chore: Rewrite to scala3 syntax

.scalafmt.conf

@@ -1,5 +1,5 @@
 version                                  = 3.11.1
-runner.dialect                           = scala213
+runner.dialect                           = scala213source3
 project.git                              = true
 style                                    = defaultWithAlign
 docstrings.style                         = Asterisk
@@ -76,3 +76,13 @@ project.excludeFilters = [
   "scripts/authors.scala"
 ]
 project.layout         = StandardConvention
+
+rewrite.scala3.convertToNewSyntax = true
+runner {
+  dialectOverride {
+    allowSignificantIndentation = false
+    allowAsForImportRename = false
+    allowStarWildcardImport = false
+    allowPostfixStarVarargSplices = false
+  }
+}

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/Effect.scala

@@ -100,7 +100,7 @@ object Effect {
       with Serializable {
 
     override def equals(other: Any) = other match {
-      case o: Spawned[_] =>
+      case o: Spawned[?] =>
         this.behavior == o.behavior &&
         this.childName == o.childName &&
         this.props == o.props
@@ -113,7 +113,7 @@ object Effect {
     override def _1: Behavior[T] = behavior
     override def _2: String = childName
     override def _3: Props = props
-    override def canEqual(o: Any) = o.isInstanceOf[Spawned[_]]
+    override def canEqual(o: Any) = o.isInstanceOf[Spawned[?]]
   }
 
   object Spawned {
@@ -131,7 +131,7 @@ object Effect {
       with Serializable {
 
     override def equals(other: Any) = other match {
-      case o: SpawnedAnonymous[_] => this.behavior == o.behavior && this.props == o.props
+      case o: SpawnedAnonymous[?] => this.behavior == o.behavior && this.props == o.props
       case _                      => false
     }
     override def hashCode: Int = behavior.## * 31 + props.##
@@ -140,7 +140,7 @@ object Effect {
     override def productPrefix = "SpawnedAnonymous"
     override def _1: Behavior[T] = behavior
     override def _2: Props = props
-    override def canEqual(o: Any) = o.isInstanceOf[SpawnedAnonymous[_]]
+    override def canEqual(o: Any) = o.isInstanceOf[SpawnedAnonymous[?]]
   }
 
   object SpawnedAnonymous {
@@ -160,15 +160,15 @@ object Effect {
       with Serializable {
 
     override def equals(other: Any) = other match {
-      case o: SpawnedAdapter[_] => this.name == o.name
+      case o: SpawnedAdapter[?] => this.name == o.name
       case _                    => false
     }
     override def hashCode: Int = name.##
     override def toString: String = s"SpawnedAdapter($name)"
 
     override def productPrefix = "SpawnedAdapter"
     override def _1: String = name
-    override def canEqual(o: Any) = o.isInstanceOf[SpawnedAdapter[_]]
+    override def canEqual(o: Any) = o.isInstanceOf[SpawnedAdapter[?]]
   }
 
   /**
@@ -192,17 +192,17 @@ object Effect {
       with Serializable {
 
     override def equals(other: Any): Boolean = other match {
-      case _: SpawnedAnonymousAdapter[_] => true
+      case _: SpawnedAnonymousAdapter[?] => true
       case _                             => false
     }
     override def hashCode: Int = Nil.##
     override def toString: String = "SpawnedAnonymousAdapter"
 
     override def productPrefix: String = "SpawnedAnonymousAdapter"
-    override def productIterator: Iterator[_] = Iterator.empty
+    override def productIterator: Iterator[?] = Iterator.empty
     override def productArity: Int = 0
     override def productElement(n: Int) = throw new NoSuchElementException
-    override def canEqual(o: Any): Boolean = o.isInstanceOf[SpawnedAnonymousAdapter[_]]
+    override def canEqual(o: Any): Boolean = o.isInstanceOf[SpawnedAnonymousAdapter[?]]
   }
 
   /**

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/TestKitSettings.scala

@@ -29,7 +29,7 @@ object TestKitSettings {
   /**
    * Reads configuration settings from `pekko.actor.testkit.typed` section.
    */
-  def apply(system: ActorSystem[_]): TestKitSettings =
+  def apply(system: ActorSystem[?]): TestKitSettings =
     Ext(system).settings
 
   /**
@@ -42,7 +42,7 @@ object TestKitSettings {
   /**
    * Java API: Reads configuration settings from `pekko.actor.testkit.typed` section.
    */
-  def create(system: ActorSystem[_]): TestKitSettings =
+  def create(system: ActorSystem[?]): TestKitSettings =
     apply(system)
 
