From 679acdc5d4aaf7591e5ca34296c553b415dc5caa Mon Sep 17 00:00:00 2001
From: Artak Mkrtchyan <artakm@corp.microsoft.com>
Date: Tue, 13 Feb 2018 13:34:16 -0800
Subject: [PATCH] Ignoring razor comments during validation

---
 .../Legacy/TagHelperParseTreeRewriter.cs      |  9 ++--
 .../Legacy/TagHelperParseTreeRewriterTest.cs  | 47 ++++++++++++++++++-
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperParseTreeRewriter.cs b/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperParseTreeRewriter.cs
index f046a8eea4..01361a9893 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperParseTreeRewriter.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperParseTreeRewriter.cs
@@ -116,7 +116,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                         continue;
                     }
                 }
-                else if (!IsCommentTag((Span)child))
+                else if (!IsComment((Span)child))
                 {
                     ValidateParentAllowsContent((Span)child, errorSink);
                 }
@@ -817,9 +817,12 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             return relevantSymbol.Type == HtmlSymbolType.ForwardSlash;
         }
 
-        private static bool IsCommentTag(Span span)
+        private static bool IsComment(Span span)
         {
-            return span.Content.StartsWith("<!--");
+            bool isHtmlComment = span.Content?.StartsWith("<!--") == true;
+            bool isRazorComment = span.Parent?.Type == BlockKindInternal.Comment;
+
+            return isHtmlComment || isRazorComment;
         }
 
         private static void EnsureTagBlock(Block tagBlock)
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperParseTreeRewriterTest.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperParseTreeRewriterTest.cs
index bf0ae602db..4a640b1990 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperParseTreeRewriterTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperParseTreeRewriterTest.cs
@@ -1109,7 +1109,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
         }
 
         [Fact]
-        public void Rewrite_AllowsCommentsAsChildren()
+        public void Rewrite_AllowsHtmlCommentsAsChildren()
         {
             // Arrangestring documentContent,
             IEnumerable<string> allowedChildren = new List<string> { "b" };
@@ -1148,6 +1148,51 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 Array.Empty<RazorDiagnostic>());
         }
 
+        [Fact]
+        public void Rewrite_AllowsRazorCommentsAsChildren()
+        {
+            // Arrangestring documentContent,
+            IEnumerable<string> allowedChildren = new List<string> { "b" };
+            string literal = "asdf";
+            string commentOutput = $"@*{literal}*@";
+            string expectedOutput = $"<p><b>{literal}</b>{commentOutput}</p>";
+
+            var pTagHelperBuilder = TagHelperDescriptorBuilder
+                .Create("PTagHelper", "SomeAssembly")
+                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"));
+            foreach (var childTag in allowedChildren)
+            {
+                pTagHelperBuilder.AllowChildTag(childTag);
+            }
+
+            var descriptors = new TagHelperDescriptor[]
+            {
+                pTagHelperBuilder.Build()
+            };
+
+            var factory = new SpanFactory();
+            var blockFactory = new BlockFactory(factory);
+
+            var expectedMarkup = new MarkupBlock(
+                new MarkupTagHelperBlock("p",
+                    blockFactory.MarkupTagBlock("<b>"),
+                    factory.Markup(literal),
+                    blockFactory.MarkupTagBlock("</b>"),
+                    new CommentBlock(
+                        Factory.MarkupTransition(HtmlSymbolType.RazorCommentTransition).Accepts(AcceptedCharactersInternal.None),
+                        Factory.MetaMarkup("*", HtmlSymbolType.RazorCommentStar).Accepts(AcceptedCharactersInternal.None),
+                        Factory.Span(SpanKindInternal.Comment, new HtmlSymbol(literal, HtmlSymbolType.RazorComment)).Accepts(AcceptedCharactersInternal.Any),
+                        Factory.MetaMarkup("*", HtmlSymbolType.RazorCommentStar).Accepts(AcceptedCharactersInternal.None),
+                        Factory.MarkupTransition(HtmlSymbolType.RazorCommentTransition).Accepts(AcceptedCharactersInternal.None))));
+
+            // Act & Assert
+            EvaluateData(
+                descriptors,
+                expectedOutput,
+                expectedMarkup,
+                Array.Empty<RazorDiagnostic>());
+        }
+
         [Fact]
         public void Rewrite_UnderstandsNullTagNameWithAllowedChildrenForCatchAll()
         {