Fix circular reference

.vscode/launch.json

@@ -412,14 +412,17 @@
       "preLaunchTask": "build",
       "program": "${workspaceFolder}/src/kiota/bin/Debug/net8.0/kiota.dll",
       "args": [
-          "generate",
-          "--openapi", "C:\\Users\\evansaboge\\Documents\\RestClient\\openapi.yaml",
-          "--language", "http",
-          "--output", "C:\\Users\\evansaboge\\Documents\\RestClient\\HTTP1"
+        "generate",
+        "--openapi",
+        "https://raw.githubusercontent.com/microsoftgraph/msgraph-sdk-powershell/dev/openApiDocs/v1.0/Mail.yml",
+        "--language",
+        "http",
+        "--output",
+        "${workspaceFolder}/samples/msgraph-mail/http",
       ],
       "cwd": "${workspaceFolder}/src/kiota",
       "stopAtEntry": false,
       "console": "internalConsole"
     }
   ]
-}
+}

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

@@ -287,19 +287,34 @@ private static void WriteRequestBody(CodeMethod method, LanguageWriter writer)
     /// </summary>
     /// <param name="requestBodyClass">The request body class containing the properties.</param>
     /// <param name="writer">The language writer to write the properties to.</param>
-    private static void WriteProperties(CodeClass requestBodyClass, LanguageWriter writer)
+    private static void WriteProperties(CodeClass requestBodyClass, LanguageWriter writer, HashSet<CodeClass>? processedClasses = null, int depth = 0)
     {
+
+        if (processedClasses == null)
+        {
+            processedClasses = new HashSet<CodeClass>();
+        }
+
+        // Add the current class to the set of processed classes
+        if (!processedClasses.Add(requestBodyClass))
+        {
+            // If the class is already processed, write its properties again up to a certain depth
+            if (depth >= 3)
+            {
+                return;
+            }
+        }
+
         var properties = requestBodyClass.Properties
             .Where(static prop => prop.IsOfKind(CodePropertyKind.Custom))
             .ToArray();
 
         var propertyCount = properties.Length;
-        var currentIndex = 0;
 
         foreach (var prop in properties)
         {
             // Add a trailing comma if there are more properties to be written
-            var separator = currentIndex < propertyCount - 1 ? "," : string.Empty;
+            var separator = ",";
             var propName = $"\"{prop.Name}\"";
             writer.Write($"{propName}: ");
 
@@ -308,7 +323,7 @@ private static void WriteProperties(CodeClass requestBodyClass, LanguageWriter w
                 // If the property is an object, write a JSON representation recursively
                 writer.WriteLine("{", includeIndent: false);
                 writer.IncreaseIndent();
-                WriteProperties(propClass, writer);
+                WriteProperties(propClass, writer, processedClasses, depth + 1);
                 writer.CloseBlock($"}}{separator}");
             }
             else
@@ -317,10 +332,13 @@ private static void WriteProperties(CodeClass requestBodyClass, LanguageWriter w
             }
         }
 
+        // Remove the current class from the set of processed classes after processing
+        processedClasses.Remove(requestBodyClass);
+
         // If the class extends another class, write properties of the base class
         if (requestBodyClass.StartBlock.Inherits?.TypeDefinition is CodeClass baseClass)
         {
-            WriteProperties(baseClass, writer);
+            WriteProperties(baseClass, writer, processedClasses, depth + 1);
         }
     }