case class was incorrectly deserialized as a Map

[impasse]

case class was incorrectly deserialized as a Map

[pjfanning]

what happens if you remove .enable(DeserializationFeature.USE_JAVA_ARRAY_FOR_JSON_ARRAY)?

[impasse]

The result is still the same, List[Map].

[pjfanning]

I see you are using Int - and type erasure makes that very hard to support.

Please read https://github.com/FasterXML/jackson-module-scala/wiki/FAQ#deserializing-optionint-seqint-and-other-primitive-challenges

[impasse]

import com.fasterxml.jackson.databind.json.JsonMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule

@main
def test(): Unit = {
  val mapper: JsonMapper = JsonMapper.builder()
    .addModule(DefaultScalaModule)
    .build()
  
  case class I(i: Option[Int])
  case class W(b: List[I])
  val d = mapper.readValue[W](
    """
      |{ "b": [ { "i": 1 }, { "i": 2 } ] }
      |""".stripMargin, classOf[W])
  println(d.b.head.i)
}

But when I replaced it with Option[Int], it's still the same List[Map]:
class scala.collection.immutable.Map$Map1 cannot be cast to class test$package$I$1

[impasse]

package com.mokahr.tntsync

import com.fasterxml.jackson.databind.json.JsonMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule

@main
def test(): Unit = {
  val mapper: JsonMapper = JsonMapper.builder()
    .addModule(DefaultScalaModule)
    .build()

  case class I(i: Option[Int])
  case class W(b: Array[I])
  val d = mapper.readValue[W](
    """
      |{ "b": [ { "i": 1 }, { "i": 2 } ] }
      |""".stripMargin, classOf[W])
  println(d.b.head.i)
}

But when I replaced List[I] with Array[I], it was able to print Some(1) normally.

[pjfanning]

There are lots of solutions in that FAQ, could you try some of them? I'm afraid that I don't have time to debug this right now.

There are a lot of other Scala libs to process JSON. This one is constrained by the fact that it uses Java reflection. If you don't like the workarounds in the FAQ, you could try another lib.

[impasse]

Okay, I'm just giving feedback on this issue. It doesn't affect my usage at the moment.

[pjfanning]

I added 6441dd9 and the test seems to work ok - maybe I'm missing something