[bazfoo]

> You know, I wonder if there's something here that a next-generation language can't get in on, some sort of help to provide to the developer who says "OK, I'd like to upgrade this package for people, could you please help me ensure that I'm not going to break anybody in the process?"

Russ has proposed a "go release" command that is intended to help with that process. It's probably simple right now, but has lots of room to grow in that direction.

See: https://research.swtch.com/vgo-cmd