[prpl]

I think you’re going to find that, out there, somebody has already built this. I’ve built one, and worked on two others that somebody built. Usually they have names like workspace manager or repo manager or whatever. Most will probably have something to build a dag and code to do a topological sort for the recursive projects. The better ones will use the topological sort to pull repos and build in parallel.

In addition, other tools can also do this to varying degrees of success, like Bazel and cmake.