Added logging for deserialization errors and unknown properties

src/Discord.Net.Rest/DiscordRestClient.cs

@@ -18,10 +18,16 @@ namespace Discord.Rest
         public DiscordRestClient(DiscordRestConfig config) : base(config)
         {
             _serializer = DiscordRestJsonSerializer.Global.CreateScope();
-            _serializer.Error += ex =>
+            if (config.LogLevel >= LogSeverity.Warning)
             {
-                _restLogger.WarningAsync("Serializer Error", ex).GetAwaiter().GetResult();
-            };
+                _serializer.ModelError += (path, ex)
+                    => _restLogger.WarningAsync($"Failed to deserialize {path}", ex).GetAwaiter().GetResult();
+            }
+            if (config.LogLevel >= LogSeverity.Debug)
+            {
+                _serializer.UnmappedProperty += path
+                    => _restLogger.DebugAsync($"Unmapped property: {path}");
+            }
 
             SetApiClient(new API.DiscordRestApiClient(config.RestClientProvider, DiscordConfig.UserAgent, _serializer, config.DefaultRetryMode));
         }

src/Discord.Net.Rest/Serialization/Json/Converters/EntityOrIdPropertyConverter.cs

@@ -12,19 +12,19 @@ namespace Discord.Serialization.Json.Converters
             _innerConverter = innerConverter;
         }
 
-        public override EntityOrId<T> Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override EntityOrId<T> Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
             if (reader.ValueType == JsonValueType.Number)
                 return new EntityOrId<T>(reader.ParseUInt64());
-            return new EntityOrId<T>(_innerConverter.Read(map, model, ref reader, false));
+            return new EntityOrId<T>(_innerConverter.Read(serializer, modelMap, propMap, model, ref reader, false));
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, EntityOrId<T> value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, EntityOrId<T> value, string key)
         {
             if (value.Object != null)
-                _innerConverter.Write(map, model, ref writer, value.Object, key);
+                _innerConverter.Write(serializer, modelMap, propMap, model, ref writer, value.Object, key);
             else
             {
                 if (key != null)

src/Discord.Net.Rest/Serialization/Json/Converters/ImagePropertyConverter.cs

@@ -5,7 +5,7 @@ namespace Discord.Serialization.Json.Converters
 {
     internal class ImagePropertyConverter : JsonPropertyConverter<API.Image>
     {
-        public override API.Image Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override API.Image Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -13,7 +13,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return new API.Image(reader.ParseString());
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, API.Image value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, API.Image value, string key)
         {
             string str;
             if (value.Stream != null)

src/Discord.Net.Rest/Serialization/Json/Converters/Int53PropertyConverter.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     internal class Int53PropertyConverter : JsonPropertyConverter<long>
     {
-        public override long Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override long Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number");
             return reader.ParseInt64();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, long value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, long value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);

src/Discord.Net.Rest/Serialization/Json/Converters/OptionalPropertyConverter.cs

@@ -11,13 +11,13 @@ namespace Discord.Serialization.Json.Converters
             _innerConverter = innerConverter;
         }
 
-        public override Optional<T> Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
-            => new Optional<T>(_innerConverter.Read(map, model, ref reader, isTopLevel));
+        public override Optional<T> Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
+            => new Optional<T>(_innerConverter.Read(serializer, modelMap, propMap, model, ref reader, isTopLevel));
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, Optional<T> value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, Optional<T> value, string key)
         {
             if (value.IsSpecified)
-                _innerConverter.Write(map, model, ref writer, value.Value, key);
+                _innerConverter.Write(serializer, modelMap, propMap, model, ref writer, value.Value, key);
         }
     }
 }

src/Discord.Net.Rest/Serialization/Json/Converters/UInt53PropertyConverter.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     internal class UInt53PropertyConverter : JsonPropertyConverter<ulong>
     {
-        public override ulong Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override ulong Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number");
             return reader.ParseUInt64();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, ulong value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, ulong value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);

