Re: [PATCH 3/4] filter-branch: fix --prune-empty on parentless commits

"Devin J. Pohly" [off-list ref] writes:

I think your point is interesting too, though.  If a commit is also
TREESAME to its parent(s?) in the _pre-filtered_ branch, it seems
reasonable that someone might want to leave it in the filtered branch as
an empty commit while pruning empt*ied* commits.  I would imagine that
as another option (--prune-newly-empty?).

I was hoping to hear from others who may care about filter-branch to
comment on this topic to help me decide, but I haven't heard
anything, so here is my tentative thinking.

I am leaning to:

 * Take your series as-is, which would mean --prune-empty will
   change the behaviour to unconditionally lose the empty root.

 * Then, people who care deeply about it can add a new option that
   prunes commits that become empty while keeping the originally
   empty ones.

Thoughts?