replace-flatmap-to-guaranteeCase

[BambooTuna]

fixes #915

[Avasil]

@alexandru The following test fails:

  test("Task.wanderUnordered should log errors if multiple errors happen") { implicit s =>
    implicit val opts = Task.defaultOptions.disableAutoCancelableRunLoops

    val ex = DummyException("dummy1")
    var errorsThrow = 0
    val gather = Task.wanderUnordered(Seq(0, 0)) { _ =>
      Task.raiseError[Int](ex).executeAsync.doOnFinish { x =>
        if (x.isDefined) errorsThrow += 1; Task.unit
      }
    }

    val result = gather.runToFutureOpt
    s.tick()

    assertEquals(result.value, Some(Failure(ex)))
    assertEquals(s.state.lastReportedError, ex)
    assertEquals(errorsThrow, 2)
  }

because with guaranteeCase it gets to the ExitCase.Canceled even with autoCancelableRunLoops disabled. Is it intended?

[BambooTuna]

If there is a sample of how autoCancelableRunLoops behave, can you tell me?

[BambooTuna]

@alexandru The following test fails:

  test("Task.wanderUnordered should log errors if multiple errors happen") { implicit s =>
    implicit val opts = Task.defaultOptions.disableAutoCancelableRunLoops

    val ex = DummyException("dummy1")
    var errorsThrow = 0
    val gather = Task.wanderUnordered(Seq(0, 0)) { _ =>
      Task.raiseError[Int](ex).executeAsync.doOnFinish { x =>
        if (x.isDefined) errorsThrow += 1; Task.unit
      }
    }

    val result = gather.runToFutureOpt
    s.tick()

    assertEquals(result.value, Some(Failure(ex)))
    assertEquals(s.state.lastReportedError, ex)
    assertEquals(errorsThrow, 2)
  }

because with guaranteeCase it gets to the ExitCase.Canceled even with autoCancelableRunLoops disabled. Is it intended?

@alexandru The following test fails:

  test("Task.wanderUnordered should log errors if multiple errors happen") { implicit s =>
    implicit val opts = Task.defaultOptions.disableAutoCancelableRunLoops

    val ex = DummyException("dummy1")
    var errorsThrow = 0
    val gather = Task.wanderUnordered(Seq(0, 0)) { _ =>
      Task.raiseError[Int](ex).executeAsync.doOnFinish { x =>
        if (x.isDefined) errorsThrow += 1; Task.unit
      }
    }

    val result = gather.runToFutureOpt
    s.tick()

    assertEquals(result.value, Some(Failure(ex)))
    assertEquals(s.state.lastReportedError, ex)
    assertEquals(errorsThrow, 2)
  }

because with guaranteeCase it gets to the ExitCase.Canceled even with autoCancelableRunLoops disabled. Is it intended?

Enabling AutoCancelableRunLoops cancels the processing after the task where the error occurred.

I want to continue processing even if an error occurs in this test, but because the processing is canceled on the way, the test did not pass.

Is this forecast correct?

[Avasil]

If there is a sample of how autoCancelableRunLoops behave, can you tell me?

It is a flag which tells whether we should check for cancelation status after asynchronous boundary

I want to continue processing even if an error occurs in this test, but because the processing is canceled on the way, the test did not pass.

Is this forecast correct?

Pretty much. I think if you add .uncancelable in the failing tests, e.g.:

val gather = Task.wanderUnordered(Seq(0, 0)) { _ =>
  Task.raiseError[Int](ex).executeAsync.doOnFinish { x =>
    if (x.isDefined) errorsThrow += 1; Task.unit
  }.uncancelable
}

they will pass with your implementation. I think the task actually finishes before cancelation but is still considered canceled so it is ExitCase.Canceled. In previous implementation if we call .doOnFinish(...).doOnCancel(...) both of these will execute... So it has different behavior than guaranteeWith. What would you expect @oleg-py @alexandru ?

[Avasil]

BTW @BambooTuna Could you also remove DoOnFinish class (it's here: https://github.com/monix/monix/blob/master/monix-eval/shared/src/main/scala/monix/eval/Task.scala#L4482) - it won't be necessary if we change it. :)

You will have to add exclude[MissingClassProblem]("monix.eval.Task$DoOnFinish")
here: https://github.com/monix/monix/blob/master/project/MimaFilters.scala#L6 because it will break Binary Compatibility

[BambooTuna]

To @Avasil
Sorry I'm late.

