Merge pull request #278 from altoo-ag/wip-277-scala3-enum-nvo

Adds Scala 3 enum serializer

README.md

@@ -3,6 +3,8 @@ akka-kryo-serialization - kryo-based serializers for Scala and Akka
 [![Full test prior to release](https://github.com/altoo-ag/akka-kryo-serialization/actions/workflows/fullTest.yml/badge.svg)](https://github.com/altoo-ag/akka-kryo-serialization/actions/workflows/fullTest.yml)
 [![Latest version](https://index.scala-lang.org/altoo-ag/akka-kryo-serialization/akka-kryo-serialization/latest.svg)](https://index.scala-lang.org/altoo-ag/akka-kryo-serialization/akka-kryo-serialization)
 
+:warning: **We found issues serializing Scala 3 Enums. If you use akka-kryo-serialization with Scala 3 you should upgrade to 2.4.1 asap.**
+
 This library provides custom Kryo-based serializers for Scala and Akka. It can be
 used for more efficient akka actor's remoting.
 

akka-kryo-serialization/src/main/scala-2.12/io/altoo/akka/serialization/kryo/ScalaVersionSerializers.scala

@@ -12,4 +12,6 @@ private[kryo] object ScalaVersionSerializers {
   def iterable(kryo: Kryo) = {
     kryo.addDefaultSerializer(classOf[scala.collection.Traversable[_]], classOf[ScalaCollectionSerializer])
   }
+
+  def enums(kryo: Kryo): Unit = () // Scala 3 only
 }

akka-kryo-serialization/src/main/scala-2.13/io/altoo/akka/serialization/kryo/ScalaVersionSerializers.scala

@@ -11,4 +11,6 @@ private[kryo] object ScalaVersionSerializers {
   def iterable(kryo: Kryo): Unit = {
     kryo.addDefaultSerializer(classOf[scala.collection.Iterable[_]], classOf[ScalaCollectionSerializer])
   }
+
+  def enums(kryo: Kryo): Unit = () // Scala 3 only
 }

akka-kryo-serialization/src/main/scala-3/io/altoo/akka/serialization/kryo/ScalaVersionSerializers.scala

@@ -0,0 +1,18 @@
+package io.altoo.akka.serialization.kryo
+
+import com.esotericsoftware.kryo.Kryo
+import io.altoo.akka.serialization.kryo.serializer.scala.{ScalaCollectionSerializer, ScalaEnumNameSerializer, ScalaImmutableMapSerializer}
+
+private[kryo] object ScalaVersionSerializers {
+  def mapAndSet(kryo: Kryo): Unit = {
+    kryo.addDefaultSerializer(classOf[scala.collection.MapFactory[_root_.scala.collection.Map]], classOf[ScalaImmutableMapSerializer])
+  }
+
+  def iterable(kryo: Kryo): Unit = {
+    kryo.addDefaultSerializer(classOf[scala.collection.Iterable[_]], classOf[ScalaCollectionSerializer])
+  }
+
+  def enums(kryo: Kryo): Unit = {
+    kryo.addDefaultSerializer(classOf[scala.runtime.EnumValue], classOf[ScalaEnumNameSerializer[scala.runtime.EnumValue]])
+  }
+}

akka-kryo-serialization/src/main/scala-3/io/altoo/akka/serialization/kryo/serializer/scala/ScalaCollectionSerializer.scala

@@ -0,0 +1,51 @@
+/**
+ * *****************************************************************************
+ * Copyright 2012 Roman Levenstein
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ****************************************************************************
+ */
+
+package io.altoo.akka.serialization.kryo.serializer.scala
+
+import com.esotericsoftware.kryo.io.{Input, Output}
+import com.esotericsoftware.kryo.{Kryo, Serializer}
+
+/**
+ * Generic serializer for traversable collections
+ *
+ * @author romix
+ */
+class ScalaCollectionSerializer() extends Serializer[Iterable[_]] {
+
+  override def read(kryo: Kryo, input: Input, typ: Class[_ <: Iterable[_]]): Iterable[_] = {
+    val len = input.readInt(true)
+    val inst = kryo.newInstance(typ)
+    val coll = inst.iterableFactory.newBuilder[Any]
+
+    var i = 0
+    while (i < len) {
+      coll += kryo.readClassAndObject(input)
+      i += 1
+    }
+    coll.result()
+  }
+
+  override def write(kryo: Kryo, output: Output, obj: Iterable[_]): Unit = {
+    val collection: Iterable[_] = obj
+    val len = collection.size
+    output.writeInt(len, true)
+    collection.foreach { (e: Any) => kryo.writeClassAndObject(output, e) }
+  }
+}
+

akka-kryo-serialization/src/main/scala-3/io/altoo/akka/serialization/kryo/serializer/scala/ScalaEnumNameSerializer.scala

