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Exception thrown when using attempt

See original GitHub issue

I am on version 2.2.0 I’ve been playing around with essential effects repo running the code titled ParMapNErrors


object ParMapNErrors extends IOApp {
  def run(args: List[String]): IO[ExitCode] =
    e1.attempt.debug *>
      IO("---").debug *>
      e2.attempt.debug *>
      IO("---").debug *>
      e3.attempt.debug *>
      IO.pure(ExitCode.Success)

  val ok = IO("hi").debug
  // how will debug ever evaluate
  val ko1 = IO.raiseError[String](new RuntimeException("oh!")).debug
  val ko2 = IO.raiseError[String](new RuntimeException("noes!")).debug

  val e1 = (ok, ko1).parTupled.void
  val e2 = (ko1, ok).parMapN((_, _) => ())
  val e3 = (ko1, ko2).parMapN((_, _) => ())

}

running this code both from Intellij and Sbt with (ThisBuild / fork := true) multiple times resulted in some occurrences generating the following stack trace

[info] running (fork) com.innerproduct.ee.parallel.ParMapNErrors 
[info] in debug mode: [ioapp-compute-1] hi
[info] in debug mode: [ioapp-compute-2] Left(java.lang.RuntimeException: oh!)
[info] in debug mode: [ioapp-compute-2] ---
[info] in debug mode: [ioapp-compute-2] hi
[info] in debug mode: [ioapp-compute-3] Left(java.lang.RuntimeException: oh!)
[info] in debug mode: [ioapp-compute-3] ---
[info] in debug mode: [ioapp-compute-1] Left(java.lang.RuntimeException: oh!)
[error] java.lang.RuntimeException: noes!
[error]         at com.innerproduct.ee.parallel.ParMapNErrors$.<clinit>(ParMapNErrors.scala:19)
[error]         at com.innerproduct.ee.parallel.ParMapNErrors.main(ParMapNErrors.scala)
[error]         at map @ com.innerproduct.ee.debug$DebugHelper.debug(debug.scala:15)
[error]         at map @ com.innerproduct.ee.debug$DebugHelper.debug(debug.scala:15)
[error]         at main$ @ com.innerproduct.ee.parallel.ParMapNErrors$.main(ParMapNErrors.scala:7)

For reference the “in debug mode…” is from a helper class

object debug {
  /** Extension methods for an effect of type `F[A]`. */
  implicit class DebugHelper[A](ioa: IO[A]) {

    /** Print to the console the value of the effect
     * along with the thread it was computed on. */
    def debug: IO[A] =
      for {
        a <- ioa
        tn = Thread.currentThread.getName
        _ = println(s"in debug mode: [${Colorize.reversed(tn)}] $a") // <1>
      } yield a
  }
}

Issue Analytics

State:
Created 2 years ago
Comments:6 (4 by maintainers)

Top GitHub Comments

2reactions

arosiencommented, Aug 4, 2021

I think runtime is printing the stacktrace of the loser of the race between ko1 and ko2, and this has nothing to do with the use of attempt.

1reaction

yisraelUcommented, Aug 4, 2021

@vasilmkd I received the same results

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