add ClientId to RemoteHost so that test window can discover our OOP from thier own OOP (#30333)

src/EditorFeatures/TestUtilities/Remote/InProcRemostHostClient.cs

@@ -29,10 +29,10 @@ public static async Task<RemoteHostClient> CreateAsync(Workspace workspace, bool
             var remoteHostStream = await inprocServices.RequestServiceAsync(WellKnownRemoteHostServices.RemoteHostService, cancellationToken).ConfigureAwait(false);
             var remotableDataRpc = new RemotableDataJsonRpc(workspace, inprocServices.Logger, await inprocServices.RequestServiceAsync(WellKnownServiceHubServices.SnapshotService, cancellationToken).ConfigureAwait(false));
 
-            var instance = new InProcRemoteHostClient(workspace, inprocServices, new ReferenceCountedDisposable<RemotableDataJsonRpc>(remotableDataRpc), remoteHostStream);
+            var current = CreateClientId(Process.GetCurrentProcess().Id.ToString());
+            var instance = new InProcRemoteHostClient(current, workspace, inprocServices, new ReferenceCountedDisposable<RemotableDataJsonRpc>(remotableDataRpc), remoteHostStream);
 
             // make sure connection is done right
-            var current = $"VS ({Process.GetCurrentProcess().Id})";
             var telemetrySession = default(string);
             var uiCultureLCIDE = 0;
             var cultureLCID = 0;
@@ -49,6 +49,7 @@ public static async Task<RemoteHostClient> CreateAsync(Workspace workspace, bool
         }
 
         private InProcRemoteHostClient(
+            string clientId,
             Workspace workspace,
             InProcRemoteServices inprocServices,
             ReferenceCountedDisposable<RemotableDataJsonRpc> remotableDataRpc,
@@ -57,6 +58,8 @@ public static async Task<RemoteHostClient> CreateAsync(Workspace workspace, bool
         {
             Contract.ThrowIfNull(remotableDataRpc);
 
+            ClientId = clientId;
+
             _inprocServices = inprocServices;
             _remotableDataRpc = remotableDataRpc;
 
@@ -76,6 +79,8 @@ public void RegisterService(string name, Func<Stream, IServiceProvider, ServiceH
             _inprocServices.RegisterService(name, serviceCreator);
         }
 
+        public override string ClientId { get; }
+
         public override async Task<Connection> TryCreateConnectionAsync(
             string serviceName, object callbackTarget, CancellationToken cancellationToken)
         {

src/VisualStudio/Core/Def/Implementation/Remote/ServiceHubRemoteHostClient.ConnectionManager.cs

@@ -57,6 +57,8 @@ private partial class ConnectionManager
                 _shutdownLock = new ReaderWriterLockSlim(LockRecursionPolicy.NoRecursion);
             }
 
+            public HostGroup HostGroup => _hostGroup;
+
             public Task<Connection> TryCreateConnectionAsync(string serviceName, object callbackTarget, CancellationToken cancellationToken)
             {
                 // pool is not enabled by option

src/VisualStudio/Core/Def/Implementation/Remote/ServiceHubRemoteHostClient.cs

@@ -7,7 +7,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.Notification;
@@ -30,8 +29,6 @@ private enum GlobalNotificationState
             Finished
         }
 
-        private static int s_instanceId = 0;
-
         private readonly JsonRpc _rpc;
         private readonly ConnectionManager _connectionManager;
 
@@ -75,9 +72,7 @@ public static async Task<ServiceHubRemoteHostClient> CreateWorkerAsync(Workspace
             try
             {
                 // let each client to have unique id so that we can distinguish different clients when service is restarted
-                var currentInstanceId = Interlocked.Add(ref s_instanceId, 1);
-
-                var current = $"VS ({Process.GetCurrentProcess().Id}) ({currentInstanceId})";
+                var current = CreateClientId(Process.GetCurrentProcess().Id.ToString());
 
                 var hostGroup = new HostGroup(current);
                 var remoteHostStream = await Connections.RequestServiceAsync(workspace, primary, WellKnownRemoteHostServices.RemoteHostService, hostGroup, timeout, cancellationToken).ConfigureAwait(false);
@@ -133,6 +128,8 @@ public static async Task<ServiceHubRemoteHostClient> CreateWorkerAsync(Workspace
             _rpc.StartListening();
         }
 
