Tony Lindgren wrote:
> Anybody have any better ideas for locking that also works with
> rsync?

Since this seems to be Push Day on the git list, here's my feeble 
attempt at the same thing (attached cg-push script).

I do stuff in this order:

     1. read remote HEAD
     2. check that a merge from local HEAD to remote would be
        fast-forward, otherwise tell people to pull and merge.
     3. push objects using --ignore-existing (or equivalent)
     4. write lock file with --ignore-existing. The lock file
        contains, in particular, the HEAD to be written.
     5. read remote HEAD (again) and the lock file. Bail if HEAD
        changed since the first read, or if the lock file isn't
        the one we attempted to write.
     6. write remote HEAD and delete lock file in using rsync's
        --delete-after

This should always be safe, since rsync (as I understand the man page) 
always writes to temp files, and then renames into place. Checking for 
fast-forward-mergability assures that other peoples changes don't get lost.

cg-push determines uri and foreign branch name using the same rules as 
cg-pull, which is real nice as it allows you to do:

$ cg-clone me@myserver.example.com:git-repos/myrepo.git mystuff
$ cd mystuff
# write some stuff
$ cg-commit
$ cg-push

and later

$ cg-update
# write more stuff
$ cg-commit
$ cg-push

and even later

$ cg-branch-add pub me@myserver.example.com:public-repos/myrepo.git
$ cg-push pub

So, you can work pretty much exactly as you would do in CVS or svn, if 
you're so inclined, safely sharing a common repository among many users.

Which is kinda neat, if I may say so myself...

/dan