SonarQube warning: Unable to get default branch, defaulting to 'master': TypeError: Cannot read property 'defaultBranch' of null

We use Azure DevOps and YAML pipelines to build and analyze our code.
This all works fine, except for the code that uses main instead of master as the default branch name. Then SonarQube emits a warning: Unable to get default branch, defaulting to 'master': TypeError: Cannot read property 'defaultBranch' of null
The warning is a false-positive. When I go to the SonarQube portal everything looks fine for the project and it even displays the default branch is main.

We have a 'no warnings' policy, so it is very sad SonarQube is emitting this warning, which should be in my opinion Information.

I think I need to instruct SonarQube not to look for the master branch or tell it to also look for the main branch. But I can't figure out how to do this. The documentation is not very helpful at this point.

This is my yaml task:

  - task: SonarQubePrepare@5
    displayName: Prepare analysis on SonarQube ($(SonarProjectKey))
    inputs:
      SonarQube: 'SonarQube - Developer Edition'
      projectKey: $(SonarProjectKey)
      projectName: '${{ parameters.AnalyseProjectName }}'
      projectVersion: '$(Build.BuildNumber)'
      extraProperties: |
        sonar.verbose=true
        sonar.branch.name=$(Build.SourceBranchName)
        sonar.branch.target=main
        sonar.cs.opencover.reportsPaths=**/coverage.opencover.xml
        sonar.cs.vscoveragexml.reportsPaths=$(Agent.BuildDirectory)\TestResults\*.coveragexml
        sonar.exclusions=**\Tests\**\*, **\TestApps\**\*, **\GlobalSuppressions.cs

If needed I can make changes to our build agents.

Please advise.

Solution

Following an extensive discussion with the SonarQube team, they have recently released a minor update to their Azure DevOps (AZDO) extension. I'm pleased to inform you that this new version has resolved the issue and no longer reports the warning.