private function rollback()
    {
        $this->output->writeln(array(
            '',
            '<error>There was an error while updating the installer.</error>',
            'The previous Symfony Installer version has been restored.',
            '',
        ));

        $this->fs->remove($this->newInstallerFile);

        if ($this->restorePreviousInstaller) {
            $this->fs->copy($this->currentInstallerBackupFile, $this->currentInstallerFile, true);
        }
    }