From 02a3ca8abb042102980c85e4dd41835aac562602 Mon Sep 17 00:00:00 2001
From: "N. Taylor Mullen" <nimullen@microsoft.com>
Date: Thu, 25 Jun 2015 15:40:28 -0700
Subject: [PATCH] React to aspnet/Razor#352.

- Moved initialization of TagHelperDescriptorResolver to be Lazy so DesignTimeMode can be set.
---
 .../MvcRazorHost.cs                           | 24 ++++++++++++++++++-
 .../Precompilation/RazorPreCompiler.cs        |  2 +-
 ...TagHelperAttributeValueCodeRendererTest.cs |  3 ++-
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs b/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
index 2278c4e941..2e7e797fd0 100644
--- a/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
+++ b/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
@@ -13,6 +13,7 @@ using Microsoft.AspNet.Razor.Chunks;
 using Microsoft.AspNet.Razor.CodeGenerators;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Runtime.TagHelpers;
+using Microsoft.AspNet.Razor.TagHelpers;
 using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Mvc.Razor
@@ -44,6 +45,7 @@ namespace Microsoft.AspNet.Mvc.Razor
         private readonly IChunkTreeCache _chunkTreeCache;
         private readonly RazorPathNormalizer _pathNormalizer;
         private ChunkInheritanceUtility _chunkInheritanceUtility;
+        private ITagHelperDescriptorResolver _tagHelperDescriptorResolver;
 
         internal MvcRazorHost(IChunkTreeCache chunkTreeCache, RazorPathNormalizer pathNormalizer)
             : base(new CSharpRazorCodeLanguage())
@@ -52,7 +54,6 @@ namespace Microsoft.AspNet.Mvc.Razor
             _baseType = BaseType;
             _chunkTreeCache = chunkTreeCache;
 
-            TagHelperDescriptorResolver = new TagHelperDescriptorResolver();
             DefaultBaseClass = BaseType + "<" + DefaultModel + ">";
             DefaultNamespace = "Asp";
             // Enable instrumentation by default to allow precompiled views to work with BrowserLink.
@@ -132,6 +133,27 @@ namespace Microsoft.AspNet.Mvc.Razor
         {
         }
 
+        /// <inheritdoc />
+        public override ITagHelperDescriptorResolver TagHelperDescriptorResolver
+        {
+            get
+            {
+                // The initialization of the _tagHelperDescriptorResolver needs to be lazy to allow for the setting
+                // of DesignTimeMode.
+                if (_tagHelperDescriptorResolver == null)
+                {
+                    _tagHelperDescriptorResolver = new TagHelperDescriptorResolver(DesignTimeMode);
+                }
+
+                return _tagHelperDescriptorResolver;
+            }
+            [param: NotNull]
+            set
+            {
+                _tagHelperDescriptorResolver = value;
+            }
+        }
+
         /// <summary>
         /// Gets the model type used by default when no model is specified.
         /// </summary>
diff --git a/src/Microsoft.AspNet.Mvc.Razor/Precompilation/RazorPreCompiler.cs b/src/Microsoft.AspNet.Mvc.Razor/Precompilation/RazorPreCompiler.cs
index 9a0f0fc5b0..cb9c5dfef2 100644
--- a/src/Microsoft.AspNet.Mvc.Razor/Precompilation/RazorPreCompiler.cs
+++ b/src/Microsoft.AspNet.Mvc.Razor/Precompilation/RazorPreCompiler.cs
@@ -191,7 +191,7 @@ namespace Microsoft.AspNet.Mvc.Razor.Precompilation
 
         protected IMvcRazorHost GetRazorHost()
         {
-            var descriptorResolver = new TagHelperDescriptorResolver(TagHelperTypeResolver);
+            var descriptorResolver = new TagHelperDescriptorResolver(TagHelperTypeResolver, designTime: false);
             return new MvcRazorHost(new DefaultChunkTreeCache(FileProvider))
             {
                 TagHelperDescriptorResolver = descriptorResolver
diff --git a/test/Microsoft.AspNet.Mvc.Razor.Host.Test/MvcTagHelperAttributeValueCodeRendererTest.cs b/test/Microsoft.AspNet.Mvc.Razor.Host.Test/MvcTagHelperAttributeValueCodeRendererTest.cs
index 5dbf4ff1c5..0c245e7260 100644
--- a/test/Microsoft.AspNet.Mvc.Razor.Host.Test/MvcTagHelperAttributeValueCodeRendererTest.cs
+++ b/test/Microsoft.AspNet.Mvc.Razor.Host.Test/MvcTagHelperAttributeValueCodeRendererTest.cs
@@ -29,7 +29,8 @@ namespace Microsoft.AspNet.Mvc.Razor
                 name: "MyAttribute",
                 propertyName: "SomeProperty",
                 typeName: propertyType,
-                isIndexer: false);
+                isIndexer: false,
+                usageDescriptor: null);
             var writer = new CSharpCodeWriter();
             var generatorContext = new ChunkGeneratorContext(
                 host: null,