scala case class extends abstract : Argument #0 of constructor ...

[Ramon Buckland]

Hi

I have some simple case classes 

sealed abstract class XYPersonCommand(@jsonProperty val timestamp: Long)

case class ABCRegisterNewPersonExtended(@jsonIgnore override val timestamp: Long,// = DateTime.now.getMillis,

                                        firstname: String,

                                        surname: String,

                                        emailAddress: String,

                                        campusOfRegistration: String,

                                        dob: Option[LocalDate]) extends XYPersonCommand(timestamp)

When I try to deserialise this case class, I get the following error.

I recall / throught I fixed this about 12 months ago by adding the @jsonProperty annotation to the super class properties .. but alas it is alluding me,

I have found a few issues that relate .. on error, but not to this. (if I remove the timestamp) from the c'tor, by changing abstract class to not have the field..

it all disappears:

thoughts ?

Argument #0 of constructor [constructor for com.soqqo.luap.web.marshalling.ABCRegisterNewPersonExtended, annotations: [null]] has no property name annotation; must have name when multiple-paramater constructor annotated as Creator

com.fasterxml.jackson.databind.JsonMappingException: Argument #0 of constructor [constructor for com.soqqo.luap.web.marshalling.ABCRegisterNewPersonExtended, annotations: [null]] has no property name annotation; must have name when multiple-paramater constructor annotated as Creator

at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:268)

[Nate Bauernfeind]

It's quite possible that the case class deserializer can't handle json ignore on a parameter. I do not see any tests for that use case here:

https://github.com/FasterXML/jackson-module-scala/blob/master/src/test/scala/com/fasterxml/jackson/module/scala/deser/CaseClassDeserializerTest.scala

Is there any chance your @JsonIgnore is from org.codehaus instead of com.fasterxml?

Also, since the base class has timestamp as a val already, does it work if you change "override val timestamp" to "private val _timestamp" and let the accessor exist from the super class?

Nate

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[Christopher Currie]

The root cause here is that, when matching properties up to constructor parameters, the BeanIntrospector uses JVM reflection to look at "declared fields", and the Scala compiler isn't generating a field for this val in the derived class. Thus, it finds "timestamp" as a member of the base class, and then starts *at the base class*, when looking for a matching constructor parameter.

I'll work on a fix that will ask the introspector to start at the most derived class when looking for constructor arguments; with luck that should fix it without breaking a bunch of other tests.

[Christopher Currie]

I've implemented a fix for this, it's available on 2.3.3-SNAPSHOT and 2.4.0-SNAPSHOT.