From 5e320e3de6b0541c5dd8703351f75a2301d05f56 Mon Sep 17 00:00:00 2001
From: Kai <450507+neko-kai@users.noreply.github.com>
Date: Sat, 3 Oct 2020 08:27:27 +0100
Subject: [PATCH] Fix resource leak in `.toResourceZIO` that could happen just
 after ZManaged was acquired but before the finalizer was registered in
 Resource interpreter
 (https://github.com/typelevel/cats-effect/blob/bf1fa530bd651325c7b060389952d37b4852d5e5/core/shared/src/main/scala/cats/effect/Resource.scala#L133)
 (#234)

---
 .../main/scala/zio/interop/catszmanaged.scala | 43 +++++++++----------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/interop-cats/shared/src/main/scala/zio/interop/catszmanaged.scala b/interop-cats/shared/src/main/scala/zio/interop/catszmanaged.scala
index 90c09786..cd4b3f23 100644
--- a/interop-cats/shared/src/main/scala/zio/interop/catszmanaged.scala
+++ b/interop-cats/shared/src/main/scala/zio/interop/catszmanaged.scala
@@ -17,12 +17,10 @@
 package zio
 package interop
 
-import cats.~>
-import cats.arrow.FunctionK
+import cats.arrow.{ ArrowChoice, FunctionK }
 import cats.effect.Resource.{ Allocate, Bind, Suspend }
 import cats.effect.{ Async, Effect, ExitCase, LiftIO, Resource, Sync, IO => CIO }
-import cats.{ Bifunctor, Monad, MonadError, Monoid, Semigroup, SemigroupK }
-import cats.arrow.ArrowChoice
+import cats.{ ~>, Bifunctor, Monad, MonadError, Monoid, Semigroup, SemigroupK }
 import zio.ZManaged.ReleaseMap
 
 trait CatsZManagedSyntax {
@@ -82,26 +80,25 @@ final class CatsIOResourceSyntax[F[_], A](private val resource: Resource[F, A])
 final class ZManagedSyntax[R, E, A](private val managed: ZManaged[R, E, A]) extends AnyVal {
 
   def toResourceZIO: Resource[ZIO[R, E, ?], A] =
-    Resource.suspend {
-      ZManaged.ReleaseMap.make.bracketExit(
-        release = (releaseMap: ReleaseMap, exit: Exit[E, _]) =>
-          exit match {
-            case Exit.Success(_) => UIO.unit
-            case Exit.Failure(_) => releaseMap.releaseAll(exit, ExecutionStrategy.Sequential)
-          },
-        use = releaseMap =>
-          managed.zio.provideSome[R]((_, releaseMap)).map {
-            case (_, a) =>
-              Resource.applyCase(ZIO.succeedNow {
-                (
-                  a,
-                  (exitCase: ExitCase[Throwable]) =>
-                    releaseMap.releaseAll(exitCaseToExit(exitCase), ExecutionStrategy.Sequential).unit
-                )
-              })
-          }
+    Resource
+      .applyCase[ZIO[R, E, ?], ReleaseMap](
+        ZManaged.ReleaseMap.make.map(
+          releaseMap =>
+            (
+              releaseMap,
+              (exitCase: ExitCase[Throwable]) =>
+                releaseMap.releaseAll(exitCaseToExit(exitCase), ExecutionStrategy.Sequential).unit
+            )
+        )
+      )
+      .flatMap(
+        releaseMap =>
+          Resource.suspend(
+            managed.zio.provideSome[R]((_, releaseMap)).map { a =>
+              Resource.applyCase(ZIO.succeedNow((a._2, (_: ExitCase[Throwable]) => ZIO.unit)))
+            }
+          )
       )
-    }
 
   def toResource[F[_]](implicit F: Async[F], ev: Effect[ZIO[R, E, ?]]): Resource[F, A] =
     toResourceZIO.mapK(Lambda[FunctionK[ZIO[R, E, ?], F]](F liftIO ev.toIO(_)))