Ensure Task is await'd in AsyncRelayCommand and AsyncRelayCommand<T>

.gitignore

@@ -232,3 +232,6 @@ msbuild.binlog
 # TAEF Log output
 WexLogFileOutput
 *.wtl
+
+#macOS Temporary Files
+*.DS_Store

CommunityToolkit.Mvvm/Input/AsyncRelayCommand.cs

@@ -277,9 +277,9 @@ public bool CanExecute(object? parameter)
     }
 
     /// <inheritdoc/>
-    public void Execute(object? parameter)
+    public async void Execute(object? parameter)
     {
-        _ = ExecuteAsync(parameter);
+        await ExecuteAsync(parameter).ConfigureAwait(false);
     }
 
     /// <inheritdoc/>

CommunityToolkit.Mvvm/Input/AsyncRelayCommand{T}.cs

@@ -214,7 +214,7 @@ static async void MonitorTask(AsyncRelayCommand<T> @this, Task task)
                 {
                     @this.PropertyChanged?.Invoke(@this, AsyncRelayCommand.ExecutionTaskChangedEventArgs);
                     @this.PropertyChanged?.Invoke(@this, AsyncRelayCommand.IsRunningChangedEventArgs);
-                    
+
                     if (@this.cancellationTokenSource is not null)
                     {
                         @this.PropertyChanged?.Invoke(@this, AsyncRelayCommand.CanBeCanceledChangedEventArgs);
@@ -273,15 +273,15 @@ public bool CanExecute(object? parameter)
 
     /// <inheritdoc/>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public void Execute(T? parameter)
+    public async void Execute(T? parameter)
     {
-        _ = ExecuteAsync(parameter);
+        await ExecuteAsync(parameter).ConfigureAwait(false);
     }
 
     /// <inheritdoc/>
-    public void Execute(object? parameter)
+    public async void Execute(object? parameter)
     {
-        _ = ExecuteAsync((T?)parameter);
+        await ExecuteAsync((T?)parameter).ConfigureAwait(false);
     }
 
     /// <inheritdoc/>

tests/CommunityToolkit.Mvvm.UnitTests/CommunityToolkit.Mvvm.UnitTests.csproj

@@ -8,6 +8,7 @@
     <PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />
     <PackageReference Include="MSTest.TestFramework" Version="2.2.8" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
+    <PackageReference Include="Nito.AsyncEx.Context" Version="5.1.2" />
   </ItemGroup>
 
   <ItemGroup>

tests/CommunityToolkit.Mvvm.UnitTests/Test_AsyncRelayCommand.cs

@@ -10,6 +10,7 @@
 using CommunityToolkit.Mvvm.Input;
 using CommunityToolkit.Mvvm.UnitTests.Helpers;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Nito.AsyncEx;
 
 namespace CommunityToolkit.Mvvm.UnitTests;
 
@@ -502,4 +503,38 @@ public void Test_AsyncRelayCommand_GetCancelCommand_WithToken()
         Assert.IsFalse(command.CanBeCanceled);
         Assert.IsTrue(command.IsCancellationRequested);
     }
+
+    [TestMethod]
+    public async Task Test_AsyncRelayCommand_EnsureExceptionThrown()
+    {
+        const int delay = 500;
+        const string exceptionMessage = "This Exception Is Thrown Inside of the Task";
+
+        Exception? executeException = null, executeAsyncException = null;
+
+        AsyncRelayCommand command = new(async () =>
+        {
+            await Task.Delay(delay);
+            throw new Exception(exceptionMessage);
+        });
+
+        try
+        {
+            // Use AsyncContext to test `async void` methods https://stackoverflow.com/a/14207615/5953643
+            AsyncContext.Run(async () =>
+            {
+                command.Execute(null);
+                await Task.Delay(delay * 2); // Ensure we don't escape `AsyncContext` before command throws Exception
+            });
+        }
+        catch (Exception e)
+        {
+            executeException = e;
+        }
+
+        executeAsyncException = await Assert.ThrowsExceptionAsync<Exception>(() => command.ExecuteAsync(null));
+
+        Assert.AreEqual(exceptionMessage, executeException?.Message);
+        Assert.AreEqual(exceptionMessage, executeAsyncException?.Message);
+    }
 }

tests/CommunityToolkit.Mvvm.UnitTests/Test_AsyncRelayCommand{T}.cs

@@ -10,6 +10,7 @@
 using CommunityToolkit.Mvvm.Input;
 using CommunityToolkit.Mvvm.UnitTests.Helpers;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Nito.AsyncEx;
 
 namespace CommunityToolkit.Mvvm.UnitTests;
 
@@ -437,4 +438,53 @@ public void Test_AsyncRelayCommandOfT_GetCancelCommand_WithToken()
         Assert.IsFalse(command.CanBeCanceled);
         Assert.IsTrue(command.IsCancellationRequested);
     }
+
+    [TestMethod]
+    public async Task Test_AsyncRelayCommand_EnsureExceptionThrown()
+    {
+        const int delay = 500;
+        const string exceptionMessage = "This Exception Is Thrown Inside of the Task";
+
+        Exception? executeException = null, executeTException = null, executeAsyncException = null;
+
+        AsyncRelayCommand<int> command = new(async delay =>
+        {
+            await Task.Delay(delay);
+            throw new Exception(exceptionMessage);
+        });
+
+        try
+        {
+            // Use AsyncContext to test `async void` methods https://stackoverflow.com/a/14207615/5953643
+            AsyncContext.Run(async () =>
+            {
+                command.Execute((object)delay);
+                await Task.Delay(delay * 2); // Ensure we don't escape `AsyncContext` before command throws Exception
+            });
+        }
+        catch (Exception e)
+        {
+            executeException = e;
+        }
+
+        try
+        {
+            // Use AsyncContext to test `async void` methods https://stackoverflow.com/a/14207615/5953643
+            AsyncContext.Run(async () =>
+            {
+                command.Execute(delay);
+                await Task.Delay(delay * 2); // Ensure we don't escape `AsyncContext` before command throws Exception
+            });
+        }
+        catch (Exception e)
+        {
+            executeTException = e;
+        }
+
+        executeAsyncException = await Assert.ThrowsExceptionAsync<Exception>(() => command.ExecuteAsync(delay));
+
+        Assert.AreEqual(exceptionMessage, executeException?.Message);
+        Assert.AreEqual(exceptionMessage, executeTException?.Message);
+        Assert.AreEqual(exceptionMessage, executeAsyncException?.Message);
+    }
 }