feat(app): observe canonical placement receipts

src/AcDream.App/Composition/FrameRootComposition.cs

@@ -585,7 +585,8 @@ internal sealed class FrameRootCompositionPhase
             session.LocalPlayerFrame,
             session.LiveSpatialReconciler,
             live.WorldAvailability,
-            live.RenderSceneShadow?.LiveProjections);
+            live.RenderSceneShadow?.LiveProjections,
+            session.PlacementProjectionRetry);
         var cameraFrame = new CameraFrameController(
             host.CameraController,
             d.InputCapture,

src/AcDream.App/Composition/LivePresentationComposition.cs

@@ -96,6 +96,7 @@ internal sealed record LivePresentationResult(
     GpuWorldState WorldState,
     RenderSceneShadowRuntime? RenderSceneShadow,
     LiveEntityRuntime LiveEntities,
+    RuntimePlacementPresentationSink PlacementProjection,
     ProjectileController ProjectileController,
     LiveEntityProjectionWithdrawalController ProjectionWithdrawal,
     LiveEntityLightController Lights,
@@ -451,6 +452,35 @@ internal sealed class LivePresentationCompositionPhase
                 liveEntities,
                 particleVisibility,
                 "particle projection visibility");
+            var placementVisibilitySinks = new List<
+                Action<LiveEntityRecord, bool>>(3)
+            {
+                wbVisibility,
+            };
+            if (liveRenderProjections is not null)
+            {
+                placementVisibilitySinks.Add(
+                    liveRenderProjections.OnProjectionVisibilityChanged);
+            }
+            placementVisibilitySinks.Add(particleVisibility);
+            var placementProjection = new RuntimePlacementPresentationSink(
+                liveEntities,
+                worldTransit,
+                d.WorldGameState,
+                d.WorldEvents,
+                d.EffectPoses,
+                d.LocalPlayerShadow,
+                () => d.PlayerIdentity.ServerGuid,
+                guid =>
+                {
+                    if (d.Selection.SelectedObjectId == guid)
+                    {
+                        d.Selection.Clear(
+                            SelectionChangeSource.System,
+                            SelectionChangeReason.SelectedObjectRemoved);
+                    }
+                },
+                placementVisibilitySinks);
             Fault(LivePresentationCompositionPoint.ProjectionVisibilityBound);
 
             var projectileController = new ProjectileController(
@@ -619,6 +649,7 @@ internal sealed class LivePresentationCompositionPhase
                 renderSceneShadow,
                 renderSceneShadowLease,
                 liveEntities,
+                placementProjection,
                 projectileController,
                 projectionWithdrawal,
                 lightsLease,
@@ -668,6 +699,7 @@ internal sealed class LivePresentationCompositionPhase
         CompositionAcquisitionScope.CompositionAcquisitionLease<
             RenderSceneShadowRuntime>? renderSceneShadowLease,
         LiveEntityRuntime liveEntities,
+        RuntimePlacementPresentationSink placementProjection,
         ProjectileController projectileController,
         LiveEntityProjectionWithdrawalController projectionWithdrawal,
         CompositionAcquisitionScope.CompositionAcquisitionLease<LiveEntityLightController> lightsLease,
@@ -1147,6 +1179,7 @@ internal sealed class LivePresentationCompositionPhase
             worldState,
             renderSceneShadow,
             liveEntities,
+            placementProjection,
             projectileController,
             projectionWithdrawal,
             lightsLease.Resource,

src/AcDream.App/Composition/SessionPlayerComposition.cs

@@ -122,6 +122,7 @@ internal sealed record SessionPlayerResult(
     PlayerModeAutoEntry PlayerModeAutoEntry,
     LocalPlayerTeleportController LocalTeleport,
     LiveSessionHost SessionHost,
+    RuntimePlacementProjectionRetrySlot PlacementProjectionRetry,
     CurrentGameRuntimeAdapter GameRuntime,
     GameplayInputActionRouter? GameplayActions,
     SessionPlayerRuntimeBindings RuntimeBindings);
@@ -832,6 +833,9 @@ internal sealed class SessionPlayerCompositionPhase
 
