Serious bug with pretty format strings & empty bodies?

I'm struggling to come up with a minimal test case that confirms this, but I seem to be hitting a bug in the pretty string formatter when trying to print bodies of commits that don't have bodies.

For example, on a private repository, I'm trying to print the subject & body of a commit. This particular commit doesn't actually have a body, so I'm expecting to see this output :

================= commit 18d2480ab689b483ef1ebbdb3f7420904049ba0b Try to flush log files before terminating the app

=================

However, when I actually run the command, I get gibberish in place of %b : ================= $ git rev-list -1- --pretty=format:"%s%n%b" 18d2480ab689b483ef1ebbdb3f7420904049ba0b commit 18d2480ab689b483ef1ebbdb3f7420904049ba0b Try to flush log files before terminating the app tree 57bc7cf30a10aee96251852125cf30fd2c81d7aa parent 04c833865828538315fcdf6e187da077869ce444 author Jonathan del Strother <jon.delStrother@bestbefore.tv> 1197901755 +0000 committer Jonathan del Strother <jon.delStrother@bestbefore.tv> 1197901755 +0000

Check that ThreadWorker's work method actually returns a value with method signatures =================

So here you can see that the full details of a different commit is appearing in place of the requested commit's (empty) body. Rerunning the rev-list produces the same output - the same string appears in place of %b every time, but it's different for each commit. Often you only get a small fragment of another commit's message, rather than the full commit as seen above.

When I use --pretty=full, it works fine.

This appears in quite a few places in my repository's history. Repacking the repo semi-fixes it - I still get junk bodies, but not quite so many.

It doesn't always happen when a commit message body is empty, but I've never seen it happen where the message body has something in.

This happens with both git 1.5.3.7 and 1.5.4.rc0.1162.g3bfea, though the output is slightly different - the former has a number of <unknown> markers in it. This is on OS X 10.5.1

Any suggestions? Cheers, Jon