$ git clone -n https://gitee.com/mgb01105731/yarnpkg.git /var/lib/mock/dist-an23-build-336452-69689/root/chroot_tmpdir/scmroot/yarnpkg
Cloning into '/var/lib/mock/dist-an23-build-336452-69689/root/chroot_tmpdir/scmroot/yarnpkg'...
$ git fetch origin a23:KOJI_FETCH_HEAD
From https://gitee.com/mgb01105731/yarnpkg
 * [new branch]      a23        -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7c19cea rebuild