Add backward compatibility to PrimitiveSerializers (#5280)

* Add backward compatibility to PrimitiveSerializers

* Update API Approver list

src/core/Akka.API.Tests/CoreAPISpec.ApproveRemote.approved.txt

@@ -440,7 +440,7 @@ namespace Akka.Remote.Serialization
     }
     public sealed class PrimitiveSerializers : Akka.Serialization.SerializerWithStringManifest
     {
-        public PrimitiveSerializers(Akka.Actor.ExtendedActorSystem system) { }
+        public PrimitiveSerializers(Akka.Actor.ExtendedActorSystem system, Akka.Configuration.Config config) { }
         public override object FromBinary(byte[] bytes, string manifest) { }
         public override string Manifest(object obj) { }
         public override byte[] ToBinary(object obj) { }

src/core/Akka.Remote.Tests/RemoteConfigSpec.cs

@@ -176,6 +176,14 @@ public void Remoting_should_contain_correct_BatchWriter_settings_in_ReferenceCon
             s.BatchWriterSettings.EnableBatching.Should().BeTrue();
             s.BatchWriterSettings.MaxExplicitFlushes.Should().Be(BatchWriterSettings.DefaultMaxPendingWrites);
         }
+
+        [Fact]
+        public void Remoting_should_contain_correct_PrimitiveSerializer_settings_in_ReferenceConf()
+        {
+            var c = RARP.For(Sys).Provider.RemoteSettings.Config.GetConfig("akka.actor.serialization-settings.primitive");
+            c.Should().NotBeNull();
+            c.GetBoolean("use-neutral-primitives").Should().BeFalse();
+        }
    }
 }
 

src/core/Akka.Remote.Tests/Serialization/BugFix5279Spec.cs

@@ -0,0 +1,43 @@
+// //-----------------------------------------------------------------------
+// // <copyright file="BugFix5279Spec.cs" company="Akka.NET Project">
+// //     Copyright (C) 2009-2021 Lightbend Inc. <http://www.lightbend.com>
+// //     Copyright (C) 2013-2021 .NET Foundation <https://github.com/akkadotnet/akka.net>
+// // </copyright>
+// //-----------------------------------------------------------------------
+
+using Akka.Actor;
+using Akka.Configuration;
+using Akka.Remote.Serialization;
+using Akka.TestKit;
+using Akka.Util;
+using Xunit;
+using FluentAssertions;
+
+namespace Akka.Remote.Tests.Serialization
+{
+    public class BugFix5279Spec: AkkaSpec
+    {
+        [Theory]
+        [InlineData(1, "I")]
+        [InlineData(1L, "L")]
+        [InlineData("1", "S")]
+        public void PrimitiveSerializer_without_useNeutralPrimitives_should_return_custom_manifest(object data, string manifest)
+        {
+            var config = ConfigurationFactory.ParseString("use-neutral-primitives = off");
+            var serializer = new PrimitiveSerializers((ExtendedActorSystem)Sys, config);
+            serializer.Manifest(data).Should().Be(manifest);
+        }
+
+        [Theory]
+        [InlineData(1)]
+        [InlineData(1L)]
+        [InlineData("1")]
+        public void PrimitiveSerializer_without_useNeutralPrimitives_should_return_type_manifest(object data)
+        {
+            var config = ConfigurationFactory.ParseString("use-neutral-primitives = on");
+            var serializer = new PrimitiveSerializers((ExtendedActorSystem)Sys, config);
+            serializer.Manifest(data).Should().Be(data.GetType().TypeQualifiedName());
+        }
+
+    }
+}

src/core/Akka.Remote/Configuration/Remote.conf

@@ -9,8 +9,12 @@
 # actor.jar, because otherwise they would be repeated in config rendering.
 
 akka {
-
   actor {
+	serialization-settings {
+      primitive {
+        use-neutral-primitives = off
+      }
+	}
 
     serializers {
       akka-containers = "Akka.Remote.Serialization.MessageContainerSerializer, Akka.Remote"

src/core/Akka.Remote/Serialization/PrimitiveSerializers.cs

@@ -8,6 +8,7 @@
 using System;
 using System.Text;
 using Akka.Actor;
+using Akka.Configuration;
 using Akka.Serialization;
 using Akka.Util;
 
@@ -29,12 +30,18 @@ public sealed class PrimitiveSerializers : SerializerWithStringManifest
         internal const string Int32ManifestNetFx = "System.Int32, mscorlib";
         internal const string Int64ManifestNetFx = "System.Int64, mscorlib";
 
+        private readonly bool _useNeutralPrimitives;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="PrimitiveSerializers" /> class.
         /// </summary>
         /// <param name="system">The actor system to associate with this serializer. </param>
-        public PrimitiveSerializers(ExtendedActorSystem system) : base(system)
+        public PrimitiveSerializers(ExtendedActorSystem system, Config config) : base(system)
         {
+            if (config == null)
+                throw new ConfigurationException("configuration is null");
+
+            _useNeutralPrimitives = config.GetBoolean("use-neutral-primitives");
         }
 
         /// <inheritdoc />
@@ -78,6 +85,9 @@ public override object FromBinary(byte[] bytes, string manifest)
         /// <inheritdoc />
         public override string Manifest(object obj)
         {
+            if (_useNeutralPrimitives)
+                return obj.GetType().TypeQualifiedName();
+
             switch (obj)
             {
                 case string _: