Only use IFeatureServiceFactory for controlling async completion

Closes #33807

src/EditorFeatures/Core/Implementation/IntelliSense/Completion/AsyncCompletionService.cs

@@ -35,13 +35,6 @@ internal class AsyncCompletionService : ForegroundThreadAffinitizedObject, IAsyn
         private readonly IEnumerable<Lazy<IBraceCompletionSessionProvider, BraceCompletionMetadata>> _autoBraceCompletionChars;
         private readonly Dictionary<IContentType, ImmutableHashSet<char>> _autoBraceCompletionCharSet;
 
-        /// <summary>
-        /// The new completion API is not checked by default - null
-        /// false - disabled
-        /// true - enabled
-        /// </summary>
-        private bool? _newCompletionAPIEnabled = null;
-
         [ImportingConstructor]
         [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
         public AsyncCompletionService(
@@ -95,40 +88,10 @@ public bool TryGetController(ITextView textView, ITextBuffer subjectBuffer, out
 
         private bool UseLegacyCompletion(IFeatureServiceFactory featureServiceFactory, ITextView textView, ITextBuffer subjectBuffer)
         {
-            if (!_newCompletionAPIEnabled.HasValue)
-            {
-                int userSetting = 0;
-                const string useAsyncCompletionOptionName = "UseAsyncCompletion";
-                if (textView.Options.GlobalOptions.IsOptionDefined(useAsyncCompletionOptionName, localScopeOnly: false))
-                {
-                    userSetting = textView.Options.GlobalOptions.GetOptionValue<int>(useAsyncCompletionOptionName);
-                }
-
-                // The meaning of the UseAsyncCompletion option definition's values:
-                // -1 - user disabled async completion
-                //  0 - no changes from the user; check the experimentation service for whether to use async completion
-                //  1 - user enabled async completion
-                if (userSetting == 1)
-                {
-                    _newCompletionAPIEnabled = true;
-                }
-                else if (userSetting == -1)
-                {
-                    _newCompletionAPIEnabled = false;
-                }
-                else
-                {
-                    if (Workspace.TryGetWorkspace(subjectBuffer.AsTextContainer(), out var workspace))
-                    {
-                        var experimentationService = workspace.Services.GetService<IExperimentationService>();
-                        _newCompletionAPIEnabled = experimentationService.IsExperimentEnabled(WellKnownExperimentNames.CompletionAPI)
-                            && featureServiceFactory.GlobalFeatureService.IsEnabled(PredefinedEditorFeatureNames.AsyncCompletion);
-                    }
-                }
-            }
+            var newCompletionEnabled = featureServiceFactory.GetOrCreate(textView).IsEnabled(PredefinedEditorFeatureNames.AsyncCompletion);
 
             // Check whether the feature flag (async completion API) is set or this feature is off.
-            if (_newCompletionAPIEnabled == true || !subjectBuffer.GetFeatureOnOffOption(InternalFeatureOnOffOptions.CompletionSet))
+            if (newCompletionEnabled || !subjectBuffer.GetFeatureOnOffOption(InternalFeatureOnOffOptions.CompletionSet))
             {
                 return false;
             }

src/EditorFeatures/TestUtilities2/Intellisense/EmptyFeatureController.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports Microsoft.VisualStudio.Utilities
+
+Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
+    Friend NotInheritable Class EmptyFeatureController
+        Implements IFeatureController
+
+        Friend Shared ReadOnly Instance As EmptyFeatureController = New EmptyFeatureController()
+
+        Private Sub New()
+        End Sub
+    End Class
+End Namespace

src/EditorFeatures/TestUtilities2/Intellisense/LegacyTestState.vb

@@ -6,6 +6,7 @@ Imports Microsoft.CodeAnalysis.Completion
 Imports Microsoft.CodeAnalysis.Editor.CommandHandlers
 Imports Microsoft.VisualStudio.Text.Editor
 Imports Microsoft.VisualStudio.Text.Editor.Commanding.Commands
+Imports Microsoft.VisualStudio.Utilities
 Imports Roslyn.Utilities
 Imports VSCommanding = Microsoft.VisualStudio.Commanding
 
@@ -32,6 +33,9 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
             MyBase.New(workspaceElement, extraCompletionProviders, excludedTypes, extraExportedTypes, includeFormatCommandHandler, workspaceKind)
 
             Me.CompletionCommandHandler = GetExportedValue(Of CompletionCommandHandler)()
+
+            Dim featureServiceFactory = GetExportedValue(Of IFeatureServiceFactory)()
+            featureServiceFactory.GlobalFeatureService.Disable(PredefinedEditorFeatureNames.AsyncCompletion, EmptyFeatureController.Instance)
         End Sub
 
 #Region "Editor Related Operations"

src/VisualStudio/IntegrationTest/TestUtilities/VisualStudioInstanceFactory.cs

@@ -11,7 +11,6 @@
 using System.Threading.Tasks;
 using EnvDTE;
 using Microsoft.VisualStudio.Setup.Configuration;
-using Microsoft.Win32;
 using RunTests;
 using Process = System.Diagnostics.Process;
 
@@ -328,19 +327,6 @@ private static Process StartNewVisualStudioProcess(string installationPath, int
                 // Disable background download UI to avoid toasts
                 Process.Start(vsRegEditExeFile, $"set \"{installationPath}\" {Settings.Default.VsRootSuffix} HKCU \"FeatureFlags\\Setup\\BackgroundDownload\" Value dword 0").WaitForExit();
 
-                // Remove legacy settings for controlling async completion to ensure they do not interfere
-                //
-                // 1. UseAsyncCompletion option
-                // 2. completionapi A/B experiment
-                Process.Start(vsRegEditExeFile, $"remove \"{installationPath}\" {Settings.Default.VsRootSuffix} HKCU \"ApplicationPrivateSettings\\WindowManagement\\Options\" UseAsyncCompletion").WaitForExit();
-
-                var disabledFlights = Registry.GetValue(@"HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\ABExp\LocalTest", "DisabledFlights", Array.Empty<string>()) as string[] ?? Array.Empty<string>();
-                if (disabledFlights.Any())
-                {
-                    disabledFlights = disabledFlights.Where(flight => !string.Equals(flight, "completionapi", StringComparison.OrdinalIgnoreCase)).ToArray();
-                    Registry.SetValue(@"HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\ABExp\LocalTest", "DisabledFlights", disabledFlights, RegistryValueKind.MultiString);
-                }
-
                 // Disable text editor error reporting because it pops up a dialog. We want to either fail fast in our
                 // custom handler or fail silently and continue testing.
                 Process.Start(vsRegEditExeFile, $"set \"{installationPath}\" {Settings.Default.VsRootSuffix} HKCU \"Text Editor\" \"Report Exceptions\" dword 0").WaitForExit();

src/Workspaces/Core/Portable/Experiments/IExperimentationService.cs

@@ -27,7 +27,6 @@ public DefaultExperimentationService()
     internal static class WellKnownExperimentNames
     {
         public const string RoslynOOP64bit = nameof(RoslynOOP64bit);
-        public const string CompletionAPI = nameof(CompletionAPI);
         public const string PartialLoadMode = "Roslyn.PartialLoadMode";
         public const string TypeImportCompletion = "Roslyn.TypeImportCompletion";
         public const string TargetTypedCompletionFilter = "Roslyn.TargetTypedCompletionFilter";