Add PrintTree method to ExtendedActorSystem

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

@@ -55,7 +55,6 @@ namespace Akka.Actor
     {
         public const int UndefinedUid = 0;
         public ActorCell(Akka.Actor.Internal.ActorSystemImpl system, Akka.Actor.IInternalActorRef self, Akka.Actor.Props props, Akka.Dispatch.MessageDispatcher dispatcher, Akka.Actor.IInternalActorRef parent) { }
-        protected Akka.Actor.ActorBase Actor { get; }
         public Akka.Actor.Internal.IChildrenContainer ChildrenContainer { get; }
         public int CurrentEnvelopeId { get; }
         public object CurrentMessage { get; }
@@ -709,6 +708,7 @@ namespace Akka.Actor
         public abstract Akka.Actor.IActorRefProvider Provider { get; }
         public abstract Akka.Actor.IInternalActorRef SystemGuardian { get; }
         public abstract void Abort();
+        public abstract string PrintTree();
         public abstract Akka.Actor.IActorRef SystemActorOf(Akka.Actor.Props props, string name = null);
         public abstract Akka.Actor.IActorRef SystemActorOf<TActor>(string name = null)
             where TActor : Akka.Actor.ActorBase, new ();
@@ -1941,6 +1941,7 @@ namespace Akka.Actor.Internal
         public override bool HasExtension(System.Type type) { }
         public override bool HasExtension<T>()
             where T :  class, Akka.Actor.IExtension { }
+        public override string PrintTree() { }
         public override object RegisterExtension(Akka.Actor.IExtensionId extension) { }
         public override void RegisterOnTermination(System.Action code) { }
         public void Start() { }
@@ -2091,6 +2092,7 @@ namespace Akka.Actor.Internal
         public override bool IsNormal { get; }
         public override bool IsTerminating { get; }
         public Akka.Actor.Internal.SuspendReason Reason { get; }
+        public System.Collections.Immutable.ImmutableHashSet<Akka.Actor.IActorRef> ToDie { get; }
         public override Akka.Actor.Internal.IChildrenContainer Add(string name, Akka.Actor.Internal.ChildRestartStats stats) { }
         public Akka.Actor.Internal.IChildrenContainer CreateCopyWithReason(Akka.Actor.Internal.SuspendReason reason) { }
         public override Akka.Actor.Internal.IChildrenContainer Remove(Akka.Actor.IActorRef child) { }

src/core/Akka/Actor/ActorCell.cs

@@ -104,7 +104,7 @@ public ActorCell(ActorSystemImpl system, IInternalActorRef self, Props props, Me
         /// <summary>
         /// TBD
         /// </summary>
-        protected ActorBase Actor { get { return _actor; } }
+        internal ActorBase Actor { get { return _actor; } }
         /// <summary>
         /// TBD
         /// </summary>

src/core/Akka/Actor/ChildrenContainer/Internal/TerminatingChildrenContainer.cs

@@ -51,6 +51,8 @@ public TerminatingChildrenContainer(IImmutableDictionary<string, IChildStats> ch
             _reason = reason;
         }
 
+        public ImmutableHashSet<IActorRef> ToDie => _toDie;
+
         /// <summary>
         /// TBD
         /// </summary>

src/core/Akka/Actor/ExtendedActorSystem.cs

@@ -71,6 +71,8 @@ public abstract class ExtendedActorSystem : ActorSystem
         /// </summary>
         public abstract void Abort();
 
+        public abstract string PrintTree();
+
         //TODO: Missing threadFactory, dynamicAccess, printTree
         //  /**
         //  * A ThreadFactory that can be used if the transport needs to create any Threads

src/core/Akka/Actor/Internal/ActorSystemImpl.cs

@@ -8,6 +8,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
@@ -16,6 +17,7 @@
 using Akka.Dispatch.SysMsg;
 using Akka.Event;
 using System.Reflection;
+using System.Text;
 using Akka.Actor.Setup;
 using Akka.Serialization;
 using Akka.Util;
@@ -569,6 +571,78 @@ public override string ToString()
         {
             return LookupRoot.Path.Root.Address.ToString();
         }
+
+        public override string PrintTree()
+        {
+            string PrintNode(IActorRef node, string indent)
+            {
+                var sb = new StringBuilder();
+                if (node is ActorRefWithCell wc)
+                {
+                    const string space = " ";
+                    var cell = wc.Underlying;
+                    sb.Append(string.IsNullOrEmpty(indent) ? "-> " : indent.Remove(indent.Length-1) + "L-> ")
+                        .Append($"{node.Path.Name} {Logging.SimpleName(node)} ");
+
+                    if (cell is ActorCell real)
+                    {
+                        var realActor = real.Actor;
+                        sb.Append(realActor is null ? "null" : realActor.GetType().ToString())
+                            .Append($" status={real.Mailbox.CurrentStatus()}");
+                    }
+                    else
+                    {
+                        sb.Append(Logging.SimpleName(cell));
+                    }
+                    sb.Append(space);
+
+                    switch (cell.ChildrenContainer)
+                    {
+                        case TerminatingChildrenContainer t:
+                            var toDie = t.ToDie.ToList();
+                            toDie.Sort();
+                            var reason = t.Reason;
+                            sb.Append($"Terminating({reason})")
+                                .Append($"\n{indent}   |    toDie: ")
+                                .Append(string.Join($"\n{indent}   |           ", toDie));
+                            break;
+                        case TerminatedChildrenContainer x:
+                            sb.Append(x);
+                            break;
+                        case EmptyChildrenContainer x:
+                            sb.Append(x);
+                            break;
+                        case NormalChildrenContainer n:
+                            sb.Append($"{n.Children.Count} children");
+                            break;
+                        case var x:
+                            sb.Append(Logging.SimpleName(x));
+                            break;
+                    }
+
+                    if (cell.ChildrenContainer.Children.Count > 0)
+                    {
+                        sb.Append("\n");
+
+                        var children = cell.ChildrenContainer.Children.ToList();
+                        children.Sort();
+                        var childStrings = children.Select((t, i) => i == 0
+                            ? PrintNode(t, $"{indent}   |")
+                            : PrintNode(t, $"{indent}    "));
+
+                        sb.Append(string.Join("\n", childStrings));
+                    }
+                }
+                else
+                {
+                    sb.Append($"{indent}{node.Path.Name} {Logging.SimpleName(node)}");
+                }
+
+                return sb.ToString();
+            }
+
+            return PrintNode(LookupRoot, "");
+        }
     }
 
     /// <summary>

src/core/Akka/Akka.csproj

@@ -4,10 +4,10 @@
   <PropertyGroup>
     <AssemblyTitle>Akka</AssemblyTitle>
     <Description>Akka.NET is a port of the popular Java/Scala framework Akka to .NET</Description>
-    <TargetFrameworks>$(NetStandardLibVersion)</TargetFrameworks>
+    <TargetFramework>$(NetStandardLibVersion)</TargetFramework>
     <PackageTags>$(AkkaPackageTags)</PackageTags>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <LangVersion>7.2</LangVersion>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>