Merge pull request #4312 from typelevel/release/3.6.0-major

Merge changes from 3.6.0 into series/3.x

Author: armanbilge

README.md

@@ -11,11 +11,11 @@
 
 ## Getting Started
 
-- Wired: **3.5.7**
+- Wired: **3.6.0**
 - Tired: **2.5.5** (end of life)
 
 ```scala
-libraryDependencies += "org.typelevel" %% "cats-effect" % "3.5.7"
+libraryDependencies += "org.typelevel" %% "cats-effect" % "3.6.0"
 ```
 
 The above represents the core, stable dependency which brings in the entirety of Cats Effect. This is *most likely* what you want. All current Cats Effect releases are published for Scala 2.12, 2.13, 3.2, and Scala.js 1.13.
@@ -30,22 +30,22 @@ Depending on your use-case, you may want to consider one of the several other mo
 
 ```scala
 libraryDependencies ++= Seq(
-  "org.typelevel" %% "cats-effect-kernel" % "3.5.7",
-  "org.typelevel" %% "cats-effect-laws"   % "3.5.7" % Test)
+  "org.typelevel" %% "cats-effect-kernel" % "3.6.0",
+  "org.typelevel" %% "cats-effect-laws"   % "3.6.0" % Test)
 ```
 
 If you're a middleware framework (like [Fs2](https://fs2.io/)), you probably want to depend on **std**, which gives you access to `Queue`, `Semaphore`, and much more without introducing a hard-dependency on `IO` outside of your tests:
 
 ```scala
 libraryDependencies ++= Seq(
-  "org.typelevel" %% "cats-effect-std" % "3.5.7",
-  "org.typelevel" %% "cats-effect"     % "3.5.7" % Test)
+  "org.typelevel" %% "cats-effect-std" % "3.6.0",
+  "org.typelevel" %% "cats-effect"     % "3.6.0" % Test)
 ```
 
 You may also find some utility in the **testkit** and **kernel-testkit** projects, which contain `TestContext`, generators for `IO`, and a few other things:
 
 ```scala
-libraryDependencies += "org.typelevel" %% "cats-effect-testkit" % "3.5.7" % Test
+libraryDependencies += "org.typelevel" %% "cats-effect-testkit" % "3.6.0" % Test
 ```
 
 Cats Effect provides backward binary compatibility within the 2.x and 3.x version lines, and both forward and backward compatibility within any major/minor line. This is analogous to the versioning scheme used by Cats itself, as well as other major projects such as Scala.js. Thus, any project depending upon Cats Effect 2.2.1 can be used with libraries compiled against Cats Effect 2.0.0 or 2.2.3, but *not* with libraries compiled against 2.3.0 or higher.

core/jvm/src/main/scala/cats/effect/unsafe/SelectorSystem.scala

@@ -88,7 +88,7 @@ final class SelectorSystem private (provider: SelectorProvider) extends PollingS
           if (cb != null) {
             cb(value)
             fibersRescheduled = true
-            if (error ne null) poller.countSucceededOperation(readyOps)
+            if (error eq null) poller.countSucceededOperation(readyOps)
             else poller.countErroredOperation(node.interest)
           } else {
             poller.countCanceledOperation(node.interest)

core/jvm/src/main/scala/cats/effect/unsafe/WorkStealingThreadPool.scala

@@ -39,8 +39,7 @@ import scala.concurrent.duration.{Duration, FiniteDuration}
 
 import java.time.Instant
 import java.time.temporal.ChronoField
-import java.util.Comparator
-import java.util.concurrent.{ConcurrentSkipListSet, ThreadLocalRandom}
+import java.util.concurrent.{LinkedTransferQueue, ThreadLocalRandom}
 import java.util.concurrent.atomic.{
   AtomicBoolean,
   AtomicInteger,
@@ -132,8 +131,8 @@ private[effect] final class WorkStealingThreadPool[P <: AnyRef](
    */
   private[this] val state: AtomicInteger = new AtomicInteger(threadCount << UnparkShift)
 
-  private[unsafe] val cachedThreads: ConcurrentSkipListSet[WorkerThread[P]] =
-    new ConcurrentSkipListSet(Comparator.comparingInt[WorkerThread[P]](_.nameIndex))
+  private[unsafe] val cachedThreads: LinkedTransferQueue[WorkerThread[P]] =
+    new LinkedTransferQueue
 
   /**
    * The shutdown latch of the work stealing thread pool.
@@ -751,7 +750,7 @@ private[effect] final class WorkStealingThreadPool[P <: AnyRef](
 
       var t: WorkerThread[P] = null
       while ({
-        t = cachedThreads.pollFirst()
+        t = cachedThreads.poll()
         t ne null
       }) {
         t.interrupt()

core/jvm/src/main/scala/cats/effect/unsafe/WorkerThread.scala

@@ -727,30 +727,19 @@ private[effect] final class WorkerThread[P <: AnyRef](
         metrics = null
         transferState = null
 
