How does git store branchpoints?

Following up this:

http://groups.google.com/group/git-version-control/browse_thread/thread/aa34d04120d0c361#

I'm trying to learn/examine the .git directory to see what Git thinks.

What I'm trying to determine is how Git knows the parent of a particular commit, how I can change it, and how that affects merging.

My problem is that I have two branches, and a merge between the two produces conflicts in files that are unchanged on one branch. Since my branches are linked to SVN branches, I'm thinking that Git is not properly clear on their shared history.

Any ideas where to look?

.git/info/refs has some strange data in it:

5a3e01a8327c6139e9311b01548baf4a8876b5e3 refs/heads/local-FOO 71560b15ad6a2a7542556dfdf2d6c763625d5db4 refs/heads/local-trunk efb2ff2ac363600a2aaae60718bc76b6c3db4228 refs/remotes/FOO

The SHA-1 for refs/heads/local-FOO (branch created via git checkout -b local-FOO FOO) doesn't show in gitk --all, but a git log of that shows it to be a somewhat old commit (not the head, nor the branch point).

The SHA-1 for local-trunk is a similarly old commit

The SHA-1 for refs/remotes/FOO is the commit right before the SHA-1 for refs/heads/local-FOO in my git log.