$ git clone -n https://src.fedoraproject.org/rpms/waf.git /var/lib/mock/f42-bootstrap-3462997-45594/root/chroot_tmpdir/scmroot/waf
Cloning into '/var/lib/mock/f42-bootstrap-3462997-45594/root/chroot_tmpdir/scmroot/waf'...
$ git fetch origin b8d4f5d75e3ef5df84574f23565abfa33544e287:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/waf
 * [new ref]         b8d4f5d75e3ef5df84574f23565abfa33544e287 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b8d4f5d Update to 2.1.5.