launchpad-login should set whoami if not already set

[Andrew Bennetts]

This came up after diagnosing bzr-gtk bug 656641 with the reporter on IRC. A factor in that bug is having no whoami set:

13:47 < spiv> Ok, got it.
13:47 < spiv> Run 'bzr whoami' in the terminal
13:48 < spiv> You haven't told bzr who you are, so it can't commit because it has no committer name to record in the commit.
13:48 < vadi2> I did do launchpad-login!

This seems to me to be a perfectly reasonable expectation: launchpad-login tells bzr who you are. Why would a user think to do that twice?

So I propose that 'bzr launchpad-login' should:

 * retrieve the user's display name and email addresss from Launchpad
 * compare them to the 'bzr whoami' details already set. Either:
    1. none are set, so automatically set them now using the name and primary email from LP (and inform the user that we have done so), or
    2. the details are set, and match the name and a email address in Launchpad, so do nothing, or
    3. the details are set, but do not match the Launchpad details. Change nothing, but warn the user that the details don't match.

Aside from reducing the steps a user needs to take, this would also help ensure users' commits will be attributed to them in Launchpad.

[Martin Pool (mbp)]

I agree those commands are a bit redundant and ought to be unified or
better related. That story doesn't seem like the cleanest solution.
Perhaps we can look more when someone's going to work on this.
--
Martin