What if generating a diff is nontrivial? Say you rename an identifier. That might be a single command in an IDE. A sufficiently high-level "diff" format could e

What if generating a diff is nontrivial? Say you rename an identifier. That might be a single command in an IDE. A sufficiently high-level "diff" format could easily capture that intent. But working backwards from hundreds of touched lines across many files to deduce that single semantic edit is not trivial. Git assumes that arbitrary diffs can be deduced from "before" and "after" files, but this isn't the case - it may be that you'd rather generate the new file from the diff!