Merge pull request #9683 from lifengl/dev/lifengl/unblockedOnProjectGuid

Allow language service to get ProjectGuid earlier in common cases.

Author: drewnoakes

src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/LanguageServices/LanguageServiceHost.cs

@@ -205,16 +205,18 @@ async Task OnSlicesChangedAsync(IProjectVersionedValue<(ConfiguredProject Active
             // Remember the first slice's workspace. We may use it later, if the active workspace is removed.
             Workspace? firstWorkspace = null;
 
+            Guid? projectGuid = null;
+
             foreach ((ProjectConfigurationSlice slice, IActiveConfigurationSubscriptionSource source) in sources)
             {
                 if (!workspaceBySlice.TryGetValue(slice, out Workspace? workspace))
                 {
                     Assumes.False(checklist.ContainsKey(slice));
 
-                    Guid projectGuid = await _projectGuidService.GetProjectGuidAsync(cancellationToken);
+                    projectGuid ??= await _projectGuidService.GetProjectGuidAsync(cancellationToken);
 
                     // New slice. Create a workspace for it.
-                    workspace = _workspaceFactory.Create(source, slice, JoinableCollection, JoinableFactory, projectGuid, cancellationToken);
+                    workspace = _workspaceFactory.Create(source, slice, JoinableCollection, JoinableFactory, projectGuid.Value, cancellationToken);
 
                     if (workspace is null)
                     {
@@ -352,18 +354,16 @@ public async Task AfterLoadInitialConfigurationAsync()
             return;
         }
 
-        // Ensure the project is not considered loaded until our first publication.
-        Task result = _tasksService.PrioritizedProjectLoadedInHostAsync(async () =>
+        // prevent spin-off task to have accidental relevance
+        using (_unconfiguredProject.Services.ThreadingPolicy.JoinableTaskContext.SuppressRelevance())
         {
-            using (JoinableCollection.Join())
-            {
-                await WhenInitialized(_tasksService.UnloadCancellationToken);
-            }
-        });
+            // Ensure the project is not considered loaded until our first publication.
+            Task result = _tasksService.PrioritizedProjectLoadedInHostAsync(() => WhenInitialized(_tasksService.UnloadCancellationToken));
 
-        // While we want make sure it's loaded before PrioritizedProjectLoadedInHost,
-        // we don't want to block project factory completion on its load, so fire and forget.
-        _projectFaultHandler.Forget(result, _unconfiguredProject, ProjectFaultSeverity.LimitedFunctionality);
+            // While we want make sure it's loaded before PrioritizedProjectLoadedInHost,
+            // we don't want to block project factory completion on its load, so fire and forget.
+            _projectFaultHandler.Forget(result, _unconfiguredProject, ProjectFaultSeverity.LimitedFunctionality);
+        }
     }
 
     protected override Task DisposeCoreAsync(bool initialized)

src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/VsSafeProjectGuidService.cs

@@ -1,5 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. See the LICENSE.md file in the project root for more information.
 
+using Microsoft.Internal.VisualStudio.Shell.Interop;
 using Microsoft.VisualStudio.Threading;
 
 namespace Microsoft.VisualStudio.ProjectSystem.VS;
@@ -13,18 +14,49 @@ internal class VsSafeProjectGuidService : ISafeProjectGuidService
 {
     private readonly UnconfiguredProject _project;
     private readonly IUnconfiguredProjectTasksService _tasksService;
+    private readonly IVsService<IVsBackgroundSolution> _backgroundSolutionImport;
 
     [ImportingConstructor]
-    public VsSafeProjectGuidService(UnconfiguredProject project, IUnconfiguredProjectTasksService tasksService)
+    public VsSafeProjectGuidService(
+        UnconfiguredProject project,
+        IUnconfiguredProjectTasksService tasksService,
+        IVsService<SVsBackgroundSolution, IVsBackgroundSolution> backgroundSolutionImport)
     {
         _project = project;
         _tasksService = tasksService;
+        _backgroundSolutionImport = backgroundSolutionImport;
     }
 
-    public async Task<Guid> GetProjectGuidAsync(CancellationToken cancellationToken = default)
+    public Task<Guid> GetProjectGuidAsync(CancellationToken cancellationToken = default)
     {
-        await _tasksService.PrioritizedProjectLoadedInHost.WithCancellation(cancellationToken);
+        if (!_tasksService.PrioritizedProjectLoadedInHost.IsCompleted)
+        {
+            return GetProjectGuidSlowAsync(cancellationToken);
+        }
 
-        return await _project.GetProjectGuidAsync();
+        return _project.GetProjectGuidAsync();
+
+        async Task<Guid> GetProjectGuidSlowAsync(CancellationToken cancellationToken)
+        {
+            Guid projectGuid = await _project.GetProjectGuidAsync();
+
+            // if this is a newly created project, the project GUID might be empty.
+            // we should wait until the project is added to the solution.
+            if (projectGuid != Guid.Empty)
+            {
+                // now, get the GUID recorded by the solution.
+                // the solution might not know the project, if this is a project just to be added to the solution.
+                // or if the project saves a different GUID, we need wait the solution to resolve this conflict.
+                IVsBackgroundSolution solution = await _backgroundSolutionImport.GetValueAsync(cancellationToken);
+                if (solution.GetProjectGuidFromAbsolutePath(_project.FullPath) == projectGuid)
+                {
+                    // If the project GUID matches the one from the solution, we can return it immediately.
+                    return projectGuid;
+                }
+            }
+
+            await _tasksService.PrioritizedProjectLoadedInHost.WithCancellation(cancellationToken);
+            return await _project.GetProjectGuidAsync();
+        }
     }
 }