         AcDream.UI.Abstractions.Panels.Vitals.VitalsVM? vitals =
             interaction.RetainedUi?.Vitals;
+        var placementProjectionRetry =
+            new RuntimePlacementProjectionRetrySlot(
+                () => d.Runtime.Generation);
         var sessionRuntimeFactory = new LiveSessionRuntimeFactory(
             new LiveSessionPlayerRuntime(
                 d.PlayerIdentity,
@@ -878,7 +882,9 @@ internal sealed class SessionPlayerCompositionPhase
                 content.AnimationHookFrames,
                 live.Presentation,
                 d.RemoteMovementObservations,
-                live.RenderSceneShadow),
+                live.RenderSceneShadow,
+                live.PlacementProjection,
+                placementProjectionRetry),
             liveSessionCommands,
             d.Log);
         LiveSessionHost sessionHost = sessionRuntimeFactory.Create(
@@ -1015,6 +1021,7 @@ internal sealed class SessionPlayerCompositionPhase
             playerModeAutoEntry,
             teleportLease.Resource,
             sessionHost,
+            placementProjectionRetry,
             gameRuntime,
             gameplayActionsLease?.Resource,
             bindings);

src/AcDream.App/Net/GraphicalSessionEventRoute.cs

@@ -0,0 +1,102 @@
+using AcDream.Runtime;
+using AcDream.Runtime.Physics;
+using AcDream.Runtime.Session;
+
+namespace AcDream.App.Net;
+
+/// <summary>
+/// Owns the inbound route, canonical placement observer, and update-thread
+/// retry lease for one exact graphical session generation.
+/// </summary>
+internal sealed class GraphicalSessionEventRoute : ILiveSessionEventRouting
+{
+    private readonly ILiveSessionEventRouting _events;
+    private readonly Func<RuntimePlacementProjectionSubscription>
+        _createSubscription;
+    private readonly Func<RuntimeGenerationToken> _generation;
+    private readonly RuntimePlacementProjectionRetrySlot _retries;
+    private RuntimePlacementProjectionSubscription? _subscription;
+    private IDisposable? _retryLease;
+    private bool _attachStarted;
+    private bool _eventsDisposed;
+    private bool _disposed;
+
+    internal GraphicalSessionEventRoute(
+        ILiveSessionEventRouting events,
+        GameRuntime runtime,
+        IRuntimePlacementProjectionSink placements,
+        RuntimePlacementProjectionRetrySlot retries)
+        : this(
+            events,
+            () => new RuntimePlacementProjectionSubscription(
+                runtime,
+                placements,
+                retryPendingOnSubscribe: false),
+            () => runtime.Generation,
+            retries)
+    {
+        ArgumentNullException.ThrowIfNull(runtime);
+        ArgumentNullException.ThrowIfNull(placements);
+    }
+
+    internal GraphicalSessionEventRoute(
+        ILiveSessionEventRouting events,
+        Func<RuntimePlacementProjectionSubscription> createSubscription,
+        Func<RuntimeGenerationToken> generation,
+        RuntimePlacementProjectionRetrySlot retries)
+    {
+        _events = events ?? throw new ArgumentNullException(nameof(events));
+        _createSubscription = createSubscription
+            ?? throw new ArgumentNullException(nameof(createSubscription));
+        _generation = generation
+            ?? throw new ArgumentNullException(nameof(generation));
+        _retries = retries ?? throw new ArgumentNullException(nameof(retries));
+    }
+
+    public void Attach()
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        if (_attachStarted)
+            return;
+
+        _attachStarted = true;
+        _events.Attach();
+
+        RuntimePlacementProjectionSubscription? subscription = null;
+        IDisposable? retryLease = null;
+        try
+        {
+            subscription = _createSubscription();
+            retryLease = _retries.BindOwned(
+                _generation(),
+                subscription.RetryPending);
+            _subscription = subscription;
+            _retryLease = retryLease;
+            _ = subscription.RetryPending();
+        }
+        catch
+        {
+            retryLease?.Dispose();
+            subscription?.Dispose();
+            throw;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (_disposed)
+            return;
+
+        // Unpublish the frame callback before detaching the observer. A frame
+        // can therefore never retry a retired generation or disposed route.
+        Interlocked.Exchange(ref _retryLease, null)?.Dispose();
+        Interlocked.Exchange(ref _subscription, null)?.Dispose();
+        if (!_eventsDisposed)
+        {
+            _events.Dispose();
+            _eventsDisposed = true;
+        }
+
+        _disposed = true;
+    }
+}