   /**
@@ -53,11 +53,11 @@ object TestKitSettings {
     new TestKitSettings(config)
 
   private object Ext extends ExtensionId[Ext] {
-    override def createExtension(system: ActorSystem[_]): Ext = new Ext(system)
-    def get(system: ActorSystem[_]): Ext = Ext.apply(system)
+    override def createExtension(system: ActorSystem[?]): Ext = new Ext(system)
+    def get(system: ActorSystem[?]): Ext = Ext.apply(system)
   }
 
-  private class Ext(system: ActorSystem[_]) extends Extension {
+  private class Ext(system: ActorSystem[?]) extends Extension {
     val settings: TestKitSettings = TestKitSettings(system.settings.config.getConfig("pekko.actor.testkit.typed"))
   }
 }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/internal/ActorSystemStub.scala

@@ -135,7 +135,7 @@ import com.typesafe.config.{ Config, ConfigFactory }
   override def extension[T <: Extension](ext: ExtensionId[T]): T =
     throw new UnsupportedOperationException("ActorSystemStub cannot register extensions")
 
-  override def hasExtension(ext: ExtensionId[_ <: Extension]): Boolean =
+  override def hasExtension(ext: ExtensionId[? <: Extension]): Boolean =
     throw new UnsupportedOperationException("ActorSystemStub cannot register extensions")
 
   override def log: Logger = LoggerFactory.getLogger(getClass)

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/internal/LoggingTestKitImpl.scala

@@ -48,7 +48,7 @@ import org.slf4j.event.Level
     source: Option[String],
     messageContains: Option[String],
     messageRegex: Option[Regex],
-    cause: Option[Class[_ <: Throwable]],
+    cause: Option[Class[? <: Throwable]],
     mdc: Map[String, String],
     checkExcess: Boolean,
     custom: Option[Function[LoggingEvent, Boolean]])
@@ -95,7 +95,7 @@ import org.slf4j.event.Level
       todo > 0
   }
 
-  override def expect[T](code: => T)(implicit system: ActorSystem[_]): T = {
+  override def expect[T](code: => T)(implicit system: ActorSystem[?]): T = {
     val effectiveLoggerName = loggerName.getOrElse("")
     checkLogback(system)
     TestAppender.setupTestAppender(effectiveLoggerName)
@@ -120,10 +120,10 @@ import org.slf4j.event.Level
     }
   }
 
-  override def expect[T](system: ActorSystem[_], code: Supplier[T]): T =
+  override def expect[T](system: ActorSystem[?], code: Supplier[T]): T =
     expect(code.get())(system)
 
-  private def checkLogback(system: ActorSystem[_]): Unit = {
+  private def checkLogback(system: ActorSystem[?]): Unit = {
     if (!system.dynamicAccess.classIsOnClasspath("ch.qos.logback.classic.spi.ILoggingEvent")) {
       throw new IllegalStateException("LoggingEventFilter requires logback-classic dependency in classpath.")
     }
@@ -166,7 +166,7 @@ import org.slf4j.event.Level
   override def withCustom(newCustom: Function[LoggingEvent, Boolean]): LoggingTestKitImpl =
     copy(custom = Option(newCustom))
 
-  override def withCause(newCause: Class[_ <: Throwable]): javadsl.LoggingTestKit =
+  override def withCause(newCause: Class[? <: Throwable]): javadsl.LoggingTestKit =
     copy(cause = Option(newCause))
 
 }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/internal/StubbedActorContext.scala

@@ -90,7 +90,7 @@ private[pekko] final class FunctionRef[-T](override val path: ActorPath, send: (
   @InternalApi private[pekko] val selfInbox = new TestInboxImpl[T](path)
 
   override val self = selfInbox.ref
-  private var _children = TreeMap.empty[String, BehaviorTestKitImpl[_]]
+  private var _children = TreeMap.empty[String, BehaviorTestKitImpl[?]]
   private val childName = Iterator.from(0).map(Helpers.base64(_))
   private val substituteLoggerFactory = new SubstituteLoggerFactory
   private val logger: Logger = substituteLoggerFactory.getLogger("StubbedLogger")
@@ -230,7 +230,7 @@ private[pekko] final class FunctionRef[-T](override val path: ActorPath, send: (
     checkCurrentActorThread()
   }
 
-  override def setLoggerName(clazz: Class[_]): Unit = {
+  override def setLoggerName(clazz: Class[?]): Unit = {
     // nop as we don't track logger
     checkCurrentActorThread()
   }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/internal/TestKitUtils.scala

@@ -79,7 +79,7 @@ private[pekko] object TestKitUtils {
   // common internal utility impls for Java and Scala
   private val TestKitRegex = """org\.apache\.pekko\.testkit\.typed\.(?:javadsl|scaladsl)\.ActorTestKit(?:\$.*)?""".r
 
-  def testNameFromCallStack(classToStartFrom: Class[_]): String =
+  def testNameFromCallStack(classToStartFrom: Class[?]): String =
     pekko.testkit.TestKitUtils.testNameFromCallStack(classToStartFrom, TestKitRegex)
 
   /**
@@ -90,7 +90,7 @@ private[pekko] object TestKitUtils {
   def scrubActorSystemName(name: String): String =
     pekko.testkit.TestKitUtils.scrubActorSystemName(name)
 
-  def shutdown(system: ActorSystem[_], timeout: Duration, throwIfShutdownTimesOut: Boolean): Unit = {
+  def shutdown(system: ActorSystem[?], timeout: Duration, throwIfShutdownTimesOut: Boolean): Unit = {
     system.terminate()
     try Await.ready(system.whenTerminated, timeout)
     catch {

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/internal/TestProbeImpl.scala

@@ -74,7 +74,7 @@ private[pekko] object TestProbeImpl {
 }
 
 @InternalApi
-private[pekko] final class TestProbeImpl[M](name: String, system: ActorSystem[_])
+private[pekko] final class TestProbeImpl[M](name: String, system: ActorSystem[?])
     extends JavaTestProbe[M]
     with ScalaTestProbe[M]
     with InternalRecipientRef[M] {

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/ActorTestKit.scala

@@ -57,7 +57,7 @@ object ActorTestKit {
    * Config loaded from the provided actor if that exists, otherwise
    * using default configuration from the reference.conf resources that ship with the Akka libraries.
    */
-  def create(system: ActorSystem[_]): ActorTestKit =
+  def create(system: ActorSystem[?]): ActorTestKit =
     new ActorTestKit(scaladsl.ActorTestKit(system))
 
   /**
@@ -123,7 +123,7 @@ object ActorTestKit {
    *                             an error is printed to stdout when the system did not shutdown but
    *                             no exception is thrown.
    */
-  def shutdown(system: ActorSystem[_], duration: Duration, throwIfShutdownTimesOut: Boolean): Unit = {
+  def shutdown(system: ActorSystem[?], duration: Duration, throwIfShutdownTimesOut: Boolean): Unit = {
     TestKitUtils.shutdown(system, duration.toScala, throwIfShutdownTimesOut)
   }
 
@@ -132,7 +132,7 @@ object ActorTestKit {
    * if more time than `system-shutdown-default` passes an exception is thrown
    * (can be configured with `throw-on-shutdown-timeout`).
    */
-  def shutdown(system: ActorSystem[_], duration: Duration): Unit = {
+  def shutdown(system: ActorSystem[?], duration: Duration): Unit = {
     val settings = TestKitSettings.create(system)
     shutdown(system, duration, settings.ThrowOnShutdownTimeout)
   }
@@ -142,7 +142,7 @@ object ActorTestKit {
    * if more time than `system-shutdown-default` passes an exception is thrown
    * (can be configured with `throw-on-shutdown-timeout`).
    */
-  def shutdown(system: ActorSystem[_]): Unit = {
+  def shutdown(system: ActorSystem[?]): Unit = {
     val settings = TestKitSettings.create(system)
     shutdown(system, settings.DefaultActorSystemShutdownTimeout.toJava, settings.ThrowOnShutdownTimeout)
   }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/JUnit5TestKitBuilder.scala

@@ -27,13 +27,13 @@ import com.typesafe.config.Config
 @deprecated("Use JUnitJupiterTestKitBuilder instead", "2.0.0")
 final class JUnit5TestKitBuilder() {
 
-  var system: Option[ActorSystem[_]] = None
+  var system: Option[ActorSystem[?]] = None
 
   var customConfig: Config = ApplicationTestConfig
 
   var name: String = TestKitUtils.testNameFromCallStack(classOf[JUnit5TestKitBuilder])
 
-  def withSystem(system: ActorSystem[_]): JUnit5TestKitBuilder = {
+  def withSystem(system: ActorSystem[?]): JUnit5TestKitBuilder = {
     this.system = Some(system)
     this
   }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/JUnitJupiterTestKitBuilder.scala

