You ideally need a directed graph where descendants can have multiple parents (which JJ supports). If you can't, then the linear tree is just as good I think.

You ideally need a directed graph where descendants can have multiple parents (which JJ supports). If you can't, then the linear tree is just as good I think. Say you do change A, add a protocol buffer API definition, then implement the server logic (B) and the front end code (C) so that both depend on A but not each other. That can be in a tree. But now you want to add an integration test (D) that depends on B and C. The tree doesn't help you there, and you were better off making it a linear chain by arbitrarily picking one of B or C to be dependant on the other so that you have a code state with all of A,B and C applied to create D on top of.