Exactly that. They all do things so differently that you end up creating and maintaining a separate parser for every SCM's diff format, and sometimes doing a lot of normalization of content or modification to include information the format lacks that's needed to apply the patches. And those are just for the ones that actually have a diff format -- many don't.

We needed something for ourselves at the very least. Much of DiffX came from thinking about these pain points and from talking to other SCM vendors whose engineers have also given some thought to these problems.