Add notification command exception handler

StabilityMatrix.Avalonia/Extensions/RelayCommandExtensions.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using CommunityToolkit.Mvvm.Input;
+using NLog;
+using StabilityMatrix.Avalonia.Services;
+using StabilityMatrix.Core.Extensions;
+
+namespace StabilityMatrix.Avalonia.Extensions;
+
+[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
+public static class RelayCommandExtensions
+{
+    private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
+
+    /// <summary>
+    /// Attach an error handler to the command that will invoke the given action when an exception occurs.
+    /// </summary>
+    /// <param name="command">The command to attach the error handler to.</param>
+    /// <param name="onError">The action to invoke when an exception occurs.</param>
+    /// <exception cref="ArgumentException">Thrown if the command was not created with the FlowExceptionsToTaskScheduler option enabled.</exception>
+    public static T WithErrorHandler<T>(this T command, Action<Exception> onError) where T : IAsyncRelayCommand
+    {
+        if (command is AsyncRelayCommand relayCommand)
+        {
+            // Check that the FlowExceptionsToTaskScheduler flag is set
+            var options = relayCommand.GetPrivateField<AsyncRelayCommandOptions>("options");
+
+            if (!options.HasFlag(AsyncRelayCommandOptions.FlowExceptionsToTaskScheduler))
+            {
+                throw new ArgumentException(
+                    "The command must be created with the FlowExceptionsToTaskScheduler option enabled"
+                );
+            }
+        }
+
+        command.PropertyChanged += (sender, e) =>
+        {
+            if (sender is not IAsyncRelayCommand senderCommand)
+            {
+                return;
+            }
+            // On ExecutionTask updates, check if there is an exception
+            if (
+                e.PropertyName == nameof(AsyncRelayCommand.ExecutionTask)
+                && senderCommand.ExecutionTask is { Exception: { } exception }
+            )
+            {
+                onError(exception);
+            }
+        };
+
+        return command;
+    }
+
+    /// <summary>
+    /// Attach an error handler to the command that will log the error and show a notification.
+    /// </summary>
+    /// <param name="command">The command to attach the error handler to.</param>
+    /// <param name="notificationService">The notification service to use to show the notification.</param>
+    /// <param name="logLevel">The log level to use when logging the error. Defaults to LogLevel.Error</param>
+    /// <exception cref="ArgumentException">Thrown if the command was not created with the FlowExceptionsToTaskScheduler option enabled.</exception>
+    public static T WithNotificationErrorHandler<T>(
+        this T command,
+        INotificationService notificationService,
+        LogLevel? logLevel = default
+    ) where T : IAsyncRelayCommand
+    {
+        logLevel ??= LogLevel.Error;
+
+        return command.WithErrorHandler(e =>
+        {
+            Logger.Log(logLevel, e, "Error executing command");
+            notificationService.ShowPersistent("Error", $"[{e.GetType().Name}] {e.Message}");
+        });
+    }
+}

StabilityMatrix.Avalonia/StabilityMatrix.Avalonia.csproj

@@ -45,6 +45,7 @@
         <PackageReference Include="Polly.Contrib.WaitAndRetry" Version="1.1.1" />
         <PackageReference Include="Polly.Extensions.Http" Version="3.0.0" />
         <PackageReference Include="Projektanker.Icons.Avalonia.FontAwesome" Version="6.6.0" />
+        <PackageReference Include="RockLib.Reflection.Optimized" Version="2.0.0" />
         <PackageReference Include="Sentry" Version="3.33.1" />
         <PackageReference Include="Sentry.NLog" Version="3.33.1" />
         <PackageReference Include="TextMateSharp.Grammars" Version="1.0.55" />

StabilityMatrix.Avalonia/ViewModels/SettingsViewModel.cs

@@ -21,6 +21,7 @@ using FluentAvalonia.UI.Controls;
 using NLog;
 using SkiaSharp;
 using StabilityMatrix.Avalonia.Controls;
+using StabilityMatrix.Avalonia.Extensions;
 using StabilityMatrix.Avalonia.Helpers;
 using StabilityMatrix.Avalonia.Models;
 using StabilityMatrix.Avalonia.Services;
@@ -112,6 +113,8 @@ public partial class SettingsViewModel : PageViewModelBase
         settingsManager.RelayPropertyFor(this,
             vm => vm.IsDiscordRichPresenceEnabled,
             settings => settings.IsDiscordRichPresenceEnabled);
+        
+        DebugThrowAsyncExceptionCommand.WithNotificationErrorHandler(notificationService, LogLevel.Warn);
     }
     
     partial void OnSelectedThemeChanged(string? value)
@@ -387,10 +390,17 @@ public partial class SettingsViewModel : PageViewModelBase
     [RelayCommand]
     private void DebugThrowException()
     {
-        // Use try-catch to generate traceback information
         throw new OperationCanceledException("Example Message");
     }
     
+    [RelayCommand(FlowExceptionsToTaskScheduler = true)]
+    private async Task DebugThrowAsyncException()
+    {
+        await Task.Yield();
+
+        throw new ApplicationException("Example Message");
+    }
+
     [RelayCommand]
     private async Task DebugMakeImageGrid()
     {

StabilityMatrix.Avalonia/Views/SettingsPage.axaml

@@ -226,9 +226,21 @@
                                 
                                 <ui:SettingsExpanderItem Content="Exceptions" IconSource="Flag">
                                     <ui:SettingsExpanderItem.Footer>
-                                        <Button
+                                        <SplitButton
                                             Command="{Binding DebugThrowExceptionCommand}"
-                                            Content="Unhandled Exception"/>
+                                            Content="Command Exception">
+                                            
+                                            <SplitButton.Flyout>
+                                                <ui:FAMenuFlyout>
+                                                    
+                                                    <ui:MenuFlyoutItem 
+                                                        Text="Async Command Exception"
+                                                        Command="{Binding DebugThrowAsyncExceptionCommand}"/>
+                                                    
+                                                </ui:FAMenuFlyout>
+                                            </SplitButton.Flyout>
+                                            
+                                        </SplitButton>
                                     </ui:SettingsExpanderItem.Footer>
                                 </ui:SettingsExpanderItem>