$ git clone -n https://src.fedoraproject.org/rpms/rust-socketpair.git /var/lib/mock/f42-build-side-1-3586319-46915/root/chroot_tmpdir/scmroot/rust-socketpair
Cloning into '/var/lib/mock/f42-build-side-1-3586319-46915/root/chroot_tmpdir/scmroot/rust-socketpair'...
$ git fetch origin 84079caa60e5acbaed4a41efe8881f4b1769ca98:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-socketpair
 * [new ref]         84079caa60e5acbaed4a41efe8881f4b1769ca98 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 84079ca Update to version 0.19.8; Fixes RHBZ#2366628