fix: the practice HUD comes back after a reconnect or a respawned layout

apps/utility-sw/src/Hud/HudKit.cs

@@ -254,7 +254,7 @@ private static uint EntityIndex(uint indexOrHandle)
 
         if (layouts.TryGetValue(slots.Layout, out Open? open))
         {
-            if (open.EntityIndex == entity.Index)
+            if (HudLayoutIdentity.Same(open.Surface.Layout, open.EntityIndex, entity, entity.Index))
             {
                 return open;
             }

apps/utility-sw/src/Hud/PracticeHud.cs

@@ -690,7 +690,7 @@ private string RowValue(LineupRecord lineup, Vec3? at)
         return from.Length > 0 ? $"{from} · {distance}" : distance;
     }
 
-    private void ForgetHud(ulong steamId, int playerId)
+    private void ForgetHud(ulong steamId)
     {
         _hudOff.Remove(steamId);
         _menus.Remove(steamId);
@@ -702,7 +702,6 @@ private void ForgetHud(ulong steamId, int playerId)
         _mapChoices.Remove(steamId);
         ForgetVerdicts(steamId);
         ClearFilters(steamId);
-        _hud?.Forget(playerId);
     }
 
     [Command("menu", registerRaw: false, permission: "")]

apps/utility-sw/src/UtilityPractice.csproj

@@ -85,6 +85,7 @@
           Link="resources/gamedata/fivestack.gamedata.json"
           CopyToOutputDirectory="PreserveNewest" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/HudSteady.cs" LinkBase="Shared" />
+    <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/HudLayoutIdentity.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/LineupNaming.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/ApproachUtility.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/SmokeVoxelCapture.cs" LinkBase="Shared" />

apps/utility-sw/src/UtilityPracticePlugin.cs

@@ -87,6 +87,7 @@ private sealed class LibraryLoad
     private EventDelegates.OnClientDisconnected? _disconnectHandler;
     private EventDelegates.OnPrecacheResource? _precacheHandler;
     private EventDelegates.OnClientSteamAuthorize? _authorizeHandler;
+    private EventDelegates.OnClientPutInServer? _putInServerHandler;
     private EventDelegates.OnCustomHudClicked? _hudClickHandler;
 
     public UtilityPracticePlugin(ISwiftlyCore core)
@@ -265,6 +266,7 @@ public override void Load(bool hotReload)
             _occupancyDirty = true;
             _prompt?.Cancel(@event.PlayerId);
             _replay.ForgetViewer(@event.PlayerId);
+            _hud?.Forget(@event.PlayerId);
 
             ForPlayer(
                 @event.PlayerId,
@@ -275,7 +277,7 @@ public override void Load(bool hotReload)
                     // invalidated never reaches this at all, which is why the
                     // drain prunes off the roster as well.
                     _libraryLoads.Remove(steamId);
-                    ForgetHud(steamId, @event.PlayerId);
+                    ForgetHud(steamId);
                     OnPlayerGone(steamId);
                 }
             );
@@ -292,6 +294,13 @@ public override void Load(bool hotReload)
         };
         Core.Event.OnClientSteamAuthorize += _authorizeHandler;
 
+        // Only the slot: ForgetHud also clears settings that outlive a map change.
+        _putInServerHandler = @event =>
+        {
+            _hud?.Forget(@event.PlayerId);
+        };
+        Core.Event.OnClientPutInServer += _putInServerHandler;
+
         InitializeConnectClientHook();
         InitializeTerminateRoundHook();
 
@@ -501,6 +510,11 @@ private void TearDown()
             Core.Event.OnClientSteamAuthorize -= _authorizeHandler;
         }
 
+        if (_putInServerHandler != null)
+        {
+            Core.Event.OnClientPutInServer -= _putInServerHandler;
+        }
+
         UninstallConnectClientHook();
         UninstallTerminateRoundHook();
 

apps/utility-sw/test/FiveStack.Tests.csproj

@@ -60,6 +60,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/UtilityTargetCluster.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/RadarMaps.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/HudSteady.cs" LinkBase="Shared" />
+    <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/HudLayoutIdentity.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/LineupNaming.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/ApproachUtility.cs" LinkBase="Shared" />
     <Compile Include="$(MSBuildThisFileDirectory)../../../shared/dotnet/FiveStack.Utilities/SmokeVoxelCapture.cs" LinkBase="Shared" />

