Option to check for no undeclared fields

[maximvl]

Hello, as I understand currently Pact only checks for fields declared in the contract and allows any number of other fields. I would like to have an option to do a 'strict' check so that no undeclared fields are allowed, in my case for a privacy & security reasons.

Do you think it makes sense to have this feature? Maybe you already discussed something like this?
Thanks!

[TimothyJones]

You might be interested in: https://docs.pact.io/getting_started/matching/gotchas/#pact-follows-postels-law

Pact is primarily for contract testing, as in "can this consumer communicate with this provider" - perhaps I'm misunderstanding your request, but it sounds like you're trying to do something outside this remit. You might want some kind of spec-based validation on top of Pact, perhaps.

[maximvl]

Hi @TimothyJones , yes I've read it, my point it is configuration options can be added to support different kinds of behaviour. It's not that this law is built into stone, right? :D And anyway it's broken for headers already, so I want to know team's opinion on it.

[bethesque]

I agree with Tim that perhaps you need another tool on top of Pact if you want to restrict the fields in the response. What would you do if you had two consumers, and only one consumer used a particular field? You'd have to make the other consumer add that field to their contract, and then you'd be back in the SOAP world, where every consumer has to update their interface document when one consumer needs to make a change. That's something that CDC's were specifically designed to avoid.