$ git clone -n https://gitee.com/src-opencloudos-rpms/firefox.git /var/lib/mock/dist-oc9-build-180497-80107/root/chroot_tmpdir/scmroot/firefox
Cloning into '/var/lib/mock/dist-oc9-build-180497-80107/root/chroot_tmpdir/scmroot/firefox'...
$ git fetch origin master:KOJI_FETCH_HEAD
From https://gitee.com/src-opencloudos-rpms/firefox
 * [new branch]      master     -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2e15f99 init git for firefox