--v1-base) how=base ;; # merge into tip from a base of this patch
--v1-dep) how=dep ;; # merge into base from a dep's tip
*) fail "bad usage" ;;
--v1-base) how=base ;; # merge into tip from a base of this patch
--v1-dep) how=dep ;; # merge into base from a dep's tip
*) fail "bad usage" ;;