JsonSerializable gets ignored on classes implementing Map

[chasebradford]

I have a class that extends Map[,] but implements its own Json serialization. I just jumped from 2.4.1 to 2.8.3 and I hit an error where its custom serialization doesn't get used. Instead, it attempts to serialize the object based on its Map interface. I expected the JsonSerializable implementation to take priority over any other modules matching the class.

I narrowed down the break to somewhere between tags 2.6.0-rc2 and 2.6.0-rc4. I'll keep looking, but it would be nice if someone might have a direction to point me in. Here's a test class I setup to reproduce the error. It's the one that works in rc2 but fails rc4.

import com.fasterxml.jackson.module.scala.BaseFixture

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule

import com.fasterxml.jackson.databind.JsonSerializable
import com.fasterxml.jackson.databind.SerializerProvider
import com.fasterxml.jackson.databind.jsontype.TypeSerializer
import com.fasterxml.jackson.core.JsonGenerator

class SerializableClass extends Map[String, String] with JsonSerializable {
  def +[B1 >: String](kv: (String, B1)) = this
  def -(key: String): Map[String,String] = this

  // Members declared in scala.collection.MapLike
  def get(key: String): Option[String] = None
  def iterator: Iterator[(String, String)] = throw new IllegalArgumentException("This shouldn't get called")

  override def serialize(jgen:JsonGenerator, provider:SerializerProvider) {
    jgen.writeNumber(10)
  }
  override def serializeWithType(jgen:JsonGenerator, provider:SerializerProvider, typeSer:TypeSerializer) {
    serialize(jgen, provider)
  }

}

class SerializableTest extends BaseFixture {

  it should "use serialize method in JsonSerializable" in { mapper =>

    mapper.writeValueAsString(new SerializableClass()) shouldBe "10"

  }
}

[chasebradford]

If it helps, this happens with Iterable too. It doesn't have to be a Map.

[cowtowncoder]

If this can be reproduced with plain Java, would be good to file against jackson-databind.

[pjfanning]

fc818b1 should fix this

[pjfanning]

fix will be in 2.13 release

[cowtowncoder]

Ok good. Although in some ways it'd be nice if jackson-databind could handle it in a way to let custom modules know the special status so that modules did not have to do extra introspection. But conversely it should always be possible to override this behavior (i.e. databind should not automatically assume JsonSerializable implementing things must be handled with default serializer). So I guess this makes most sense for now.