u-sonar-status is a bot to report a SonarQube (or SonarCloud) "Pull Request Quality Gate Status" as "External Status Check" on Merge Requests in GitLab Ultimate.

On a MR where the tool is configured, you will see next to the comment posted by sonar, the quality gate reported as external status:

If your project is configured to not allow you to merge when external checks are failing, you will ensure that the quality gate has to be green before you merge.

The recommended approach (see the GitLab integration integration page) is to fail a CI pipeline in case of a "Failed" quality gate. But this requires to re-run this pipeline when the status has changed in Sonar (for example when some findings are marked as false positives).

With this tool the external status check in Gitlab and the Quality Gate status in Sonar are always in sync.