@@ -0,0 +1,26 @@
+package io.altoo.akka.serialization.kryo.serializer.scala
+
+import com.esotericsoftware.kryo.{Kryo, Serializer}
+import com.esotericsoftware.kryo.io.{Input, Output}
+
+import scala.runtime.EnumValue
+
+/** Serializes enums using the enum's name. This prevents invalidating previously serialized bytes when the enum order changes */
+class ScalaEnumNameSerializer[T <: EnumValue] extends Serializer[T]  {
+
+  def read(kryo: Kryo, input: Input, typ: Class[_ <: T]): T = {
+    val clazz = kryo.readClass(input).getType
+    val name = input.readString()
+    // using value instead of ordinal to make serialization more stable, e.g. allowing reordering without breaking compatibility
+    clazz.getDeclaredMethod("valueOf", classOf[String]).invoke(null, name).asInstanceOf[T]
+  }
+
+  def write(kryo: Kryo, output: Output, obj: T): Unit = {
+    val enumClass = obj.getClass.getSuperclass
+    val productPrefixMethod = obj.getClass.getDeclaredMethod("productPrefix")
+    if (!productPrefixMethod.canAccess(obj)) productPrefixMethod.setAccessible(true)
+    val name = productPrefixMethod.invoke(obj).asInstanceOf[String]
+    kryo.writeClass(output, enumClass)
+    output.writeString(name)
+  }
+}

akka-kryo-serialization/src/main/scala/io/altoo/akka/serialization/kryo/DefaultKryoInitializer.scala

@@ -70,6 +70,7 @@ class DefaultKryoInitializer {
     // Map/Set Factories
     ScalaVersionSerializers.mapAndSet(kryo)
     ScalaVersionSerializers.iterable(kryo)
+    ScalaVersionSerializers.enums(kryo)
   }
 
   /**

akka-kryo-serialization/src/main/scala/io/altoo/akka/serialization/kryo/serializer/scala/ScalaKryo.scala

@@ -23,7 +23,7 @@ import com.esotericsoftware.kryo.serializers.FieldSerializer
 class ScalaKryo(classResolver: ClassResolver, referenceResolver: ReferenceResolver)
   extends Kryo(classResolver, referenceResolver) {
 
-  lazy val objSer = new ObjectSerializer[AnyRef]
+  lazy val objSer = new ScalaObjectSerializer[AnyRef]
 
   override def getDefaultSerializer(typ: Class[_]): Serializer[_] = {
     if(isSingleton(typ)) {

akka-kryo-serialization/src/main/scala/io/altoo/akka/serialization/kryo/serializer/scala/ScalaObjectSerializer.scala

@@ -27,7 +27,7 @@ import scala.collection.mutable.{Map => MMap}
 import scala.util.control.Exception.allCatch
 
 // Stolen with pride from Chill ;-)
-class ObjectSerializer[T] extends Serializer[T] {
+class ScalaObjectSerializer[T] extends Serializer[T] {
   private val cachedObj = MMap[Class[_], Option[T]]()
 
   // Does nothing

akka-kryo-serialization/src/test/scala-3/io/altoo/akka/serialization/kryo/serializer/scala/ScalaEnumSerializationTest.scala

@@ -0,0 +1,49 @@
+package io.altoo.akka.serialization.kryo.serializer.scala
+
+import com.esotericsoftware.kryo.util.{DefaultClassResolver, ListReferenceResolver}
+import io.altoo.akka.serialization.kryo.testkit.{AbstractKryoTest, KryoSerializationTesting}
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+import io.altoo.akka.serialization.kryo.ScalaVersionSerializers
+
+object ScalaEnumSerializationTest {
+  enum Sample(val name: String, val value: Int) {
+    case A extends Sample("a", 1)
+    case B extends Sample("b", 2)
+    case C extends Sample("c", 3)
+  }
+
+  case class EmbeddedEnum(sample: Sample) {
+    def this() = this(null)
+  }
+}
+
+class ScalaEnumSerializationTest  extends AnyFlatSpec with Matchers with KryoSerializationTesting {
+  import ScalaEnumSerializationTest._
+
+  val kryo = new ScalaKryo(new DefaultClassResolver(), new ListReferenceResolver())
+  kryo.setRegistrationRequired(false)
+  kryo.addDefaultSerializer(classOf[scala.runtime.EnumValue], new ScalaEnumNameSerializer[scala.runtime.EnumValue])
+
+
+  behavior of "Kryo serialization"
+
+  it should "reoundtrip enum" in {
+    kryo.setRegistrationRequired(false)
+
+    testSerializationOf(Sample.B)
+  }
+
+  it should "reoundtrip external enum" in {
+    kryo.setRegistrationRequired(false)
+
+    testSerializationOf(io.altoo.external.ExternalEnum.A)
+  }
+
+  it should "reoundtrip embedded enum" in {
+    kryo.setRegistrationRequired(false)
+    kryo.register(classOf[EmbeddedEnum], 46)
+
+    testSerializationOf(EmbeddedEnum(Sample.C))
+  }
+}