src/AcDream.App/Net/LiveSessionRuntimeFactory.cs

@@ -83,7 +83,9 @@ internal sealed record LiveSessionWorldRuntime(
     AnimationHookFrameQueue AnimationHookFrames,
     LiveEntityPresentationController Presentation,
     RemoteMovementObservationTracker RemoteMovementObservations,
-    RenderSceneShadowRuntime? RenderSceneShadow);
+    RenderSceneShadowRuntime? RenderSceneShadow,
+    RuntimePlacementPresentationSink PlacementProjection,
+    RuntimePlacementProjectionRetrySlot PlacementRetries);
 
 /// <summary>
 /// Builds the exact per-generation route/reset graph for the canonical live
@@ -225,7 +227,7 @@ internal sealed class LiveSessionRuntimeFactory
         _player.WorldOrigin.Reset();
     }
 
-    private LiveSessionEventRouter CreateEventRouter(WorldSession session)
+    private ILiveSessionEventRouting CreateEventRouter(WorldSession session)
     {
         SkillTable? skillTable = _world.Dats.Get<SkillTable>(0x0E000004u);
         if (_ui.CharacterSheet is not null)
@@ -235,7 +237,7 @@ internal sealed class LiveSessionRuntimeFactory
                 CharacterSheetProvider.LoadExperienceTable(_world.Dats, _log);
         }
 
-        return new LiveSessionEventRouter(
+        var route = new LiveSessionEventRouter(
             session,
             _world.EntitySession.CreateSink(),
             new LiveEnvironmentSessionSink(
@@ -248,6 +250,11 @@ internal sealed class LiveSessionRuntimeFactory
                 _domain.Communication.TurbineChat,
                 _domain.Communication.Friends,
                 _domain.Communication.Squelch));
+        return new GraphicalSessionEventRoute(
+            route,
+            _domain.Runtime,
+            _world.PlacementProjection,
+            _world.PlacementRetries);
     }
 
     private LiveInventorySessionBindings CreateInventoryBindings() => new(

src/AcDream.App/Net/RuntimePlacementProjectionRetrySlot.cs

@@ -0,0 +1,87 @@
+using AcDream.Runtime;
+
+namespace AcDream.App.Net;
+
+internal interface IRuntimePlacementProjectionRetryPhase
+{
+    void RetryPending();
+}
+
+/// <summary>
+/// Publishes the retry callback owned by the exact active graphical session
+/// route. The frame thread may only reach the binding whose Runtime
+/// generation is still current; disposing an older lease cannot unbind a
+/// replacement route.
+/// </summary>
+internal sealed class RuntimePlacementProjectionRetrySlot
+    : IRuntimePlacementProjectionRetryPhase
+{
+    private sealed record Binding(
+        long Id,
+        RuntimeGenerationToken Generation,
+        Func<bool> Retry);
+
+    private readonly Func<RuntimeGenerationToken> _currentGeneration;
+    private Binding? _current;
+    private long _nextBindingId;
+
+    internal RuntimePlacementProjectionRetrySlot(
+        Func<RuntimeGenerationToken> currentGeneration)
+    {
+        _currentGeneration = currentGeneration
+            ?? throw new ArgumentNullException(nameof(currentGeneration));
+    }
+
+    internal int BindingCount => _current is null ? 0 : 1;
+
+    internal IDisposable BindOwned(
+        RuntimeGenerationToken generation,
+        Func<bool> retry)
+    {
+        if (generation.Value == 0UL)
+        {
+            throw new ArgumentException(
+                "A placement retry route requires a live Runtime generation.",
+                nameof(generation));
+        }
+        ArgumentNullException.ThrowIfNull(retry);
+        if (_current is not null)
+        {
+            throw new InvalidOperationException(
+                "A graphical placement retry route is already bound.");
+        }
+
+        var binding = new Binding(
+            checked(++_nextBindingId),
+            generation,
+            retry);
+        _current = binding;
+        return new DelegateDisposable(() => Unbind(binding));
+    }
+
+    public void RetryPending()
+    {
+        Binding? binding = _current;
+        if (binding is null
+            || binding.Generation != _currentGeneration())
+        {
+            return;
+        }
+
+        _ = binding.Retry();
+    }
+
+    private void Unbind(Binding binding)
+    {
+        if (ReferenceEquals(_current, binding))
+            _current = null;
+    }
+
+    private sealed class DelegateDisposable(Action dispose) : IDisposable
+    {
+        private Action? _dispose = dispose
+            ?? throw new ArgumentNullException(nameof(dispose));
+
+        public void Dispose() => Interlocked.Exchange(ref _dispose, null)?.Invoke();
+    }
+}

