Communicate with OOP process to determine if an AnalyzerReference has analyzers or source generators.

src/VisualStudio/Core/Impl/SolutionExplorer/AnalyzerItem/AnalyzerItem.cs

@@ -2,19 +2,18 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.Internal.VisualStudio.PlatformUI;
 using Microsoft.VisualStudio.Imaging;
 using Microsoft.VisualStudio.Imaging.Interop;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer;
 
-internal partial class AnalyzerItem(
+internal sealed partial class AnalyzerItem(
     AnalyzersFolderItem analyzersFolder,
     AnalyzerReference analyzerReference,
-    IContextMenuController contextMenuController) : BaseItem(GetNameText(analyzerReference))
+    IContextMenuController contextMenuController)
+    : BaseItem(GetNameText(analyzerReference))
 {
     public AnalyzersFolderItem AnalyzersFolder { get; } = analyzersFolder;
     public AnalyzerReference AnalyzerReference { get; } = analyzerReference;
@@ -37,14 +36,7 @@ public void Remove()
         => this.AnalyzersFolder.RemoveAnalyzer(this.AnalyzerReference.FullPath);
 
     private static string GetNameText(AnalyzerReference analyzerReference)
-    {
-        if (analyzerReference is UnresolvedAnalyzerReference)
-        {
-            return analyzerReference.FullPath;
-        }
-        else
-        {
-            return analyzerReference.Display;
-        }
-    }
+        => analyzerReference is UnresolvedAnalyzerReference unresolvedAnalyzerReference
+           ? unresolvedAnalyzerReference.FullPath
+           : analyzerReference.Display;
 }

src/VisualStudio/Core/Impl/SolutionExplorer/AnalyzerItem/AnalyzerItemSourceProvider.cs

@@ -2,40 +2,28 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System;
 using System.ComponentModel.Composition;
 using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Shared.TestHooks;
 using Microsoft.Internal.VisualStudio.PlatformUI;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Utilities;
 
-namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer
-{
-    [Export(typeof(IAttachedCollectionSourceProvider))]
-    [Name(nameof(AnalyzerItemSourceProvider))]
-    [Order]
-    [AppliesToProject("(CSharp | VB) & !CPS")]  // in the CPS case, the Analyzers items are created by the project system
-    internal sealed class AnalyzerItemSourceProvider : AttachedCollectionSourceProvider<AnalyzersFolderItem>
-    {
-        [Import(typeof(AnalyzersCommandHandler))]
-        private readonly IAnalyzersCommandHandler _commandHandler = null;
-
-        [ImportingConstructor]
-        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
-        public AnalyzerItemSourceProvider()
-        {
-        }
+namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer;
 
-        protected override IAttachedCollectionSource CreateCollectionSource(AnalyzersFolderItem analyzersFolder, string relationshipName)
-        {
-            if (relationshipName == KnownRelationships.Contains)
-            {
-                return new AnalyzerItemSource(analyzersFolder, _commandHandler);
-            }
-
-            return null;
-        }
-    }
+[Export(typeof(IAttachedCollectionSourceProvider))]
+[Name(nameof(AnalyzerItemSourceProvider)), Order]
+[AppliesToProject("(CSharp | VB) & !CPS")]  // in the CPS case, the Analyzers items are created by the project system
+[method: ImportingConstructor]
+[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
+internal sealed class AnalyzerItemSourceProvider(
+    [Import(typeof(AnalyzersCommandHandler))] IAnalyzersCommandHandler commandHandler,
+    IAsynchronousOperationListenerProvider listenerProvider)
+    : AttachedCollectionSourceProvider<AnalyzersFolderItem>
+{
+    protected override IAttachedCollectionSource? CreateCollectionSource(AnalyzersFolderItem analyzersFolder, string relationshipName)
+        => relationshipName == KnownRelationships.Contains
+            ? new AnalyzerItemSource(analyzersFolder, commandHandler, listenerProvider)
+            : null;
 }

src/VisualStudio/Core/Impl/SolutionExplorer/AnalyzersFolderItem/AnalyzersFolderItem.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.Internal.VisualStudio.PlatformUI;
 using Microsoft.VisualStudio.Imaging;
 using Microsoft.VisualStudio.Imaging.Interop;
@@ -13,11 +14,13 @@
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer;
 
