Re: Allow "git shortlog" to group by committer information

On Tue, Oct 11, 2016 at 11:45:58AM -0700, Linus Torvalds wrote:

In some situations you may want to group the commits not by author,
but by committer instead.

For example, when I just wanted to look up what I'm still missing from
linux-next in the current merge window, I don't care so much about who
wrote a patch, as what git tree it came from, which generally boils
down to "who committed it".

So make git shortlog take a "-c" or "--committer" option to switch
grouping to that.

I made a very similar patch as part of a larger series:

  http://public-inbox.org/git/20151229073515.GK8842@sigill.intra.peff.net/

but never followed through with it because it wasn't clear that grouping
by anything besides author was actually useful to anybody.

My implementation is a little more complicated because it's also setting
things up for grouping by trailers (so you can group by "signed-off-by",
for example). I don't know if that's useful to your or not.

I'm fine with this less invasive version, but a few suggestions:

 - do you want to call it --group-by=committer (with --group-by=author
   as the default), which could later extend naturally to other forms of
   grouping?

 - you might want to steal the tests and documentation from my patch
   (though obviously they would need tweaked to match your interface)

-Peff