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Fix ZManaged parallel combinators: nested finalizer ordering #4040

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merged 2 commits into from
Aug 3, 2020
Merged

Fix ZManaged parallel combinators: nested finalizer ordering #4040

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80a786a
Fix ZManaged parallel combinators: nested finalizer ordering
iravid Aug 2, 2020
4527d22
Stray nonFlaky
iravid Aug 2, 2020
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59 changes: 50 additions & 9 deletions core-tests/shared/src/test/scala/zio/ZManagedSpec.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -39,15 +39,6 @@ object ZManagedSpec extends ZIOBaseSpec {
values <- program.use_(ZIO.unit) *> effects.get
} yield assert(values)(equalTo(List(1, 2, 3, 3, 2, 1)))
},
testM("Properly performs parallel acquire and release") {
for {
log <- Ref.make[List[String]](Nil)
a = ZManaged.make(UIO.succeed("A"))(_ => log.update("A" :: _))
b = ZManaged.make(UIO.succeed("B"))(_ => log.update("B" :: _))
result <- a.zipWithPar(b)(_ + _).use(ZIO.succeed(_))
cleanups <- log.get
} yield assert(result.length)(equalTo(2)) && assert(cleanups)(hasSize(equalTo(2)))
},
testM("Constructs an uninterruptible Managed value") {
doInterrupt(io => ZManaged.make(io)(_ => IO.unit), _ => None)
},
Expand Down Expand Up @@ -126,6 +117,32 @@ object ZManagedSpec extends ZIOBaseSpec {
} yield assert(result)(equalTo(List[Exit[Any, Any]](Exit.Failure(Cause.Die(acquireEx)))))
}
) @@ zioTag(errors),
suite("zipWithPar")(
testM("Properly performs parallel acquire and release") {
for {
log <- Ref.make[List[String]](Nil)
a = ZManaged.make(UIO.succeed("A"))(_ => log.update("A" :: _))
b = ZManaged.make(UIO.succeed("B"))(_ => log.update("B" :: _))
result <- a.zipWithPar(b)(_ + _).use(ZIO.succeed(_))
cleanups <- log.get
} yield assert(result.length)(equalTo(2)) && assert(cleanups)(hasSize(equalTo(2)))
},
testM("preserves ordering of nested finalizers") {
val inner = Ref.make(List[Int]()).toManaged_.flatMap { ref =>
ZManaged.finalizer(ref.update(1 :: _)) *>
ZManaged.finalizer(ref.update(2 :: _)) *>
ZManaged.finalizer(ref.update(3 :: _)).as(ref)
}

(inner <&> inner).useNow.flatMap {
case (l, r) => l.get <*> r.get
}.map {
case (l, r) =>
assert(l)(equalTo(List(1, 2, 3))) &&
assert(r)(equalTo(List(1, 2, 3)))
}
} @@ TestAspect.nonFlaky
),
suite("fromEffect")(
testM("Performed interruptibly") {
assertM(ZManaged.fromEffect(ZIO.checkInterruptible(ZIO.succeed(_))).use(ZIO.succeed(_)))(
Expand Down Expand Up @@ -337,6 +354,9 @@ object ZManagedSpec extends ZIOBaseSpec {
},
testM("Runs acquisitions in parallel") {
testAcquirePar(4, res => ZManaged.foreachPar(List(1, 2, 3, 4))(_ => res))
},
testM("Maintains finalizer ordering in inner ZManaged values") {
checkM(Gen.int(5, 100))(l => testParallelNestedFinalizerOrdering(l, ZManaged.foreachPar(_)(identity)))
}
),
suite("foreachParN")(
Expand All @@ -355,6 +375,11 @@ object ZManagedSpec extends ZIOBaseSpec {
},
testM("Runs finalizers") {
testAcquirePar(2, res => ZManaged.foreachParN(2)(List(1, 2, 3, 4))(_ => res))
},
testM("Maintains finalizer ordering in inner ZManaged values") {
checkM(Gen.int(4, 10), Gen.int(5, 100)) { (n, l) =>
testParallelNestedFinalizerOrdering(l, ZManaged.foreachParN(n)(_)(identity))
}
}
),
suite("foreach_")(
Expand Down Expand Up @@ -1649,4 +1674,20 @@ object ZManagedSpec extends ZIOBaseSpec {
count <- effects.get
_ <- reserveLatch.succeed(())
} yield assert(count)(equalTo(n))

def testParallelNestedFinalizerOrdering(
listLength: Int,
f: List[ZManaged[Any, Nothing, Ref[List[Int]]]] => ZManaged[Any, Nothing, List[Ref[List[Int]]]]
) = {
val inner = Ref.make(List[Int]()).toManaged_.flatMap { ref =>
ZManaged.finalizer(ref.update(1 :: _)) *>
ZManaged.finalizer(ref.update(2 :: _)) *>
ZManaged.finalizer(ref.update(3 :: _)).as(ref)
}

f(List.fill(listLength)(inner)).useNow
.flatMap(refs => ZIO.foreach(refs)(_.get))
.map(results => assert(results)(forall(equalTo(List(1, 2, 3)))))
}

