From e8aa54dcd68a43e1be9727e3f90dacf97288e5b7 Mon Sep 17 00:00:00 2001
From: kyri-petrou <67301607+kyri-petrou@users.noreply.github.com>
Date: Sat, 27 Jul 2024 09:14:04 +0300
Subject: [PATCH] Fix propagation of interruption from CIO to ZIO (#697)

* Fix propagation of interruption from CIO to ZIO

* Wrap method in F.delay

* Allow interruption of interruption

* Fix compiling

* Make sure to complete the interruption CB

* Simplify logic by making interruption un-cancellable
---
 .../scala/zio/interop/CatsInteropSpec.scala   | 24 ++++++++++++++++++-
 .../src/main/scala/zio/interop/package.scala  | 24 ++++++++++++-------
 2 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/zio-interop-cats-tests/jvm/src/test/scala/zio/interop/CatsInteropSpec.scala b/zio-interop-cats-tests/jvm/src/test/scala/zio/interop/CatsInteropSpec.scala
index f83c3c00..26c7e7d6 100644
--- a/zio-interop-cats-tests/jvm/src/test/scala/zio/interop/CatsInteropSpec.scala
+++ b/zio-interop-cats-tests/jvm/src/test/scala/zio/interop/CatsInteropSpec.scala
@@ -6,6 +6,9 @@ import zio.interop.catz.*
 import zio.test.*
 import zio.*
 
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.atomic.AtomicBoolean
+
 object CatsInteropSpec extends CatsRunnableSpec {
   def spec: Spec[Any, Throwable] = suite("Cats interop")(
     test("cats fiber wrapped in Resource can be canceled") {
@@ -203,6 +206,25 @@ object CatsInteropSpec extends CatsRunnableSpec {
         !exception.get.getMessage.contains("Boxed Exception") &&
           exception.get.getMessage.contains("The fiber was canceled")
       )
-    }
+    },
+    test("CIO propagates interruption to ZIO") {
+      ZIO.succeedBlocking {
+        val latch              = new CompletableFuture[Unit]()
+        val ref                = new AtomicBoolean(false)
+        val zioF: CIO[Nothing] =
+          (ZIO.yieldNow.as(latch.complete(())) *> ZIO.never)
+            .onInterrupt(ZIO.succeed(ref.set(true)))
+            .toEffect[CIO]
+
+        val value = zioF.start
+          .productL(CIO.fromCompletableFuture(CIO(latch)))
+          .flatMap { (fib: cats.effect.FiberIO[Nothing]) =>
+            fib.cancel *> CIO(ref.get())
+          }
+          .unsafeRunSync()
+
+        assertTrue(value)
+      }
+    } @@ TestAspect.nonFlaky(1000)
   )
 }
diff --git a/zio-interop-cats/shared/src/main/scala/zio/interop/package.scala b/zio-interop-cats/shared/src/main/scala/zio/interop/package.scala
index 046bfa0d..9736e6f7 100644
--- a/zio-interop-cats/shared/src/main/scala/zio/interop/package.scala
+++ b/zio-interop-cats/shared/src/main/scala/zio/interop/package.scala
@@ -34,21 +34,27 @@ package object interop {
   @inline def toEffect[F[_], R, A](rio: RIO[R, A])(implicit R: Runtime[R], F: Async[F], trace: Trace): F[A] =
     F.defer {
       val interrupted = new AtomicBoolean(true)
-      F.async[Exit[Throwable, A]] { cb =>
-        Unsafe.unsafe { implicit unsafe =>
-          val fiber          = R.unsafe.fork {
+      F.asyncCheckAttempt[Exit[Throwable, A]] { cb =>
+        F.delay {
+          implicit val unsafe: Unsafe = Unsafe.unsafe
+
+          val out = R.unsafe.runOrFork {
             signalOnNoExternalInterrupt {
               rio
             }(ZIO.succeed(interrupted.set(false)))
           }
-          fiber.unsafe
-            .addObserver(exit => cb(Right(exit)))
-          val cancelerEffect = F.delay {
-            val _ = fiber.interrupt
+          out match {
+            case Left(fiber) =>
+              val completeCb = (exit: Exit[Throwable, A]) => cb(Right(exit))
+              fiber.unsafe.addObserver(completeCb)
+              Left(Some(F.async_ { cb =>
+                fiber.unsafe.addObserver(_ => cb(Right(())))
+                fiber.unsafe.removeObserver(completeCb)
+                fiber.tellInterrupt(Cause.interrupt(fiber.id))
+              }))
+            case Right(v)    => Right(v) // No need to invoke the callback, sync resumption will take place
           }
-          F.pure(Some(cancelerEffect))
         }
-
       }.flatMap { exit =>
         toOutcomeThrowableOtherFiber(interrupted.get())(F.pure(_: A), exit) match {
           case Outcome.Succeeded(fa) =>