Merge pull request #323 from SolidAlloy/throw-exception-fix

Fix exceptions never being reported when UniTask is executed without await and Forget()

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

@@ -194,6 +194,7 @@ namespace Cysharp.Threading.Tasks
         sealed class ExceptionResultSource : IUniTaskSource
         {
             readonly ExceptionDispatchInfo exception;
+            bool calledGet;
 
             public ExceptionResultSource(Exception exception)
             {
@@ -202,6 +203,11 @@ namespace Cysharp.Threading.Tasks
 
             public void GetResult(short token)
             {
+                if (!calledGet)
+                {
+                    calledGet = true;
+                    GC.SuppressFinalize(this);
+                }
                 exception.Throw();
             }
 
@@ -219,11 +225,20 @@ namespace Cysharp.Threading.Tasks
             {
                 continuation(state);
             }
+
+            ~ExceptionResultSource()
+            {
+                if (!calledGet)
+                {
+                    UniTaskScheduler.PublishUnobservedTaskException(exception.SourceException);
+                }
+            }
         }
 
         sealed class ExceptionResultSource<T> : IUniTaskSource<T>
         {
             readonly ExceptionDispatchInfo exception;
+            bool calledGet;
 
             public ExceptionResultSource(Exception exception)
             {
@@ -232,12 +247,22 @@ namespace Cysharp.Threading.Tasks
 
             public T GetResult(short token)
             {
+                if (!calledGet)
+                {
+                    calledGet = true;
+                    GC.SuppressFinalize(this);
+                }
                 exception.Throw();
                 return default;
             }
 
             void IUniTaskSource.GetResult(short token)
             {
+                if (!calledGet)
+                {
+                    calledGet = true;
+                    GC.SuppressFinalize(this);
+                }
                 exception.Throw();
             }
 
@@ -255,6 +280,14 @@ namespace Cysharp.Threading.Tasks
             {
                 continuation(state);
             }
+
+            ~ExceptionResultSource()
+            {
+                if (!calledGet)
+                {
+                    UniTaskScheduler.PublishUnobservedTaskException(exception.SourceException);
+                }
+            }
         }
 
         sealed class CanceledResultSource : IUniTaskSource

src/UniTask/Assets/Tests/AsyncTest.cs

@@ -366,6 +366,28 @@ namespace Cysharp.Threading.TasksTests
             UniTaskScheduler.UnobservedTaskException -= action;
         });
 
+        [UnityTest]
+        public IEnumerator ThrowExceptionUnawaited() => UniTask.ToCoroutine(async () =>
+        {
+            LogAssert.Expect(LogType.Exception, "Exception: MyException");
+
+#pragma warning disable 1998
+            async UniTask Throw() => throw new Exception("MyException");
+#pragma warning restore 1998
+
+#pragma warning disable 4014
+            Throw();
+#pragma warning restore 4014
+
+            await UniTask.DelayFrame(3);
+
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            GC.Collect();
+
+            await UniTask.DelayFrame(1);
+        });
+
         async UniTask InException1()
         {
             await UniTask.Yield();