+        public override string ClientId => _connectionManager.HostGroup.Id;
+
         public override Task<Connection> TryCreateConnectionAsync(string serviceName, object callbackTarget, CancellationToken cancellationToken)
         {
             return _connectionManager.TryCreateConnectionAsync(serviceName, callbackTarget, cancellationToken);
@@ -158,6 +155,15 @@ protected override void OnStopped()
             _connectionManager.Shutdown();
         }
 
+        public HostGroup HostGroup
+        {
+            get
+            {
+                Debug.Assert(_connectionManager.HostGroup.Id == ClientId);
+                return _connectionManager.HostGroup;
+            }
+        }
+
         private void RegisterGlobalOperationNotifications()
         {
             var globalOperationService = this.Workspace.Services.GetService<IGlobalOperationNotificationService>();
@@ -295,4 +301,4 @@ private void OnRpcDisconnected(object sender, JsonRpcDisconnectedEventArgs e)
             Stopped();
         }
     }
-}
+}
\ No newline at end of file

src/VisualStudio/Core/Test.Next/Remote/RemoteHostClientServiceFactoryTests.cs

@@ -52,6 +52,26 @@ public async Task Enable_Disable()
             Assert.Null(disabledClient);
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.RemoteHost)]
+        public async Task ClientId()
+        {
+            var service = CreateRemoteHostClientService();
+            service.Enable();
+
+            var client1 = await service.TryGetRemoteHostClientAsync(CancellationToken.None);
+            var id1 = client1.ClientId;
+
+            await service.RequestNewRemoteHostAsync(CancellationToken.None);
+
+            var client2 = await service.TryGetRemoteHostClientAsync(CancellationToken.None);
+            var id2 = client2.ClientId;
+
+            Assert.NotEqual(id1, id2);
+
+            service.Disable();
+        }
+
+
         [Fact, Trait(Traits.Feature, Traits.Features.RemoteHost)]
         public async Task GlobalAssets()
         {

src/Workspaces/Core/Portable/Remote/RemoteHostClient.cs

@@ -26,6 +26,14 @@ protected RemoteHostClient(Workspace workspace)
 
         public event EventHandler<bool> StatusChanged;
 
+        /// <summary>
+        /// Return an unique string per client.
+        /// 
+        /// one can use this to distinguish different clients that are connected to different RemoteHosts including
+        /// cases where 2 external process finding each others
+        /// </summary>
+        public abstract string ClientId { get; }
+
         /// <summary>
         /// Create <see cref="RemoteHostClient.Connection"/> for the <paramref name="serviceName"/> if possible.
         /// otherwise, return null.
@@ -64,6 +72,11 @@ private void OnStatusChanged(bool started)
             StatusChanged?.Invoke(this, started);
         }
 
+        public static string CreateClientId(string prefix)
+        {
+            return $"VS ({prefix}) ({Guid.NewGuid().ToString()})";
+        }
+
         /// <summary>
         /// NoOpClient is used if a user killed our remote host process. Basically this client never
         /// create a session
@@ -75,6 +88,8 @@ public class NoOpClient : RemoteHostClient
             {
             }
 
+            public override string ClientId => nameof(NoOpClient);
+
             public override Task<Connection> TryCreateConnectionAsync(string serviceName, object callbackTarget, CancellationToken cancellationToken)
             {
                 return SpecializedTasks.Default<Connection>();
@@ -140,7 +155,7 @@ public void Dispose()
                 // when that happen, we don't want to crash VS, so this is debug only check
                 if (!Environment.HasShutdownStarted)
                 {
-                    Debug.Assert(false, 
+                    Debug.Assert(false,
                         $"Unless OOP process (RoslynCodeAnalysisService) is explicitly killed, this should have been disposed!\r\n {_creationCallStack}");
                 }
             }