added initial reproduction for akkadotnet#7247

src/core/Akka.Tests/Actor/Scheduler/BugFix7247Spec.cs

@@ -0,0 +1,52 @@
+// -----------------------------------------------------------------------
+//  <copyright file="7247BugFixSpec.cs" company="Akka.NET Project">
+//      Copyright (C) 2009-2024 Lightbend Inc. <http://www.lightbend.com>
+//      Copyright (C) 2013-2024 .NET Foundation <https://github.com/akkadotnet/akka.net>
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using System;
+using System.Threading.Tasks;
+using Akka.Actor;
+using Akka.TestKit;
+using Xunit;
+
+namespace Akka.Tests.Actor.Scheduler;
+
+public class BugFix7247Spec : AkkaSpec {
+    public sealed class NoCellActorRef : MinimalActorRef
+    {
+        public NoCellActorRef(ActorPath path, TaskCompletionSource<object> firstMessage)
+        {
+            Path = path;
+            FirstMessage = firstMessage;
+        }
+
+        protected override void TellInternal(object message, IActorRef sender)
+        {
+            FirstMessage.TrySetResult(message);
+        }
+
+        public TaskCompletionSource<object> FirstMessage { get; }
+
+        public override ActorPath Path { get; }
+        public override IActorRefProvider Provider => throw new NotImplementedException();
+    }
+
+    [Fact(DisplayName = "Should not send ScheduledTellMsg envelopes to IActorRefs with no cell")]
+    public async Task ShouldNotSendScheduledTellMsgToNoCellActorRefs()
+    {
+        // arrange
+        var noCellPath = new RootActorPath(Address.AllSystems);
+        var tcs = new TaskCompletionSource<object>(TaskCreationOptions.RunContinuationsAsynchronously);
+        var noCellRef = new NoCellActorRef(noCellPath, tcs);
+
+        // act
+        var msg = "hit";
+        Sys.Scheduler.ScheduleTellOnce(TimeSpan.FromMicroseconds(1), noCellRef, msg, ActorRefs.NoSender);
+        var respMsg = await tcs.Task;
+
+        // assert
+        Assert.Equal(msg, respMsg);
+    }
+}