Emit [GeneratedCode] attribute for C# types

Emit `[GeneratedCode]` attribute for C# types.
Resolves #4907.

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - References to C# types generated by kiota are prefixed with `global::` to avoid name collisions. [#4796](https://github.com/microsoft/kiota/issues/4796)
 - Ensures HashSet properties in `KiotaLock` maintain IgnoreCase comparer across runs [#4916](https://github.com/microsoft/kiota/issues/4916)
 - Dropped `client base url set to` message when generating plugins. [#4905](https://github.com/microsoft/kiota/issues/4905)
+- Emit `[GeneratedCode]` attribute for C# types. [#4907](https://github.com/microsoft/kiota/issues/4907)
 
 ## [1.15.0] - 2024-06-06
 

src/Kiota.Builder/Writers/CSharp/CodeClassDeclarationWriter.cs

@@ -7,6 +7,7 @@ namespace Kiota.Builder.Writers.CSharp;
 public class CodeClassDeclarationWriter : BaseElementWriter<ClassDeclaration, CSharpConventionService>
 {
     public static string AutoGenerationHeader => "// <auto-generated/>";
+    public static string GeneratedCodeAttribute { get; } = $"[global::System.CodeDom.Compiler.GeneratedCode(\"Kiota\", \"{typeof(CodeClassDeclarationWriter).Assembly.GetName().Version}\")]";
     public CodeClassDeclarationWriter(CSharpConventionService conventionService) : base(conventionService) { }
     public override void WriteCodeElement(ClassDeclaration codeElement, LanguageWriter writer)
     {
@@ -37,6 +38,7 @@ public override void WriteCodeElement(ClassDeclaration codeElement, LanguageWrit
         var derivation = derivedTypes.Length != 0 ? ": " + derivedTypes.Aggregate(static (x, y) => $"{x}, {y}") : string.Empty;
         bool hasDescription = conventions.WriteLongDescription(parentClass, writer);
         conventions.WriteDeprecationAttribute(parentClass, writer);
+        writer.WriteLine(GeneratedCodeAttribute);
         if (!hasDescription) writer.WriteLine("#pragma warning disable CS1591");
         writer.WriteLine($"public partial class {codeElement.Name.ToFirstCharacterUpperCase()} {derivation}");
         if (!hasDescription) writer.WriteLine("#pragma warning restore CS1591");

src/Kiota.Builder/Writers/CSharp/CodeEnumWriter.cs

@@ -9,6 +9,7 @@ namespace Kiota.Builder.Writers.CSharp;
 public class CodeEnumWriter : BaseElementWriter<CodeEnum, CSharpConventionService>
 {
     public static string AutoGenerationHeader => "// <auto-generated/>";
+    public static string GeneratedCodeAttribute { get; } = $"[global::System.CodeDom.Compiler.GeneratedCode(\"Kiota\", \"{typeof(CodeClassDeclarationWriter).Assembly.GetName().Version}\")]";
     public CodeEnumWriter(CSharpConventionService conventionService) : base(conventionService) { }
     public override void WriteCodeElement(CodeEnum codeElement, LanguageWriter writer)
     {
@@ -30,6 +31,7 @@ public override void WriteCodeElement(CodeEnum codeElement, LanguageWriter write
             writer.WriteLine($"namespace {codeNamespace.Name}");
             writer.StartBlock();
         }
+        writer.WriteLine(GeneratedCodeAttribute);
         bool hasDescription = conventions.WriteShortDescription(codeElement, writer);
         if (codeElement.Flags)
             writer.WriteLine("[Flags]");

tests/Kiota.Builder.Tests/Writers/CSharp/CodeClassDeclarationWriterTests.cs

@@ -107,4 +107,13 @@ public void WritesImports()
         Assert.Contains("Project.Graph", result);
         Assert.Contains("System.Util", result);
     }
+
+    [Fact]
+    public void WritesGeneratedCodeAttribute()
+    {
+        codeElementWriter.WriteCodeElement(parentClass.StartBlock, writer);
+        var result = tw.ToString();
+        var pattern = @"\s+\[global::System\.CodeDom\.Compiler\.GeneratedCode\(""Kiota"", ""[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+""\)\]";
+        Assert.Matches(pattern, result);
+    }
 }

tests/Kiota.Builder.Tests/Writers/CSharp/CodeEnumWriterTests.cs

@@ -110,6 +110,7 @@ public void WritesFlagsEnum()
         Assert.Contains("= 1", result);
         Assert.Contains("= 2", result);
     }
+
     [Fact]
     public void WritesEnumOptionDescription()
     {
@@ -120,11 +121,22 @@ public void WritesEnumOptionDescription()
         Assert.Contains($"<summary>{Option.Documentation.DescriptionTemplate}</summary>", result);
         AssertExtensions.CurlyBracesAreClosed(result, 1);
     }
+
     [Fact]
     public void DoesntWriteAnythingOnNoOption()
     {
         writer.Write(currentEnum);
         var result = tw.ToString();
         Assert.Empty(result);
     }
+
+    [Fact]
+    public void WritesGeneratedCodeAttribute()
+    {
+        currentEnum.AddOption(new CodeEnumOption { Name = "option2" });
+        writer.Write(currentEnum);
+        var result = tw.ToString();
+        var pattern = @"\s+\[global::System\.CodeDom\.Compiler\.GeneratedCode\(""Kiota"", ""[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+""\)\]";
+        Assert.Matches(pattern, result);
+    }
 }