[naive wish mode]

I'm really fond of how Google does versioning in their internal codebase (from the public information about it that I know). They have a monorepo containing a single version of every library. When updating something, you're supposed to take into account all the places it's being used, and avoid breakages. Tests and tooling play an important role in making it possible.

I really want something like that for the open-source world, instead of having to deal with maintaining multiple versions, and dealing with the complexity of interactions between the all the permutations of different versions.

[/naive wish mode]