What I added

• Add uncancelable(Three places)
• Remove DoOnFinish class
• Add exclude[MissingClassProblem]("monix.eval.Task$DoOnFinish") to here: https://github.com/monix/monix/blob/master/project/MimaFilters.scala#L6
• Use scalafmt to fmt code(no change)

Question

In the test, I get an error of

monix.reactive.internal.operators.MapParallelUnorderedSuite
- MVar (async) — issue #380: with foreverM; with latch *** FAILED ***
  AssertionException: ; timed-out after 10 seconds (MVarJVMSuite.scala:318)
    minitest.api.Asserts.assert(Asserts.scala:38)
    minitest.api.Asserts.assert$(Asserts.scala:34)
    monix.catnap.BaseMVarJVMSuite.assert(MVarJVMSuite.scala:100)
    monix.catnap.BaseMVarJVMSuite.$anonfun$new$94(MVarJVMSuite.scala:318)
    scala.collection.immutable.Range.foreach$mVc$sp(Range.scala:158)
    monix.catnap.BaseMVarJVMSuite.$anonfun$new$93(MVarJVMSuite.scala:303)
    minitest.TestSuite.$anonfun$test$1(TestSuite.scala:33)
    minitest.api.TestSpec$.$anonfun$sync$1(TestSpec.scala:51)
    minitest.api.TestSpec.apply(TestSpec.scala:27)
    minitest.api.Properties.$anonfun$iterator$2(Properties.scala:38)
    minitest.api.TestSpec.apply(TestSpec.scala:27)
    minitest.runner.Task.loop$1(Task.scala:56)
    minitest.runner.Task.$anonfun$execute$1(Task.scala:63)
    scala.concurrent.Future.$anonfun$flatMap$1(Future.scala:307)
    scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
    scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
    java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
    java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

, in my local environment.
So, I tried to increase the timeout time, and the test succeeded

https://github.com/BambooTuna/monix/blob/feature/replace-flatMap-to-guaranteeCase-at-Task.doOnFinish/monix-catnap/jvm/src/test/scala/monix/catnap/MVarJVMSuite.scala#L121
To

val timeout = if (isCI) 30.seconds else 30.seconds

I don't know if i have to change it.

Other

val gather = Task.wanderUnordered(Seq(0, 0)) { _ =>
  Task.raiseError[Int](ex).executeAsync.doOnFinish { x =>
    if (x.isDefined) errorsThrow += 1; Task.unit
  }.uncancelable
}

Thanks for the sample code!
I just thought that uncancelable should be added here.

final def doOnFinish(f: Option[Throwable] => Task[Unit]): Task[A] =
  this.uncancelable.guaranteeCase {
    case ExitCase.Completed => f(None)
    case ExitCase.Canceled => Task.unit
    case ExitCase.Error(e) => f(Some(e))
  }

[Avasil]

There are two lists, this one is older, try putting it at the top in the first Seq

You can verify it with mimaReportBinaryIssues

[Avasil]

Sorry I'm late.

Take your time and thank you for the interest in contributing!

I don't know if i have to change it.

I don't recall any problems with it so let's see if it fails on CI

Thanks for the sample code!
I just thought that uncancelable should be added here.

The issue was possibly wrong test (unless I'm wrong here but in that case, guaranteeWith might be buggy), doOnFinish should still work with cancelable Task. In the test, it was canceled because if any of the tasks in Task.wander and Task.gather fails, the others are canceled.

[BambooTuna]

Tests pass in a local environment, but it is useless in CI. . .

[Avasil]

I think tests arent formatted, try test:scalafmt or scalafmtAll

[BambooTuna]

@Avasil
The test passed successfully!
Thank you very much for your support, and I would like to put out a PR if there is something I can do in the future!

[Avasil]

Thank you @BambooTuna ! That's awesome.

I'm going back to Europe soon. I'll wait until I come back to merge PR in case other maintainers have thoughts about the issue with earlier version of the test.

[Avasil]

@Avasil
The test passed successfully!
Thank you very much for your support, and I would like to put out a PR if there is something I can do in the future!

@BambooTuna
If you are still interested and have time, a while ago I have prepared a lot of issues at https://github.com/monix/monix-bio/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22