When a TypeReference is provided, @JsonTypeInfo should be ignored.

[nucatus]

In case of a deserialization where a TypeReference is provided, the deserializer should favor the type reference information in the detriment of a possible JsonTypeInfo annotation.

Since the information related to the concrete types to be used for deserialization is provided in a declarative way, it makes much more sense to override whatever strategy a @JsonTypeInfo annotation enforces.

POC

[cowtowncoder]

I think this is fundamentally conflicting with the main idea of @JsonTypeInfo, but I think 2.9.6 (just released) does allow behavior of omitting type information.
If type information exists, however, I think it should have precedence over whatever user gave.

[nucatus]

My argumentation in this case would be that annotations are a generic way, and here generic is used with the sense of broad, general, to express a configuration.

Using a declarative approach in the code is more granular and usually, the granular configuration should have precedence over the general/broad one.

BTW, can you please point me to some documentation on how to suppress JsonTypeInfo? Thanks!

[cowtowncoder]

Ideally you avoid @JsonTypeInfo generally by not adding annotation.

But if you need to mask existing annotation, this can be done by custom AnnotationIntrospector, and overriding relevant method(s) (I forget specific name but JacksonAnnotationInstospector).
Or, you can use mix-in annotation to add @JsonTypeInfo with property of use = Id.NONE, which effectively means "do not use", and exists mostly to allow such blocking.

As to behavior itself: @JsonTypeInfo declares a thing (values of a class, or value of specific property) to require polymorphic handling. This is a fundamental property, and all handlers are built accordingly. It is not something that can be handled dynamically with current design.

Having said all that, overriding of just the root value type might be doable.

[cowtowncoder]

Hmmh. Quickly looking at the test case, I am not quite sure this can be supported after all.
Problem is that the type info is not for root value directly, but for generic type within (element type of List that is a property of the non-generic root value).

But... unless this is radically simplified version, do you think you actually need @JsonTypeInfo in there?
It does not seem to serve a purpose since you do pass full type information (like you said).
If so I could see you wanting to add mix-in annotation for Child to disable @JsonTypeInfo handling altogether. Or, if common enough theme, to create custom JacksonAnnotationIntrospector sub-class that masks all or some instances out. Both would achieve your goal as far as I can see.

[nucatus]

@cowtowncoder , thanks for the prompt replies.

Yes, this is a over simplified example in which @JsonTypeInfo wouldn't be necessary at all. I used is just for the sake of the demonstration. However, in our environment it is required because those objects are serialized/deserialized in another context where type information is needed.

And yes, the MixIn approach was something I was looking at.

[cowtowncoder]

I think #2968 covers this: marking that one as "most-wanted", closing this.