@@ -26,13 +26,13 @@ import com.typesafe.config.Config
 
 final class JUnitJupiterTestKitBuilder() {
 
-  var system: Option[ActorSystem[_]] = None
+  var system: Option[ActorSystem[?]] = None
 
   var customConfig: Config = ApplicationTestConfig
 
   var name: String = TestKitUtils.testNameFromCallStack(classOf[JUnitJupiterTestKitBuilder])
 
-  def withSystem(system: ActorSystem[_]): JUnitJupiterTestKitBuilder = {
+  def withSystem(system: ActorSystem[?]): JUnitJupiterTestKitBuilder = {
     this.system = Some(system)
     this
   }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/LoggingTestKit.scala

@@ -78,7 +78,7 @@ import org.slf4j.event.Level
    * Matching events with an included `throwable` that is a class or subclass of the given
    * `Throwable` class.
    */
-  def withCause(newCause: Class[_ <: Throwable]): LoggingTestKit
+  def withCause(newCause: Class[? <: Throwable]): LoggingTestKit
 
   /**
    * Matching events with MDC containing all entries of the given `Map`.
@@ -109,7 +109,7 @@ import org.slf4j.event.Level
    *
    * Care is taken to remove the testkit when the block is finished or aborted.
    */
-  def expect[T](system: ActorSystem[_], code: Supplier[T]): T
+  def expect[T](system: ActorSystem[?], code: Supplier[T]): T
 
 }
 
@@ -198,7 +198,7 @@ object LoggingTestKit {
    *
    * More conditions can be added to the returned [LoggingEventFilter].
    */
-  def error(causeClass: Class[_ <: Throwable]): LoggingTestKit =
+  def error(causeClass: Class[? <: Throwable]): LoggingTestKit =
     empty.withLogLevel(Level.ERROR).withCause(causeClass)
 
   /**

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/ManualTime.scala

@@ -73,7 +73,7 @@ final class ManualTime(delegate: pekko.testkit.ExplicitlyTriggeredScheduler) {
   def timePasses(amount: Duration): Unit = delegate.timePasses(amount.toScala)
 
   @varargs
-  def expectNoMessageFor(duration: Duration, on: TestProbe[_]*): Unit = {
+  def expectNoMessageFor(duration: Duration, on: TestProbe[?]*): Unit = {
     delegate.timePasses(duration.toScala)
     on.foreach(_.expectNoMessage(Duration.ZERO))
   }

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/SerializationTestKit.scala

@@ -20,7 +20,7 @@ import pekko.actor.typed.ActorSystem
 /**
  * Utilities to test serialization.
  */
-class SerializationTestKit(system: ActorSystem[_]) {
+class SerializationTestKit(system: ActorSystem[?]) {
 
   private val delegate = new scaladsl.SerializationTestKit(system)
 

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/TestKitJunitResource.scala

@@ -72,7 +72,7 @@ final class TestKitJunitResource(_kit: ActorTestKit) extends ExternalResource {
   /**
    * Use a custom [[pekko.actor.typed.ActorSystem]] for the actor system.
    */
-  def this(system: ActorSystem[_]) = this(ActorTestKit.create(system))
+  def this(system: ActorSystem[?]) = this(ActorTestKit.create(system))
 
   /**
    * Use a custom config for the actor system.

actor-testkit-typed/src/main/scala/org/apache/pekko/actor/testkit/typed/javadsl/TestProbe.scala

@@ -55,16 +55,16 @@ object FishingOutcomes {
 
 object TestProbe {
 
-  def create[M](system: ActorSystem[_]): TestProbe[M] =
+  def create[M](system: ActorSystem[?]): TestProbe[M] =
     create(name = "testProbe", system)
 
-  def create[M](@nowarn("msg=never used") clazz: Class[M], system: ActorSystem[_]): TestProbe[M] =
+  def create[M](@nowarn("msg=never used") clazz: Class[M], system: ActorSystem[?]): TestProbe[M] =
     create(system)
 
-  def create[M](name: String, system: ActorSystem[_]): TestProbe[M] =
+  def create[M](name: String, system: ActorSystem[?]): TestProbe[M] =
     new TestProbeImpl[M](name, system)
 
-  def create[M](name: String, @nowarn("msg=never used") clazz: Class[M], system: ActorSystem[_]): TestProbe[M] =
+  def create[M](name: String, @nowarn("msg=never used") clazz: Class[M], system: ActorSystem[?]): TestProbe[M] =
     new TestProbeImpl[M](name, system)
 }