ZStream: merge and debounce are not compatible

[artembakhanov]

I encountered an unexpected fiber interruption error when attempting to foreach on two streams merged: one debounced and the other not. Here is the min. reproducible code example (Scala 3):

import zio.*
import zio.stream.*

val stream1: UStream[Int | Unit] =
  (ZStream.succeed(0) ++ ZStream.fromZIO(ZIO.sleep(200.millis)))
    .debounce(100.millis)
val stream2: UStream[Nothing] = ZStream.empty

val effectAll = (stream1 merge stream2).runDrain

object Kek extends ZIOAppDefault:
  val run =
    for
      _ <- effectAll
        .catchAllDefect(ZIO.fail(_))
        .tapErrorCause(ZIO.logErrorCause("mmm sweet", _))
    yield ()

Expected: the application logs nothing

Actual: When I run this app, I get this in the logs:

timestamp=2024-04-11T00:31:15.544135400Z level=ERROR thread=#zio-fiber-4 message="mmm sweet" cause="Exception in thread "zio-fiber-" java.lang.InterruptedException: Interrupted by thread "zio-fiber-6"
        Suppressed: java.lang.InterruptedException: Interrupted by thread "zio-fiber-6"" location=<empty>.Kek.run file=IKILLEDHOURSLOL.scala line=16

However for some reason if you replace 100.millis with 300.millis it works just fine, ofc it is not the case with real applications.

I tried it on every possible zio version from 2.0.0 until 2.1-RC1 and it does not work.

[jdegoes]

/bounty $125

[algora-pbc]

💎 $125 bounty • ZIO

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