Converter.WriteJson is not called if the value is null.

[6e06d03f]

Steps to reproduce

    public class NullToNumberConverter<T> : JsonConverter<T?>
    {
        public override T? ReadJson(JsonReader reader, Type objectType, T? existingValue, bool hasExistingValue, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override void WriteJson(JsonWriter writer, T? value, JsonSerializer serializer)
        {
            writer.WriteValue(value == null ? 0 : 1);
        }
    }

    public class TestClass
    {
        [JsonProperty("name")]
        [JsonConverter(typeof(NullToNumberConverter<string>))]
        public string? Name{ get; set; }
    }

    public class Program
    {
        static void Main(string[] args)
        {
            var obj = new TestClass();
            string json = JsonConvert.SerializeObject(obj);

            Console.WriteLine(json);
        }
    }

Expected behavior

{"name":0}

Actual behavior

{"name":null}

Note

I've found out why this is happening.

JsonSerializerInternalWriter.cs

        private void SerializeValue(JsonWriter writer, object? value, JsonContract? valueContract, JsonProperty? member, JsonContainerContract? containerContract, JsonProperty? containerProperty)
        {
            if (value == null)
            {
                writer.WriteNull();
                return;
            }
            JsonConverter jsonConverter = member?.Converter ?? containerProperty?.ItemConverter ?? containerContract?.ItemConverter ?? valueContract!.Converter ?? Serializer.GetMatchingConverter(valueContract!.UnderlyingType) ?? valueContract!.InternalConverter;
            if (jsonConverter != null && jsonConverter.CanWrite)
            {
                SerializeConvertable(writer, jsonConverter, value, valueContract, containerContract, containerProperty);
                return;
            }
.....

Can we change like this??

        private void SerializeValue(JsonWriter writer, object? value, JsonContract? valueContract, JsonProperty? member, JsonContainerContract? containerContract, JsonProperty? containerProperty)
        {
            JsonConverter jsonConverter = member?.Converter ?? containerProperty?.ItemConverter ?? containerContract?.ItemConverter ?? valueContract!.Converter ?? Serializer.GetMatchingConverter(valueContract!.UnderlyingType) ?? valueContract!.InternalConverter;
            if (value == null && jsonConverter == null && !jsonConverter.CanWrite)
            {
                writer.WriteNull();
                return;
            }
            if (jsonConverter != null && jsonConverter.CanWrite)
            {
                SerializeConvertable(writer, jsonConverter, value, valueContract, containerContract, containerProperty);
                return;
            }
.....