Yes! That should be built straight into git. The abstraction leaks are no worse than with submodules (it's just making different trade-offs) but the usability

Yes! That should be built straight into git. The abstraction leaks are no worse than with submodules (it's just making different trade-offs) but the usability is so much more sane, it's not funny. The importance of having this in core-git can not be overstated. When it's not in core then it's not getting used. Case in point: count the number of projects on github using one of the external training wheels (subtree etc.). Submodules has proven inadequate for reality (again: count the number of subprojects on github). I wish one of the core-dev's would make a kickstarter for a solution...