Comment 2 for bug 1614010

> The change was brought in because `juju register` seems designed for a new user to connect and configure a client

I agree that that is how the register command was designed, but I think it's worth considering the situation that I encountered when the controller already exists. As controllers are long lived, this will inevitably happen to some users. Currently there's no way to transfer a new account to someone with an existing controller entry without having them delete the controller entry manually.

ISTM that this bug isn't "Invalid" but perhaps "Won't fix", as it is still an actual issue that can be encountered by users.

One other thing - the error should be better - it prompted for a new name for the controller, but it actually disallowed the new name because of the duplicate UUID. It would be better if it failed earlier because of the duplicate UUID without prompting for the new password.