$ git clone -n https://src.fedoraproject.org/rpms/rubygem-process_executer.git /var/lib/mock/f42-build-3427156-45202/root/chroot_tmpdir/scmroot/rubygem-process_executer
Cloning into '/var/lib/mock/f42-build-3427156-45202/root/chroot_tmpdir/scmroot/rubygem-process_executer'...
$ git fetch origin 273a793a8fcd2c104ec022f31531943dc8257b3b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-process_executer
 * [new ref]         273a793a8fcd2c104ec022f31531943dc8257b3b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 273a793 Update to 1.2.0