$ git clone -n https://github.com/xcp-ng-rpms/samba.git /var/lib/mock/v8.3-incoming-9366-28121/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-incoming-9366-28121/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin 862d2699f99100c6ac8910e083bb80fa98186ef7:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         862d2699f99100c6ac8910e083bb80fa98186ef7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 862d269 Merge pull request #3 from xcp-ng-rpms/8.3-XS-1586