}
51 changes: 36 additions & 15 deletions core/shared/src/main/scala/zio/ZManaged.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -1114,15 +1114,22 @@ abstract class ZManaged[-R, +E, +A] extends Serializable { self =>
*/
def zipWithPar[R1 <: R, E1 >: E, A1, A2](that: ZManaged[R1, E1, A1])(f: (A, A1) => A2): ZManaged[R1, E1, A2] =
ZManaged.ReleaseMap.makeManaged(ExecutionStrategy.Parallel).mapM { parallelReleaseMap =>
self.zio
.zipWithPar(that.zio) {
// We can safely discard the finalizers here because the resulting ZManaged's early
// release will trigger the ReleaseMap, which would release both finalizers in
// parallel.
case ((_, a), (_, b)) =>
f(a, b)
}
.provideSome[R1]((_, parallelReleaseMap))
val innerMap =
ZManaged.ReleaseMap.makeManaged(ExecutionStrategy.Sequential).zio.provideSome[R1]((_, parallelReleaseMap))

(innerMap zip innerMap) flatMap {
case ((_, l), (_, r)) =>
self.zio
.provideSome[R1]((_, l))
.zipWithPar(that.zio.provideSome[R1]((_, r))) {
// We can safely discard the finalizers here because the resulting ZManaged's early
// release will trigger the ReleaseMap, which would release both finalizers in
// parallel.
case ((_, a), (_, b)) =>
f(a, b)
}

}
}
}

Expand Down Expand Up @@ -1649,10 +1656,14 @@ object ZManaged extends ZManagedPlatformSpecific {
ReleaseMap
.makeManaged(ExecutionStrategy.Parallel)
.mapM { parallelReleaseMap =>
val makeInnerMap =
ReleaseMap.makeManaged(ExecutionStrategy.Sequential).zio.map(_._2).provideSome[Any]((_, parallelReleaseMap))

ZIO
.foreachPar(as.toIterable)(f(_).zio.map(_._2))
.foreachPar(as.toIterable)(a =>
makeInnerMap.flatMap(innerMap => f(a).zio.map(_._2).provideSome[R]((_, innerMap)))
)
.map(bf.fromSpecific(as))
.provideSome[R]((_, parallelReleaseMap))
}

/**
Expand All @@ -1668,10 +1679,14 @@ object ZManaged extends ZManagedPlatformSpecific {
ReleaseMap
.makeManaged(ExecutionStrategy.ParallelN(n))
.mapM { parallelReleaseMap =>
val makeInnerMap =
ReleaseMap.makeManaged(ExecutionStrategy.Sequential).zio.map(_._2).provideSome[Any]((_, parallelReleaseMap))

ZIO
.foreachParN(n)(as.toIterable)(f(_).zio.map(_._2))
.foreachParN(n)(as.toIterable)(a =>
makeInnerMap.flatMap(innerMap => f(a).zio.map(_._2).provideSome[R]((_, innerMap)))
)
.map(bf.fromSpecific(as))
.provideSome[R]((_, parallelReleaseMap))
}

/**
Expand All @@ -1695,7 +1710,10 @@ object ZManaged extends ZManagedPlatformSpecific {
*/
def foreachPar_[R, E, A](as: Iterable[A])(f: A => ZManaged[R, E, Any]): ZManaged[R, E, Unit] =
ReleaseMap.makeManaged(ExecutionStrategy.Parallel).mapM { parallelReleaseMap =>
ZIO.foreachPar_(as)(f(_).zio.map(_._2)).provideSome[R]((_, parallelReleaseMap))
val makeInnerMap =
ReleaseMap.makeManaged(ExecutionStrategy.Sequential).zio.map(_._2).provideSome[Any]((_, parallelReleaseMap))

ZIO.foreachPar_(as)(a => makeInnerMap.flatMap(innerMap => f(a).zio.map(_._2).provideSome[R]((_, innerMap))))
}

/**
Expand All @@ -1712,7 +1730,10 @@ object ZManaged extends ZManagedPlatformSpecific {
f: A => ZManaged[R, E, Any]
): ZManaged[R, E, Unit] =
ReleaseMap.makeManaged(ExecutionStrategy.ParallelN(n)).mapM { parallelReleaseMap =>
ZIO.foreachParN_(n)(as)(f(_).zio.map(_._2)).provideSome[R]((_, parallelReleaseMap))
val makeInnerMap =
ReleaseMap.makeManaged(ExecutionStrategy.Sequential).zio.map(_._2).provideSome[Any]((_, parallelReleaseMap))

ZIO.foreachParN_(n)(as)(a => makeInnerMap.flatMap(innerMap => f(a).zio.map(_._2).provideSome[R]((_, innerMap))))
}

/**
Expand Down