Re: Honor extractor's umask in git-tar-tree.

"H. Peter Anvin" [off-list ref] writes:

My point is that I believe it should.  It has the bitfield for it, it 
just doesn't use it at the moment.

It is a bit more complicated than that.

Long time ago, we used to store the full permission bits and
ended up storing files in 0644 and 0664 modes, depending on who
is writing the tree object.  People with umask 022 checked out
from a tree that recorded blobs with 0664 bits and ended up
getting "mode changed" diff all the time, which was unacceptable
from the SCM point of view.  We _could_ have really changed the
mode bits representation in the tree objects back then to have
type + executable bit, but to preserve backward compatibility,
we chose to keep the bitfield layout and changed the code to
treat 1006xx and 1007yy in older trees to be equivalent to
100644 and 100755.  These days, for newly written tree objects,
above xx and yy 6-bit fields are "Must Be 4" and "Must Be 5"
fields, respectively, not bitfields to store arbitrary group and
other permission information.  git-fsck-objects even complains
about them.

So in that sense, it does _not_ have the bitfield for it, and
obviously we cannot use what we do not have.