$ git clone -n https://src.fedoraproject.org/rpms/rust-diesel.git /var/lib/mock/f40-build-2268530-54745/root/chroot_tmpdir/scmroot/rust-diesel
Cloning into '/var/lib/mock/f40-build-2268530-54745/root/chroot_tmpdir/scmroot/rust-diesel'...
$ git fetch origin f648b59aa87ea910ef11cafc04676b822d2c4a7b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-diesel
 * [new ref]         f648b59aa87ea910ef11cafc04676b822d2c4a7b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f648b59 Update to version 2.1.4; Fixes RHBZ#2249652