-        // Add this thread to the cached threads data structure, to be picked up
-        // by another thread in the future.
-        pool.cachedThreads.add(this)
         try {
+          // Try to transfer this thread via the cached threads data structure, to be picked up
+          // by another thread in the future.
           val len = runtimeBlockingExpiration.length
           val unit = runtimeBlockingExpiration.unit
-          var newState = stateTransfer.poll(len, unit)
-          if (newState eq null) {
-            // The timeout elapsed and no one woke up this thread. Try to remove
-            // the thread from the cached threads data structure.
-            if (pool.cachedThreads.remove(this)) {
-              // The thread was successfully removed. It's time to exit.
-              pool.blockedWorkerThreadCounter.decrementAndGet()
-              return
-            } else {
-              // Someone else concurrently stole this thread from the cached
-              // data structure and will transfer the data soon. Time to wait
-              // for it again.
-              newState = stateTransfer.take()
-              init(newState)
-            }
-          } else {
-            // Some other thread woke up this thread. Time to take its place.
+          if (pool.cachedThreads.tryTransfer(this, len, unit)) {
+            // Someone accepted the transfer of this thread and will transfer the state soon.
+            val newState = stateTransfer.take()
             init(newState)
+          } else {
+            // The timeout elapsed and no one woke up this thread. It's time to exit.
+            pool.blockedWorkerThreadCounter.decrementAndGet()
+            return
           }
         } catch {
           case _: InterruptedException =>
@@ -939,7 +928,7 @@ private[effect] final class WorkerThread[P <: AnyRef](
       // Set the name of this thread to a blocker prefixed name.
       setName(s"$prefix-$nameIndex")
 
-      val cached = pool.cachedThreads.pollFirst()
+      val cached = pool.cachedThreads.poll()
       if (cached ne null) {
         // There is a cached worker thread that can be reused.
         val idx = index

docs/core/native-image.md

@@ -33,7 +33,7 @@ ThisBuild / scalaVersion := "2.13.8"
 
 lazy val root = (project in file(".")).enablePlugins(NativeImagePlugin).settings(
   name                := "cats-effect-3-hello-world",
-  libraryDependencies += "org.typelevel" %% "cats-effect" % "3.5.7",
+  libraryDependencies += "org.typelevel" %% "cats-effect" % "3.6.0",
   Compile / mainClass := Some("com.example.Main"),
   nativeImageOptions  += "--no-fallback",
   nativeImageVersion  := "22.1.0" // It should be at least version 21.0.0

docs/core/scala-native.md

@@ -22,7 +22,7 @@ lazy val root = project.in(file("."))
   .enablePlugins(ScalaNativePlugin)
   .settings(
     name                := "cats-effect-3-hello-world",
-    libraryDependencies += "org.typelevel" %%% "cats-effect" % "3.5.7",
+    libraryDependencies += "org.typelevel" %%% "cats-effect" % "3.6.0",
     Compile / mainClass := Some("com.example.Main")
  )
 

docs/core/test-runtime.md

@@ -28,7 +28,7 @@ For those migrating code from Cats Effect 2, `TestControl` is a considerably mor
 In order to use `TestControl`, you will need to bring in the **cats-effect-testkit** dependency:
 
 ```scala
-libraryDependencies += "org.typelevel" %% "cats-effect-testkit" % "3.5.7" % Test
+libraryDependencies += "org.typelevel" %% "cats-effect-testkit" % "3.6.0" % Test
 ```
 
 ## Example

docs/faq.md

@@ -9,7 +9,7 @@ title: FAQ
 
 ```scala-cli
 //> using scala "2.13.8"
-//> using lib "org.typelevel::cats-effect::3.5.7"
+//> using lib "org.typelevel::cats-effect::3.6.0"
 
 import cats.effect._
 

docs/getting-started.md

@@ -6,7 +6,7 @@ title: Getting Started
 Add the following to your **build.sbt**:
 
 ```scala
-libraryDependencies += "org.typelevel" %% "cats-effect" % "3.5.7"
+libraryDependencies += "org.typelevel" %% "cats-effect" % "3.6.0"
 ```
 
 Naturally, if you're using ScalaJS, you should replace the double `%%` with a triple `%%%`. If you're on Scala 2, it is *highly* recommended that you enable the [better-monadic-for](https://github.com/oleg-py/better-monadic-for) plugin, which fixes a number of surprising elements of the `for`-comprehension syntax in the Scala language:
@@ -68,7 +68,7 @@ We will learn more about constructs like `start` and `*>` in later pages, but fo
 Of course, the easiest way to play with Cats Effect is to try it out in a Scala REPL. We recommend using [Ammonite](https://ammonite.io/#Ammonite-REPL) for this kind of thing. To get started, run the following lines (if not using Ammonite, skip the first line and make sure that Cats Effect and its dependencies are correctly configured on the classpath):
 
 ```scala
-import $ivy.`org.typelevel::cats-effect:3.5.7`
+import $ivy.`org.typelevel::cats-effect:3.6.0`
 
 import cats.effect.unsafe.implicits._
 import cats.effect.IO

docs/migration-guide.md

@@ -81,9 +81,9 @@ Cats Effect 3 splits the code dependency into multiple modules. If you were prev
 The current non-test modules are:
 
 ```scala
-"org.typelevel" %% "cats-effect-kernel" % "3.5.7",
-"org.typelevel" %% "cats-effect-std"    % "3.5.7",
-"org.typelevel" %% "cats-effect"        % "3.5.7",
+"org.typelevel" %% "cats-effect-kernel" % "3.6.0",
+"org.typelevel" %% "cats-effect-std"    % "3.6.0",
+"org.typelevel" %% "cats-effect"        % "3.6.0",
 ```
 
 - `kernel` - type class definitions, simple concurrency primitives
@@ -96,7 +96,7 @@ The current non-test modules are:
 libraryDependencies ++= Seq(
   //...
 -  "org.typelevel" %% "cats-effect" % "2.4.0",
-+  "org.typelevel" %% "cats-effect" % "3.5.7",
++  "org.typelevel" %% "cats-effect" % "3.6.0",
   //...
 )
 ```