public function sniffFileSets() {
    $bin = $this->getConfigValue('composer.bin');
    $result = $this->taskExecStack()
      ->dir($this->getConfigValue('repo.root'))
      ->exec("$bin/phpcs")
      ->run();
    $exit_code = $result->getExitCode();
    if ($exit_code) {
      if ($this->input()->isInteractive()) {
        $this->fixViolationsInteractively();
        throw new BltException("Initial execution of PHPCS failed. Re-run now that PHPCBF has fixed some violations.");
      }
      else {
        $this->logger->notice('Try running `blt source:fix:php-standards` to automatically fix standards violations.');
        throw new BltException("PHPCS failed.");
      }
    }
  }