$ git clone -n https://src.fedoraproject.org/rpms/ghc-cassava.git /var/lib/mock/f41-build-side-1-2672279-29195/root/chroot_tmpdir/scmroot/ghc-cassava
Cloning into '/var/lib/mock/f41-build-side-1-2672279-29195/root/chroot_tmpdir/scmroot/ghc-cassava'...
$ git fetch origin 857e414254ef0b74b85008734483793a0ef65627:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-cassava
 * [new ref]         857e414254ef0b74b85008734483793a0ef65627 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 857e414 https://hackage.haskell.org/package/cassava-0.5.3.1/changelog