symfony/symfony — pull request #5353 by Seldaek (2012-08-26 13:22:32+00:00)
Title: [Process] Add workaround for PHP's internal sigchild failing to return proper exit codes

PHP compiled with --enable-sigchild basically fails to return exit codes, and randomly returns -1 instead most of the time (see https://bugs.php.net/bug.php?id=29123).

This works around it by having the exit code going through another pipe. It's enabled by default for linux because the new pipe trick won't work on windows I think, but that's unlikely to be an issue because most people don't compile their own php there.

I could have it enabled only when sigchild is enabled using the code below, but obviously that adds some overhead, so I'm not sure what's worst.

```php
ob_start();
phpinfo(INFO_GENERAL);
$sigchild = false !== strpos(ob_get_clean(), '--enable-sigchild');
```

That said, this renders composer unusable (because we do check exit codes) for people having sigchild enabled, and it's not so easy to workaround outside of the Process class itself, so I hope this is an acceptable fix.