Proper error messages

[frankbharath]

Hello Team,

We are doing some contract negotiations, and if the policies are not matching, then the we get a response like this

{
"@type": "ContractNegotiation",
"@id": "13a30b8b-d35f-4a5a-ae07-d20f06d9f6c8",
"type": "CONSUMER",
"protocol": "dataspace-protocol-http",
"state": "TERMINATED",
"counterPartyId": $counterPartyId,
"counterPartyAddress": $counterPartyId,
"callbackAddresses": [],
"createdAt": 1763735655698,
"assetId": $assetId,
"errorDetail": "Failed to send termination to counter party: Value in JsonObjects name/value pair cannot be null",
"@context": {
"eox-policy": "https://w3id.org/eonax/policy/",
"@vocab": "https://w3id.org/edc/v0.0.1/ns/",
"edc": "https://w3id.org/edc/v0.0.1/ns/",
"odrl": "http://www.w3.org/ns/odrl/2/"
}
}

The error detail does not really convey that there was policy failure or there was some internal server error. Only if we look at the logs, we can say it was policy issue "[Provider] Contract offer rejected as invalid: Policy in scope contract.negotiation not fulfilled:"

Is there way we can modify the errorDetail message, so that it can be more user friendly?

Thanks,
Bharath

[ndr-brt]

The message can be modified though an appropriate code contribution :)
By experience, the "Value in JsonObjects name/value pair cannot be null" comes when in a json transformer (serializer) there's a null value where it shouldn't, it's a sort of NPE.
It should definitely be detected before the serialization and return a more readable message.

Would you mind reporting in a comprehensive way (how to replicate, edc version, and so on...) in an issue? then let's see if someone would like to contribute.

PS: please wrap code blocks into triple backtick blocks, that will improve readability a lot