<?php

require 'vendor/autoload.php';

use Symfony\Component\Process\Process;

$process = new Process(
    [realpath(__DIR__.'/bin/chromedriver-linux')], null, ['DISPLAY' => ':0']
);

$process->start();

if (!$process->isSuccessful()) {
    throw new \Symfony\Component\Process\Exception\ProcessFailedException($process);
}

然而情况更糟。现在没有错误输出，只是抛出一个Exception，如：

Fatal error: Uncaught Symfony\Component\Process\Exception\ProcessFailedException: The command "'/home/vagrant/Code/development/test-project/bin/chromedriver-linux'" failed. Exit Code: () Working directory: /home/vagrant/Code/development/dusk-2.0 Output: ================ Error Output: ================ in /home/vagrant/Code/development/test-project/index.php on line 14