Fix TriggerEvent problem with iterate breaking on Remove when it has multiple handlers

Revert "Fixed https://github.com/Cysharp/UniTask/issues/444"

src/UniTask/Assets/Plugins/UniTask/Runtime/TriggerEvent.cs

@@ -42,7 +42,6 @@ namespace Cysharp.Threading.Tasks
             while (h != null)
             {
                 iteratingNode = h;
-                var next = h.Next;
 
                 try
                 {
@@ -54,7 +53,9 @@ namespace Cysharp.Threading.Tasks
                     Remove(h);
                 }
 
-                h = next;
+                // If `h` itself is removed by OnNext, h.Next is null.
+                // Therefore, instead of looking at h.Next, the `iteratingNode` reference itself is replaced.
+                h = h == iteratingNode ? h.Next : iteratingNode;
             }
 
             iteratingNode = null;
@@ -86,7 +87,7 @@ namespace Cysharp.Threading.Tasks
                 }
 
                 iteratingNode = null;
-                var next = h.Next;
+                var next = h == iteratingNode ? h.Next : iteratingNode;
                 Remove(h);
                 h = next;
             }
@@ -119,8 +120,8 @@ namespace Cysharp.Threading.Tasks
                     LogError(ex);
                 }
 
+                var next = h == iteratingNode ? h.Next : iteratingNode;
                 iteratingNode = null;
-                var next = h.Next;
                 Remove(h);
                 h = next;
             }
@@ -153,8 +154,8 @@ namespace Cysharp.Threading.Tasks
                     LogError(ex);
                 }
 
+                var next = h == iteratingNode ? h.Next : iteratingNode;
                 iteratingNode = null;
-                var next = h.Next;
                 Remove(h);
                 h = next;
             }
@@ -238,18 +239,20 @@ namespace Cysharp.Threading.Tasks
             {
                 head = next;
             }
-            else if (handler == iteratingHead)
+            // when handler is head, prev indicate last so don't use it.
+            else if (prev != null)
+            {
+                prev.Next = next;
+            }
+
+            if (handler == iteratingNode)
+            {
+                iteratingNode = next;
+            }
+            if (handler == iteratingHead)
             {
                 iteratingHead = next;
             }
-            else
-            {
-                // when handler is head, prev indicate last so don't use it.
-                if (prev != null)
-                {
-                    prev.Next = next;
-                }
-            }
 
             if (head != null)
             {

src/UniTask/Assets/Tests/AsyncReactivePropertyTest.cs

@@ -1,63 +0,0 @@
-using Cysharp.Threading.Tasks;
-using FluentAssertions;
-using System;
-using System.Collections;
-using System.Threading;
-using UnityEngine.TestTools;
-
-namespace Cysharp.Threading.TasksTests
-{
-    public class AsyncReactivePropertyTest
-    {
-        private int _callCounter;
-        
-        [UnityTest]
-        public IEnumerator WaitCancelWait() => UniTask.ToCoroutine(async () =>
-        {
-            // Test case for https://github.com/Cysharp/UniTask/issues/444
-            
-            var property = new AsyncReactiveProperty<int>(0);
-            
-            var cts1 = new CancellationTokenSource();
-            var cts2 = new CancellationTokenSource();
-            WaitForProperty(property, cts1.Token);
-            WaitForProperty(property, cts2.Token);
-
-            _callCounter = 0;
-            property.Value = 1;
-            _callCounter.Should().Be(2);
-
-            cts2.Cancel();
-            cts2.Dispose();
-            cts1.Cancel();
-            cts1.Dispose();
-
-            var cts3 = new CancellationTokenSource();
-            WaitForProperty(property, cts3.Token);
-
-            _callCounter = 0;
-            property.Value = 2;
-            _callCounter.Should().Be(1);
-            
-            cts3.Cancel();
-            cts3.Dispose();
-            await UniTask.CompletedTask;
-        });
-
-        private async void WaitForProperty(AsyncReactiveProperty<int> property, CancellationToken token)
-        {
-            while (true)
-            {
-                try
-                {
-                    await property.WaitAsync(token);
-                    _callCounter++;
-                }
-                catch (OperationCanceledException)
-                {
-                    break;
-                }
-            }
-        }
-    }
-}

src/UniTask/Assets/Tests/AsyncReactivePropertyTest.cs.meta

@@ -1,3 +0,0 @@
-fileFormatVersion: 2
-guid: 27665955eefb4448969b8cc4dd204600
-timeCreated: 1676129650