The ClearCase SCM does something similar - it has the notion of "derived objects" and "audited builds". You can run an audited build command under a special Cl

The ClearCase SCM does something similar - it has the notion of "derived objects" and "audited builds". You can run an audited build command under a special ClearCase wrapper and it will look at the versions of the elements used in the build - if that build has already occurred with the same input elements before, even if in a different view, it can "wink in" the derived object result - that is, it can cause that previous build to be visible in your current view. This can save a lot of time when you're building a large codebase.