Inconsistent encoding/decoding of nested sum types #2110
Description
As of 0.14.5, derived encoder and decoder of a nested sum type are inconsistent. The Decoder can't decode a JSON encoded by the Encoder.
Minimal example:
import io.circe.Decoder
import io.circe.Encoder
import io.circe.generic.semiauto.deriveDecoder
import io.circe.generic.semiauto.deriveEncoder
import io.circe.parser.decode
import io.circe.syntax._
sealed trait Top
object Top {
sealed trait Middle extends Top
object Middle {
case object Bottom extends Middle
}
implicit val decodeTop: Decoder[Top] = deriveDecoder
implicit val encodeTop: Encoder[Top] = deriveEncoder
}
object Main {
def main(args: Array[String]): Unit = {
val s = (Top.Middle.Bottom: Top).asJson.noSpaces
println(s)
println(decode[Top](s))
}
}Expected output (scala:3.2.2, circe:0.14.3)
{"Middle":{"Bottom":{}}}
Right(Bottom)
Actual output (scala:3.2.2, circe:0.14.5)
{"Middle":{"Bottom":{}}}
Left(DecodingFailure at .Middle: type Top has no class/object/case named 'Middle'.)
^ In this case, the decoder can decode {"Bottom":{}} to Bottom.
It turned out that both of the above are also inconsistent with scala 2.13 build of circe:
Output (scala:2.13.0, circe:0.14.3/0.14.5)
{"Bottom":{}}
Right(Bottom)
So I'm not sure which encoding is correct.