Fix @section directive incorrectly allowed in .razor files

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/SectionDirectivePassTest.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Linq;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Xunit;
 using static Microsoft.AspNetCore.Razor.Language.Intermediate.IntermediateNodeAssert;
@@ -76,4 +77,47 @@ public void Execute_WrapsStatementInSectionNode()
         Assert.Equal("Header", section.SectionName);
         Children(section, c => Html(" <p>Hello World</p> ", c));
     }
+
+    [Fact]
+    public void SectionDirective_IsRecognizedInLegacyFiles()
+    {
+        // Arrange
+        var content = "@section Header { <p>Hello World</p> }";
+        var source = TestRazorSourceDocument.Create(content, filePath: "test.cshtml", relativePath: "test.cshtml");
+
+        // Act
+        var codeDocument = ProjectEngine.CreateCodeDocument(source, RazorFileKind.Legacy);
+        ProjectEngine.Engine.Process(codeDocument);
+
+        // Assert
+        var syntaxTree = codeDocument.GetSyntaxTree();
+        Assert.NotNull(syntaxTree);
+
+        // The section directive should be recognized without errors
+        var diagnostics = syntaxTree.Diagnostics;
+        Assert.Empty(diagnostics);
+    }
+
+    [Fact]
+    public void SectionDirective_IsNotRecognizedInComponentFiles()
+    {
+        // Arrange
+        var content = "@section Header { <p>Hello World</p> }";
+        var source = TestRazorSourceDocument.Create(content, filePath: "test.razor", relativePath: "test.razor");
+
+        // Act
+        var codeDocument = ProjectEngine.CreateCodeDocument(source, RazorFileKind.Component);
+        ProjectEngine.Engine.Process(codeDocument);
+
+        // Assert
+        var syntaxTree = codeDocument.GetSyntaxTree();
+        Assert.NotNull(syntaxTree);
+
+        // The section directive should NOT be recognized in component files.
+        // Verify that no RazorDirective node for 'section' exists in the syntax tree
+        var directiveNodes = syntaxTree.Root.DescendantNodes()
+            .OfType<Microsoft.AspNetCore.Razor.Language.Syntax.RazorDirectiveSyntax>();
+
+        Assert.DoesNotContain(directiveNodes, d => d.DirectiveDescriptor?.Directive == "section");
+    }
 }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs

@@ -12968,5 +12968,21 @@ @inject float Value5
         CompileToAssembly(generated);
     }
 
+    [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/11273")]
+    public void SectionDirective_NotAllowed()
+    {
+        // Verify that @section is not recognized in components and produces appropriate code-gen
+        // Act
+        var generated = CompileToCSharp("""
+            @{ var section = "Section"; }
+            @section One { <p>Content</p> }
+            """);
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
     #endregion
 }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/CSharpSectionTest.cs

@@ -300,5 +300,4 @@ public void _WithDoubleTransition2()
     {
         ParseDocumentTest("@section s {<span foo='@DateTime.Now @@' />}", [SectionDirective.Directive]);
     }
-
 }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.codegen.cs

@@ -0,0 +1,45 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line default
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    #line default
+    #line hidden
+    #nullable restore
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    #nullable disable
+    {
+        #pragma warning disable 219
+        private void __RazorDirectiveTokenHelpers__() {
+        }
+        #pragma warning restore 219
+        #pragma warning disable 0414
+        private static object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+   var section = "Section"; 
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = section;
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+    }
+}
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.ir.txt

@@ -0,0 +1,27 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [20] ) - global::System
+        UsingDirective - (26:2,1 [40] ) - global::System.Collections.Generic
+        UsingDirective - (69:3,1 [25] ) - global::System.Linq
+        UsingDirective - (97:4,1 [36] ) - global::System.Threading.Tasks
+        UsingDirective - (136:5,1 [45] ) - global::Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            DesignTimeDirective - 
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning disable 0414
+            CSharpCode - 
+                IntermediateToken -  - CSharp - private static object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                CSharpCode - (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp -  var section = "Section"; 
+                CSharpExpression - (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - section
+                HtmlContent - (39:1,8 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (39:1,8 [7] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  One { 
+                MarkupElement - (46:1,15 [14] x:\dir\subdir\Test\TestComponent.cshtml) - p
+                    HtmlContent - (49:1,18 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (49:1,18 [7] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Content
+                HtmlContent - (60:1,29 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (60:1,29 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.mappings.txt

@@ -0,0 +1,10 @@
+Source Location: (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml)
+| var section = "Section"; |
+Generated Location: (987:28,2 [26] )
+| var section = "Section"; |
+
+Source Location: (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+|section|
+Generated Location: (1141:35,6 [7] )
+|section|
+

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.codegen.cs

@@ -0,0 +1,42 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line default
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    #line default
+    #line hidden
+    #nullable restore
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    #nullable disable
+    {
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+#nullable restore
+#line (1,3)-(1,29) "x:\dir\subdir\Test\TestComponent.cshtml"
+ var section = "Section"; 
+
+#line default
+#line hidden
+#nullable disable
+
+#nullable restore
+#line (2,2)-(2,9) 24 "x:\dir\subdir\Test\TestComponent.cshtml"
+__builder.AddContent(0, section
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __builder.AddContent(1, " One { ");
+            __builder.AddMarkupContent(2, "<p>Content</p> }");
+        }
+        #pragma warning restore 1998
+    }
+}
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.ir.txt

@@ -0,0 +1,16 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [20] ) - global::System
+        UsingDirective - (26:2,1 [40] ) - global::System.Collections.Generic
+        UsingDirective - (69:3,1 [25] ) - global::System.Linq
+        UsingDirective - (97:4,1 [36] ) - global::System.Threading.Tasks
+        UsingDirective - (136:5,1 [45] ) - global::Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                CSharpCode - (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp -  var section = "Section"; 
+                CSharpExpression - (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - section
+                HtmlContent - (39:1,8 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (39:1,8 [7] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  One { 
+                MarkupBlock -  - <p>Content</p> }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/SectionDirective_NotAllowed/TestComponent.mappings.txt

@@ -0,0 +1,10 @@
+Source Location: (2:0,2 [26] x:\dir\subdir\Test\TestComponent.cshtml)
+| var section = "Section"; |
+Generated Location: (735:21,0 [26] )
+| var section = "Section"; |
+
+Source Location: (32:1,1 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+|section|
+Generated Location: (922:29,24 [7] )
+|section|
+

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/SectionDirective.cs

@@ -26,7 +26,7 @@ public static void Register(RazorProjectEngineBuilder builder)
             throw new ArgumentNullException(nameof(builder));
         }
 
-        builder.AddDirective(Directive, RazorFileKind.Legacy, RazorFileKind.Component);
+        builder.AddDirective(Directive, RazorFileKind.Legacy);
         builder.Features.Add(new SectionDirectivePass());
         builder.AddTargetExtension(new SectionTargetExtension());
     }