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Fix issue where fromAsyncStateAction is not safe for user code (Backport to 2.x) #475

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Merged
alexandru merged 1 commit into from
Dec 26, 2017
Merged

Fix issue where fromAsyncStateAction is not safe for user code (Backport to 2.x) #475

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5 changes: 4 additions & 1 deletion AUTHORS
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Original file line number Diff line number Diff line change
Expand Up @@ -17,4 +17,7 @@ Jisoo Park
https://github.com/guersam

Dawid Dworak
https://github.com/ddworak
https://github.com/ddworak

Ryo Fukumuro
https://github.com/rfkm
16 changes: 11 additions & 5 deletions ...e/shared/src/main/scala/monix/reactive/internal/builders/AsyncStateActionObservable.scala
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Expand Up @@ -46,12 +46,18 @@ class AsyncStateActionObservable[S,A](seed: => S, f: S => Task[(A,S)]) extends O
}

def loop(subscriber: Subscriber[A], state: S): Task[Unit] =
try f(state).flatMap { case (a, newState) =>
Task.fromFuture(subscriber.onNext(a)).flatMap {
case Continue => loop(subscriber, newState)
case Stop => Task.unit
try f(state).transformWith(
{ case (a, newState) =>
Task.fromFuture(subscriber.onNext(a)).flatMap {
case Continue => loop(subscriber, newState)
case Stop => Task.unit
}
},
{ ex =>
subscriber.onError(ex)
Task.unit
}
} catch {
) catch {
case NonFatal(ex) =>
Task.raiseError(ex)
}
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13 changes: 13 additions & 0 deletions ...red/src/test/scala/monix/reactive/internal/builders/AsyncStateActionObservableSuite.scala
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Expand Up @@ -22,10 +22,13 @@ import monix.eval.Task
import monix.execution.Ack.Continue
import monix.execution.internal.Platform
import monix.execution.ExecutionModel.AlwaysAsyncExecution
import monix.execution.exceptions.DummyException
import monix.execution.schedulers.TestScheduler
import monix.reactive.Observable
import monix.reactive.observers.Subscriber

import scala.util.Failure

object AsyncStateActionObservableSuite extends TestSuite[TestScheduler] {
def setup() = TestScheduler()
def tearDown(s: TestScheduler): Unit = {
Expand Down Expand Up @@ -88,6 +91,15 @@ object AsyncStateActionObservableSuite extends TestSuite[TestScheduler] {
assert(!wasCompleted)
}

test("should protect against user code errors") { implicit s =>
val ex = DummyException("dummy")
val f = Observable.fromAsyncStateAction(intError(ex))(s.currentTimeMillis())
.runAsyncGetFirst

s.tick()
assertEquals(f.value, Some(Failure(ex)))
}

test("should respect the ExecutionModel") { scheduler =>
implicit val s = scheduler.withExecutionModel(AlwaysAsyncExecution)

Expand All @@ -109,6 +121,7 @@ object AsyncStateActionObservableSuite extends TestSuite[TestScheduler] {

def intAsync(seed: Long) = Task(int(seed))
def intNow(seed: Long) = Task.now(int(seed))
def intError(ex: Throwable)(seed: Long) = Task.raiseError[(Int, Long)](ex)

def int(seed: Long): (Int, Long) = {
// `&` is bitwise AND. We use the current seed to generate a new seed.
Expand Down