$ git clone -n https://src.fedoraproject.org/rpms/rust-portable-atomic.git /var/lib/mock/f42-build-side-1-3582471-46885/root/chroot_tmpdir/scmroot/rust-portable-atomic
Cloning into '/var/lib/mock/f42-build-side-1-3582471-46885/root/chroot_tmpdir/scmroot/rust-portable-atomic'...
$ git fetch origin d7695eab64173c98b1de7a6543a8304184398ae0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-portable-atomic
 * [new ref]         d7695eab64173c98b1de7a6543a8304184398ae0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d7695ea Update to version 1.11.1; Fixes RHBZ#2370607