[filoeleven]

He’s been thinking some really interesting thoughts about dependency management and libraries. It sounds like if he had his way, library versions might disappear entirely.

From the interview: “But there are really two very distinct kinds of change - there are breaking changes, where your expectations have been violated, and there are accretions, where there's just some more stuff where there wasn't stuff before. And in general, accretion is not breaking.”

To paraphrase stuff I’ve heard him talk about elsewhere, your library should never change a function to require more input or provide less output. If you decide to do that, call it something else and keep the old function around. He’s talked about function-level versioning too, touches on it here a bit. If I use library functions x y and z and the maintainers only broke (the contract for) functions a b and c, then I probably don’t care and can grab the latest version for its other new goodies. But that decision still requires me to read the library source or at least a changelog, even though it’s simple enough for the right tool to be able to report it to me. Spec looks like a step in that direction.