Fixed JsonUtility implementation for CLI so it can work with private fields

src/NuGetForUnity.Cli/Fakes/JsonUtility.cs

@@ -1,14 +1,42 @@
 #nullable enable
 
+using System;
+using System.Collections.Generic;
+using System.Reflection;
 using System.Text.Json;
+using System.Text.Json.Serialization;
+using NugetForUnity.Configuration;
 
 namespace UnityEngine
 {
     internal static class JsonUtility
     {
+        private static JsonSerializerOptions? options;
+
+        private static JsonSerializerOptions? prettyOptions;
+
+        private static JsonSerializerOptions Options
+        {
+            get
+            {
+                if (options != null)
+                {
+                    return options;
+                }
+
+                options = new JsonSerializerOptions { IncludeFields = true };
+                options.Converters.Add(new PrivateFieldConverter<NativeRuntimeSettings>());
+                options.Converters.Add(new PrivateFieldConverter<NativeRuntimeAssetConfiguration>());
+
+                return options;
+            }
+        }
+
+        private static JsonSerializerOptions PrettyOptions => prettyOptions ??= new JsonSerializerOptions(Options) { WriteIndented = true };
+
         public static T? FromJson<T>(string output)
         {
-            return JsonSerializer.Deserialize<T>(output, new JsonSerializerOptions { IncludeFields = true });
+            return JsonSerializer.Deserialize<T>(output, Options);
         }
 
         public static void FromJsonOverwrite<T>(string jsonString, T target)
@@ -18,7 +46,77 @@ public static void FromJsonOverwrite<T>(string jsonString, T target)
 
         internal static string ToJson<T>(T value, bool pretty = false)
         {
-            return JsonSerializer.Serialize(value, new JsonSerializerOptions { IncludeFields = true, WriteIndented = pretty });
+            return JsonSerializer.Serialize(value, pretty ? PrettyOptions : Options);
+        }
+
+        // special converter for classes with private fields e.g. NativeRuntimeSettings and NativeRuntimeAssetConfiguration
+        private sealed class PrivateFieldConverter<T> : JsonConverter<T>
+            where T : new()
+        {
+            public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+            {
+                if (reader.TokenType != JsonTokenType.StartObject)
+                {
+                    throw new JsonException($"Expected first token to be {nameof(JsonTokenType.StartObject)} but got {reader.TokenType}");
+                }
+
+                var result = new T();
+
+                var fieldMap = new Dictionary<string, FieldInfo>();
+                foreach (var field in typeof(T).GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
+                {
+                    fieldMap[field.Name] = field;
+                }
+
+                while (reader.Read())
+                {
+                    if (reader.TokenType == JsonTokenType.EndObject)
+                    {
+                        return result;
+                    }
+
+                    if (reader.TokenType != JsonTokenType.PropertyName)
+                    {
+                        throw new JsonException($"Expected {nameof(JsonTokenType.PropertyName)} but got {reader.TokenType}");
+                    }
+
+                    var propName = reader.GetString();
+
+                    if (propName == null || !reader.Read())
+                    {
+                        throw new JsonException("Expected the name of the property but got null");
+                    }
+
+                    if (fieldMap.TryGetValue(propName, out var field))
+                    {
+                        var value = JsonSerializer.Deserialize(ref reader, field.FieldType, options);
+                        field.SetValue(result, value);
+                    }
+                    else
+                    {
+                        // Skip unknown field
+                        reader.Skip();
+                    }
+                }
+
+                throw new JsonException($"Incomplete JSON object. Not reached {nameof(JsonTokenType.EndObject)}");
+            }
+
+            public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
+            {
+                writer.WriteStartObject();
+
+                var fields = typeof(T).GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
+
+                foreach (var field in fields)
+                {
+                    var fieldValue = field.GetValue(value);
+                    writer.WritePropertyName(field.Name);
+                    JsonSerializer.Serialize(writer, fieldValue, fieldValue?.GetType() ?? typeof(object), options);
+                }
+
+                writer.WriteEndObject();
+            }
         }
     }
 }