src/Discord.Net.Serialization/BufferDictionary.cs

@@ -41,6 +41,17 @@ namespace Discord.Serialization
         }
 
         public void Add(ReadOnlyBuffer<byte> key, TValue value)
+        {
+            if (!TryAdd(key, value))
+                throw new ArgumentException("Duplicate key");
+        }
+        public void Add(ReadOnlySpan<byte> key, TValue value)
+        {
+            if (!TryAdd(key, value))
+                throw new ArgumentException("Duplicate key");
+        }
+
+        public bool TryAdd(ReadOnlyBuffer<byte> key, TValue value)
         {
             int hashCode = GetKeyHashCode(key) & 0x7FFFFFFF;
             int targetBucket = hashCode % _buckets.Length;
@@ -48,7 +59,7 @@ namespace Discord.Serialization
             for (int i = _buckets[targetBucket]; i >= 0; i = _entries[i].next)
             {
                 if (_entries[i].hashCode == hashCode && KeyEquals(_entries[i].key, key))
-                    throw new ArgumentException("Duplicate key", nameof(key));
+                    return false;
             }
             int index;
             if (_freeCount > 0)
@@ -73,6 +84,43 @@ namespace Discord.Serialization
             _entries[index].key = key;
             _entries[index].value = value;
             _buckets[targetBucket] = index;
+            return true;
+        }
+        //Duplicate code for perf reasons
+        public bool TryAdd(ReadOnlySpan<byte> key, TValue value)
+        {
+            int hashCode = GetKeyHashCode(key) & 0x7FFFFFFF;
+            int targetBucket = hashCode % _buckets.Length;
+
+            for (int i = _buckets[targetBucket]; i >= 0; i = _entries[i].next)
+            {
+                if (_entries[i].hashCode == hashCode && KeyEquals(_entries[i].key, key))
+                    return false;
+            }
+            int index;
+            if (_freeCount > 0)
+            {
+                index = _freeList;
+                _freeList = _entries[index].next;
+                _freeCount--;
+            }
+            else
+            {
+                if (_count == _entries.Length)
+                {
+                    Resize();
+                    targetBucket = hashCode % _buckets.Length;
+                }
+                index = _count;
+                _count++;
+            }
+
+            _entries[index].hashCode = hashCode;
+            _entries[index].next = _buckets[targetBucket];
+            _entries[index].key = new ReadOnlyBuffer<byte>(key.ToArray());
+            _entries[index].value = value;
+            _buckets[targetBucket] = index;
+            return true;
         }
         private void Resize()
         {

src/Discord.Net.Serialization/ConverterCollection.cs

@@ -94,13 +94,13 @@ namespace Discord.Serialization
         public void AddSelector(Serializer serializer, string groupKey, Type keyType, object keyValue, Type converterType)
         {
             var group = CreateSelectorGroup(keyType, groupKey);
-            group.AddDynamicConverter(keyValue, BuildConverter(converterType, serializer));
+            group.AddDynamicConverter(keyValue, BuildConverter(converterType, serializer ));
         }
 
         public object Get(Serializer serializer, Type type, PropertyInfo propInfo = null, bool throwOnNotFound = true)
         {
             //Check parent
-            object converter = _parent?.Get(serializer, type, propInfo, false);
+            var converter = _parent?.Get(serializer, type, propInfo, false);
             if (converter != null)
                 return converter;
 
@@ -190,6 +190,7 @@ namespace Discord.Serialization
                 else
                     throw new SerializationException($"{converterType.Name} has an unsupported constructor");
             }
+
             return constructor.Invoke(args);
         }
 

src/Discord.Net.Serialization/Discord.Net.Serialization.csproj

@@ -7,6 +7,9 @@
     <TargetFrameworks>net45;netstandard1.1;netstandard1.3</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="..\Discord.Net.Core\Utils\ConcurrentHashSet.cs" Link="Utils\ConcurrentHashSet.cs" />
+  </ItemGroup>
   <ItemGroup>
     <PackageReference Include="System.Buffers" Version="4.4.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.4.0" />

src/Discord.Net.Serialization/Json/Converters/Dictionary.cs

@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
             _valueConverter = valueConverter;
         }
 
