Well, approval is a different beast from passing tests. But also, that's not how I was imagining this. I was imagining maintaining separate branches on top of each release, only combining them (merge or rebase or whatever) when you have a good reason to. That keeps things independent and makes it so you can always cut a release with solely the critical fixes (and test them in isolation, etc.) whenever needed, letting you integrate the noncritical ones opportunistically.