pre-receive - 1st push

Hi I want ensure that commits are in particular format before doing
receive-pack. I use pre-receive hook

I use git-revlist command. This works fine when that branch exist in
destination origin.

When I am doing a push 1st ever time and sending clone is sending 3
commits; how do i determine which are those 3 commits on the specific
branch.

git rev-list <commit> gives just too many commits ; I have done only 3
commits on source repository. destination repo don't have that branch
yet so no use of git-show-branch)


Thx/ Mahesh