-        public override Dictionary<string, TValue> Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override Dictionary<string, TValue> Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if ((isTopLevel && !reader.Read()) || reader.TokenType != JsonTokenType.StartObject)
                 throw new SerializationException("Bad input, expected StartObject");
@@ -26,20 +26,20 @@ namespace Discord.Serialization.Json.Converters
                     throw new SerializationException("Bad input, expected PropertyName");
 
                 string key = reader.Value.ParseString();
-                var value = _valueConverter.Read(map, model, ref reader, false);
+                var value = _valueConverter.Read(serializer, modelMap, propMap, model, ref reader, false);
                 dic.Add(key, value);
             }
             return dic;
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, Dictionary<string, TValue> value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, Dictionary<string, TValue> value, string key)
         {
             if (key != null)
                 writer.WriteObjectStart(key);
             else
                 writer.WriteObjectStart();
             foreach (var pair in value)
-                _valueConverter.Write(map, model, ref writer, pair.Value, pair.Key);
+                _valueConverter.Write(serializer, modelMap, propMap, model, ref writer, pair.Value, pair.Key);
             writer.WriteObjectEnd();
         }
     }

src/Discord.Net.Serialization/Json/Converters/Dynamic.cs

@@ -5,10 +5,10 @@ namespace Discord.Serialization.Json.Converters
     //TODO: Only supports cases where the key arrives first
     public class DynamicPropertyConverter : JsonPropertyConverter<object>
     {
-        public override object Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override object Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
-            if (map.GetDynamicConverter(model, false) is IJsonPropertyReader<object> converter)
-                return converter.Read(map, model, ref reader, isTopLevel);
+            if (propMap.GetDynamicConverter(model, false) is IJsonPropertyReader<object> converter)
+                return converter.Read(serializer, modelMap, propMap, model, ref reader, isTopLevel);
             else
             {
                 JsonReaderUtils.Skip(ref reader);
@@ -16,7 +16,7 @@ namespace Discord.Serialization.Json.Converters
             }
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, object value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, object value, string key)
         {
             if (value == null)
             {
@@ -27,8 +27,8 @@ namespace Discord.Serialization.Json.Converters
             }
             else
             {
-                var converter = (IJsonPropertyWriter)map.GetDynamicConverter(model, true);
-                converter.Write(map, model, ref writer, value, key);
+                var converter = (IJsonPropertyWriter)propMap.GetDynamicConverter(model, true);
+                converter.Write(serializer, modelMap, propMap, model, ref writer, value, key);
             }
         }
     }

src/Discord.Net.Serialization/Json/Converters/Enum.cs

@@ -7,7 +7,7 @@ namespace Discord.Serialization.Json.Converters
     {
         private static readonly EnumMap<T> _map = EnumMap.For<T>();
 
-        public override T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -15,7 +15,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return _map.FromInt64(reader.Value);
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key)
         {
             long intVal = _map.ToInt64(value);
             if (key != null)
@@ -30,7 +30,7 @@ namespace Discord.Serialization.Json.Converters
     {
         private static readonly EnumMap<T> _map = EnumMap.For<T>();
 
-        public override T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -38,7 +38,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return _map.FromUInt64(reader.Value);
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key)
         {
             ulong uintVal = _map.ToUInt64(value);
             if (key != null)
@@ -53,7 +53,7 @@ namespace Discord.Serialization.Json.Converters
     {
         private static readonly EnumMap<T> _map = EnumMap.For<T>();
 
-        public override T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -61,7 +61,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return _map.FromKey(reader.Value);
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key)
         {
             string strVal = _map.ToUtf16Key(value);
             if (key != null)

src/Discord.Net.Serialization/Json/Converters/List.cs

@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
             _innerConverter = innerConverter;
         }
 
-        public override T[] Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T[] Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if ((isTopLevel && !reader.Read()) || reader.TokenType != JsonTokenType.StartArray)
                 throw new SerializationException("Bad input, expected StartArray");
@@ -22,19 +22,19 @@ namespace Discord.Serialization.Json.Converters
             {
                 if (reader.TokenType == JsonTokenType.EndArray)
                     return list.ToArray();
-                list.Add(_innerConverter.Read(map, model, ref reader, false));
+                list.Add(_innerConverter.Read(serializer, modelMap, propMap, model, ref reader, false));
             }
             throw new SerializationException("Bad input, expected EndArray");
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T[] value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T[] value, string key)
         {
             if (key != null)
                 writer.WriteArrayStart(key);
             else
                 writer.WriteArrayStart();
             for (int i = 0; i < value.Length; i++)
-                _innerConverter.Write(map, model, ref writer, value[i], null);
+                _innerConverter.Write(serializer, modelMap, propMap, model, ref writer, value[i], null);
             writer.WriteArrayEnd();
         }
     }
@@ -48,7 +48,7 @@ namespace Discord.Serialization.Json.Converters
             _innerConverter = innerConverter;
         }
 
-        public override List<T> Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override List<T> Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if ((isTopLevel && !reader.Read()) || reader.TokenType != JsonTokenType.StartArray)
                 throw new SerializationException("Bad input, expected StartArray");
@@ -58,19 +58,19 @@ namespace Discord.Serialization.Json.Converters
             {
                 if (reader.TokenType == JsonTokenType.EndArray)
                     return list;
-                list.Add(_innerConverter.Read(map, model, ref reader, false));
+                list.Add(_innerConverter.Read(serializer, modelMap, propMap, model, ref reader, false));
             }
             throw new SerializationException("Bad input, expected EndArray");
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, List<T> value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, List<T> value, string key)
         {
             if (key != null)
                 writer.WriteArrayStart(key);
             else
                 writer.WriteArrayStart();
             for (int i = 0; i < value.Count; i++)
-                _innerConverter.Write(map, model, ref writer, value[i], null);
+                _innerConverter.Write(serializer, modelMap, propMap, model, ref writer, value[i], null);
             writer.WriteArrayEnd();
         }
     }

src/Discord.Net.Serialization/Json/Converters/Nullable.cs

@@ -12,19 +12,19 @@ namespace Discord.Serialization.Json.Converters
             _innerConverter = innerConverter;
         }
 
-        public override T? Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T? Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
             if (reader.ValueType == JsonValueType.Null)
                 return null;
-            return _innerConverter.Read(map, model, ref reader, false);
+            return _innerConverter.Read(serializer, modelMap, propMap, model, ref reader, false);
         }
 
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T? value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T? value, string key)
         {
             if (value.HasValue)
-                _innerConverter.Write(map, model, ref writer, value.Value, key);
+                _innerConverter.Write(serializer, modelMap, propMap, model, ref writer, value.Value, key);
             else
             {
                 if (key != null)

src/Discord.Net.Serialization/Json/Converters/Object.cs

@@ -1,18 +1,19 @@
-using System.Text.Json;
+using System;
+using System.Text.Json;
 
 namespace Discord.Serialization.Json.Converters
 {
     public class ObjectPropertyConverter<T> : JsonPropertyConverter<T>
         where T : class, new()
     {
-        private readonly ModelMap<T> _map;
+        private readonly ModelMap _map;
 
         public ObjectPropertyConverter(Serializer serializer)
         {
             _map = serializer.MapModel<T>();
         }
 
-        public override T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             var subModel = new T();
 
