Fix #773 (for real this time)

The problem is that the new HTML rewrite pass was traversing into
attributes of all kinds and would turn any HTML content inside those
attributes into elements where possible. The solution is to not do
that.

src/Microsoft.AspNetCore.Blazor.Razor.Extensions/BlazorRuntimeNodeWriter.cs

@@ -355,7 +355,8 @@ namespace Microsoft.AspNetCore.Blazor.Razor
             else if (node.Children.Count == 1 && node.Children[0] is HtmlContentIntermediateNode htmlNode)
             {
                 // This is how string attributes are lowered by default, a single HTML node with a single HTML token.
-                context.CodeWriter.WriteStringLiteral(((IntermediateToken)htmlNode.Children[0]).Content);
+                var content = string.Join(string.Empty, GetHtmlTokens(htmlNode).Select(t => t.Content));
+                context.CodeWriter.WriteStringLiteral(content);
             }
             else
             {
@@ -391,6 +392,12 @@ namespace Microsoft.AspNetCore.Blazor.Razor
                 // We generally expect all children to be CSharp, this is here just in case.
                 return attribute.FindDescendantNodes<IntermediateToken>().Where(t => t.IsCSharp).ToArray();
             }
+
+            IReadOnlyList<IntermediateToken> GetHtmlTokens(HtmlContentIntermediateNode html)
+            {
+                // We generally expect all children to be HTML, this is here just in case.
+                return html.FindDescendantNodes<IntermediateToken>().Where(t => t.IsHtml).ToArray();
+            }
         }
 
         public override void WriteReferenceCapture(CodeRenderingContext context, RefExtensionNode node)

src/Microsoft.AspNetCore.Blazor.Razor.Extensions/ComponentDocumentRewritePass.cs

@@ -81,6 +81,21 @@ namespace Microsoft.AspNetCore.Blazor.Razor
                 }
             }
             
+            public override void VisitHtmlAttribute(HtmlAttributeIntermediateNode node)
+            {
+                // Don't rewrite inside of attributes
+            }
+
+            public override void VisitTagHelperHtmlAttribute(TagHelperHtmlAttributeIntermediateNode node)
+            {
+                // Don't rewrite inside of attributes
+            }
+
+            public override void VisitTagHelperProperty(TagHelperPropertyIntermediateNode node)
+            {
+                // Don't rewrite inside of attributes
+            }
+
             private void RewriteChildren(RazorSourceDocument source, IntermediateNode node)
             {
                 // We expect all of the immediate children of a node (together) to comprise

test/Microsoft.AspNetCore.Blazor.Build.Test/ComponentRenderingRazorIntegrationTest.cs

@@ -409,5 +409,38 @@ namespace Test
                 GetFrames((RenderFragment)innerFrames[1].AttributeValue),
                 frame => AssertFrame.Text(frame, "Some text", 4));
         }
+
+        [Fact] // https://github.com/aspnet/Blazor/issues/773
+        public void Regression_773()
+        {
+            // Arrange
+            AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Blazor.Components;
+
+namespace Test
+{
+    public class SurveyPrompt : BlazorComponent
+    {
+        [Parameter] private string Title { get; set; }
+    }
+}
+"));
+
+            var component = CompileToComponent(@"
+@addTagHelper *, TestAssembly
+@page ""/""
+
+<SurveyPrompt Title=""<div>Test!</div>"" />
+");
+
+            // Act
+            var frames = GetRenderTree(component);
+
+            // Assert
+            Assert.Collection(
+                frames,
+                frame => AssertFrame.Component(frame, "Test.SurveyPrompt", 2, 0),
+                frame => AssertFrame.Attribute(frame, "Title", "<div>Test!</div>", 1));
+        }
     }
 }

test/Microsoft.AspNetCore.Blazor.Build.Test/DesignTimeCodeGenerationTest.cs

@@ -425,6 +425,7 @@ namespace Test
 
             // Act
             var generated = CompileToCSharp(@"
+@addTagHelper *, TestAssembly
 @page ""/""
 
 <h1>Hello, world!</h1>
@@ -437,6 +438,7 @@ Welcome to your new app.
             // Assert
             AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
             AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+            CompileToAssembly(generated);
         }
 
         [Fact]

test/Microsoft.AspNetCore.Blazor.Build.Test/RuntimeCodeGenerationTest.cs

@@ -660,6 +660,8 @@ Welcome to your new app.
         [Fact] // https://github.com/aspnet/Blazor/issues/773
         public void Regression_773()
         {
+            GenerateBaselines = true;
+
             // Arrange
             AdditionalSyntaxTrees.Add(Parse(@"
 using Microsoft.AspNetCore.Blazor.Components;
@@ -675,6 +677,7 @@ namespace Test
 
