$ git clone -n https://src.fedoraproject.org/rpms/ghc-ObjectName.git /var/lib/mock/f45-build-9925-411/root/chroot_tmpdir/scmroot/ghc-ObjectName
Cloning into '/var/lib/mock/f45-build-9925-411/root/chroot_tmpdir/scmroot/ghc-ObjectName'...
$ git fetch origin 59df299dbd52638361993ba94000b5fd6eccd094:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-ObjectName
 * [new ref]         59df299dbd52638361993ba94000b5fd6eccd094 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 59df299 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild