$ git clone -n https://src.fedoraproject.org/rpms/petsc.git /var/lib/mock/f42-build-3357694-45030/root/chroot_tmpdir/scmroot/petsc
Cloning into '/var/lib/mock/f42-build-3357694-45030/root/chroot_tmpdir/scmroot/petsc'...
$ git fetch origin 8713cb873648a03fffceaee193c1d39c9059a158:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/petsc
 * [new ref]         8713cb873648a03fffceaee193c1d39c9059a158 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
Updating files:  50% (6/12)
Updating files:  58% (7/12)
Updating files:  66% (8/12)
Updating files:  75% (9/12)
Updating files:  83% (10/12)
Updating files:  91% (11/12)
Updating files: 100% (12/12)
Updating files: 100% (12/12), done.
HEAD is now at 8713cb8 Rebuild for scalapack SONAME change.