See https://gerrit.wikimedia.org/r/#/c/401410/3/maintenance/loginAttempt.php
I had accidentally used two spaces instead of a tab in certain lines, and CodeSniffer failed to detect it.
class LoginAttempt extends Maintenance { » /** » * Constructor » * » * Retrieves the arguments from the command line » */ public function __construct() { ^^ problem » » parent::__construct(); » » $this->requireExtension( 'LoginNotify' ); » } }