$ git clone -n https://src.fedoraproject.org/rpms/ghc-double-conversion.git /var/lib/mock/f39-build-1507055-35222/root/chroot_tmpdir/scmroot/ghc-double-conversion
Cloning into '/var/lib/mock/f39-build-1507055-35222/root/chroot_tmpdir/scmroot/ghc-double-conversion'...
$ git fetch origin 7995f67c61188a2d134da7010711cd97d1491252:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-double-conversion
 * [new ref]         7995f67c61188a2d134da7010711cd97d1491252 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7995f67 bump release