$ git clone -n https://github.com/xcp-ng-rpms/samba /var/lib/mock/v8.3-incoming-10694-29242/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-incoming-10694-29242/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin 763042682bd2fafc7ba9a31647131248fb3b840e:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         763042682bd2fafc7ba9a31647131248fb3b840e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7630426 Merge pull request #4 from xcp-ng-rpms/pcoval/review/master