[thechriswalker]

That's not entirely true. Go allows you to tag with the Go version you are aiming for and imports will use that. You do not have to keep your master clean. If you clone explicitly into your GOPATH then you can develop on any branch you like. Similarly, if you use git for version control and so does your library then you can always submodule your dep into your GOPATH and submodules allow you to specific the exact commit you wish to use.

[cmccabe]

Yes, you do have to keep your master clean. The version tagging thing is only intended to be used when you start depending on a new language feature not available in older versions of Go. For example, if your new code needs something that's only in Go 1.1, you could create a 1.0 tag right before making that change. But people using new versions of Go will get whatever is in master, not whatever is at that tag.

Yes, you can always clone explicitly into a path, but then we're not talking about the module system any more, are we? We're just talking about you copying around files locally. It's misleading to state this like it's the recommended or usual way to do things.