$ git clone -n https://src.fedoraproject.org/rpms/rust-diesel_derives.git /var/lib/mock/f40-build-1956622-25197/root/chroot_tmpdir/scmroot/rust-diesel_derives
Cloning into '/var/lib/mock/f40-build-1956622-25197/root/chroot_tmpdir/scmroot/rust-diesel_derives'...
$ git fetch origin d64d5cc5e3b51df51bec079c1c8928e6c3a9ae9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-diesel_derives
 * [new ref]         d64d5cc5e3b51df51bec079c1c8928e6c3a9ae9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d64d5cc Update to version 2.2.1; Fixes RHBZ#2284104