using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

using System.Threading.Tasks;

using System.Threading;

using System.Runtime.CompilerServices;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/78668463/newtonsoft-how-to-find-self-referencing-loop

​

#nullable enable

​

    public class MyClass

    {

        public MyClass Myself => this;

    }

​

    public class MyFieldClass

    {

        public MyFieldClass() => this.Myself = this;

        public MyFieldClass Myself;

    }

​

    public class MyEnumerable : IEnumerable<MyEnumerable>

    {

        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

        public IEnumerator<MyEnumerable> GetEnumerator() { yield return this; }

    }

​

    [JsonConverter(typeof(MyConverter))]

    public record MyConvertable;

​

    public class MyConverter : JsonConverter<MyConvertable>

    {

        public override void WriteJson(JsonWriter writer, MyConvertable? value, JsonSerializer serializer) =>

            serializer.Serialize(writer, value);

        public override MyConvertable? ReadJson(JsonReader reader, Type objectType, MyConvertable? existingValue, bool hasExistingValue, JsonSerializer serializer) =>

            throw new NotImplementedException();

    }

​

​

    class TestClass

    {

        public static void Test()

        {

            Test(new MyClass());

            Test(new MyFieldClass());

            var dictionary = new Dictionary<string, object>();

            dictionary.Add("Myself", dictionary);

            Test(dictionary);

​

            var list = new List<object>();

            list.Add(list);

            Test(list);

            Test(new MyEnumerable());

            Test(new MyConvertable());

            var root = new { data = new List<object?>() { null } };

            root.data.Add(new { Value = root });

​

            Test(root);

​

        }   

        static void Test<T>(T value)

        {

            try

            {

                Console.WriteLine(JsonConvert.SerializeObject(value));

            }

            catch (Exception ex)

            {

                Console.WriteLine("\nCaught exception {1} when serializing {0}:\n   {2}", value, ex.GetType().Name, ex.Message);

            }

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("{0} version: {1}", typeof(JsonSerializer).Namespace, typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​