$ git clone -n https://src.fedoraproject.org/rpms/rust-bumpalo.git /var/lib/mock/f45-build-40550-773/root/chroot_tmpdir/scmroot/rust-bumpalo
Cloning into '/var/lib/mock/f45-build-40550-773/root/chroot_tmpdir/scmroot/rust-bumpalo'...
$ git fetch origin 8253d0df2248595e4555ca0609faefa41bdf0117:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bumpalo
 * [new ref]         8253d0df2248595e4555ca0609faefa41bdf0117 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8253d0d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild