Improve language services in edge cases

Directory.Packages.props

@@ -26,6 +26,7 @@
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="$(RoslynVersion)" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.CodeStyle" Version="$(RoslynVersion)" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Features" Version="$(RoslynVersion)" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.VisualBasic.Features" Version="$(RoslynVersion)" />
     <PackageVersion Include="Microsoft.DotNet.Arcade.Sdk" Version="9.0.0-beta.24372.7" />
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="$(NetCoreVersion)" />
     <PackageVersion Include="Microsoft.FluentUI.AspNetCore.Components" Version="$(FluentUIVersion)" />

src/App/Lab/LanguageServicesClient.cs

@@ -171,7 +171,6 @@ public void OnDidChangeModel(ModelChangedEvent args)
         }
 
         currentModelUrl = args.NewModelUrl;
-        worker.OnDidChangeModel(modelUri: currentModelUrl);
         UpdateDiagnostics();
     }
 
@@ -183,7 +182,14 @@ public void OnDidChangeModelContent(ModelContentChangedEvent args)
         }
 
         InvalidateCaches();
-        worker.OnDidChangeModelContent(args);
+
+        if (currentModelUrl is null)
+        {
+            logger.LogWarning("No current document to change content of.");
+            return;
+        }
+
+        worker.OnDidChangeModelContent(modelUri: currentModelUrl, args);
         UpdateDiagnostics();
     }
 
@@ -199,7 +205,7 @@ private void UpdateDiagnostics()
         Debounce(ref diagnosticsDebounce, (worker, jsRuntime, currentModelUrl), static async args =>
         {
             var (worker, jsRuntime, currentModelUrl) = args;
-            var markers = await worker.GetDiagnosticsAsync();
+            var markers = await worker.GetDiagnosticsAsync(currentModelUrl);
             var model = await BlazorMonaco.Editor.Global.GetModel(jsRuntime, currentModelUrl);
             await BlazorMonaco.Editor.Global.SetModelMarkers(jsRuntime, model, MonacoConstants.MarkersOwner, markers.ToList());
         },

src/App/Lab/Page.razor

@@ -256,7 +256,7 @@
     private sealed record Input(string FileName, TextModel Model) : EditorState(Model)
     {
         public string FileName { get; set; } = FileName;
-        public string? NewContent { get; set; }
+        public required string? NewContent { get; set; }
     }
 
     private readonly record struct CacheInfo(DateTimeOffset? Timestamp);
@@ -288,6 +288,22 @@
         }
     }
 
+    private IEnumerable<(Input Input, bool IsConfiguration)> InputsAndConfiguration
+    {
+        get
+        {
+            foreach (var input in inputs)
+            {
+                yield return (input, false);
+            }
+
+            if (configuration is { } config)
+            {
+                yield return (config, true);
+            }
+        }
+    }
+
     private IEnumerable<CompiledFileOutput> AllOutputs
     {
         get => (CurrentCompiledFile?.Outputs)
@@ -545,9 +561,10 @@
         {
             await SaveStateToUrlAsync();
 
-            configuration = new(
-                InitialCode.Configuration.SuggestedFileName,
-                await CreateModelAsync(InitialCode.Configuration.ToInputCode()));
+            var fileName = InitialCode.Configuration.SuggestedFileName;
+            var inputCode = InitialCode.Configuration.ToInputCode();
+            var model = await CreateModelAsync(inputCode);
+            configuration = new(fileName, model) { NewContent = inputCode.Text };
             OnWorkspaceChanged();
 
             await SaveStateToUrlAsync();
@@ -624,7 +641,7 @@
 
         // Compile.
         var input = state.ToCompilationInput();
-        var output = await Worker.CompileAsync(input);
+        var output = await Worker.CompileAsync(input, languageServicesEnabled: LanguageServices.Enabled);
         compiled = (input, output, null);
         outputOutdated = false;
 
@@ -1011,7 +1028,7 @@
     }
 
     /// <summary>
-    /// Should be called before SetModel of Monaco editor whenever (after) <see cref="inputs"/> change.
+    /// Should be called before SetModel of Monaco editor whenever (after) <see cref="InputsAndConfiguration"/> change.
     /// </summary>
     public void OnWorkspaceChanged()
     {
@@ -1022,10 +1039,14 @@
             return;
         }
 
-        var models = inputs
-            .Select(i => new ModelInfo(Uri: i.Model.Uri, FileName: i.FileName) { NewContent = i.NewContent })
+        var models = InputsAndConfiguration
+            .Select(t => new ModelInfo(Uri: t.Input.Model.Uri, FileName: t.Input.FileName) 
+            {
+                NewContent = t.Input.NewContent,
+                IsConfiguration = t.IsConfiguration,
+            })
             .ToImmutableArray();
-        inputs.ForEach(i => { i.NewContent = null; });
+        InputsAndConfiguration.ForEach(t => { t.Input.NewContent = null; });
         LanguageServices.OnDidChangeWorkspace(models);
     }
 
@@ -1039,8 +1060,12 @@
             return;
         }
 
-        var models = await inputs
-            .SelectAsArrayAsync(static async i => new ModelInfo(Uri: i.Model.Uri, FileName: i.FileName) { NewContent = await i.Model.GetTextAsync() });
+        var models = await InputsAndConfiguration
+            .SelectAsArrayAsync(static async t => new ModelInfo(Uri: t.Input.Model.Uri, FileName: t.Input.FileName)
+            {
+                NewContent = await t.Input.Model.GetTextAsync(),
+                IsConfiguration = t.IsConfiguration,
+            });
         LanguageServices.OnDidChangeWorkspace(models, updateDiagnostics: updateDiagnostics);
     }
 

src/App/Lab/SavedState.cs

@@ -98,7 +98,7 @@ _ when WellKnownSlugs.ShorthandToState.TryGetValue(slug, out var wellKnownState)
         if (savedState.Configuration is { } savedConfiguration)
         {
             var input = InitialCode.Configuration.ToInputCode() with { Text = savedConfiguration };
-            configuration = new(input.FileName, await CreateModelAsync(input));
+            configuration = new(input.FileName, await CreateModelAsync(input)) { NewContent = input.Text };
         }
         else
         {

src/App/Lab/WorkerController.cs

@@ -394,10 +394,10 @@ private async Task<TIn> PostAndReceiveMessageAsync<TOut, TIn>(
         };
     }
 
-    public Task<CompiledAssembly> CompileAsync(CompilationInput input)
+    public Task<CompiledAssembly> CompileAsync(CompilationInput input, bool languageServicesEnabled)
     {
         return PostAndReceiveMessageAsync(
-            new WorkerInputMessage.Compile(input) { Id = messageId++ },
+            new WorkerInputMessage.Compile(input, languageServicesEnabled) { Id = messageId++ },
             fallback: CompiledAssembly.Fail);
     }
 
@@ -475,22 +475,16 @@ public void OnDidChangeWorkspace(ImmutableArray<ModelInfo> models)
             new WorkerInputMessage.OnDidChangeWorkspace(models) { Id = messageId++ });
     }
 
-    public void OnDidChangeModel(string modelUri)
+    public void OnDidChangeModelContent(string modelUri, ModelContentChangedEvent args)
     {
         PostMessage(
-            new WorkerInputMessage.OnDidChangeModel(ModelUri: modelUri) { Id = messageId++ });
+            new WorkerInputMessage.OnDidChangeModelContent(modelUri, args) { Id = messageId++ });
     }
 
-    public void OnDidChangeModelContent(ModelContentChangedEvent args)
-    {
-        PostMessage(
-            new WorkerInputMessage.OnDidChangeModelContent(args) { Id = messageId++ });
-    }
-
-    public Task<ImmutableArray<MarkerData>> GetDiagnosticsAsync()
+    public Task<ImmutableArray<MarkerData>> GetDiagnosticsAsync(string modelUri)
     {
         return PostAndReceiveMessageAsync(
-            new WorkerInputMessage.GetDiagnostics() { Id = messageId++ },
+            new WorkerInputMessage.GetDiagnostics(modelUri) { Id = messageId++ },
             deserializeAs: default(ImmutableArray<MarkerData>));
     }
 }

src/Compiler/Compiler.cs

@@ -15,41 +15,48 @@
 
 namespace DotNetLab;
 
-public class Compiler(
+public sealed class Compiler(
     ILogger<DecompilerAssemblyResolver> decompilerAssemblyResolverLogger) : ICompiler
 {
     private const string ToolchainHelpText = """
 
         You can try selecting different Razor toolchain in Settings / Advanced.
         """;
 
-    private (CompilationInput Input, CompiledAssembly Output)? lastResult;
+    public static readonly string ConfigurationGlobalUsings = """
+        global using DotNetLab;
+        global using Microsoft.CodeAnalysis;
+        global using Microsoft.CodeAnalysis.CSharp;
+        global using System;
+        """;
 
     /// <summary>
     /// Reused for incremental source generation.
     /// </summary>
     private GeneratorDriver? generatorDriver;
 
+    internal (CompilationInput Input, LiveCompilationResult Output)? LastResult { get; private set; }
+
     public CompiledAssembly Compile(
         CompilationInput input,
         ImmutableDictionary<string, ImmutableArray<byte>>? assemblies,
         ImmutableDictionary<string, ImmutableArray<byte>>? builtInAssemblies,
         AssemblyLoadContext alc)
     {
-        if (lastResult is { } cached)
+        if (LastResult is { } cached)
         {
             if (input.Equals(cached.Input))
             {
-                return cached.Output;
+                return cached.Output.CompiledAssembly;
             }
         }
 
         var result = CompileNoCache(input, assemblies, builtInAssemblies, alc);
-        lastResult = (input, result);
-        return result;
+        LastResult = (input, result);
+        return result.CompiledAssembly;
     }
 
-    private CompiledAssembly CompileNoCache(
+    private LiveCompilationResult CompileNoCache(
         CompilationInput compilationInput,
         ImmutableDictionary<string, ImmutableArray<byte>>? assemblies,
         ImmutableDictionary<string, ImmutableArray<byte>>? builtInAssemblies,
@@ -59,13 +66,15 @@ private CompiledAssembly CompileNoCache(
         const string directory = "/";
 
         var parseOptions = CreateDefaultParseOptions();
+        CSharpCompilationOptions? options = null;
 
         var references = RefAssemblyMetadata.All;
         var referenceInfos = RefAssemblies.All;
 
         // If we have a configuration, compile and execute it.
         Config.Reset();
         ImmutableArray<Diagnostic> configDiagnostics;
+        ImmutableDictionary<string, ImmutableArray<byte>>? compilerAssembliesUsed = null;
         if (compilationInput.Configuration is { } configuration)
         {
             if (!executeConfiguration(configuration, out configDiagnostics))
@@ -74,7 +83,7 @@ private CompiledAssembly CompileNoCache(
                 ImmutableArray<DiagnosticData> configDiagnosticData = configDiagnostics
                     .Select(d => d.ToDiagnosticData())
                     .ToImmutableArray();
-                return new CompiledAssembly(
+                var configResult = new CompiledAssembly(
                     Files: ImmutableSortedDictionary<string, CompiledFile>.Empty,
                     GlobalOutputs:
                     [
@@ -93,6 +102,7 @@ private CompiledAssembly CompileNoCache(
                 {
                     ConfigDiagnosticCount = configDiagnosticData.Length,
                 };
+                return getResult(configResult);
             }
 
             parseOptions = Config.ConfigureCSharpParseOptions(parseOptions);
@@ -140,7 +150,7 @@ private CompiledAssembly CompileNoCache(
 
         var outputKind = GetDefaultOutputKind(cSharpSources.Select(s => s.SyntaxTree));
 
-        var options = CreateDefaultCompilationOptions(outputKind);
+        options = CreateDefaultCompilationOptions(outputKind);
 
         options = Config.ConfigureCSharpCompilationOptions(options);
 
@@ -335,7 +345,18 @@ .. string.IsNullOrEmpty(razorDiagnostics)
             ConfigDiagnosticCount = configDiagnostics.Count(filterDiagnostic),
         };
 
-        return result;
+        return getResult(result);
+
+        LiveCompilationResult getResult(CompiledAssembly result)
+        {
+            return new LiveCompilationResult
+            {
+                CompiledAssembly = result,
+                CompilerAssemblies = compilerAssembliesUsed,
+                CSharpParseOptions = compilerAssembliesUsed != null ? parseOptions : null,
+                CSharpCompilationOptions = compilerAssembliesUsed != null ? options : null,
+            };
+        }
 
         static bool filterDiagnostic(Diagnostic d) => d.Severity != DiagnosticSeverity.Hidden;
 