akka-kryo-serialization/src/test/scala-3/io/altoo/akka/serialization/kryo/serializer/scala/ScalaVersionRegistry.scala

@@ -0,0 +1,16 @@
+package io.altoo.akka.serialization.kryo.serializer.scala
+
+import com.esotericsoftware.kryo.Kryo
+
+object ScalaVersionRegistry {
+  final val immutableHashMapImpl = "scala.collection.immutable.HashMap"
+  final val immutableHashSetImpl = "scala.collection.immutable.HashSet"
+
+  def registerHashMap(kryo: Kryo): Unit = {
+    kryo.register(classOf[scala.collection.immutable.HashMap[_, _]], 40)
+  }
+
+  def registerHashSet(kryo: Kryo): Unit = {
+    kryo.register(classOf[scala.collection.immutable.HashSet[_]], 41)
+  }
+}

akka-kryo-serialization/src/test/scala-3/io/altoo/external/ExternalEnum.scala

@@ -0,0 +1,7 @@
+package io.altoo.external
+
+import io.altoo.akka.serialization.kryo.serializer.scala.ScalaEnumSerializationTest.Sample
+
+enum ExternalEnum(val name: String) {
+  case A extends ExternalEnum("a")
+}

akka-kryo-serialization/src/test/scala/io/altoo/akka/serialization/kryo/serializer/scala/TupleSerializationTest.scala

@@ -9,7 +9,9 @@ class TupleSerializationTest extends AbstractKryoTest {
 
   type IntTuple6 = (Int, Int, Int, Int, Int, Int)
 
-  "Kryo" should "roundtrip tuples" in {
+  behavior of "Kryo serialization"
+
+  it should "roundtrip tuples" in {
     kryo.setRegistrationRequired(false)
     kryo.register(classOf[scala.Tuple1[Any]], 45)
     kryo.register(classOf[scala.Tuple2[Any, Any]], 46)

build.sbt

@@ -7,8 +7,8 @@ val typesafe = "Typesafe Repository" at "https://repo.typesafe.com/typesafe/rele
 val typesafeSnapshot = "Typesafe Snapshots Repository" at "https://repo.typesafe.com/typesafe/snapshots/"
 val sonatypeSnapshot = "Sonatype Snapshots Repository" at "https://oss.sonatype.org/content/repositories/snapshots/"
 
-val mainScalaVersion = "2.13.8"
-val secondayScalaVersions = Seq("2.12.15", "3.0.2") // note: Scala 3.1 is not forward compatible - publishing with 3.1 would force users to Scala 3.1
+val mainScalaVersion = "3.0.2" // note: Scala 3.1 is not forward compatible - publishing with 3.1 would force users to Scala 3.1
+val secondayScalaVersions = Seq("2.12.15", "2.13.8")
 
 val kryoVersion = "5.3.0"
 val defaultAkkaVersion = "2.6.18"
@@ -41,13 +41,15 @@ lazy val core: Project = Project("akka-kryo-serialization", file("akka-kryo-seri
     .settings(Compile / unmanagedSourceDirectories += {
       scalaBinaryVersion.value match {
         case "2.12" => baseDirectory.value / "src" / "main" / "scala-2.12"
-        case _ => baseDirectory.value / "src" / "main" / "scala-2.13"
+        case "2.13" => baseDirectory.value / "src" / "main" / "scala-2.13"
+        case _ => baseDirectory.value / "src" / "main" / "scala-3"
       }
     })
     .settings(Test / unmanagedSourceDirectories += {
       scalaBinaryVersion.value match {
         case "2.12" => baseDirectory.value / "src" / "test" / "scala-2.12"
-        case _ => baseDirectory.value / "src" / "test" / "scala-2.13"
+        case "2.13" => baseDirectory.value / "src" / "test" / "scala-2.13"
+        case _ => baseDirectory.value / "src" / "test" / "scala-3"
       }
     })