src/AcDream.App/World/RetailLiveFrameCoordinator.cs

@@ -27,6 +27,8 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
     private readonly ILiveSpatialReconcilePhase _spatialReconciler;
     private readonly IWorldGenerationAvailability _availability;
     private readonly IRenderProjectionSyncPhase? _renderProjectionSync;
+    private readonly IRuntimePlacementProjectionRetryPhase?
+        _placementProjectionRetry;
 
     public RetailLiveFrameCoordinator(
         ILiveObjectFramePhase objects,
@@ -35,7 +37,8 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
         IPostNetworkCommandFramePhase localPlayer,
         ILiveSpatialReconcilePhase spatialReconciler,
         IWorldGenerationAvailability? availability = null,
-        IRenderProjectionSyncPhase? renderProjectionSync = null)
+        IRenderProjectionSyncPhase? renderProjectionSync = null,
+        IRuntimePlacementProjectionRetryPhase? placementProjectionRetry = null)
     {
         _objects = objects ?? throw new ArgumentNullException(nameof(objects));
         _worldState = worldState ?? throw new ArgumentNullException(nameof(worldState));
@@ -45,6 +48,7 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
             ?? throw new ArgumentNullException(nameof(spatialReconciler));
         _availability = availability ?? AlwaysAvailableWorldGeneration.Instance;
         _renderProjectionSync = renderProjectionSync;
+        _placementProjectionRetry = placementProjectionRetry;
     }
 
     public void Tick(float deltaSeconds)
@@ -53,7 +57,14 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
         if (_availability.IsWorldAvailable)
             _objects.Tick(frameDelta);
         using (_worldState.BeginMutationBatch())
+        {
             _session.Tick();
+            // Streaming publication precedes this coordinator, while inbound
+            // network dispatch completes immediately above. A graphical
+            // receipt that previously lacked its destination backend can now
+            // retry against both readiness edges on the update thread.
+            _placementProjectionRetry?.RetryPending();
+        }
         _localPlayer.RunPostNetworkCommandPhase();
         if (_availability.IsWorldAvailable)
             _spatialReconciler.Reconcile();

src/AcDream.App/World/RuntimePlacementPresentationSink.cs

@@ -14,9 +14,9 @@ namespace AcDream.App.World;
 /// and renderer/VFX visibility projections. Runtime physics, shadows, body
 /// state, clocks, and worksets were committed before this sink is invoked.
 ///
-/// This adapter deliberately owns no subscription: production composition
+/// This adapter deliberately owns no subscription. The exact graphical
-/// activates the shared observer only after both graphical and no-window hosts
+/// session route owns the shared Runtime observer and its generation-scoped
-/// implement the same presentation-only contract.
+/// update-thread retry lease.
 /// </summary>
 internal sealed class RuntimePlacementPresentationSink
     : IRuntimePlacementProjectionSink

