`@JsonSetter(nulls=...)` not working with XML

[cowtowncoder]

(note: follow-up from #209)

Ok it looks like feature added in 2.9 for configurable null handling:

FasterXML/jackson-databind#1402

does not quite work with XML. Need to figure out why, and fix it.

[markaren]

The following seems to work as expected

    class Real

    class ScalarVariable {

        @JsonSetter(nulls = Nulls.AS_EMPTY)
        @JacksonXmlProperty(localName = "Real")
        var real: Real? = null

    }

    @Test
    fun test() {

        val xml = """
            <ScalarVariable >
                <Real />
             </ScalarVariable >
            """

        val mapper = XmlMapper().apply {
            registerModule(KotlinModule())
        }
        val variable = mapper.readValue<ScalarVariable>(xml)

        Assert.assertNotNull(variable.real)

    }

Removing

@JsonSetter(nulls = Nulls.AS_EMPTY)

And the test will fail

Version 2.9.5

[cowtowncoder]

@markaren thank you for testing it.

I actually noticed the same: I have a more elaborate case that uses generic type, and that is problematic for some reason... but simple POJO dependency does work.

[cowtowncoder]

Actually, looks like it IS working, but... As per #246, only empty tag (like <value/>) gets coerced to null, but not (yet) <value></value>. But @JsonSetter itself does work.

There may be 2 follow up things here:

1. Make start/end tag also coerce to null with same feature (seems reasonable)
2. Ensure that on databind side, coercing empty String to null will appropriately honor @JsonSetter setting.

[cowtowncoder]

Will work better in 2.9.6 as well.

[PaulBenn]

• Make start/end tag also coerce to null with same feature (seems reasonable)

Hi, is this planned for a future milestone?

Nulls.AS_EMPTY does not support the following form of empty collection yet (as of version 2.11):

<MyList></MyList>

[cowtowncoder]

@PaulBenn You may try this against 2.12.0-rc1 (released couple of days ago). I think handling should result in empty List with 2.12.0, regardless of this configuration (that is, should not even need to set it).