Thanks @clevi,
I see, so currently the most sane option has two elements:
- Ensure the working tree is the HEAD of the PR, with
uses: actions/checkout@v2 with: ref: ${{ github.event.pull_request.head.sha }}
- Ensure the decoration will target the HEAD of the PR, with
-Dsonar.scm.revision=${{ github.event.pull_request.head.sha }}
Thanks for the clarification!