$ git clone -n https://src.fedoraproject.org/rpms/rust-just.git /var/lib/mock/f42-build-side-1-3587783-46935/root/chroot_tmpdir/scmroot/rust-just
Cloning into '/var/lib/mock/f42-build-side-1-3587783-46935/root/chroot_tmpdir/scmroot/rust-just'...
$ git fetch origin 56bbbba75ad59b8314eb9f30ef6e42cd21d56e5c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-just
 * [new ref]         56bbbba75ad59b8314eb9f30ef6e42cd21d56e5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 56bbbba Relax 'which' dev-dependency from 7.0.0 to >=7,<9