Process host outputs by GeneratorDriver

.github/CODEOWNERS

@@ -51,4 +51,4 @@ src/Features/**/PublicAPI.Unshipped.txt @dotnet/roslyn-api-owners
 src/EditorFeatures/**/PublicAPI.Unshipped.txt @dotnet/roslyn-api-owners
 
 src/Tools/ExternalAccess/OmniSharp*/ @333fred @joerobich
-src/Tools/ExternalAccess/RazorCompiler @dotnet/roslyn-compiler
+src/Tools/ExternalAccess/RazorCompiler*/ @dotnet/roslyn-compiler

Compilers.slnf

@@ -60,6 +60,7 @@
       "src\\Scripting\\CoreTestUtilities\\Microsoft.CodeAnalysis.Scripting.TestUtilities.csproj",
       "src\\Test\\PdbUtilities\\Roslyn.Test.PdbUtilities.csproj",
       "src\\Tools\\ExternalAccess\\RazorCompiler\\Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.csproj",
+      "src\\Tools\\ExternalAccess\\RazorCompilerTest\\Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests.csproj",
       "src\\Tools\\PrepareTests\\PrepareTests.csproj",
       "src\\Tools\\Source\\CompilerGeneratorTools\\Source\\CSharpSyntaxGenerator\\CSharpSyntaxGenerator.csproj",
       "src\\Tools\\Source\\CompilerGeneratorTools\\Source\\BoundTreeGenerator\\CompilersBoundTreeGenerator.csproj",

Roslyn.sln

@@ -523,6 +523,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TestDiscoveryWorker", "src\
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler", "src\Tools\ExternalAccess\RazorCompiler\Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.csproj", "{E5E0BF73-95F7-4BC3-8443-2336C4FF4297}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests", "src\Tools\ExternalAccess\RazorCompilerTest\Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests.csproj", "{828FD0DB-9927-42AC-B6C2-D1514965D6C3}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -1277,6 +1279,10 @@ Global
 		{E5E0BF73-95F7-4BC3-8443-2336C4FF4297}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{E5E0BF73-95F7-4BC3-8443-2336C4FF4297}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{E5E0BF73-95F7-4BC3-8443-2336C4FF4297}.Release|Any CPU.Build.0 = Release|Any CPU
+		{828FD0DB-9927-42AC-B6C2-D1514965D6C3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{828FD0DB-9927-42AC-B6C2-D1514965D6C3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{828FD0DB-9927-42AC-B6C2-D1514965D6C3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{828FD0DB-9927-42AC-B6C2-D1514965D6C3}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -1515,6 +1521,7 @@ Global
 		{8A29449D-411E-49E4-B99E-E8428076BB21} = {55A62CFA-1155-46F1-ADF3-BEEE51B58AB5}
 		{8BC50AFF-1EBF-4E9A-AEBB-04F387AA800F} = {FD0FAF5F-1DED-485C-99FA-84B97F3A8EEC}
 		{E5E0BF73-95F7-4BC3-8443-2336C4FF4297} = {8977A560-45C2-4EC2-A849-97335B382C74}
+		{828FD0DB-9927-42AC-B6C2-D1514965D6C3} = {8977A560-45C2-4EC2-A849-97335B382C74}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {604E6B91-7BC0-4126-AE07-D4D2FEFC3D29}

src/Compilers/Core/Portable/SourceGeneration/GeneratorDriver.cs

@@ -26,6 +26,8 @@ namespace Microsoft.CodeAnalysis
     /// </remarks>
     public abstract class GeneratorDriver
     {
+        internal const IncrementalGeneratorOutputKind HostKind = (IncrementalGeneratorOutputKind)0b100000; // several steps higher than IncrementalGeneratorOutputKind.Implementation
+
         internal readonly GeneratorDriverState _state;
 
         internal GeneratorDriver(GeneratorDriverState state)
@@ -293,7 +295,7 @@ internal GeneratorDriverState RunGeneratorsCore(Compilation compilation, Diagnos
                 try
                 {
                     // We do not support incremental step tracking for v1 generators, as the pipeline is implicitly defined.
-                    var context = UpdateOutputs(generatorState.OutputNodes, IncrementalGeneratorOutputKind.Source | IncrementalGeneratorOutputKind.Implementation, new GeneratorRunStateTable.Builder(state.TrackIncrementalSteps), cancellationToken, driverStateBuilder);
+                    var context = UpdateOutputs(generatorState.OutputNodes, IncrementalGeneratorOutputKind.Source | IncrementalGeneratorOutputKind.Implementation | HostKind, new GeneratorRunStateTable.Builder(state.TrackIncrementalSteps), cancellationToken, driverStateBuilder);
                     (var sources, var generatorDiagnostics, var generatorRunStateTable, var hostOutputs) = context.ToImmutableAndFree();
                     generatorDiagnostics = FilterDiagnostics(compilation, generatorDiagnostics, driverDiagnostics: diagnosticsBag, cancellationToken);
 

src/Compilers/Test/Core/Microsoft.CodeAnalysis.Test.Utilities.csproj

@@ -57,6 +57,7 @@
     <InternalsVisibleTo Include="Microsoft.VisualStudio.LanguageServices.CSharp.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.FSharp.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.UnitTests" />
+    <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.Rebuild.UnitTests" />
     <InternalsVisibleTo Include="Roslyn.Test.PdbUtilities" />
     <InternalsVisibleTo Include="Roslyn.VisualStudio.Next.UnitTests" />

src/Compilers/Test/Utilities/CSharp/Microsoft.CodeAnalysis.CSharp.Test.Utilities.csproj

@@ -30,6 +30,7 @@
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.CSharp.Syntax.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.CSharp.ExpressionEvaluator.ExpressionCompiler.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExpressionEvaluator.FunctionResolver.UnitTests" />
+    <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests" />
     <InternalsVisibleTo Include="InteractiveHost.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.CSharp.Scripting.UnitTests" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.CSharp.EditorFeatures.UnitTests" />

src/Tools/ExternalAccess/RazorCompiler/HostOutputNode.cs

@@ -26,7 +26,7 @@ public HostOutputNode(IIncrementalGeneratorNode<TInput> source, Action<HostProdu
             _action = action;
         }
 
-        public IncrementalGeneratorOutputKind Kind => (IncrementalGeneratorOutputKind)0b100000; // several steps higher than IncrementalGeneratorOutputKind.Implementation
+        public IncrementalGeneratorOutputKind Kind => GeneratorDriver.HostKind;
 
         public NodeStateTable<TOutput> UpdateStateTable(DriverStateTable.Builder graphState, NodeStateTable<TOutput>? previousTable, CancellationToken cancellationToken)
         {

src/Tools/ExternalAccess/RazorCompiler/Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.csproj

@@ -15,10 +15,13 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests" />
+
     <!--
       ⚠ ONLY RAZOR ASSEMBLIES MAY BE ADDED HERE ⚠
     -->
     <InternalsVisibleTo Include="Microsoft.NET.Sdk.Razor.SourceGenerators" Key="$(RazorKey)" />
+    <InternalsVisibleTo Include="Microsoft.NET.Sdk.Razor.SourceGenerators.Test" Key="$(RazorKey)" />
   </ItemGroup>
 
   <ItemGroup>

src/Tools/ExternalAccess/RazorCompilerTest/HostOutputsTests.cs

@@ -0,0 +1,51 @@
+// 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 file in the project root for more information.
+
+using System.Linq;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
+using Microsoft.CodeAnalysis.CSharp.UnitTests;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Roslyn.Test.Utilities.TestGenerators;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests
+{
+    public class HostOutputsTests : CSharpTestBase
+    {
+        [Fact]
+        public void Added()
+        {
+            var source = """
+                class C { }
+                """;
+            var parseOptions = TestOptions.Regular;
+            var compilation = CreateCompilation(source, options: TestOptions.DebugDllThrowing, parseOptions: parseOptions);
+            compilation.VerifyDiagnostics();
+
+            Assert.Single(compilation.SyntaxTrees);
+
+            var generator = new PipelineCallbackGenerator(ctx =>
+            {
+                var syntaxProvider = ctx.SyntaxProvider.CreateSyntaxProvider((n, _) => n.IsKind(SyntaxKind.ClassDeclaration), (c, _) => c.Node);
+
+                ctx.RegisterHostOutput(syntaxProvider, static (hpc, node, _) =>
+                {
+                    hpc.AddOutput("test", node.ToFullString());
+                });
+            });
+
+            GeneratorDriver driver = CSharpGeneratorDriver.Create(new[] { generator.AsSourceGenerator() }, parseOptions: parseOptions);
+            driver = driver.RunGenerators(compilation);
+
+            var result = driver.GetRunResult().Results.Single();
+            Assert.Empty(result.Diagnostics);
+
+            var hostOutputs = result.GetHostOutputs();
+            Assert.Equal(1, hostOutputs.Length);
+            Assert.Equal("test", hostOutputs[0].Key);
+            Assert.Equal(source, hostOutputs[0].Value);
+        }
+    }
+}

src/Tools/ExternalAccess/RazorCompilerTest/Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests.csproj

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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 file in the project root for more information. -->
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <RootNamespace>Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.UnitTests</RootNamespace>
+    <TargetFrameworks>net7.0;net472</TargetFrameworks>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\Compilers\Test\Utilities\CSharp\Microsoft.CodeAnalysis.CSharp.Test.Utilities.csproj" />
+    <ProjectReference Include="..\..\..\Compilers\CSharp\Portable\Microsoft.CodeAnalysis.CSharp.csproj" />
+    <ProjectReference Include="..\RazorCompiler\Microsoft.CodeAnalysis.ExternalAccess.RazorCompiler.csproj" />
+  </ItemGroup>
+</Project>