utf8Decode bug

Utf8Bug.scala

package zio.stream

import zio._

object Utf8Bug extends App {

  val char = "\u00BB"
  val string = List.fill(10)(char).mkString
  val bytes = string.getBytes("UTF-8")

  override def run(args: List[String]): ZIO[Environment, Nothing, Int] =
    app.fold(_ => 1, _ => 0)

  val app = for {
    res1 <- Stream
      .fromIterable(bytes)
      .transduce(Sink.utf8Decode(19))
      .runCollect
      .map(_.mkString)
    res2 <- Stream
      .fromIterable(bytes)
      .transduce(Sink.utf8Decode(20))
      .runCollect
      .map(_.mkString)
  } yield assert(res1 == res2)
}