https://github.com/symfony/symfony/pull/21841 demo

reproduction.php

<?php
<<<CONFIG
packages:
    - "symfony/console: 3.2.4"
    - "symfony/event-dispatcher: ~3.0"
CONFIG;

use Symfony\Component\Console\Application;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\ConsoleEvents;
use Symfony\Component\Console\Event\ConsoleCommandEvent;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\EventDispatcher\EventDispatcher;

class GreetCommand extends Command
{
    public function configure()
    {
        $this->setName('greet');
    }

    public function execute(InputInterface $input, OutputInterface $output)
    {
        $output->writeln(sprintf("Hello %s!", $input->getArgument('name')));
    }
}

$dispatcher = new EventDispatcher();
$app = new Application();
$app->setDispatcher($dispatcher);
$app->add(new GreetCommand());

$dispatcher->addListener(ConsoleEvents::COMMAND, function (ConsoleCommandEvent $event) {
    $command = $event->getCommand();
    if ($command instanceof GreetCommand) {
        $command->addArgument('name', InputArgument::REQUIRED, 'Who do you want to greet?');
    }
});
$app->run();