$ git clone -n https://src.fedoraproject.org/rpms/ghc-gitrev.git /var/lib/mock/f45-build-10342-415/root/chroot_tmpdir/scmroot/ghc-gitrev
Cloning into '/var/lib/mock/f45-build-10342-415/root/chroot_tmpdir/scmroot/ghc-gitrev'...
$ git fetch origin d422212b203635e2d8efe7267d4bbea7f9ffefc6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-gitrev
 * [new ref]         d422212b203635e2d8efe7267d4bbea7f9ffefc6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d422212 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild