Misleading decoder errors when decoding non-objects on Scala 2 derived codecs #2297
Description
Using a derived codec on Scala 2, if one tries to decode an object from a non-object (e.g. a JSON string), the error message points to a "Missing required field", instead of pointing to the wrong type.
This is particularly annoying on objects with optional fields, as it wrongly says that an optional field as required :/
import io.circe._
import io.circe.generic.semiauto._
case class Foo(optionalField: Option[String] = None)
object Foo {
val codec: Codec[Foo] = deriveCodec
}
// Decodes to Foo(Node), as expected
Foo.codec.decodeJson(Json.obj())
// Scala 2: DecodingFailure at .optionalField: Missing required field
// Scala 3: DecodingFailure at : Got value '""' with wrong type, expecting object
Foo.codec.decodeJson(Json.fromString(""))Scastie link: https://scastie.scala-lang.org/nghQc65yQTGyvtIVWxIbcQ