$ git clone -n https://gitee.com/uestc-cheng/libxml2.git /var/lib/mock/dist-an8.8-build-299224-65890/root/chroot_tmpdir/scmroot/libxml2
Cloning into '/var/lib/mock/dist-an8.8-build-299224-65890/root/chroot_tmpdir/scmroot/libxml2'...
$ git fetch origin 173086bbed5b680ecb9fa0e4963f2b8d390f32a0:KOJI_FETCH_HEAD
From https://gitee.com/uestc-cheng/libxml2
 * [new ref]         173086bbed5b680ecb9fa0e4963f2b8d390f32a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 173086b update libxml2.spec.