[BUG?] git log picks up bad commit

Hi, I think I either found a bug in git log, or I'm working with a broken repository. I can reproduce this with current git master.

I'm trying to list the last n commits since a given commit on a given
branch like this:
  git log -n N commit.. branch
The problem is, if there are less than N commits that match the
criteria, git log also prints the very first commit of the repository.

I'm operating on a bare repository here. When I actually check out the branch I'm interested in, git log behaves as expected.

I've uploaded the .git directory to http://crux.nu/~tilman/broken_repo.tar.bz2 (use -C to extract!)

Reproduce like this: mkdir /tmp/blah cd /tmp/blah tar xjf broken_repo.tar.bz2

git log -n 3 --abbrev-commit --pretty=oneline \ 1dd567d596b072e3ce44ea5ad8c373871686b078.. 2.4

The output I'm getting is:

47f585a... syslinux: Updated 3.54 -> 3.60 b3444e1... lzma: 4.32.4 -> 4.32.5 d5d6fa1... Created repository

When I check out the "2.4" branch and run the git log command again, I get the expected output:

47f585a... syslinux: Updated 3.54 -> 3.60 b3444e1... lzma: 4.32.4 -> 4.32.5

Any idea on what's going on there?

Thanks, Tilman