Re: [BUG?] git checkout $commit -- somedir doesn't drop files

Jeff King [off-list ref] writes:

     But I think that points to a larger problem, which is that we do
     not want to just look at the entries that are different between the
     tree and the index.

True.  The unpack-trees API knows how to walk the index and trees in
parallel, and I tend to agree that it may be a more suitable vehicle
for this purpose.