> but it feels a bit contrived to me ('missing fields are ok'?) IIUC, the idea is that an object can be safely deserialized if its field set upon deserializati

> but it feels a bit contrived to me ('missing fields are ok'?) IIUC, the idea is that an object can be safely deserialized if its field set upon deserialization is a strict subset of its field set upon serialization. I think that's a sound approach, it's in line with (the second part of) the robustness principle: "be liberal in what you accept".