multipass shell launching a VM is unexpected

[OddBloke]

I just typed multipass shell and accidentally hit Return before typing my instance name in, and was very surprised to see multipass launch a new VM. This was particularly confusing given that the short help says "Open a shell on a running instance" (emphasis mine, of course), so that's what I assumed it did.

Once I'd seen this happen, I looked at the full help text, and I think we also have some confusing wording there. Specifically, "If the instance is not running, an attempt is made to start it" is inaccurate, as multipass did not attempt to start it, it instead launched a completely new VM.

[Saviq]

This is the primary instance (see release notes for 0.7.0) feature. It's meant to be a shortcut to your default instance, which gets launched for you if you just issue a multipass shell.

We should probably improve the help text around it, and add a bit more feedback when first launching it.

[OddBloke]

On Tue, Oct 22, 2019 at 12:19:57AM -0700, Michał Sawicz wrote: This is the `primary` instance (see [release notes for 0.7.0](https://github.com/CanonicalLtd/multipass/releases/tag/v0.7.0)). It's meant to be a shortcut to your default instance, which gets launched for you if you just issue a `multipass shell`.

I'm unlikely to ever want a `primary` instance as an Ubuntu user (if there's something that I just want a pet Ubuntu instance for, I have my desktop; anything more specific and I'm going to want to choose the Ubuntu release I launch); is there any way I can configure multipass to disable this behaviour?

We should probably improve the help text around it, and add a bit more feedback when first launching it.

Yep, to be clear, I understand why this is the behaviour; it's knowing that this _is_ the behaviour that was missing. :)