[FridgeSeal]

> Nothing is preventing a system from sending you a un-deserializable message disguised as a protobuf,

I guess it depends on where you come down on Postel’s law. If you’re an adherent, and are prepared to be flexible in what you accept, then yeah, you will have extra work on your hands.

Personally, I’m not a fan of Postels law, and I’m camp “send correct data, that deserializes and upholds invariants, or get your request rejected”. I’ve played enough games with systems that weren’t strict enough about their boundaries and it’s just not worth the pain.

[withinboredom]

When you have hundreds of millions of clients, there’s a good chance the client thinks it’s sending you the right data (especially when the customer says everything looks right on their end). You need to figure out if there is packet corruption (misbehaving switch), an outdated client, an egress load balancer screwing with packet contents, an office proxy trying to be smart, etc.

This requires looking at what is going over the wire in a lot of cases. It has nothing to do with Postel’s Law, but more to telling a customer what is wrong and making your own software more resilient in the face of the world.