$ git clone -n https://src.fedoraproject.org/rpms/scotch.git /var/lib/mock/f42-build-864847-172603/root/chroot_tmpdir/scmroot/scotch
Cloning into '/var/lib/mock/f42-build-864847-172603/root/chroot_tmpdir/scmroot/scotch'...
$ git fetch origin ffa139a24c095553dc1b7b8b5584883d474f6d28:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/scotch
 * [new ref]         ffa139a24c095553dc1b7b8b5584883d474f6d28 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ffa139a Update %files