Cannot deserialize @JsonValue of type long in nested objects

Using jackson-kotlin 2.9.3 the following test throws an Exception when deserializing:

data class Foo(
        @JsonValue
        val value: Long
)

data class Bar(
        val foo: Foo
)

@Test
fun name() {
    val om = ObjectMapper()
    om.registerModule(KotlinModule())
    val foo = Foo(4711L)
    val bar = Bar(foo)
    val asString = om.writeValueAsString(bar)
    println(asString)
    val fromString = om.readValue(asString, Bar::class.java)
    println(fromString)
}

The output is:

{“foo”:4711}

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `de.ottonow.contracts.CustomerIdTest$Foo` (although at least one Creator exists): no int/Int-argument constructor/factory method to deserialize from Number value (4711)
at [Source: (String)"{"foo":4711}"; line: 1, column: 8] (through reference chain: de.ottonow.contracts.CustomerIdTest$Bar["foo"])

at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63)
at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1342)
at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1031)
at com.fasterxml.jackson.databind.deser.ValueInstantiator.createFromInt(ValueInstantiator.java:261)
at com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.createFromInt(StdValueInstantiator.java:347)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromNumber(BeanDeserializerBase.java:1302)
at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:172)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:161)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:519)
at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeWithErrorWrapping(BeanDeserializer.java:527)
at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:416)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1265)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:325)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4001)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2992)

[apatrida]

@BastianVoigt that is the correct workaround, this is because normally Jackson isn’t trying to find and infer a creator method automatically, and when the Jackson-Kotlin module does this, it sets the mode to DEFAULT which isn’t compatible with what you are trying.

The test case showing the workaround without creating a new creator method, but instead just annotate the class constructor is:

class Github120Test {
    data class Foo @JsonCreator(mode = JsonCreator.Mode.DELEGATING) constructor (
            @JsonValue
            val value: Long
    )

    data class Bar(
            val foo: Foo
    )

    @Test
    fun testNestedJsonValue() {
        val om = jacksonObjectMapper()
        val foo = Foo(4711L)
        val bar = Bar(foo)
        val asString = om.writeValueAsString(bar)
        assertEquals("{\"foo\":4711}", asString)

        val fromString = om.readValue(asString, Bar::class.java)
        assertEquals(bar, fromString)
    }
}

[BastianVoigt]

Workaround: add a static @JsonCreator factory which accepts Int or Number

companion object {
    @JsonCreator(mode = JsonCreator.Mode.DELEGATING)
    @JvmStatic
    fun createFrom(value: Number): CustomerId {
        return CustomerId(value.toLong())
    }
}