src/AcDream.Runtime/Physics/RuntimePlacementProjectionSubscription.cs

@@ -34,11 +34,25 @@ public sealed class RuntimePlacementProjectionSubscription
     public RuntimePlacementProjectionSubscription(
         GameRuntime runtime,
         IRuntimePlacementProjectionSink sink)
+        : this(runtime, sink, retryPendingOnSubscribe: true)
+    {
+    }
+
+    /// <summary>
+    /// Subscribes before optionally draining the pending FIFO. A session route
+    /// which must publish its own disposal/retry ownership first passes
+    /// <c>false</c>, stores those owners, then calls <see cref="RetryPending"/>.
+    /// </summary>
+    public RuntimePlacementProjectionSubscription(
+        GameRuntime runtime,
+        IRuntimePlacementProjectionSink sink,
+        bool retryPendingOnSubscribe)
         : this(
             runtime?.Placements
                 ?? throw new ArgumentNullException(nameof(runtime)),
             () => runtime.Generation,
-            sink)
+            sink,
+            retryPendingOnSubscribe)
     {
     }
 
@@ -46,13 +60,27 @@ public sealed class RuntimePlacementProjectionSubscription
         RuntimePlacementProjectionChannel channel,
         Func<RuntimeGenerationToken> generation,
         IRuntimePlacementProjectionSink sink)
+        : this(
+            channel,
+            generation,
+            sink,
+            retryPendingOnSubscribe: true)
+    {
+    }
+
+    internal RuntimePlacementProjectionSubscription(
+        RuntimePlacementProjectionChannel channel,
+        Func<RuntimeGenerationToken> generation,
+        IRuntimePlacementProjectionSink sink,
+        bool retryPendingOnSubscribe)
     {
         _channel = channel ?? throw new ArgumentNullException(nameof(channel));
         _generation = generation
             ?? throw new ArgumentNullException(nameof(generation));
         _sink = sink ?? throw new ArgumentNullException(nameof(sink));
         _subscription = _channel.Subscribe(this);
-        _ = RetryPending();
+        if (retryPendingOnSubscribe)
+            _ = RetryPending();
     }
 
     public bool HasAppliedReceiptAwaitingAcknowledgement =>

tests/AcDream.App.Tests/Rendering/GameWindowSlice8BoundaryTests.cs

@@ -162,7 +162,7 @@ public sealed class GameWindowSlice8BoundaryTests
             "LiveSessionRuntimeFactory.cs"));
         string sessionFactory = Slice(
             sessionFactorySource,
-            "private LiveSessionEventRouter CreateEventRouter(",
+            "private ILiveSessionEventRouting CreateEventRouter(",
             "private LiveInventorySessionBindings CreateInventoryBindings()");
         string worldPhase = File.ReadAllText(Path.Combine(
             FindRepoRoot(),

tests/AcDream.App.Tests/Runtime/RuntimePhysicsOwnershipTests.cs

@@ -5,28 +5,36 @@ namespace AcDream.App.Tests.Runtime;
 public sealed class RuntimePhysicsOwnershipTests
 {
     [Fact]
-    public void GraphicalPlacementProjectionRemainsDormantUntilCoordinatedCutover()
+    public void ProductionHostsUseSharedPlacementSubscriptionWithoutDirectChannel()
     {
         string root = FindRepositoryRoot();
-        string relative = Path.Combine("src", "AcDream.App");
+        foreach (string relative in new[]
-        foreach (string file in Directory.EnumerateFiles(
+                 {
-                     Path.Combine(root, relative),
+                     Path.Combine("src", "AcDream.App"),
-                     "*.cs",
+                     Path.Combine("src", "AcDream.Headless"),
-                     SearchOption.AllDirectories))
+                 })
         {
-            string source = File.ReadAllText(file);
+            string[] sources = Directory.EnumerateFiles(
+                    Path.Combine(root, relative),
+                    "*.cs",
+                    SearchOption.AllDirectories)
+                .Select(File.ReadAllText)
+                .ToArray();
             Assert.DoesNotContain(
-                ".Placements.",
+                sources,
-                source,
+                source => source.Contains(
-                StringComparison.Ordinal);
+                    ".Placements.",
+                    StringComparison.Ordinal));
             Assert.DoesNotContain(
-                "RuntimePlacementProjectionChannel",
+                sources,
-                source,
+                source => source.Contains(
-                StringComparison.Ordinal);
+                    "RuntimePlacementProjectionChannel",
-            Assert.DoesNotContain(
+                    StringComparison.Ordinal));
-                "RuntimePlacementProjectionSubscription",
+            Assert.Contains(
-                source,
+                sources,
-                StringComparison.Ordinal);
+                source => source.Contains(
+                    "RuntimePlacementProjectionSubscription",
+                    StringComparison.Ordinal));
         }
     }
 

