using System;

using System.Text.Json;

using System.Text.Json.Nodes;

using System.Collections.Generic;

​

#nullable enable

​

public class Program

{

    public static void Main()

    {

        // Deserializing any well-formed JSON to JsonNode works

        var node = JsonSerializer.Deserialize<JsonNode>("[null]");

        Console.WriteLine(node);

​

        var node2 = JsonSerializer.Deserialize<JsonNode>("null");

        Console.WriteLine($"(node2 == null) == {node2 == null}");

​

        // Deserializing any well-formed JSON array to List<JsonNode> works unless the array contains a null:

        var list = JsonSerializer.Deserialize<JsonNode>("""[1,2,"a",[],[null],{}]""");

        Console.WriteLine(JsonSerializer.Serialize(list));

        // Deserializing any well-formed JSON object to Dictionary<string, JsonNode> works unless the dictionary contains a null value:

        var dictionary = JsonSerializer.Deserialize<Dictionary<string, JsonNode?>>(

            """

            {

                "a" : "a",

                "c" : [null],

                "d" : {"q" : null}

            }

            """);

        Console.WriteLine(JsonSerializer.Serialize(dictionary));

        // So in general we can say that System.Text.Json knows how to deserialize the abstract type JsonNode -- except when in collections and when the JSON value is null.

        // So, bug in System.Text.Json

    }

}