[brokentone]

This is something I've been working on a bit myself.

Figuring out which files change is relatively easy (as you've demonstrated). Figuring out what the impact of that is quite hard in non-compiled languages (tools like Maven, Buck, Bazel, etc do this well for compiled languages). I.e. In a repo which is primarily JavaScript, I can get the list of changed files, and hopefully have unit test files which are obviously linear to those. However, knowing if these are depended on by other files/modules (at some depth) is much harder. Same for integration tests -- which of these are related?

[Rapzid]

I believe the typical approach is to have project.yml list its dependency projects. Build a DAG(error on cycles) and then build all changed and downstream projects.