git filter-branch not removing commits when it should in 2.7.0

This seems to be a 2.7.0 regression in filter-branch.  The bug is reproducible on Mac/Windows (haven't tried Linux) in the 2.7.0 production releases.

Make an empty repo and put an empty commit in the history.  E.g.,

echo > foo && git add . && git commit -m "commit 1" && git commit --allow-empty -m "commit 2"

Now try to use filter-branch to remove the empty commit.  Both of the following methods leave master unchanged, but both worked in 2.6.4:

git filter-branch --prune-empty
git filter-branch --commit-filter 'git_commit_non_empty_tree "$@"'

Let me know if you need any more information.  Thanks.

Sincerely,

John Fultz
jfultz@wolfram.com
User Interface Group
Wolfram Research, Inc.