ZStream.groupedWithin works in unexpected way for infinite stream

[DenisKusakin]

The behavior is only reproducible on ZIO v1.0.18, works as expected for elder versions

import zio.clock.Clock
import zio.duration.durationInt
import zio.stream.ZStream
import zio.{ExitCode, URIO}
object Main extends zio.App {

  override def run(args: List[String]): URIO[zio.ZEnv, ExitCode] = {
    ZStream
      .fromIterable(Seq(1, 2))
      .forever
      .mapAccum(Set[Int]())(
        (acc, i) =>
          if (acc.contains(i)) {
            (acc, None)
          } else {
            (acc + i, Some(i))
        }
      )
      .collectSome
      //The stream above generates only two elements
      // so after 5 seconds those two elements should be grouped
      .groupedWithin(3, 5.seconds)
      .take(1)
      .runCollect
      .map(_ => ExitCode.success)
      .provideCustomLayer(Clock.live)
  }
}

Expected result: Complete with exit code 0
Actual result: The program is never completed

[krsvital]

forever ???

[DenisKusakin]

forever ???

Yes, the top-level stream is an infinite stream of 1, 2, 1, 2,..., then there is filtering that produces only two elements: 1, 2. I expect that groupedWithin will produce chunk [1, 2] in 5 seconds, take(1) will take this chunk and program completed

[jdegoes]

We will take a PR for ZIO 1.x issues, of course, but we will need a volunteer to fix this issue.

[jdegoes]

/bounty $50

[algora-pbc]

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Attempt	Started (GMT+0)	Solution
🟡 @DenisKusakin	May 11, 2024, 2:42:17 PM	#8873

[DenisKusakin]

/attempt #8686
Looks like the issue is related with PR. I believe that by making concat faster it somehow introduced this behavior

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[algora-pbc]

@DenisKusakin: Reminder that in 7 days the bounty will become up for grabs, so please submit a pull request before then 🙏

[algora-pbc]

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