Sure, but that's just a bug in an application introduced by accident, and fixed when they found out about it. That is going to happen no matter what. The same

Sure, but that's just a bug in an application introduced by accident, and fixed when they found out about it. That is going to happen no matter what. The same thing goes for libraries. That is the best part of this tool, since they control the library and all the clients they can automatically run their tests across everything. Which would help you catch more of these types of problems, but it will never be perfect. My point is that if a user of your library is failing after a change, you should treat that as a bug in the library. Backwards incompatible changes should only be on purpose, and only when absolutely necessary. Of course, it's only their own code they're affecting here, so it doesn't really matter as much as a library for users you don't know. Plus it is a pretty cool solution, I just don't think it should be necessary.