Moved scope writer logic to BasicWriter

src/Microsoft.AspNetCore.Razor.Language/CodeGeneration/BasicWriter.cs

@@ -24,5 +24,9 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
         public abstract void WriteCSharpExpressionAttributeValue(CSharpRenderingContext context, CSharpExpressionAttributeValueIRNode node);
 
         public abstract void WriteCSharpCodeAttributeValue(CSharpRenderingContext context, CSharpCodeAttributeValueIRNode node);
+
+        public abstract void BeginWriterScope(CSharpRenderingContext context, string writer);
+
+        public abstract void EndWriterScope(CSharpRenderingContext context);
     }
 }

src/Microsoft.AspNetCore.Razor.Language/CodeGeneration/DesignTimeBasicWriter.cs

@@ -269,5 +269,15 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
         {
             // Do nothing
         }
+
+        public override void BeginWriterScope(CSharpRenderingContext context, string writer)
+        {
+            // Do nothing
+        }
+
+        public override void EndWriterScope(CSharpRenderingContext context)
+        {
+            // Do nothing
+        }
     }
 }

src/Microsoft.AspNetCore.Razor.Language/CodeGeneration/RuntimeBasicWriter.cs

@@ -269,7 +269,7 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
 
             using (context.Writer.BuildAsyncLambda(endLine: false, parameterNames: ValueWriterName))
             {
-                context.Writer.WriteMethodInvocation(PushWriterMethod, ValueWriterName);
+                BeginWriterScope(context, ValueWriterName);
 
                 for (var i = 0; i < node.Children.Count; i++)
                 {
@@ -310,7 +310,7 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
                     }
                 }
 
-                context.Writer.WriteMethodInvocation(PopWriterMethod);
+                EndWriterScope(context);
             }
 
             context.Writer.WriteEndMethodInvocation(false);
@@ -364,5 +364,15 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
                 charactersConsumed += textToRender.Length;
             }
         }
+
+        public override void BeginWriterScope(CSharpRenderingContext context, string writer)
+        {
+            context.Writer.WriteMethodInvocation(PushWriterMethod, writer);
+        }
+
+        public override void EndWriterScope(CSharpRenderingContext context)
+        {
+            context.Writer.WriteMethodInvocation(PopWriterMethod);
+        }
     }
 }

src/Microsoft.AspNetCore.Razor.Language/Extensions/TemplateTargetExtension.cs

@@ -8,15 +8,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
     public class TemplateTargetExtension : ITemplateTargetExtension
     {
         public static readonly string DefaultTemplateTypeName = "Template";
-        public static readonly string DefaultPushWriterMethod = "PushWriter";
-        public static readonly string DefaultPopWriterMethod = "PopWriter";
 
         public string TemplateTypeName { get; set; } = DefaultTemplateTypeName;
 
-        public string PushWriterMethod { get; set; } = DefaultPushWriterMethod;
-
-        public string PopWriterMethod { get; set; } = DefaultPopWriterMethod;
-
         public void WriteTemplate(CSharpRenderingContext context, TemplateIRNode node)
         {
             const string ItemParameterName = "item";
@@ -28,17 +22,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
 
             using (context.Writer.BuildAsyncLambda(endLine: false, parameterNames: TemplateWriterName))
             {
-                if (!context.Options.DesignTime)
-                {
-                    context.Writer.WriteMethodInvocation(PushWriterMethod, TemplateWriterName);
-                }
+                context.BasicWriter.BeginWriterScope(context, TemplateWriterName);
 
                 context.RenderChildren(node);
 
-                if (!context.Options.DesignTime)
-                {
-                    context.Writer.WriteMethodInvocation(PopWriterMethod);
-                }
+                context.BasicWriter.EndWriterScope(context);
             }
 
             context.Writer.WriteEndMethodInvocation(endLine: false);

test/Microsoft.AspNetCore.Razor.Language.Test/CodeGeneration/RuntimeBasicWriterTest.cs

@@ -433,6 +433,7 @@ if (true) { }
         [Fact]
         public void WriteHtmlContent_RendersContentCorrectly()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = new CSharpRenderingContext()
             {
@@ -462,6 +463,7 @@ if (true) { }
         [Fact]
         public void WriteHtmlContent_LargeStringLiteral_UsesMultipleWrites()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = new CSharpRenderingContext()
             {
@@ -493,6 +495,7 @@ WriteLiteral(@""{1}"");
         [Fact]
         public void WriteHtmlAttribute_RendersCorrectly()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = GetCSharpRenderingContext(writer);
 
@@ -519,6 +522,7 @@ EndWriteAttribute();
         [Fact]
         public void WriteHtmlAttributeValue_RendersCorrectly()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = GetCSharpRenderingContext(writer);
 
@@ -543,6 +547,7 @@ EndWriteAttribute();
         [Fact]
         public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = GetCSharpRenderingContext(writer);
 
@@ -571,6 +576,7 @@ WriteAttributeValue("" "", 27, false, 28, 6, false);
         [Fact]
         public void WriteCSharpCodeAttributeValue_BuffersResult()
         {
+            // Arrange
             var writer = new RuntimeBasicWriter();
             var context = GetCSharpRenderingContext(writer);
 
@@ -602,6 +608,50 @@ WriteAttributeValue("" "", 27, false, 28, 6, false);
                 ignoreLineEndingDifferences: true);
         }
 
+        [Fact]
+        public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
+        {
+            // Arrange
+            var writer = new RuntimeBasicWriter()
+            {
+                PushWriterMethod = "TestPushWriter"
+            };
+            var context = GetCSharpRenderingContext(writer);
+
+            // Act
+            writer.BeginWriterScope(context, "MyWriter");
+
+            // Assert
+            var csharp = context.Writer.Builder.ToString();
+            Assert.Equal(
+@"TestPushWriter(MyWriter);
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public void EndWriterScope_RendersCorrectly()
+        {
+            // Arrange
+            var writer = new RuntimeBasicWriter()
+            {
+                PopWriterMethod = "TestPopWriter"
+            };
+            var context = GetCSharpRenderingContext(writer);
+
+            // Act
+            writer.EndWriterScope(context);
+
+            // Assert
+            var csharp = context.Writer.Builder.ToString();
+            Assert.Equal(
+@"TestPopWriter();
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
         private static CSharpRenderingContext GetCSharpRenderingContext(BasicWriter writer)
         {
             var options = RazorCodeGenerationOptions.CreateDefault();

test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/TemplateTargetExtensionTest.cs

@@ -17,14 +17,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
 
             var extension = new TemplateTargetExtension()
             {
-                TemplateTypeName = "global::TestTemplate",
-                PushWriterMethod = "TestPushWriter",
-                PopWriterMethod = "TestPopWriter"
+                TemplateTypeName = "global::TestTemplate"
             };
 
             var context = new CSharpRenderingContext()
             { 
-                BasicWriter = new RuntimeBasicWriter(),
+                BasicWriter = new RuntimeBasicWriter()
+                {
+                    PushWriterMethod = "TestPushWriter",
+                    PopWriterMethod = "TestPopWriter"
+                },
                 TagHelperWriter = new RuntimeTagHelperWriter(),
                 Writer = new CSharpCodeWriter(),
                 Options = RazorCodeGenerationOptions.CreateDefault(),