I'm sure there was a task for this somewhere, but searching for related terms didn't help.
Anyway, right now I have a build plan that runs on every commit for a certain repository I have. This build plan not only builds the code, but on success, pushes out the new version to other repositories (which use the tool). I have "Wait for Previous Commits" build step in there to ensure things happen in the right order.
However, this means I can only ever have "master" as a branch in that repository; if I was to push to another branch, it would build and publish the commits on that branch. What I really want to do is build all commits, but only publish the HEAD of master. Unfortunately right now Harbormaster doesn't have any conditional logic for steps (you can only really do conditional logic as part of the Run Command in the command line), and there's no way to tell Harbormaster to run a build plan in response to a branch push (even on the push hooks).
There's also no way of saying in Herald "this commit is a descendant of this specific branch", but that rule doesn't make a lot of sense anyway because that won't get refired when the same commit is pushed to a different branch (because it's already been imported).
This issue actively discourages developers (me in this particular case) from pushing their changes to a branch where people can review them. Because this project is on GitHub, Differential is not a good fit for getting people to review or download experimental or unverified versions of the software.