Disallow LogicLooper.Dispose on the loop thread.

Author: mayuki

src/LogicLooper/LogicLooper.cs

@@ -1,4 +1,4 @@
-using Cysharp.Threading.Internal;
+using Cysharp.Threading.Internal;
 
 // ReSharper disable StringLiteralTypo
 // ReSharper disable IdentifierTypo
@@ -187,6 +187,11 @@ public async Task RegisterActionAsync<TState>(LogicLooperAsyncActionWithStateDel
     /// <param name="shutdownDelay"></param>
     public async Task ShutdownAsync(TimeSpan shutdownDelay)
     {
+        if (_runLoopThread == Thread.CurrentThread)
+        {
+            throw new InvalidOperationException("Cannot dispose the looper from the run loop thread. ShutdownAsync or Dispose must be called outside the loop.");
+        }
+
         if (Interlocked.CompareExchange(ref _isShuttingDown, 1, 0) == 0)
         {
             _ctsAction.Cancel();

test/LogicLooper.Test/LogicLooperTest.cs

@@ -1,4 +1,4 @@
-using Cysharp.Threading;
+using Cysharp.Threading;
 using Cysharp.Threading.Internal;
 
 namespace LogicLooper.Test;
@@ -384,4 +384,37 @@ public async Task TargetFrameRateOverride_2()
 
         Assert.Equal(1, overriddenFrameCount);
     }
+
+    [Fact]
+    public async Task Dispose_DisallowOnLoopThread()
+    {
+        using var looper = new Cysharp.Threading.LogicLooper(30);
+        Exception? ex = default;
+
+        await looper.RegisterActionAsync((in LogicLooperActionContext ctx) =>
+        {
+            ex = Record.Exception(() => looper.Dispose());
+            return false;
+        });
+
+        Assert.NotNull(ex);
+        Assert.IsType<InvalidOperationException>(ex);
+    }
+
+    [Fact]
+    public async Task Dispose_OutsideTheLoop()
+    {
+        using var looper = new Cysharp.Threading.LogicLooper(30);
+        Exception? ex = default;
+
+        var t = looper.RegisterActionAsync((in LogicLooperActionContext ctx) =>
+        {
+            return true;
+        });
+
+        await Task.Delay(100);
+
+        looper.Dispose();
+    }
+
 }