apps/utility-sw/test/HudSlotResetTests.cs

@@ -0,0 +1,117 @@
+using System.Text.RegularExpressions;
+using FiveStack.Utilities;
+using Xunit;
+
+public class HudSlotResetTests
+{
+    private const uint Index = 412;
+
+    // Comments out first: a call that has been commented out is not a call.
+    private static string Code(params string[] path)
+    {
+        DirectoryInfo? directory = new DirectoryInfo(AppContext.BaseDirectory);
+
+        while (directory != null)
+        {
+            string candidate = Path.Combine(
+                new[] { directory.FullName, "apps", "utility-sw", "src" }.Concat(path).ToArray()
+            );
+
+            if (File.Exists(candidate))
+            {
+                return Regex.Replace(File.ReadAllText(candidate), @"//[^\n]*", "");
+            }
+
+            directory = directory.Parent;
+        }
+
+        throw new FileNotFoundException($"{path[^1]} was not found above the test output");
+    }
+
+    private static string Hook(string start, string end)
+    {
+        string source = Code("UtilityPracticePlugin.cs");
+        int from = source.IndexOf(start, StringComparison.Ordinal);
+
+        Assert.True(from >= 0, $"{start} is gone");
+
+        int to = source.IndexOf(end, from, StringComparison.Ordinal);
+
+        Assert.True(to >= 0, $"{end} is gone");
+
+        return source[from..to];
+    }
+
+    [Fact]
+    public void TheSameEntityKeepsItsSurface()
+    {
+        object layout = new();
+
+        Assert.True(HudLayoutIdentity.Same(layout, Index, layout, Index));
+    }
+
+    [Fact]
+    public void ALayoutRespawnedOnTheFreedIndexIsANewLayout()
+    {
+        Assert.False(HudLayoutIdentity.Same(new object(), Index, new object(), Index));
+    }
+
+    [Fact]
+    public void ALayoutOnAnotherIndexIsANewLayout()
+    {
+        object layout = new();
+
+        Assert.False(HudLayoutIdentity.Same(layout, Index, layout, Index + 1));
+    }
+
+    [Fact]
+    public void ADisconnectForgetsTheSlotWithoutResolvingTheLeaver()
+    {
+        string beforeResolving = Hook("_disconnectHandler = @event =>", "ForPlayer(");
+
+        Assert.Contains("_hud?.Forget(@event.PlayerId);", beforeResolving);
+        Assert.Contains(
+            "Core.Event.OnClientDisconnected += _disconnectHandler;",
+            Code("UtilityPracticePlugin.cs")
+        );
+    }
+
+    [Fact]
+    public void AnArrivalForgetsWhateverTheSlotWasHolding()
+    {
+        string hook = Hook("_putInServerHandler = @event =>", "};");
+
+        Assert.Contains("_hud?.Forget(@event.PlayerId);", hook);
+        Assert.Contains(
+            "Core.Event.OnClientPutInServer += _putInServerHandler;",
+            Code("UtilityPracticePlugin.cs")
+        );
+    }
+
+    [Fact]
+    public void TheArrivalHookIsLetGoOnUnload()
+    {
+        Assert.Contains(
+            "Core.Event.OnClientPutInServer -= _putInServerHandler;",
+            Code("UtilityPracticePlugin.cs")
+        );
+    }
+
+    [Fact]
+    public void AnArrivalLeavesAPlayersOwnHudSettingsAlone()
+    {
+        Assert.DoesNotContain("ForgetHud", Hook("_putInServerHandler = @event =>", "};"));
+    }
+
+    [Fact]
+    public void TheKitAsksTheIdentityRuleBeforeKeepingASurface()
+    {
+        string kit = Code("Hud", "HudKit.cs");
+
+        Assert.Contains(
+            "HudLayoutIdentity.Same(open.Surface.Layout, open.EntityIndex, entity, entity.Index)",
+            kit
+        );
+        Assert.DoesNotContain("open.EntityIndex == entity.Index", kit);
+    }
+}

shared/dotnet/FiveStack.Utilities/HudLayoutIdentity.cs

@@ -0,0 +1,12 @@
+namespace FiveStack.Utilities;
+
+// Whether a surface can still be used on the layout entity in hand. A respawned
+// entity can be given the index the old one freed, and what was sent to the old
+// one is gone with it, so the index alone does not say the client holds anything.
+public static class HudLayoutIdentity
+{
+    public static bool Same(object held, uint heldIndex, object current, uint currentIndex)
+    {
+        return heldIndex == currentIndex && ReferenceEquals(held, current);
+    }
+}