Add VS agnostic non-OOP DefaultTagHelperResolver.

- Added tests for the VisualStudio.Editor tag helper resolver.

#1789

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/Properties/AssemblyInfo.cs

@@ -4,3 +4,4 @@
 using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("Microsoft.AspNetCore.Mvc.Razor.Extensions.Test, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Editor.Razor, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]

src/Microsoft.CodeAnalysis.Razor.Workspaces/TagHelperResolver.cs

@@ -9,8 +9,6 @@ namespace Microsoft.CodeAnalysis.Razor
 {
     internal abstract class TagHelperResolver : ILanguageService
     {
-        public abstract TagHelperResolutionResult GetTagHelpers(Compilation compilation);
-
         public abstract Task<TagHelperResolutionResult> GetTagHelpersAsync(Project project, CancellationToken cancellationToken);
     }
 }

src/Microsoft.CodeAnalysis.Remote.Razor/DefaultTagHelperResolver.cs

@@ -19,7 +19,7 @@ namespace Microsoft.CodeAnalysis.Remote.Razor
 
         public bool DesignTime { get; }
 
-        public override TagHelperResolutionResult GetTagHelpers(Compilation compilation)
+        private TagHelperResolutionResult GetTagHelpers(Compilation compilation)
         {
             var descriptors = new List<TagHelperDescriptor>();
 

src/Microsoft.VisualStudio.Editor.Razor/DefaultTagHelperResolver.cs

@@ -0,0 +1,60 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.Razor.Extensions;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Razor;
+
+namespace Microsoft.VisualStudio.Editor.Razor
+{
+    internal class DefaultTagHelperResolver : TagHelperResolver
+    {
+        // Hack for testability. The view component visitor will normally just no op if we're not referencing
+        // an appropriate version of MVC.
+        internal bool ForceEnableViewComponentDiscovery { get; set; }
+
+        public override async Task<TagHelperResolutionResult> GetTagHelpersAsync(Project project, CancellationToken cancellationToken)
+        {
+            if (project == null)
+            {
+                throw new ArgumentNullException(nameof(project));
+            }
+
+            var compilation = await project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
+            var result = GetTagHelpers(compilation);
+            return result;
+        }
+
+        // Internal for testing
+        internal TagHelperResolutionResult GetTagHelpers(Compilation compilation)
+        {
+            var descriptors = new List<TagHelperDescriptor>();
+
+            var providers = new ITagHelperDescriptorProvider[]
+            {
+                new DefaultTagHelperDescriptorProvider() { DesignTime = true, },
+                new ViewComponentTagHelperDescriptorProvider() { ForceEnabled = ForceEnableViewComponentDiscovery },
+            };
+
+            var results = new List<TagHelperDescriptor>();
+            var context = TagHelperDescriptorProviderContext.Create(results);
+            context.SetCompilation(compilation);
+
+            for (var i = 0; i < providers.Length; i++)
+            {
+                var provider = providers[i];
+                provider.Execute(context);
+            }
+
+            var diagnostics = new List<RazorDiagnostic>();
+            var resolutionResult = new TagHelperResolutionResult(results, diagnostics);
+
+            return resolutionResult;
+        }
+    }
+}

src/Microsoft.VisualStudio.Editor.Razor/DefaultTagHelperResolverFactory.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.CodeAnalysis.Host;
+using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Razor;
+
+namespace Microsoft.VisualStudio.Editor.Razor
+{
+    [Shared]
+    [ExportLanguageServiceFactory(typeof(TagHelperResolver), RazorLanguage.Name, ServiceLayer.Default)]
+    internal class DefaultTagHelperResolverFactory : ILanguageServiceFactory
+    {
+        public ILanguageService CreateLanguageService(HostLanguageServices languageServices)
+        {
+            return new DefaultTagHelperResolver();
+        }
+    }
+}

src/Microsoft.VisualStudio.LanguageServices.Razor/OOPTagHelperResolver.cs

@@ -2,27 +2,30 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc.Razor.Extensions;
-using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor;
+using Microsoft.VisualStudio.Editor.Razor;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 
 namespace Microsoft.VisualStudio.LanguageServices.Razor
 {
-    internal class DefaultTagHelperResolver : TagHelperResolver
+    internal class OOPTagHelperResolver : TagHelperResolver
     {
-        private readonly ErrorReporter _errorReporter;
+        private readonly DefaultTagHelperResolver _defaultResolver;
         private readonly Workspace _workspace;
 
-        public DefaultTagHelperResolver(ErrorReporter errorReporter, Workspace workspace)
+        public OOPTagHelperResolver(Workspace workspace)
         {
-            _errorReporter = errorReporter;
+            if (workspace == null)
+            {
+                throw new ArgumentNullException(nameof(workspace));
+            }
+
             _workspace = workspace;
+            _defaultResolver = new DefaultTagHelperResolver();
         }
 
         public override async Task<TagHelperResolutionResult> GetTagHelpersAsync(Project project, CancellationToken cancellationToken)
@@ -34,7 +37,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor
 
             try
             {
-                TagHelperResolutionResult result;
+                TagHelperResolutionResult result = null;
 
                 // We're being defensive here because the OOP host can return null for the client/session/operation
                 // when it's disconnected (user stops the process).
@@ -51,24 +54,20 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor
                                 cancellationToken).ConfigureAwait(false);
 
                             result = GetTagHelperResolutionResult(jsonObject);
-
-                            if (result != null)
-                            {
-                                return result;
-                            }
                         }
                     }
                 }
 
