Address code review feedback

- Remove redundant SubscribeToPasteAIProviders call from InitializePasteAIProviderState since AttachConfigurationHandlers already handles all subscriptions
- Remove unnecessary GetDispatcherQueue override from test class as AdvancedPasteViewModel doesn't use a virtual method pattern for dispatcher

Co-authored-by: moooyo <42196638+moooyo@users.noreply.github.com>

src/settings-ui/Settings.UI.UnitTests/ViewModelTests/AdvancedPaste.cs

@@ -0,0 +1,122 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using Microsoft.PowerToys.Settings.UI.Library;
+using Microsoft.PowerToys.Settings.UI.Library.Interfaces;
+using Microsoft.PowerToys.Settings.UI.UnitTests.Mocks;
+using Microsoft.PowerToys.Settings.UI.ViewModels;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+
+namespace ViewModelTests
+{
+    [TestClass]
+    public class AdvancedPaste
+    {
+        private Mock<SettingsUtils> mockAdvancedPasteSettingsUtils;
+
+        [TestInitialize]
+        public void SetUpStubSettingUtils()
+        {
+            mockAdvancedPasteSettingsUtils = ISettingsUtilsMocks.GetStubSettingsUtils<AdvancedPasteSettings>();
+        }
+
+        private sealed class TestAdvancedPasteViewModel : AdvancedPasteViewModel
+        {
+            public TestAdvancedPasteViewModel(
+                SettingsUtils settingsUtils,
+                ISettingsRepository<GeneralSettings> generalSettingsRepository,
+                ISettingsRepository<AdvancedPasteSettings> advancedPasteSettingsRepository,
+                Func<string, int> ipcMSGCallBackFunc)
+                : base(settingsUtils, generalSettingsRepository, advancedPasteSettingsRepository, ipcMSGCallBackFunc)
+            {
+            }
+        }
+
+        [TestMethod]
+        public void ViewModelInitialization_WithEmptySettings_ShouldNotCrash()
+        {
+            // Arrange
+            var mockGeneralSettingsUtils = ISettingsUtilsMocks.GetStubSettingsUtils<GeneralSettings>();
+            var generalSettingsRepository = new Mock<ISettingsRepository<GeneralSettings>>();
+            generalSettingsRepository.Setup(x => x.SettingsConfig).Returns(new GeneralSettings());
+
+            var advancedPasteSettings = new AdvancedPasteSettings();
+            var advancedPasteSettingsRepository = new Mock<ISettingsRepository<AdvancedPasteSettings>>();
+            advancedPasteSettingsRepository.Setup(x => x.SettingsConfig).Returns(advancedPasteSettings);
+
+            Func<string, int> sendMockIPCConfigMSG = msg => 0;
+
+            // Act - Creating the ViewModel should not throw
+            var viewModel = new TestAdvancedPasteViewModel(
+                mockAdvancedPasteSettingsUtils.Object,
+                generalSettingsRepository.Object,
+                advancedPasteSettingsRepository.Object,
+                sendMockIPCConfigMSG);
+
+            // Assert
+            Assert.IsNotNull(viewModel);
+            Assert.IsNotNull(viewModel.PasteAIConfiguration, "PasteAIConfiguration should be initialized");
+        }
+
+        [TestMethod]
+        public void ViewModelInitialization_WithNullPasteAIConfiguration_ShouldInitialize()
+        {
+            // Arrange
+            var mockGeneralSettingsUtils = ISettingsUtilsMocks.GetStubSettingsUtils<GeneralSettings>();
+            var generalSettingsRepository = new Mock<ISettingsRepository<GeneralSettings>>();
+            generalSettingsRepository.Setup(x => x.SettingsConfig).Returns(new GeneralSettings());
+
+            var advancedPasteSettings = new AdvancedPasteSettings();
+            // Simulate old settings file where PasteAIConfiguration might be null
+            advancedPasteSettings.Properties.PasteAIConfiguration = null;
+
+            var advancedPasteSettingsRepository = new Mock<ISettingsRepository<AdvancedPasteSettings>>();
+            advancedPasteSettingsRepository.Setup(x => x.SettingsConfig).Returns(advancedPasteSettings);
+
+            Func<string, int> sendMockIPCConfigMSG = msg => 0;
+
+            // Act - Creating the ViewModel should not throw even with null PasteAIConfiguration
+            var viewModel = new TestAdvancedPasteViewModel(
+                mockAdvancedPasteSettingsUtils.Object,
+                generalSettingsRepository.Object,
+                advancedPasteSettingsRepository.Object,
+                sendMockIPCConfigMSG);
+
+            // Assert
+            Assert.IsNotNull(viewModel);
+            Assert.IsNotNull(viewModel.PasteAIConfiguration, "PasteAIConfiguration should be initialized even when starting as null");
+            Assert.IsNotNull(viewModel.PasteAIConfiguration.Providers, "Providers collection should be initialized");
+        }
+
+        [TestMethod]
+        public void ViewModelInitialization_WithNullAdditionalActions_ShouldInitialize()
+        {
+            // Arrange
+            var mockGeneralSettingsUtils = ISettingsUtilsMocks.GetStubSettingsUtils<GeneralSettings>();
+            var generalSettingsRepository = new Mock<ISettingsRepository<GeneralSettings>>();
+            generalSettingsRepository.Setup(x => x.SettingsConfig).Returns(new GeneralSettings());
+
+            var advancedPasteSettings = new AdvancedPasteSettings();
+            // Simulate old settings file where AdditionalActions might be null
+            advancedPasteSettings.Properties.AdditionalActions = null;
+
+            var advancedPasteSettingsRepository = new Mock<ISettingsRepository<AdvancedPasteSettings>>();
+            advancedPasteSettingsRepository.Setup(x => x.SettingsConfig).Returns(advancedPasteSettings);
+
+            Func<string, int> sendMockIPCConfigMSG = msg => 0;
+
+            // Act - Creating the ViewModel should not throw
+            var viewModel = new TestAdvancedPasteViewModel(
+                mockAdvancedPasteSettingsUtils.Object,
+                generalSettingsRepository.Object,
+                advancedPasteSettingsRepository.Object,
+                sendMockIPCConfigMSG);
+
+            // Assert
+            Assert.IsNotNull(viewModel);
+        }
+    }
+}

src/settings-ui/Settings.UI/ViewModels/AdvancedPasteViewModel.cs

@@ -95,6 +95,10 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
             _advancedPasteSettings.Properties.AdditionalActions ??= new AdvancedPasteAdditionalActions();
             _advancedPasteSettings.Properties.CustomActions ??= new AdvancedPasteCustomActions();
 
+            // Ensure PasteAIConfiguration is initialized before attaching handlers
+            // This prevents crashes when settings file doesn't have PasteAIConfiguration property
+            InitializePasteAIProviderState();
+
             AttachConfigurationHandlers();
 
             // set the callback functions value to handle outgoing IPC message.
@@ -105,8 +109,6 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
 
             SetupSettingsFileWatcher();
 
-            InitializePasteAIProviderState();
-
             InitializeEnabledValue();
             MigrateLegacyAIEnablement();
 
@@ -1428,8 +1430,6 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
             }
 
             pasteConfig.Providers ??= new ObservableCollection<PasteAIProviderDefinition>();
-
-            SubscribeToPasteAIProviders(pasteConfig);
         }
 
         private static string RetrieveCredentialValue(string credentialResource, string credentialUserName)