@JsonIdentityReference not used when setup on class only

[vboulaye]

I am trying to setup @JsonIdentityInfo/@JsonIdentityReference in order to serialize all references to a given class as Object Id (and deserialize them later using a custom ObjectIdResolver to retrieve the proper referenced instance)

I use @JsonIdentityReference(alwaysAsId=true) in order to enforce exporting the object id in all cases.
It does not work as expected when I define the annotation only on the class (but it works fine when I set it directly on the property). I would rather not have to define it on every property as I will probably miss some...

From what I see in BeanSerializerBase, the alwaysAsId is reset when not ObjectIdInfo is found on the accessor:

            ObjectIdInfo objectIdInfo = intr.findObjectIdInfo(accessor);
            if (objectIdInfo == null) {
                // no ObjectId override, but maybe ObjectIdRef?
                if (oiw != null) {
                    objectIdInfo = intr.findObjectReferenceInfo(accessor,
                            new ObjectIdInfo(NAME_FOR_OBJECT_REF, null, null, null));
oiw = _objectIdWriter.withAlwaysAsId(objectIdInfo.getAlwaysAsId());

Shouldn't it be kept to the current value when no override is found ?
I tried to set it back in the default ObjectIdInfo created with NAME_FOR_OBJECT_REF but I am not sure if this is the right way to fix this.

Here is test I added in TestObjectIdSerialization for this case:

    @JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="id")
    @JsonIdentityReference(alwaysAsId=true)
    static class ReallyAlwaysAsId
    {
        public int value;

        public ReallyAlwaysAsId() { this(0); }
        public ReallyAlwaysAsId(int v) {
            value = v;
        }
    }

    @JsonPropertyOrder(alphabetic=true)
    static class ReallyAlwaysContainer
    {

        @JsonIdentityReference(alwaysAsId=true)
        public AlwaysAsId a = new AlwaysAsId(13);

        public ReallyAlwaysAsId b = new ReallyAlwaysAsId(13);

    }

    public void testReallyAlwaysAsId() throws Exception
    {
        String json = MAPPER.writeValueAsString(new ReallyAlwaysContainer());
        assertEquals("{\"a\":1,\"b\":2}", json);
    }

[cowtowncoder]

Thank you for reporting this; it sounds like a bug from first reading.

One quick question: is this with a recent version like 2.8.8?

[vboulaye]

Yes, this is on a recent version, I am testing with 2.9.0.pr2 and I reproduced it on master.

[cowtowncoder]

Yes, fixed. Not sure if this is the best fix either (handling of defaulting done in a bit odd way), but handles this case, does not break any other tests.