let create
?id ?name ?metadata
?(depends_on=[]) ?(on_failure_activate=[]) ?(on_success_activate=[])
?(make=Build_process.nop)
?condition ?(equivalence=`Same_active_condition) ?(tags=[])
() =
let history = `Passive (State.make_log ()) in
let id = Option.value id ~default:(Unique_id.create ()) in
{ id; name = Option.value name ~default:id; metadata; tags;
log = []; depends_on; make; condition; history; equivalence;
on_failure_activate; on_success_activate; }