BUG: git subtree split gets confused on removed and readded directory

Hi,

I made a simple test repository showing the problem here: https://github.com/lambdafu/git-subtree-split-test

After creating the master branch, I created the split/bar branch like this:

$ git subtree split -P bar -b split/bar

The resulting history is confused by the directory "bar" which was added, removed and then re-added again. The recent history up to adding the directory the second time is fine. But then it seems to loose track and add the parent of that commit up to the initial commit in the history.

I'd expect that the parent of the readding commit is an empty tree commit (which removed the last files in the directory), and that before that are commits that reflect the initial creation of that directory with its files, but rewritten as a subtree, of course.

Thanks! Marcus