             // Act
             var generated = CompileToCSharp(@"
+@addTagHelper *, TestAssembly
 @page ""/""
 
 <h1>Hello, world!</h1>
@@ -687,6 +690,7 @@ Welcome to your new app.
             // Assert
             AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
             AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+            CompileToAssembly(generated);
         }
 
         [Fact]

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/DesignTimeCodeGenerationTest/Regression_772/TestComponent.codegen.cs

@@ -31,7 +31,6 @@ global::System.Object __typeHelper = "/";
         protected override void BuildRenderTree(Microsoft.AspNetCore.Blazor.RenderTree.RenderTreeBuilder builder)
         {
             base.BuildRenderTree(builder);
-            __o = ;
             builder.AddAttribute(-1, "ChildContent", (Microsoft.AspNetCore.Blazor.RenderFragment)((builder2) => {
             }
             ));

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/DesignTimeCodeGenerationTest/Regression_772/TestComponent.ir.txt

@@ -33,3 +33,5 @@ Document -
                     IntermediateToken - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
                 ComponentExtensionNode - (98:7,0 [23] x:\dir\subdir\Test\TestComponent.cshtml) - SurveyPrompt - Test.SurveyPrompt
                     ComponentAttributeExtensionNode - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml) - Title - Title
+                        HtmlContent - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml)
+                            IntermediateToken - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml) - Html - 

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/DesignTimeCodeGenerationTest/Regression_773/TestComponent.codegen.cs

@@ -15,6 +15,10 @@ namespace Test
         #pragma warning disable 219
         private void __RazorDirectiveTokenHelpers__() {
         ((System.Action)(() => {
+global::System.Object __typeHelper = "*, TestAssembly";
+        }
+        ))();
+        ((System.Action)(() => {
 global::System.Object __typeHelper = "/";
         }
         ))();
@@ -27,6 +31,9 @@ global::System.Object __typeHelper = "/";
         protected override void BuildRenderTree(Microsoft.AspNetCore.Blazor.RenderTree.RenderTreeBuilder builder)
         {
             base.BuildRenderTree(builder);
+            builder.AddAttribute(-1, "ChildContent", (Microsoft.AspNetCore.Blazor.RenderFragment)((builder2) => {
+            }
+            ));
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/DesignTimeCodeGenerationTest/Regression_773/TestComponent.ir.txt

@@ -11,7 +11,8 @@ Document -
             DesignTimeDirective - 
                 DirectiveToken - (14:0,14 [32] ) - "*, Microsoft.AspNetCore.Blazor"
                 DirectiveToken - (14:0,14 [9] ) - "*, Test"
-                DirectiveToken - (6:0,6 [3] x:\dir\subdir\Test\TestComponent.cshtml) - "/"
+                DirectiveToken - (14:0,14 [15] x:\dir\subdir\Test\TestComponent.cshtml) - *, TestAssembly
+                DirectiveToken - (37:1,6 [3] x:\dir\subdir\Test\TestComponent.cshtml) - "/"
             CSharpCode - 
                 IntermediateToken -  - CSharp - #pragma warning disable 0414
             CSharpCode - 
@@ -21,16 +22,18 @@ Document -
             MethodDeclaration -  - protected override - void - BuildRenderTree
                 CSharpCode - 
                     IntermediateToken -  - CSharp - base.BuildRenderTree(builder);
-                HtmlContent - (11:1,0 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                HtmlContent - (29:0,29 [2] x:\dir\subdir\Test\TestComponent.cshtml)
-                    IntermediateToken - (11:1,0 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                    IntermediateToken - (29:0,29 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
-                HtmlElement - (13:2,0 [22] x:\dir\subdir\Test\TestComponent.cshtml) - h1
+                HtmlContent - (42:2,0 [2] x:\dir\subdir\Test\TestComponent.cshtml)
-                    HtmlContent - (17:2,4 [13] x:\dir\subdir\Test\TestComponent.cshtml)
+                    IntermediateToken - (42:2,0 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
-                        IntermediateToken - (17:2,4 [13] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Hello, world!
+                HtmlElement - (44:3,0 [22] x:\dir\subdir\Test\TestComponent.cshtml) - h1
-                HtmlContent - (35:2,22 [32] x:\dir\subdir\Test\TestComponent.cshtml)
+                    HtmlContent - (48:3,4 [13] x:\dir\subdir\Test\TestComponent.cshtml)
-                    IntermediateToken - (35:2,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
+                        IntermediateToken - (48:3,4 [13] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Hello, world!
-                HtmlElement - (67:6,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - surveyprompt
+                HtmlContent - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml)
-                    HtmlAttribute -  -  - 
+                    IntermediateToken - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
-                        HtmlAttributeValue -  - 
+                ComponentExtensionNode - (98:7,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - SurveyPrompt - Test.SurveyPrompt
-                            IntermediateToken -  - Html - <div>Test!</div>
+                    ComponentAttributeExtensionNode - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml) - Title - Title
-                HtmlContent - (108:6,41 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                        HtmlContent - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml)
-                    IntermediateToken - (108:6,41 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                            IntermediateToken - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml) - Html - <div>Test!</div>
+                HtmlContent - (139:7,41 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    IntermediateToken - (139:7,41 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/DesignTimeCodeGenerationTest/Regression_773/TestComponent.mappings.txt

@@ -1,5 +1,10 @@
-Source Location: (6:0,6 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+Source Location: (14:0,14 [15] x:\dir\subdir\Test\TestComponent.cshtml)
+|*, TestAssembly|
+Generated Location: (625:17,38 [15] )
+|*, TestAssembly|
+
+Source Location: (37:1,6 [3] x:\dir\subdir\Test\TestComponent.cshtml)
 |"/"|
-Generated Location: (624:17,37 [3] )
+Generated Location: (741:21,37 [3] )
 |"/"|
 

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/RuntimeCodeGenerationTest/Regression_772/TestComponent.codegen.cs

@@ -21,7 +21,7 @@ namespace Test
             builder.CloseElement();
             builder.AddContent(2, "\n\nWelcome to your new app.\n\n");
             builder.OpenComponent<Test.SurveyPrompt>(3);
-            builder.AddAttribute(4, "Title", );
+            builder.AddAttribute(4, "Title", "");
             builder.CloseComponent();
         }
         #pragma warning restore 1998

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/RuntimeCodeGenerationTest/Regression_772/TestComponent.ir.txt

@@ -18,3 +18,5 @@ Document -
                     IntermediateToken - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
                 ComponentExtensionNode - (98:7,0 [23] x:\dir\subdir\Test\TestComponent.cshtml) - SurveyPrompt - Test.SurveyPrompt
                     ComponentAttributeExtensionNode - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml) - Title - Title
+                        HtmlContent - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml)
+                            IntermediateToken - (119:7,21 [0] x:\dir\subdir\Test\TestComponent.cshtml) - Html - 

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/RuntimeCodeGenerationTest/Regression_773/TestComponent.codegen.cs

@@ -20,9 +20,9 @@ namespace Test
             builder.AddContent(1, "Hello, world!");
             builder.CloseElement();
             builder.AddContent(2, "\n\nWelcome to your new app.\n\n");
-            builder.OpenElement(3, "surveyprompt");
+            builder.OpenComponent<Test.SurveyPrompt>(3);
-            builder.AddAttribute(4, "title", "<div>Test!</div>");
+            builder.AddAttribute(4, "Title", "<div>Test!</div>");
-            builder.CloseElement();
+            builder.CloseComponent();
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Blazor.Build.Test/TestFiles/RuntimeCodeGenerationTest/Regression_773/TestComponent.ir.txt

@@ -11,12 +11,12 @@ Document -
             MethodDeclaration -  - protected override - void - BuildRenderTree
                 CSharpCode - 
                     IntermediateToken -  - CSharp - base.BuildRenderTree(builder);
-                HtmlElement - (13:2,0 [22] x:\dir\subdir\Test\TestComponent.cshtml) - h1
+                HtmlElement - (44:3,0 [22] x:\dir\subdir\Test\TestComponent.cshtml) - h1
-                    HtmlContent - (17:2,4 [13] x:\dir\subdir\Test\TestComponent.cshtml)
+                    HtmlContent - (48:3,4 [13] x:\dir\subdir\Test\TestComponent.cshtml)
-                        IntermediateToken - (17:2,4 [13] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Hello, world!
+                        IntermediateToken - (48:3,4 [13] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Hello, world!
-                HtmlContent - (35:2,22 [32] x:\dir\subdir\Test\TestComponent.cshtml)
+                HtmlContent - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml)
-                    IntermediateToken - (35:2,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
+                    IntermediateToken - (66:3,22 [32] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\nWelcome to your new app.\n\n
-                HtmlElement - (67:6,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - surveyprompt
+                ComponentExtensionNode - (98:7,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - SurveyPrompt - Test.SurveyPrompt
-                    HtmlAttribute -  -  - 
+                    ComponentAttributeExtensionNode - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml) - Title - Title
-                        HtmlAttributeValue -  - 
+                        HtmlContent - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml)
-                            IntermediateToken -  - Html - <div>Test!</div>
+                            IntermediateToken - (119:7,21 [16] x:\dir\subdir\Test\TestComponent.cshtml) - Html - <div>Test!</div>