refactor: Added indicator for auto-generated code and nullability+

Author: linkdotnet

src/bunit.generators/Web.Stubs/AddStubMethodStubGenerator/AddStubGenerator.cs

@@ -124,7 +124,8 @@ public InterceptsLocationAttribute(string filePath, int line, int column)
 		                         """;
 
 		// Generate the interceptor
-		var interceptorSource = new StringBuilder();
+		var interceptorSource = new StringBuilder(1000);
+		interceptorSource.AppendLine(HeaderProvider.Header);
 		interceptorSource.AppendLine(attribute);
 		interceptorSource.AppendLine();
 		interceptorSource.AppendLine("namespace Bunit");

src/bunit.generators/Web.Stubs/AddStubMethodStubGenerator/StubComponentBuilder.cs

@@ -13,8 +13,9 @@ public static bool GenerateStubComponent(AddStubClassInfo classInfo, SourceProdu
 	{
 		var hasSomethingToStub = false;
 		var targetTypeSymbol = (INamedTypeSymbol)classInfo!.TargetType;
-		var sourceBuilder = new StringBuilder();
+		var sourceBuilder = new StringBuilder(1000);
 
+		sourceBuilder.AppendLine(HeaderProvider.Header);
 		sourceBuilder.AppendLine($"namespace {classInfo.TargetTypeNamespace};");
 		sourceBuilder.AppendLine();
 		sourceBuilder.AppendLine($"internal partial class {classInfo.StubClassName} : global::Microsoft.AspNetCore.Components.ComponentBase");
@@ -39,7 +40,7 @@ public static bool GenerateStubComponent(AddStubClassInfo classInfo, SourceProdu
 			var attributeLine = GetAttributeLine(member);
 			sourceBuilder.AppendLine(attributeLine);
 
-			sourceBuilder.AppendLine($"\tpublic {propertyType} {propertyName} {{ get; set; }}");
+			sourceBuilder.AppendLine($"\tpublic {propertyType} {propertyName} {{ get; set; }} = default!;");
 		}
 
 		sourceBuilder.AppendLine("}");

src/bunit.generators/Web.Stubs/AttributeStubGenerator/ComponentStubAttribute.cs

@@ -2,7 +2,9 @@ namespace Bunit.Web.Stubs.AttributeStubGenerator;
 
 internal static class ComponentStubAttribute
 {
-	public static string ComponentStubAttributeSource = """
+	public static string ComponentStubAttributeSource = $$"""
+	                                                    {{HeaderProvider.Header}}
+
 	                                                    #if NET5_0_OR_GREATER
 	                                                    namespace Bunit;
 

src/bunit.generators/Web.Stubs/AttributeStubGenerator/ComponentStubAttributeGenerator.cs

@@ -73,8 +73,9 @@ private static void Execute(StubClassInfo classInfo, SourceProductionContext con
 	{
 		var hasSomethingToStub = false;
 		var targetTypeSymbol = (INamedTypeSymbol)classInfo!.TargetType;
-		var sourceBuilder = new StringBuilder();
+		var sourceBuilder = new StringBuilder(1000);
 
+		sourceBuilder.AppendLine(HeaderProvider.Header);
 		sourceBuilder.AppendLine($"namespace {classInfo.Namespace};");
 
 		sourceBuilder.AppendLine(
@@ -104,7 +105,7 @@ private static void Execute(StubClassInfo classInfo, SourceProductionContext con
 				: "\t[global::Microsoft.AspNetCore.Components.CascadingParameter]";
 
 			sourceBuilder.AppendLine(attributeLine);
-			sourceBuilder.AppendLine($"\tpublic {propertyType} {propertyName} {{ get; set; }}");
+			sourceBuilder.AppendLine($"\tpublic {propertyType} {propertyName} {{ get; set; }} = default!;");
 		}
 
 		sourceBuilder.AppendLine("}");

src/bunit.generators/Web.Stubs/HeaderProvider.cs

@@ -0,0 +1,13 @@
+namespace Bunit.Web.Stubs;
+
+internal static class HeaderProvider
+{
+	public const string Header = """
+	                             // <auto-generated>
+	                             //   This code was generated by bunit.generators.
+	                             //   Changes to this file may cause incorrect behavior and will be lost if
+	                             //   the code is regenerated.
+	                             // </auto-generated>
+	                             #nullable enable
+	                             """;
+}