tests/AcDream.App.Tests/World/RuntimePlacementPresentationSinkTests.cs

@@ -1,6 +1,7 @@
 using System.Numerics;
 using AcDream.App.Streaming;
 using AcDream.App.World;
+using AcDream.App.Net;
 using AcDream.App.Physics;
 using AcDream.App.Rendering.Vfx;
 using AcDream.Core.Net;
@@ -11,6 +12,7 @@ using AcDream.Core.World;
 using AcDream.Runtime;
 using AcDream.Runtime.Entities;
 using AcDream.Runtime.Physics;
+using AcDream.Runtime.Session;
 using AcDream.Runtime.World;
 using DatReaderWriter.DBObjs;
 
@@ -409,6 +411,108 @@ public sealed class RuntimePlacementPresentationSinkTests
         Assert.False(subscription.HasAppliedReceiptAwaitingAcknowledgement);
     }
 
+    [Fact]
+    public void GraphicalRoute_ReentrantInitialDrainTeardownLeavesHeadForReplacement()
+    {
+        using var fixture = SubscriptionFixture.Create();
+        Assert.True(fixture.Lifetime.Physics.SetPosition.Cancel(
+            fixture.Record.Canonical,
+            publishWithdrawal: true));
+        Assert.Equal(1, fixture.Lifetime.Placements.PendingCount);
+
+        RuntimeGenerationToken generation = fixture.Generation;
+        var retries = new RuntimePlacementProjectionRetrySlot(
+            () => generation);
+        var firstEvents = new RecordingEventRoute();
+        GraphicalSessionEventRoute? first = null;
+        int applications = 0;
+        var sink = new DelegatePlacementSink(
+            (in RuntimePlacementProjectionSnapshot projection) =>
+        {
+            applications++;
+            bool applied = fixture.Sink.TryApply(in projection);
+            if (applications == 1)
+                first!.Dispose();
+            return applied;
+        });
+        first = new GraphicalSessionEventRoute(
+            firstEvents,
+            () => new RuntimePlacementProjectionSubscription(
+                fixture.Lifetime.Placements,
+                () => generation,
+                sink,
+                retryPendingOnSubscribe: false),
+            () => generation,
+            retries);
+
+        first.Attach();
+
+        Assert.Equal(1, applications);
+        Assert.Equal(1, fixture.Lifetime.Placements.PendingCount);
+        Assert.Equal(0, retries.BindingCount);
+        Assert.Equal(0, fixture.Lifetime.Events.PlacementSubscriberCount);
+        Assert.Equal(1, firstEvents.DisposeCount);
+
+        var replacementEvents = new RecordingEventRoute();
+        var replacement = new GraphicalSessionEventRoute(
+            replacementEvents,
+            () => new RuntimePlacementProjectionSubscription(
+                fixture.Lifetime.Placements,
+                () => generation,
+                sink,
+                retryPendingOnSubscribe: false),
+            () => generation,
+            retries);
+        replacement.Attach();
+
+        Assert.Equal(2, applications);
+        Assert.Equal(0, fixture.Lifetime.Placements.PendingCount);
+        Assert.Equal(1, retries.BindingCount);
+        Assert.Equal(1, fixture.Lifetime.Events.PlacementSubscriberCount);
+
+        replacement.Dispose();
+
+        Assert.Equal(0, retries.BindingCount);
+        Assert.Equal(0, fixture.Lifetime.Events.PlacementSubscriberCount);
+        Assert.Equal(1, replacementEvents.DisposeCount);
+    }
+
+    [Fact]
+    public void RetrySlot_InvokesOnlyExactCurrentGenerationBinding()
+    {
+        RuntimeGenerationToken generation = new(7UL);
+        var retries = new RuntimePlacementProjectionRetrySlot(
+            () => generation);
+        int firstCalls = 0;
+        IDisposable first = retries.BindOwned(
+            generation,
+            () =>
+            {
+                firstCalls++;
+                return true;
+            });
+
+        retries.RetryPending();
+        generation = new RuntimeGenerationToken(8UL);
+        retries.RetryPending();
+        first.Dispose();
+
+        int replacementCalls = 0;
+        using IDisposable replacement = retries.BindOwned(
+            generation,
+            () =>
+            {
+                replacementCalls++;
+                return true;
+            });
+        first.Dispose();
+        retries.RetryPending();
+
+        Assert.Equal(1, firstCalls);
+        Assert.Equal(1, replacementCalls);
+        Assert.Equal(1, retries.BindingCount);
+    }
+
     private static RuntimePlacementProjectionSnapshot Placement(
         Fixture fixture,
         LiveEntityRecord record,
@@ -805,6 +909,27 @@ public sealed class RuntimePlacementPresentationSinkTests
         }
     }
 
