cd victim &&
git-config receive.denyNonFastforwards true &&
cd .. &&
- git-update-ref refs/heads/master master^ &&
- git-send-pack --force ./victim/.git/ master &&
+ git-update-ref refs/heads/master master^ || return 1
+ git-send-pack --force ./victim/.git/ master && return 1
! git diff .git/refs/heads/master victim/.git/refs/heads/master
'