git rebase failing when using ZFS partition on Mac OS X

[Alex Blewitt <alex.blewitt@gmail.com>]

I've found out why git rebase wasn't working for me. It appears to be  
something to do with the fact that the filesystem is running on ZFS  
(and frankly, could well be a ZFS bug). I'd be loathe to move away  
from ZFS generally but it would be good to find out why it's  
complaining.

apple:egit alex$ git status
# On branch master
# Your branch is ahead of 'origin/master' by 3 commits.
#
nothing to commit (working directory clean)
apple:egit alex$ git rebase -i HEAD~1
Working tree is dirty

Here's what running a stat on TODO (an arbitrary file at the head of  
the project) gives on a ZFS mounted file:

apple:egit alex$ stat -r TODO
754974724 135333 0100644 1 1000 100 0 2179 1241639236 1241034917  
1241639236 1241034917 2560 5 0 TODO
apple:egit alex$ stat TODO
754974724 135333 -rw-r--r-- 1 alex bandlem 0 2179 "May  6 20:47:16  
2009" "Apr 29 20:55:17 2009" "May  6 20:47:16 2009" "Apr 29 20:55:17  
2009" 2560 5 0 TODO

Here's what running a stat on the same file on an HFS partition gives:

apple:egit alex$ stat -r TODO
234881026 930759 0100644 1 1000 0 0 2179 1241643695 1241034917  
1241643690 1241034917 4096 8 0 TODO
apple:egit alex$ stat TODO
234881026 930759 -rw-r--r-- 1 alex wheel 0 2179 "May  6 22:01:35 2009"  
"Apr 29 20:55:17 2009" "May  6 22:01:30 2009" "Apr 29 20:55:17 2009"  
4096 8 0 TODO

These are repeatable; if I re-run this periodically, it doesn't seem  
to change. However, I wonder if there's any dependency on an 'inode'  
or similar, which doesn't really have a comparable concept in ZFS.

Is there any more information that I can provide to assist with  
finding out what's going on?

Alex