 internal sealed partial class AnalyzersFolderItem(
+    IThreadingContext threadingContext,
     Workspace workspace,
     ProjectId projectId,
     IVsHierarchyItem parentItem,
     IContextMenuController contextMenuController) : BaseItem(SolutionExplorerShim.Analyzers)
 {
+    public readonly IThreadingContext ThreadingContext = threadingContext;
     public Workspace Workspace { get; } = workspace;
     public ProjectId ProjectId { get; } = projectId;
     public IVsHierarchyItem ParentItem { get; } = parentItem;
@@ -64,7 +67,7 @@ public void AddAnalyzer(string path)
     /// <summary>
     /// Remove an analyzer with the given path from this folder.
     /// </summary>
-    public void RemoveAnalyzer(string path)
+    public void RemoveAnalyzer(string? path)
     {
         var vsproject = GetVSProject();
         if (vsproject == null)

src/VisualStudio/Core/Impl/SolutionExplorer/AnalyzersFolderItem/AnalyzersFolderItemSource.cs

@@ -4,48 +4,30 @@
 
 using System.Collections;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.VisualStudio.Shell;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer;
 
-internal sealed class AnalyzersFolderItemSource : IAttachedCollectionSource
+internal sealed class AnalyzersFolderItemSource(
+    IThreadingContext threadingContext,
+    Workspace workspace,
+    ProjectId projectId,
+    IVsHierarchyItem projectHierarchyItem,
+    IAnalyzersCommandHandler commandHandler)
+    : IAttachedCollectionSource
 {
-    private readonly IVsHierarchyItem _projectHierarchyItem;
-    private readonly Workspace _workspace;
-    private readonly ProjectId _projectId;
-    private readonly ObservableCollection<AnalyzersFolderItem> _folderItems;
-    private readonly IAnalyzersCommandHandler _commandHandler;
-
-    public AnalyzersFolderItemSource(Workspace workspace, ProjectId projectId, IVsHierarchyItem projectHierarchyItem, IAnalyzersCommandHandler commandHandler)
-    {
-        _workspace = workspace;
-        _projectId = projectId;
-        _projectHierarchyItem = projectHierarchyItem;
-        _commandHandler = commandHandler;
-
-        _folderItems = [];
-
-        Update();
-    }
+    private readonly ObservableCollection<AnalyzersFolderItem> _folderItems = [new AnalyzersFolderItem(
+        threadingContext,
+        workspace,
+        projectId,
+        projectHierarchyItem,
+        commandHandler.AnalyzerFolderContextMenuController)];
 
     public bool HasItems => true;
 
     public IEnumerable Items => _folderItems;
 
-    public object SourceItem => _projectHierarchyItem;
-
-    internal void Update()
-    {
-        // Don't create the item a 2nd time.
-        if (_folderItems.Any())
-            return;
-
-        _folderItems.Add(new AnalyzersFolderItem(
-            _workspace,
-            _projectId,
-            _projectHierarchyItem,
-            _commandHandler.AnalyzerFolderContextMenuController));
-    }
+    public object SourceItem => projectHierarchyItem;
 }

src/VisualStudio/Core/Impl/SolutionExplorer/AnalyzersFolderItem/AnalyzersFolderItemSourceProvider.cs

@@ -7,6 +7,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.Internal.VisualStudio.PlatformUI;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Shell.Interop;
@@ -21,13 +22,16 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplore
 [method: SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
 [method: ImportingConstructor]
 internal sealed class AnalyzersFolderItemSourceProvider(
+    IThreadingContext threadingContext,
     VisualStudioWorkspace workspace,
     [Import(typeof(AnalyzersCommandHandler))] IAnalyzersCommandHandler commandHandler)
     : AttachedCollectionSourceProvider<IVsHierarchyItem>
 {
+    private readonly IThreadingContext _threadingContext = threadingContext;
+    private readonly Workspace _workspace = workspace;
     private readonly IAnalyzersCommandHandler _commandHandler = commandHandler;
+
     private IHierarchyItemToProjectIdMap? _projectMap;
-    private readonly Workspace _workspace = workspace;
 
     protected override IAttachedCollectionSource? CreateCollectionSource(IVsHierarchyItem item, string relationshipName)
     {
@@ -46,7 +50,7 @@ internal sealed class AnalyzersFolderItemSourceProvider(
                 if (hierarchyMapper != null &&
                     hierarchyMapper.TryGetProjectId(item.Parent, targetFrameworkMoniker: null, projectId: out var projectId))
                 {
-                    return new AnalyzersFolderItemSource(_workspace, projectId, item, _commandHandler);
+                    return new AnalyzersFolderItemSource(_threadingContext, _workspace, projectId, item, _commandHandler);
                 }
 
                 return null;

src/VisualStudio/Core/Impl/SolutionExplorer/DiagnosticItem/BaseDiagnosticAndGeneratorItemSource.cs

