ZioJsonEncodingChange.scala

/*
 * These codec used to work with zio-json 2.0.0-M3 but are not working anymore with 
 * zio-json 3.0.0-R7. 
 * Even more strange, if I remove the encoder part (ie from codec to simple decoder),
 * then the decoding works in 3.0.0-R7. 
 * It looks like a bug
 */
 

package test

import org.junit.runner.RunWith
import org.specs2.mutable.Specification
import org.specs2.runner.JUnitRunner

import zio.json._
import zio.json.internal.Write

@RunWith(classOf[JUnitRunner])
class ReproduceErrorTest extends Specification {

  final case class JsonExpectedValueId7_1(id: String, v: String)
  final case class JsonValueExpectedReport7_1(
      vid: String
    , vs: List[Either[List[String],JsonExpectedValueId7_1]]
  )

  implicit lazy val codecJsonExpectedValueId7_1: JsonCodec[JsonExpectedValueId7_1] = DeriveJsonCodec.gen
  implicit lazy val codecJsonEitherValue: JsonCodec[Either[List[String],JsonExpectedValueId7_1]] = {

    // invariance is complicated
    def toRight(x: JsonExpectedValueId7_1): Either[List[String],JsonExpectedValueId7_1] = Right(x)
    def toLeft(x: List[String]): Either[List[String],JsonExpectedValueId7_1] = Left(x)

    val decoder = JsonDecoder[List[String]].map(toLeft).orElse(codecJsonExpectedValueId7_1.decoder.map(toRight))
    val encoder = new JsonEncoder[Either[List[String],JsonExpectedValueId7_1]] {
      override def unsafeEncode(a: Either[List[String], JsonExpectedValueId7_1], indent: Option[Int], out: Write): Unit = {
        a match {
          case Left(x)  => JsonEncoder[List[String]].unsafeEncode(x, indent, out)
          case Right(x) => codecJsonExpectedValueId7_1.encoder.unsafeEncode(x, indent, out)
        }
      }
    }
    JsonCodec(encoder, decoder)
  }

  implicit lazy val codecJsonValueExpectedReport7_1: JsonCodec[JsonValueExpectedReport7_1] = DeriveJsonCodec.gen



  sequential


  "the left case" >> {

    import zio.json._
    val jsonMin =
      """
      {
        "vid": "Command execution",
        "vs": [
          [ "/bin/echo \"restore\"" ]
         ]
      }
      """.stripMargin
    val expected = JsonValueExpectedReport7_1(
        "Command execution"
      , List(Left(List("/bin/echo \"restore\"")))
    )

    (jsonMin.fromJson[JsonValueExpectedReport7_1]) must beEqualTo(Right(expected))
  }
/*  
Left(.vs[0](expected '{' got '[')) != Right(JsonValueExpectedReport7_1(Command execution,List(Left(List(/bin/echo "restore"))))) expected:<[Right(JsonValueExpectedReport7_1(Command execution,List(Left(List(/bin/echo "restore")))]))> but was:<[Left(.vs[0](expected '{' got '[']))>
Comparison Failure: 
Expected :Right(JsonValueExpectedReport7_1(Command execution,List(Left(List(/bin/echo "restore")))))
Actual   :Left(.vs[0](expected '{' got '['))
*/
  
  "the right case" >> {

    import zio.json._
    val jsonMin =
      """
      {
        "vid": "Command execution",
        "vs": [
          {"id": "id", "v":"value"}
         ]
      }
      """.stripMargin
    val expected = JsonValueExpectedReport7_1(
        "Command execution"
      , List(Right(JsonExpectedValueId7_1("id", "value")))
    )

    (jsonMin.fromJson[JsonValueExpectedReport7_1]) must beEqualTo(Right(expected))
  }
/*
Left(.vs[0](missing fields)) != Right(JsonValueExpectedReport7_1(Command execution,List(Right(JsonExpectedValueId7_1(id,value))))) expected:<[Right(JsonValueExpectedReport7_1(Command execution,List(Right(JsonExpectedValueId7_1(id,value)))]))> but was:<[Left(.vs[0](missing fields]))>
Comparison Failure: 
Expected :Right(JsonValueExpectedReport7_1(Command execution,List(Right(JsonExpectedValueId7_1(id,value)))))
Actual   :Left(.vs[0](missing fields))
*/
  
}

//
// REMOVING encoder makes the decoder works?!?
//

@RunWith(classOf[JUnitRunner])
class ReproduceErrorTest extends Specification {

  final case class JsonExpectedValueId7_1(id: String, v: String)
  final case class JsonValueExpectedReport7_1(
      vid: String
    , vs: List[Either[List[String],JsonExpectedValueId7_1]]
  )

  implicit lazy val codecJsonExpectedValueId7_1: JsonDecoder[JsonExpectedValueId7_1] = DeriveJsonDecoder.gen
  implicit lazy val codecJsonEitherValue: JsonDecoder[Either[List[String],JsonExpectedValueId7_1]] = {

    // invariance is complicated
    def toRight(x: JsonExpectedValueId7_1): Either[List[String],JsonExpectedValueId7_1] = Right(x)
    def toLeft(x: List[String]): Either[List[String],JsonExpectedValueId7_1] = Left(x)

    JsonDecoder[List[String]].map(toLeft).orElse(codecJsonExpectedValueId7_1.map(toRight))
  }

  implicit lazy val codecJsonValueExpectedReport7_1: JsonDecoder[JsonValueExpectedReport7_1] = DeriveJsonDecoder.gen


  sequential


  "the left case" >> {

    import zio.json._
    val jsonMin =
      """
      {
        "vid": "Command execution",
        "vs": [
          [ "/bin/echo \"restore\"" ]
         ]
      }
      """.stripMargin
    val expected = JsonValueExpectedReport7_1(
        "Command execution"
      , List(Left(List("/bin/echo \"restore\"")))
    )

    (jsonMin.fromJson[JsonValueExpectedReport7_1]) must beEqualTo(Right(expected))
  }
  // SUCCESS

  "the right case" >> {

    import zio.json._
    val jsonMin =
      """
      {
        "vid": "Command execution",
        "vs": [
          {"id": "id", "v":"value"}
         ]
      }
      """.stripMargin
    val expected = JsonValueExpectedReport7_1(
        "Command execution"
      , List(Right(JsonExpectedValueId7_1("id", "value")))
    )

    (jsonMin.fromJson[JsonValueExpectedReport7_1]) must beEqualTo(Right(expected))
  }
  
  // SUCCESS
}