Converter Inheritance

Hi guys,

I think there is a bug emerged in #288 Converter: Bean to AnotherBean. It fires when you want to use the same converter between parent and derived classes by forcing the expected type of deserialization to the base of converter input type (i.e. the parent class), while it looks like it could perfectly be a derived type.

Here is an example:

@JsonDeserialize(converter = ParentEntity.MyConverter.class)
public class ParentEntity {
    String a, b;

    static class MyConverter<T extends Parent> extends StdConverter<T, T> {
        @Override
        public T convert(T entity) {
            entity.a = entity.a.toLowerCase();
            return entity;
        }
    }
}

@JsonIgnoreProperty({"b"})
public class ChildEntity extends ParentEntity {
    public ChildEntity() {
        b = "whatever";
    }
}

DeserializerCache::_createDeserializer(…) currently creates deserializer with return type of ParentEntity while in code it is expected to be an instance of ChildEntity. This results in java.lang.IllegalStateException: argument type mismatch exception.

The commit introduced this behavior, should the check consider hierarchy as well?

(BTW Jackson version used: 2.9.1, Spring 4.3.22)

[amirtu]

I have accidently closed the issue, didn’t actually mean to.

[cowtowncoder]

@amirtu I think that might work? Sub-class relationship does retain generic typing, so T should resolve properly within convert method.