quoted

I don't even think we need to query the user to fill out all of the
fields.  We can prepopulate a lot of the fields (name, e-mail address,
etc.) from OS specific defaults that are available on most systems ---
specifically, the default values we would use the name and e-mail
address are not specified in a config file.

Please don't. Or you end up again with Commiters like sb@localhost,
sbeller@(None) or alike. I mean it's just one question once you setup
a new computer, so I'd really like to see that question and then
answer myself (at university/employer I might put in another email
address than at home anyway, and I'm sure my boxes have no sane
defaults)

Yes, try to guess a good default but let the user change it if he
wants to, and if he presses enter the default is used. It's not a big
deal to have to press enter a few times the first time you use git.

That or make a new "git setup" command which interactively sets up
your .gitconfig.

Philippe