$ git clone -n https://src.fedoraproject.org/rpms/ghc.git /var/lib/mock/f41-build-side-1-2805245-32863/root/chroot_tmpdir/scmroot/ghc
Cloning into '/var/lib/mock/f41-build-side-1-2805245-32863/root/chroot_tmpdir/scmroot/ghc'...
$ git fetch origin 1769aa3942571452aa4bacad49750b585465607c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc
 * [new ref]         1769aa3942571452aa4bacad49750b585465607c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1769aa3 remove directory.buildinfo