Feat: New "Mixin" Hint

[f-aubert]

Is your feature request related to a problem? Please describe.

I'm facing issues when I want to ignore @JsonIdentityInfo for some specific reason

• 1. when deserializing new entities (which don't have an id yet, but are annoted with PropertyGenerator "id") or
• 2. when serializing a list of objects sharing a common reference to some object which I want to serialize multiple time to make it easier for the frontend UI to display as a table

Describe the solution you'd like

Though my current use cases can be very specific to JsonIdentityInfo, I'd think it can be more flexible and allow to customize the serializer / deserializer used for a specific rest method (HttpMessageConverter).

• A new annotation/hint?
• @JsonApplyMixin(value=MixinClass) annotation on method parameter or return type ?
• @JsonCustomizeBuilder (target=Serialization/Deserialization/Both value=CustomizerClass) annotation or hint on method?

Can it be discussed here? I'd happily talk about it and hear back from Jackson experts before submitting some PushRequest. Alternatively I could take the discussion to the Spring Rest Controller section as it lays between the two framework. @cowtowncoder your valuable inputs would be welcome.

Usage example

No response

Additional context

No response

[f-aubert]

For Issue i, there might be an issue/bug in tools.jackson.databind.deser.bean.PropertyValueBuffer.handleIdValue where an _idValue == null might be OK if the DeserializationFeature.FAIL_ON_UNRESOLVED_OBJECT_ID is disabled. In my use case it reports an unresolved object id exception. Can we consider being more lenient?

[cowtowncoder]

Perhaps -- depends on what exactly it means. Can also add new DeserializationFeatures if necessary.
You could try coming up with a pr with just test case showing desired behavior.

[f-aubert]

For Issue ii, an elegant solution might be a new hint that allow the serializer to be further configured either with a mixin or a buildercustomizer (in my case it would mixin jsonidentityinfo generator none).

[cowtowncoder]

If this is conversation, let's make it Discussion.

[f-aubert]

Sure great. Didn't know of this. Maybe it will turn back to new feature at the end. Regards

[cowtowncoder]

I am not sure these mix-in changes are feasible: annotations do not know about mix-ins nor can (nor, I think, should) refer to mix-in definitions. Mix-ins are overrides sort of outside (or above) annotation handling.