+    private sealed class DelegatePlacementSink(
+        PlacementApply apply) : IRuntimePlacementProjectionSink
+    {
+        public bool TryApply(
+            in RuntimePlacementProjectionSnapshot projection) =>
+            apply(in projection);
+    }
+
+    private delegate bool PlacementApply(
+        in RuntimePlacementProjectionSnapshot projection);
+
+    private sealed class RecordingEventRoute : ILiveSessionEventRouting
+    {
+        public int AttachCount { get; private set; }
+        public int DisposeCount { get; private set; }
+
+        public void Attach() => AttachCount++;
+
+        public void Dispose() => DisposeCount++;
+    }
+
     private sealed class RecordingResources : ILiveEntityResourceLifecycle
     {
         public void Register(WorldEntity entity) { }

tests/AcDream.App.Tests/World/UpdateFrameOrchestratorTests.cs

@@ -1,9 +1,11 @@
 using System.Reflection;
 using AcDream.App.Rendering;
+using AcDream.App.Net;
 using AcDream.App.Streaming;
 using AcDream.App.Update;
 using AcDream.App.World;
 using AcDream.Runtime;
+using AcDream.Runtime.Session;
 using AcDream.Runtime.World;
 
 namespace AcDream.App.Tests.World;
@@ -387,6 +389,65 @@ public sealed class UpdateFrameOrchestratorTests
         Assert.Equal(1, CountOccurrences(source, "_scripts.Tick("));
     }
 
