$ git clone -n https://src.fedoraproject.org/rpms/rust-portable-atomic.git /var/lib/mock/f39-build-1853963-42380/root/chroot_tmpdir/scmroot/rust-portable-atomic
Cloning into '/var/lib/mock/f39-build-1853963-42380/root/chroot_tmpdir/scmroot/rust-portable-atomic'...
$ git fetch origin f88f80c2f3d73a5c744fd6a05ab718a1cc4fb309:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-portable-atomic
 * [new ref]         f88f80c2f3d73a5c744fd6a05ab718a1cc4fb309 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f88f80c Update to version 1.5.1; Fixes RHBZ#2246855