On our master branch we have a pipeline that we want to test each commit, but because of external resources used as part of the integration test suite we can only run one job at a time. This means we have to have a merge master who is only merging one job, waiting for it to finish and then merging another job. It would be great to be able to set the parallelism allowed on that branch to 1 WITHOUT having to turn off Kill Redundant Builds, which we want on PR branches.

Similarly, we have branches for deployment to various environments based on merge to a branch. Killing a redundant build there can screw up the deployment, so a release manager has to merge to that branch and then wait for it to finish. As a last step on that job we push a commit to the release branch with the version, which triggers a new build, which creates a race condition for killing the redundant build. We are happy to have it spin up another job and we can cancel that build based on the author of the commit, but not being able to limit parallelism and prevent killing redundant means we cannot push the version commit when we make it we have to do it as the VERY last step and hope the deploy job doesn't get killed by redundant.