Gush\Command\PullRequest\PullRequestMergeCommand::guardPullRequestMerge PHP Method

    private function guardPullRequestMerge(array $pr)
    {
        if ('open' !== $pr['state']) {
            throw new UserException(sprintf('Pull request #%s is already merged/closed, current status: %s', $pr['number'], $pr['state']), self::COMMAND_FAILURE);
        }
    }