@@ -26,7 +26,7 @@ internal abstract partial class BaseDiagnosticAndGeneratorItemSource : IAttached
     private static readonly DiagnosticDescriptorComparer s_comparer = new();
 
     private readonly IDiagnosticAnalyzerService _diagnosticAnalyzerService;
-    private readonly BulkObservableCollection<BaseItem> _items = new();
+    private readonly BulkObservableCollection<BaseItem> _items = [];
 
     private readonly CancellationTokenSource _cancellationTokenSource = new();
     private readonly AsyncBatchingWorkQueue _workQueue;
@@ -103,7 +103,16 @@ private async ValueTask ProcessQueueAsync(CancellationToken cancellationToken)
             this.Workspace.WorkspaceChanged -= OnWorkspaceChanged;
 
             _cancellationTokenSource.Cancel();
-            _items.Clear();
+
+            // Note: mutating _items will be picked up automatically by clients who are bound to the collection.  We do
+            // not need to notify them through some other mechanism.
+            if (_items.Count > 0)
+            {
+                // Go back to UI thread to update the observable collection.  Otherwise, it enqueue its own UI work that we cannot track.
+                await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
+                _items.Clear();
+            }
+
             return;
         }
 
@@ -115,6 +124,7 @@ private async ValueTask ProcessQueueAsync(CancellationToken cancellationToken)
         if (_items.SequenceEqual([.. newDiagnosticItems, .. newSourceGeneratorItems]))
             return;
 
+        // Go back to UI thread to update the observable collection.  Otherwise, it enqueue its own UI work that we cannot track.
         await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
 
         _items.BeginBulkOperation();

src/VisualStudio/Core/Impl/SolutionExplorer/SourceGeneratedFileItems/SourceGeneratedFileItemSource.cs

@@ -10,7 +10,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.CodeAnalysis.Shared.TestHooks;
 using Microsoft.Internal.VisualStudio.PlatformUI;
@@ -19,16 +18,21 @@
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer;
 
-internal sealed class SourceGeneratedFileItemSource(SourceGeneratorItem parentGeneratorItem, Workspace workspace, IAsynchronousOperationListener asyncListener, IThreadingContext threadingContext) : Shell.IAttachedCollectionSource, ISupportExpansionEvents
+internal sealed class SourceGeneratedFileItemSource(
+    SourceGeneratorItem parentGeneratorItem,
+    IThreadingContext threadingContext,
+    Workspace workspace,
+    IAsynchronousOperationListener asyncListener)
+    : Shell.IAttachedCollectionSource, ISupportExpansionEvents
 {
     private readonly SourceGeneratorItem _parentGeneratorItem = parentGeneratorItem;
+    private readonly IThreadingContext _threadingContext = threadingContext;
     private readonly Workspace _workspace = workspace;
     private readonly IAsynchronousOperationListener _asyncListener = asyncListener;
-    private readonly IThreadingContext _threadingContext = threadingContext;
 
     /// <summary>
-    /// The returned collection of items. Can only be mutated on the UI thread, as other parts of WPF are subscribed to the change
-    /// events and expect that.
+    /// The returned collection of items. Can only be mutated on the UI thread, as other parts of WPF are subscribed to
+    /// the change events and expect that.
     /// </summary>
     private readonly BulkObservableCollectionWithInit<BaseItem> _items = [];
 

src/VisualStudio/Core/Impl/SolutionExplorer/SourceGeneratedFileItems/SourceGeneratedFileItemSourceProvider.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.ComponentModel.Composition;
-using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Shared.TestHooks;
@@ -29,6 +28,6 @@ internal sealed class SourceGeneratedFileItemSourceProvider(
 
     protected override IAttachedCollectionSource? CreateCollectionSource(SourceGeneratorItem item, string relationshipName)
         => relationshipName == KnownRelationships.Contains
-            ? new SourceGeneratedFileItemSource(item, workspace, _asyncListener, threadingContext)
+            ? new SourceGeneratedFileItemSource(item, threadingContext, workspace, _asyncListener)
             : null;
 }

src/VisualStudio/Core/Test/SolutionExplorer/AnalyzerItemTests.vb

@@ -2,13 +2,14 @@
 ' The .NET Foundation licenses this file to you under the MIT license.
 ' See the LICENSE file in the project root for more information.
 