-                // The OOP host is turned off, so let's do this in process.
+                if (result == null)
-                var compilation = await project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
+                {
-                result = GetTagHelpers(compilation);
+                    // Was unable to get tag helpers OOP, fallback to default behavior.
+                    result = await _defaultResolver.GetTagHelpersAsync(project, cancellationToken);
+                }
+
                 return result;
             }
             catch (Exception exception)
             {
-                _errorReporter.ReportError(exception, project);
-
                 throw new InvalidOperationException(
                     Resources.FormatUnexpectedException(
                         typeof(DefaultTagHelperResolver).FullName,
@@ -77,32 +76,6 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor
             }
         }
 
-        public override TagHelperResolutionResult GetTagHelpers(Compilation compilation)
-        {
-            var descriptors = new List<TagHelperDescriptor>();
-
-            var providers = new ITagHelperDescriptorProvider[]
-            {
-                new DefaultTagHelperDescriptorProvider() { DesignTime = true, },
-                new ViewComponentTagHelperDescriptorProvider(),
-            };
-
-            var results = new List<TagHelperDescriptor>();
-            var context = TagHelperDescriptorProviderContext.Create(results);
-            context.SetCompilation(compilation);
-
-            for (var i = 0; i < providers.Length; i++)
-            {
-                var provider = providers[i];
-                provider.Execute(context);
-            }
-
-            var diagnostics = new List<RazorDiagnostic>();
-            var resolutionResult = new TagHelperResolutionResult(results, diagnostics);
-
-            return resolutionResult;
-        }
-
         private TagHelperResolutionResult GetTagHelperResolutionResult(JObject jsonObject)
         {
             var serializer = new JsonSerializer();

src/Microsoft.VisualStudio.LanguageServices.Razor/OOPTagHelperResolverFactory.cs

@@ -1,20 +1,21 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System.ComponentModel.Composition;
+using System.Composition;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Razor;
 
 namespace Microsoft.VisualStudio.LanguageServices.Razor
 {
-    [ExportLanguageServiceFactory(typeof(TagHelperResolver), RazorLanguage.Name, ServiceLayer.Default)]
+    [Shared]
-    internal class DefaultTagHelperResolverFactory : ILanguageServiceFactory
+    [ExportLanguageServiceFactory(typeof(TagHelperResolver), RazorLanguage.Name, ServiceLayer.Host)]
+    internal class OOPTagHelperResolverFactory : ILanguageServiceFactory
     {
         public ILanguageService CreateLanguageService(HostLanguageServices languageServices)
         {
             var workspace = languageServices.WorkspaceServices.Workspace;
-            return new DefaultTagHelperResolver(workspace.Services.GetRequiredService<ErrorReporter>(), workspace);
+            return new OOPTagHelperResolver(workspace);
         }
     }
 }

test/Microsoft.VisualStudio.Editor.Razor.Test/DefaultTagHelperResolverTest.cs

@@ -0,0 +1,63 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Reflection;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Xunit;
+
+namespace Microsoft.VisualStudio.Editor.Razor
+{
+    public class DefaultTagHelperResolverTest
+    {
+        private static readonly Assembly Assembly = typeof(DefaultTagHelperResolverTest).GetTypeInfo().Assembly;
+
+        [Fact]
+        public void GetTagHelpers_DiscoversViewComponentTagHelpers()
+        {
+            // Arrange
+            var code = @"
+public class TestViewComponent
+{
+    public string Invoke(string foo, string bar) => null;
+}";
+            var syntaxTree = CSharpSyntaxTree.ParseText(code);
+            var compilation = TestCompilation.Create(Assembly, syntaxTree);
+            var tagHelperResolver = new DefaultTagHelperResolver()
+            {
+                ForceEnableViewComponentDiscovery = true
+            };
+
+            // Act
+            var result = tagHelperResolver.GetTagHelpers(compilation);
+
+            // Assert
+            Assert.Empty(result.Diagnostics);
+            Assert.Equal(1, result.Descriptors.Count);
+        }
+
+        [Fact]
+        public void GetTagHelpers_DiscoversTagHelpers()
+        {
+            // Arrange
+            var code = $@"
+public class TestTagHelper : {typeof(TagHelper).FullName}
+{{
+}}";
+            var syntaxTree = CSharpSyntaxTree.ParseText(code);
+            var compilation = TestCompilation.Create(Assembly, syntaxTree);
+            var tagHelperResolver = new DefaultTagHelperResolver()
+            {
+                ForceEnableViewComponentDiscovery = true
+            };
+
+            // Act
+            var result = tagHelperResolver.GetTagHelpers(compilation);
+
+            // Assert
+            Assert.Empty(result.Diagnostics);
+            Assert.Equal(1, result.Descriptors.Count);
+        }
+    }
+}

test/Microsoft.VisualStudio.Editor.Razor.Test/Microsoft.VisualStudio.Editor.Razor.Test.csproj

@@ -2,13 +2,19 @@
 
   <PropertyGroup>
     <TargetFramework>net461</TargetFramework>
+    <PreserveCompilationContext>true</PreserveCompilationContext>
   </PropertyGroup>
 
+  <ItemGroup>
+    <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+  
   <ItemGroup>
     <Reference Include="WindowsBase" />
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj" />
     <ProjectReference Include="..\Microsoft.VisualStudio.Editor.Razor.Test.Common\Microsoft.VisualStudio.Editor.Razor.Test.Common.csproj" />
   </ItemGroup>
 

test/Microsoft.VisualStudio.Editor.Razor.Test/xunit.runner.json

@@ -0,0 +1,4 @@
+{
+  "methodDisplay": "method",
+  "shadowCopy": false
+}