$ git clone -n https://src.fedoraproject.org/rpms/rust-portable-atomic-util.git /var/lib/mock/f40-build-2251023-54102/root/chroot_tmpdir/scmroot/rust-portable-atomic-util
Cloning into '/var/lib/mock/f40-build-2251023-54102/root/chroot_tmpdir/scmroot/rust-portable-atomic-util'...
$ git fetch origin ebea34f2393db9bf17a0f86ad782f31272ee5ef8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-portable-atomic-util
 * [new ref]         ebea34f2393db9bf17a0f86ad782f31272ee5ef8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ebea34f Update to version 0.1.5; Fixes RHBZ#2254842