java.lang.UnsupportedOperationException: Position.point on NoPosition in chimney 0.8.0 about chimney HOT 17 CLOSED

I commented on the Scala ticket that it is failing just sorting warnings by position: probably it's not defensive about unpositioned trees produced by the macro. In that case, the workaround is not to lint it with -Wmacros:both. I'll try to confirm that and provide a fix, since sort order should not be fatal.

from chimney.

@codesurf42 if it's not macro:both check if it also isn't (lack of) -Xss flag.

from chimney.

a.patchUsing(b) seems to be the culprit. a.using(b).patch is working fine.

from chimney.

Hey, thanks for the ticket!

I would need:

• Scala version
• some small reproduction

I don't see our macros in the stack trace, so I can only guess there is a bug in the compiler which we haven't triggered before and are triggering now(?). When I google NoPosition I see issues like scalameta/scalameta#1183 but the only position we are using is c.enclosingPosition, so I cannot tell anything more without any reproduction.

It doesn't have to be super minimized or using only Chimney, just remove all NDA-company-specific details.

Alternatively I found a similar ticker for scala/bug#10604. I am not sure if it is still relevant but you might try increasing the stack size and see if that's an issue with hidden StackOverflow inside a compiler.

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Scala version is 2.13.12.

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I was able to pinpoint the error to an interaction with Circe, specifically if there is a configured codec implicit val codec: Codec[Event] = io.circe.generic.extras.semiauto.deriveConfiguredCodec available for the class that is either patcher or patchee. io.circe.generic.semiauto.deriveCodec is working fine.

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import io.circe.Codec
import io.circe.generic.extras.Configuration
import io.circe.generic.extras.semiauto.deriveConfiguredCodec
import io.circe.generic.semiauto.deriveCodec
import io.scalaland.chimney.dsl._

object ChimneyBug {
  private def handleEvent(state: State, event: Event) =
    (state, event) match {
      case (active: State.Active, updated: Event.A) =>
        //  Working: active.using(updated).patch
        active.patchUsing(updated)
    }

  sealed trait Event
  object Event {
    case class A(
                  a: String,
                ) extends Event

    implicit val configuration = Configuration.default.withDiscriminator("class").withDefaults
    implicit val codec: Codec[Event] = deriveConfiguredCodec
    // Working: implicit val codec: Codec[Event] = deriveCodec
  }
  
  sealed trait State
  object State {
    case class Active(
                       a: String,
                     ) extends State

    implicit val configuration = Configuration.default.withDiscriminator("class").withDefaults
    implicit val codec: Codec[State] = deriveConfiguredCodec
    // Working: implicit val codec: Codec[Event] = deriveCodec
  }
}

from chimney.

When I am testing your code in Scastie it compiles. Could you check if setting e.g. -Xss8m for Java options changes anything? It only needs to be changed for compilation, not for the deployment.

from chimney.

We're already at -J-Xss64m in our .sbtopts files.

from chimney.

But indeed the Scastie is working fine 😕

from chimney.

The issue seems to be with the compiler setting -Wmacros:both ("Lints code before and after applying a macro").

As soon as I disable this setting, the code compiles.

from chimney.

Unfortunatelly, I still cannot reproduce. I created this Scala CLI snippet, but it runs without issues.

//> using scala 2.13.12
//> using options -Wmacros:both -verbose -Xlog-implicits
//> using dep io.scalaland::chimney::0.8.0
//> using dep io.circe::circe-generic::0.14.6
//> using dep io.circe::circe-generic-extras::0.14.3

import io.circe.Codec
import io.circe.generic.extras.Configuration
import io.circe.generic.extras.semiauto.deriveConfiguredCodec
import io.circe.generic.semiauto.deriveCodec
import io.scalaland.chimney.dsl._

object ChimneyBug {
  private def handleEvent(state: State, event: Event) =
    (state, event) match {
      case (active: State.Active, updated: Event.A) =>
        //  Working: active.using(updated).patch
        active.patchUsing(updated)
    }

  sealed trait Event
  object Event {
    case class A(
                  a: String,
                ) extends Event

    implicit val configuration = Configuration.default.withDiscriminator("class").withDefaults
    implicit val codec: Codec[Event] = deriveConfiguredCodec
    // Working: implicit val codec: Codec[Event] = deriveCodec
  }

  sealed trait State
  object State {
    case class Active(
                       a: String,
                     ) extends State

    implicit val configuration = Configuration.default.withDiscriminator("class").withDefaults
    implicit val codec: Codec[State] = deriveConfiguredCodec
    // Working: implicit val codec: Codec[Event] = deriveCodec
  }

  def test = handleEvent(ChimneyBug.State.Active("A"), ChimneyBug.Event.A("B"))
}

object Main {
  def main(args: Array[String]): Unit =
    println(ChimneyBug.test)
}

scala-cli run .
Compiling project (Scala 2.13.12, JVM)
[a lot of verbose logs]
Compiled project (Scala 2.13.12, JVM)
Active(B)

There must be something more to your setup which produces the error. Do you use the newest sbt, are you using Windows?

from chimney.

Please also add the option "-Xlint:unused".

from chimney.

Alternatively -Wunused:explicits, -Wunused:params, -Wunused:linted, or -Wunused:implicits.

Any of them in combination with -Wmacros:both trigger the error.

from chimney.

Thanks!

from chimney.

I have seen these errors quite often recently in my code base (using upgraded to 0.8.0 chimney for conversions to scalapb-generated hierarchy), usually appearing at some point when adding more and more of data structures. The only pattern I have found was related to missing internal conversions in the ADT for chimney, however instead of expected macro compile error for missing transformations, it was bluntly reported by NoPosition.
We don't use macros:both.
Scala 2.13.9 and 2.13.12
If I find it again, I can try to extract it.

from chimney.

Since this issue seem to be related to a compiler's bug, I'll close it for now. When the fix is released I'll add the information about it to the documentation.

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