+    [Fact]
+    public void PlacementRetryRunsAfterStreamingAndInboundBeforeCommandReconcile()
+    {
+        string root = FindRepoRoot();
+        string outer = File.ReadAllText(Path.Combine(
+            root,
+            "src",
+            "AcDream.App",
+            "Update",
+            "UpdateFrameOrchestrator.cs"));
+        string live = File.ReadAllText(Path.Combine(
+            root,
+            "src",
+            "AcDream.App",
+            "World",
+            "RetailLiveFrameCoordinator.cs"));
+
+        AssertAppearsInOrder(
+            outer,
+            "_streaming.Tick();",
+            "_liveFrame.Tick(");
+        AssertAppearsInOrder(
+            live,
+            "_session.Tick();",
+            "_placementProjectionRetry?.RetryPending();",
+            "_localPlayer.RunPostNetworkCommandPhase();",
+            "_spatialReconciler.Reconcile();");
+    }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void LiveFrameRetriesPlacementAfterInboundEvenWhenWorldIsQuiesced(
+        bool worldAvailable)
+    {
+        var calls = new List<string>();
+        var phases = new RecordingLivePhases(calls)
+        {
+            IsWorldAvailable = worldAvailable,
+        };
+        var frame = new RetailLiveFrameCoordinator(
+            phases,
+            new GpuWorldState(),
+            phases,
+            phases,
+            phases,
+            phases,
+            phases,
+            phases);
+
+        frame.Tick(1f / 60f);
+
+        Assert.Equal(
+            worldAvailable
+                ? ["objects", "network", "placement-retry", "commands", "reconcile"]
+                : ["network", "placement-retry", "commands", "render-sync"],
+            calls);
+    }
+
     [Fact]
     public void GameWindow_ComposesTheLiveFrameOwnersWithoutOwningTheirBodies()
     {
@@ -1048,6 +1109,26 @@ public sealed class UpdateFrameOrchestratorTests
         }
     }
 
+    private sealed class RecordingLivePhases(List<string> calls) :
+        ILiveObjectFramePhase,
+        IRuntimeLiveSessionFramePhase,
+        IPostNetworkCommandFramePhase,
+        ILiveSpatialReconcilePhase,
+        IRenderProjectionSyncPhase,
+        IWorldGenerationAvailability,
+        IRuntimePlacementProjectionRetryPhase
+    {
+        public bool IsWorldAvailable { get; set; }
+        public long QuiescedGeneration => IsWorldAvailable ? 0L : 1L;
+
+        public void Tick(float deltaSeconds) => calls.Add("objects");
+        public void Tick() => calls.Add("network");
+        public void RunPostNetworkCommandPhase() => calls.Add("commands");
+        public void Reconcile() => calls.Add("reconcile");
+        public void SynchronizeActiveSources() => calls.Add("render-sync");
+        public void RetryPending() => calls.Add("placement-retry");
+    }
+
     private sealed class RecordingCommit(List<string> calls)
         : IUpdateFrameCommitPhase
     {

tests/AcDream.Runtime.Tests/Physics/RuntimePlacementProjectionSubscriptionTests.cs

@@ -173,6 +173,28 @@ public sealed class RuntimePlacementProjectionSubscriptionTests
         Assert.False(subscription.HasAppliedReceiptAwaitingAcknowledgement);
     }
 
+    [Fact]
+    public void SubscribeWithoutDrainPublishesOnlyAfterExplicitRetry()
+    {
+        using var fixture = new Fixture();
+        RuntimeSetPositionOutcome pending = fixture.Place(
+            fixture.First,
+            new Vector3(18.5f, 18f, 7f));
+        var sink = new RecordingSink();
+
+        using var subscription = fixture.Subscribe(
+            sink,
+            retryPendingOnSubscribe: false);
+
+        Assert.Empty(sink.Applied);
+        Assert.Equal(1, fixture.Lifetime.Placements.PendingCount);
+
+        Assert.True(subscription.RetryPending());
+
+        Assert.Equal(pending.Projection, Assert.Single(sink.Applied).Token);
+        Assert.Equal(0, fixture.Lifetime.Placements.PendingCount);
+    }
+
     [Fact]
     public void SyntheticWithdrawalUsesTheSameExactSinkAndAckPath()
     {
@@ -263,10 +285,12 @@ public sealed class RuntimePlacementProjectionSubscriptionTests
         internal RuntimeEntityRecord? Second { get; }
 
         internal RuntimePlacementProjectionSubscription Subscribe(
-            IRuntimePlacementProjectionSink sink) => new(
+            IRuntimePlacementProjectionSink sink,
+            bool retryPendingOnSubscribe = true) => new(
                 Lifetime.Placements,
                 () => _generation,
-                sink);
+                sink,
+                retryPendingOnSubscribe);
 
         internal RuntimeSetPositionOutcome Place(
             RuntimeEntityRecord record,