Basically, if you want to manage a large collection of git source repositories, you'll probably end up using Repo and Gerrit and piggybacking on the work of the android ecosystem (and beyond, gerrit is used all over the place now)
There really isn't another solution out there right now (at least not anything open source) for very large single repositories.
> There really isn't another solution out there right now
What about Git submodules? They do fundamentally the same thing as Repo, but it's a built-in Git feature and not a bunch of scripts.
Repo can make your life very hard and you have to be a black belt Git ninja to understand what's going on when things don't go as you intended. Git submodules don't depend on having arbitrary GUID strings in your commit messages either (like Repo's Change-Id).
GitHub's reviews can handle Git submodules (but it's not free or open source). If someone knows any open source code review tools that can handle, please tell us.
Sorry for beating a dead horse, but I really want to save someone from fucking up (or at least re-centralizing) their workflow with repo scripts, when native git is better.
There really isn't another solution out there right now (at least not anything open source) for very large single repositories.