<?php declare(strict_types = 1);

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

final class BrokenFormatterCommand extends Command
{
	protected static $defaultName = 'broken-formatter';

	/**
	 * @param InputInterface  $input
	 * @param OutputInterface $output
	 *
	 * @return int
	 */
	protected function execute(InputInterface $input, OutputInterface $output): int
	{
		$output->writeln('ok');
		
		// fails here
		$output->writeln(null);

		return 0;
	}
}

preg_match_all("#<(($openTagRegex) | /($closeTagRegex)?)>#ix", $message ?? '', $matches, \PREG_OFFSET_CAPTURE);