▲ 9 ▼ We need to add package versioning to Go by @rsc

We need to add package versioning to Go. More precisely, we need to add the concept of package versions to the working vocabulary of both Go developers and our tools, so that they can all be precise when talking to each other about exactly which program should be built, run, or analyzed. The go command needs to be able to tell developers exactly which versions of which packages are in a particular build, and vice versa.