@@ -346,28 +367,22 @@ bool executeConfiguration(string code, out ImmutableArray<Diagnostic> diagnostic
                 syntaxTrees:
                 [
                     CSharpSyntaxTree.ParseText(code, parseOptions, "Configuration.cs", Encoding.UTF8),
-                    CSharpSyntaxTree.ParseText("""
-                        global using DotNetLab;
-                        global using Microsoft.CodeAnalysis;
-                        global using Microsoft.CodeAnalysis.CSharp;
-                        global using System;
-                        """, parseOptions, "GlobalUsings.cs", Encoding.UTF8)
+                    CSharpSyntaxTree.ParseText(ConfigurationGlobalUsings, parseOptions, "GlobalUsings.cs", Encoding.UTF8)
                 ],
                 references:
                 [
                     ..references,
                     ..assemblies!.Values.Select(b => MetadataReference.CreateFromImage(b)),
                 ],
-                options: CreateDefaultCompilationOptions(OutputKind.ConsoleApplication)
-                    .WithSpecificDiagnosticOptions(
-                    [
-                        // warning CS1701: Assuming assembly reference 'System.Runtime, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' used by 'Microsoft.CodeAnalysis.CSharp' matches identity 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' of 'System.Runtime', you may need to supply runtime policy
-                        KeyValuePair.Create("CS1701", ReportDiagnostic.Suppress),
-                    ]));
+                options: CreateConfigurationCompilationOptions());
 
             var emitStream = getEmitStream(configCompilation, out diagnostics);
 
-            if (emitStream == null)
+            if (emitStream != null)
+            {
+                compilerAssembliesUsed = assemblies;
+            }
+            else
             {
                 // If compilation fails, it might be because older Roslyn is referenced, re-try with built-in versions.
                 var configCompilationWithBuiltInReferences = configCompilation.WithReferences(
@@ -379,6 +394,7 @@ bool executeConfiguration(string code, out ImmutableArray<Diagnostic> diagnostic
                 if (emitStream != null)
                 {
                     diagnostics = diagnosticsWithBuiltInReferences;
+                    compilerAssembliesUsed = builtInAssemblies;
                 }
             }
 
@@ -791,6 +807,16 @@ public static CSharpCompilationOptions CreateDefaultCompilationOptions(OutputKin
             nullableContextOptions: NullableContextOptions.Enable,
             concurrentBuild: false);
     }
+
+    public static CSharpCompilationOptions CreateConfigurationCompilationOptions()
+    {
+        return CreateDefaultCompilationOptions(OutputKind.ConsoleApplication)
+            .WithSpecificDiagnosticOptions(
+            [
+                // warning CS1701: Assuming assembly reference 'System.Runtime, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' used by 'Microsoft.CodeAnalysis.CSharp' matches identity 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' of 'System.Runtime', you may need to supply runtime policy
+                KeyValuePair.Create("CS1701", ReportDiagnostic.Suppress),
+            ]);
+    }
 }
 
 public sealed class DecompilerAssemblyResolver(ILogger<DecompilerAssemblyResolver> logger, ImmutableArray<RefAssembly> references) : ICSharpCode.Decompiler.Metadata.IAssemblyResolver
@@ -954,3 +980,26 @@ public Result<R> Map<R>(Func<T, R> mapper)
             : new Result<R>(() => mapper(value!));
     }
 }
+
+/// <summary>
+/// Additional data on top of <see cref="CompiledAssembly"/> that are never cached.
+/// </summary>
+internal sealed class LiveCompilationResult
+{
+    public required CompiledAssembly CompiledAssembly { get; init; }
+
+    /// <summary>
+    /// Assemblies used to compile <see cref="CompilationInput.Configuration"/>.
+    /// </summary>
+    public required ImmutableDictionary<string, ImmutableArray<byte>>? CompilerAssemblies { get; init; }
+
+    /// <summary>
+    /// Set to <see langword="null"/> if the default options were used.
+    /// </summary>
+    public required CSharpParseOptions? CSharpParseOptions { get; init; }
+
+    /// <summary>
+    /// Set to <see langword="null"/> if the default options were used.
+    /// </summary>
+    public required CSharpCompilationOptions? CSharpCompilationOptions { get; init; }
+}