+Imports Microsoft.CodeAnalysis.Editor.[Shared].Utilities
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
 Imports Microsoft.CodeAnalysis.Test.Utilities
 Imports Microsoft.VisualStudio.LanguageServices.Implementation
 Imports Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer
 
 Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
-    <[UseExportProvider]>
+    <UseExportProvider>
     <Trait(Traits.Feature, Traits.Features.Diagnostics)>
     Public Class AnalyzerItemTests
         <Fact>
@@ -23,7 +24,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
             Using workspace = EditorTestWorkspace.Create(workspaceXml)
                 Dim project = workspace.Projects.Single()
 
-                Dim analyzerFolder = New AnalyzersFolderItem(workspace, project.Id, Nothing, Nothing)
+                Dim analyzerFolder = New AnalyzersFolderItem(workspace.GetService(Of IThreadingContext), workspace, project.Id, Nothing, Nothing)
                 Dim analyzer = New AnalyzerItem(analyzerFolder, project.AnalyzerReferences.Single(), Nothing)
 
                 Assert.Equal(expected:="Goo", actual:=analyzer.Text)
@@ -42,7 +43,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
             Using workspace = EditorTestWorkspace.Create(workspaceXml)
                 Dim project = workspace.Projects.Single()
 
-                Dim analyzerFolder = New AnalyzersFolderItem(workspace, project.Id, Nothing, Nothing)
+                Dim analyzerFolder = New AnalyzersFolderItem(workspace.GetService(Of IThreadingContext), workspace, project.Id, Nothing, Nothing)
                 Dim analyzer = New AnalyzerItem(analyzerFolder, project.AnalyzerReferences.Single(), Nothing)
                 Dim browseObject = DirectCast(analyzer.GetBrowseObject(), AnalyzerItem.BrowseObject)
 

src/VisualStudio/Core/Test/SolutionExplorer/AnalyzerItemsSourceTests.vb

@@ -2,15 +2,17 @@
 ' The .NET Foundation licenses this file to you under the MIT license.
 ' See the LICENSE file in the project root for more information.
 
-Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
+Imports Microsoft.CodeAnalysis.Editor.Shared.Utilities
+Imports Microsoft.CodeAnalysis.Shared.TestHooks
 Imports Microsoft.CodeAnalysis.Test.Utilities
 Imports Microsoft.VisualStudio.LanguageServices.Implementation.SolutionExplorer
+Imports Roslyn.Test.Utilities
 
 Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
-    <[UseExportProvider]>
-    Public Class AnalyzerItemsSourceTests
-        <Fact, Trait(Traits.Feature, Traits.Features.Diagnostics)>
-        Public Sub Ordering()
+    <UseExportProvider>
+    Public NotInheritable Class AnalyzerItemsSourceTests
+        <WpfFact, Trait(Traits.Feature, Traits.Features.Diagnostics)>
+        Public Async Function Ordering() As Task
             Dim workspaceXml =
                 <Workspace>
                     <Project Language="C#" CommonReferences="true">
@@ -23,8 +25,13 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
             Using workspace = EditorTestWorkspace.Create(workspaceXml)
                 Dim project = workspace.Projects.Single()
 
-                Dim analyzerFolder = New AnalyzersFolderItem(workspace, project.Id, Nothing, Nothing)
-                Dim analyzerItemsSource = New AnalyzerItemSource(analyzerFolder, New FakeAnalyzersCommandHandler)
+                Dim analyzerFolder = New AnalyzersFolderItem(workspace.GetService(Of IThreadingContext), workspace, project.Id, Nothing, Nothing)
+                Dim listenerProvider = workspace.GetService(Of IAsynchronousOperationListenerProvider)
+                Dim analyzerItemsSource = New AnalyzerItemSource(
+                    analyzerFolder, New FakeAnalyzersCommandHandler(), listenerProvider)
+
+                Dim waiter = listenerProvider.GetWaiter(FeatureAttribute.SourceGenerators)
+                Await waiter.ExpeditedWaitAsync()
 
                 Dim analyzers = analyzerItemsSource.Items.Cast(Of AnalyzerItem)().ToArray()
 
@@ -33,7 +40,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.SolutionExplorer
                 Assert.Equal(expected:="Beta", actual:=analyzers(1).Text)
                 Assert.Equal(expected:="Gamma", actual:=analyzers(2).Text)
             End Using
-        End Sub
+        End Function
     End Class
 End Namespace