Sync less project attributes.

src/VisualStudio/Core/Test.Next/Remote/SerializationValidator.cs

@@ -27,12 +27,12 @@ private sealed class AssetProvider(SerializationValidator validator) : AbstractA
             public override async ValueTask<T> GetAssetAsync<T>(AssetPath assetPath, Checksum checksum, CancellationToken cancellationToken)
                 => await validator.GetValueAsync<T>(checksum).ConfigureAwait(false);
 
-            public override async ValueTask GetAssetsAsync<T, TArg>(AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg> callback, TArg arg, CancellationToken cancellationToken)
+            public override async ValueTask GetAssetsAsync<T, TArg>(AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg>? callback, TArg? arg, CancellationToken cancellationToken) where TArg : default
             {
                 foreach (var checksum in checksums)
                 {
                     var value = await GetAssetAsync<T>(assetPath, checksum, cancellationToken).ConfigureAwait(false);
-                    callback(checksum, value, arg);
+                    callback?.Invoke(checksum, value, arg!);
                 }
             }
         }

src/Workspaces/Core/Portable/Workspace/Solution/AssetHint.cs

@@ -45,15 +45,6 @@ private AssetPath(AssetPathKind kind, ProjectId? projectId = null, DocumentId? d
         _kind = kind;
         ProjectId = projectId;
         DocumentId = documentId;
-
-        // If this isn't a test lookup, and we're searching into projects or documents, then we must have at least a
-        // projectId to limit the search.  If we don't, that risks very expensive searches where we look into *every*
-        // project in the solution for matches.
-        if ((kind & AssetPathKind.Testing) == 0)
-        {
-            if (IncludeProjects || IncludeDocuments)
-                Contract.ThrowIfNull(projectId);
-        }
     }
 
     public bool IncludeSolution => (_kind & AssetPathKind.Solution) == AssetPathKind.Solution;

src/Workspaces/Core/Portable/Workspace/Solution/StateChecksums.cs

@@ -270,10 +270,13 @@ public async Task FindAsync(
                 if (projectCone != null && !projectCone.Contains(projectId))
                     continue;
 
-                if (projectState.TryGetStateChecksums(out var projectStateChecksums) &&
-                    searchingChecksumsLeft.Remove(projectStateChecksums.Checksum))
+                if (projectState.TryGetStateChecksums(out var projectStateChecksums))
                 {
-                    result[projectStateChecksums.Checksum] = projectStateChecksums;
+                    if (searchingChecksumsLeft.Remove(projectStateChecksums.Checksum))
+                        result[projectStateChecksums.Checksum] = projectStateChecksums;
+
+                    if (searchingChecksumsLeft.Remove(projectStateChecksums.Info))
+                        result[projectStateChecksums.Info] = projectState.Attributes;
                 }
             }
         }
@@ -435,19 +438,15 @@ public async Task FindAsync(
         if (assetPath.IncludeProjects)
         {
             if (searchingChecksumsLeft.Remove(Checksum))
-            {
                 result[Checksum] = this;
-            }
 
             // It's normal for callers to just want to sync a single ProjectStateChecksum.  So quickly check this, without
             // doing all the expensive linear work below if we can bail out early here.
             if (searchingChecksumsLeft.Count == 0)
                 return;
 
             if (searchingChecksumsLeft.Remove(Info))
-            {
                 result[Info] = state.ProjectInfo.Attributes;
-            }
 
             if (searchingChecksumsLeft.Remove(CompilationOptions))
             {

src/Workspaces/Remote/Core/AbstractAssetProvider.cs

@@ -23,7 +23,7 @@ internal abstract class AbstractAssetProvider
     /// return data of type T whose checksum is the given checksum
     /// </summary>
     public abstract ValueTask<T> GetAssetAsync<T>(AssetPath assetPath, Checksum checksum, CancellationToken cancellationToken);
-    public abstract ValueTask GetAssetsAsync<T, TArg>(AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg> callback, TArg arg, CancellationToken cancellationToken);
+    public abstract ValueTask GetAssetsAsync<T, TArg>(AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg>? callback, TArg? arg, CancellationToken cancellationToken);
 
     public async Task<SolutionInfo> CreateSolutionInfoAsync(Checksum solutionChecksum, CancellationToken cancellationToken)
     {

src/Workspaces/Remote/ServiceHub/Host/AssetProvider.cs

@@ -5,12 +5,13 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Runtime.InteropServices;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Serialization;
+using Microsoft.CodeAnalysis.Shared.Utilities;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Remote;
@@ -51,7 +52,7 @@ await this.SynchronizeAssetsAsync<T, ArrayBuilder<T>>(
     }
 
     public override async ValueTask GetAssetsAsync<T, TArg>(
-        AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg> callback, TArg arg, CancellationToken cancellationToken)
+        AssetPath assetPath, HashSet<Checksum> checksums, Action<Checksum, T, TArg>? callback, TArg? arg, CancellationToken cancellationToken) where TArg : default
     {
         await this.SynchronizeAssetsAsync(assetPath, checksums, callback, arg, cancellationToken).ConfigureAwait(false);
     }

src/Workspaces/Remote/ServiceHub/Host/RemoteWorkspace.SolutionCreator.cs

@@ -243,6 +243,15 @@ private async Task<Solution> UpdateProjectsAsync(
                 Dictionary<ProjectId, ProjectStateChecksums> newProjectIdToStateChecksums,
                 CancellationToken cancellationToken)
             {
+                // Note: it's common to see a whole lot of project-infos change.  So attempt to collect that in one go
+                // if we can.
+                using var _ = PooledHashSet<Checksum>.GetInstance(out var projectInfoChecksums);
+                foreach (var (projectId, newProjectChecksums) in newProjectIdToStateChecksums)
+                    projectInfoChecksums.Add(newProjectChecksums.Info);
+
+                await _assetProvider.GetAssetsAsync<ProjectInfo.ProjectAttributes, VoidResult>(
+                    assetPath: AssetPath.SolutionAndTopLevelProjectsOnly, projectInfoChecksums, callback: null, arg: default, cancellationToken).ConfigureAwait(false);
+
                 // added project
                 foreach (var (projectId, newProjectChecksums) in newProjectIdToStateChecksums)
                 {