$ git clone -n https://src.fedoraproject.org/rpms/rust-proc-macro-hack.git /var/lib/mock/f45-build-44029-809/root/chroot_tmpdir/scmroot/rust-proc-macro-hack
Cloning into '/var/lib/mock/f45-build-44029-809/root/chroot_tmpdir/scmroot/rust-proc-macro-hack'...
$ git fetch origin 969d02215c9224eb9ad152ec36e8793ab8ad1a26:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-proc-macro-hack
 * [new ref]         969d02215c9224eb9ad152ec36e8793ab8ad1a26 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 969d022 Regenerate with rust2rpm v28