$ git clone -n https://gitee.com/opencloudos-stream/R-knitr.git /var/lib/mock/dist-oc9-epol-build-109462-67426/root/chroot_tmpdir/scmroot/R-knitr
Cloning into '/var/lib/mock/dist-oc9-epol-build-109462-67426/root/chroot_tmpdir/scmroot/R-knitr'...
$ git fetch origin master:KOJI_FETCH_HEAD
From https://gitee.com/opencloudos-stream/R-knitr
 * [new branch]      master     -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 89f0e55 update