Possibly related, or the same as T171510, but not sure...
codesniffer upgrading to 14.1 on mw-config is completely borked
https://integration.wikimedia.org/ci/job/operations-mw-config-composer-hhvm-jessie/8504/console
20:49:09 20:49:09 [Symfony\Component\Process\Exception\ProcessTimedOutException] 20:49:09 The process "composer phpcs" exceeded the timeout of 600 seconds. 20:49:09