@JsonUnwrapped and JsonTypeInfo.As.EXTERNAL_PROPERTY in the same bean doesn't work

[tlevavasseur-innovantic]

Hi, using @JsonUnwrapped for a propery and @JsonTypeInfo(include = JsonTypeInfo.As.**EXTERNAL_PROPERTY**, ...) on another property in the same bean make the parser totally ignore the @JsonTypeInfo property :

public class MainType {
    @JsonProperty public String text;
    public static class Wrapped { public String wrapped; }

    @JsonUnwrapped public Wrapped wrapped;
    public static class SubType {
        public static class SubA extends SubType {
            @JsonProperty public boolean bool;
        }
    }

    @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXTERNAL_PROPERTY, property = "subtype")
    @JsonSubTypes({ @JsonSubTypes.Type(value = SubType.SubA.class, name = "SubA") })
    public SubType sub;
}

{
  "text": "this is A",
  "wrapped": "yes",
  "subtype": "SubA",
  "sub": {
    "bool": true
  }
}

        final MainType main = mapper.readValue(json, MainType.class);

        assertEquals("this is A", main.text);
        assertEquals("yes", main.wrapped.wrapped);

        assertTrue(main.sub instanceof MainType.SubType.SubA); // <- fails here
        assertEquals(true, ((MainType.SubType.SubA) main.sub).bool);

Note : using @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type") in SubType class (instead of sub property in MainType) is ok but I need to have subtype in the parent class and then @JsonTypeInfo annotation must be on the sub property.

Tested with 2.9.5

[cowtowncoder]

Thank you for reporting this, troubleshooting, and especially including version information!

I suspect the difference from behavior stems from slightly different code path taken in presence of handlers needed for unwrapped values. Both approaches should work I think.

[vellotis]

I just fell on this bug 7 years later. I'm using the current latest v2.19.2.

[vellotis]

It is either one or the other https://github.com/FasterXML/jackson-databind/blob/2.x/src/main/java/com/fasterxml/jackson/databind/deser/BeanDeserializer.java#L334-L339

[vellotis]

It is a known issue that also a test. https://github.com/FasterXML/jackson-databind/blob/70deb562a742ce36a7fceaa6f3c330ba9334ccbe/src/test/java/com/fasterxml/jackson/databind/tofix/ExternalTypeIdWithUnwrapped2039Test.java#L13

[JooHyukKim]

Oh wow still on going. Will see what we can do.

[cowtowncoder]

EXTERNAL_PROPERTY handling is quite specialized, as is Unwrapping. So while reproduction is easy, fixing may or may not be. But of course would be great to resolve.