Gatekeeper automatically merges master to a branch before kicking off the build. But if someone makes a commit on master before the Gatekeeper build finishes, Gatekeeper will be unable to push at the end. This is already filed as BAM-11007 and BAM-12146.

Those bugs propose serializing Gatekeeper builds, so no two builds may run simultaneously. But that's not good enough if people are allowed to push commits to master directly, as they are at our company.

Instead, we'd like for Gatekeeper to automatically do a second merge after the build is done, and push that. The resulting pushed branch wouldn't be guaranteed to build safely, but we're willing to take that risk if it allows us to run concurrent Gatekeeper builds. (We only wanted Gatekeeper to protect against blatant build breakages, not to protect against merge conflicts per se.)