if user.email & user.name are not set, some of the git commands that devtool upgrade runs result in erroneous behaviour. we should probably check these settings when running an upgrade. I'm not sure if any of the other devtool features need this to be set as well.
I sent out a patch for this but it wasn't merged - reason being it breaks oe-selftest on the autobuilder where git isn't configured. I'm not entirely sure what to do about this - the autobuilder shouldn't need git configured, but we don't want oe-selftest to be messing with the user's git configuration either. Still thinking about it.
The autobuilder configurations were fixed to have these values set, and thus the patch got merged to master: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=6426136655cb00996c1870e2075a57716bfba846