@@ -30,13 +31,19 @@ namespace Discord.Serialization.Json.Converters
                     throw new SerializationException("Bad input, expected PropertyName");
 
                 if (_map.TryGetProperty(reader.Value, out var property))
-                    (property as IJsonPropertyMap<T>).Read(subModel, ref reader);
+                {
+                    try { (property as IJsonPropertyMap<T>).Read(serializer, subModel, ref reader); }
+                    catch (Exception ex) { RaiseModelError(serializer, property, ex); }
+                }
                 else
+                {
+                    RaiseUnmappedProperty(serializer, _map, reader.Value);
                     JsonReaderUtils.Skip(ref reader); //Unknown property, skip
+                }
             }
             throw new SerializationException("Bad input, expected EndObject");
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key)
         {
             if (value == null)
             {
@@ -51,8 +58,8 @@ namespace Discord.Serialization.Json.Converters
                     writer.WriteObjectStart(key);
                 else
                     writer.WriteObjectStart();
-                for (int i = 0; i < _map.Properties.Length; i++)
-                    (_map.Properties[i] as IJsonPropertyMap<T>).Write(value, ref writer);
+                for (int i = 0; i < _map.Properties.Count; i++)
+                    (_map.Properties[i] as IJsonPropertyMap<T>).Write(serializer, value, ref writer);
                 writer.WriteObjectEnd();
             }
         }

src/Discord.Net.Serialization/Json/Converters/Primitives.DateTime.cs

@@ -5,7 +5,7 @@ namespace Discord.Serialization.Json.Converters
 {
     public class DateTimePropertyConverter : JsonPropertyConverter<DateTime>
     {
-        public override DateTime Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override DateTime Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -13,7 +13,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return reader.ParseDateTime();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, DateTime value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, DateTime value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -24,7 +24,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class DateTimeOffsetPropertyConverter : JsonPropertyConverter<DateTimeOffset>
     {
-        public override DateTimeOffset Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override DateTimeOffset Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -32,7 +32,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return reader.ParseDateTimeOffset();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, DateTimeOffset value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, DateTimeOffset value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);

src/Discord.Net.Serialization/Json/Converters/Primitives.Float.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     public class SinglePropertyConverter : JsonPropertyConverter<float>
     {
-        public override float Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override float Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseSingle();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, float value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, float value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());
@@ -23,7 +23,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class DoublePropertyConverter : JsonPropertyConverter<double>
     {
-        public override double Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override double Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -31,7 +31,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseDouble();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, double value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, double value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());
@@ -42,7 +42,7 @@ namespace Discord.Serialization.Json.Converters
 
     internal class DecimalPropertyConverter : JsonPropertyConverter<decimal>
     {
-        public override decimal Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override decimal Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -50,7 +50,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseDecimal();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, decimal value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, decimal value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());

src/Discord.Net.Serialization/Json/Converters/Primitives.Other.cs

@@ -5,7 +5,7 @@ namespace Discord.Serialization.Json.Converters
 {
     public class BooleanPropertyConverter : JsonPropertyConverter<bool>
     {
-        public override bool Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override bool Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -16,7 +16,7 @@ namespace Discord.Serialization.Json.Converters
                 default: throw new SerializationException("Bad input, expected False or True");
             }
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, bool value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, bool value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -27,7 +27,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class GuidPropertyConverter : JsonPropertyConverter<Guid>
     {
-        public override Guid Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override Guid Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -35,7 +35,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return reader.ParseGuid();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, Guid value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, Guid value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());

src/Discord.Net.Serialization/Json/Converters/Primitives.Signed.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     public class Int8PropertyConverter : JsonPropertyConverter<sbyte>
     {
-        public override sbyte Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override sbyte Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseInt8();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, sbyte value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, sbyte value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -23,7 +23,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class Int16PropertyConverter : JsonPropertyConverter<short>
     {
-        public override short Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override short Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -31,7 +31,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseInt16();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, short value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, short value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -42,7 +42,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class Int32PropertyConverter : JsonPropertyConverter<int>
     {
-        public override int Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override int Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -50,7 +50,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseInt32();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, int value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, int value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -61,7 +61,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class Int64PropertyConverter : JsonPropertyConverter<long>
     {
-        public override long Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override long Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -69,7 +69,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseInt64();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, long value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, long value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());

src/Discord.Net.Serialization/Json/Converters/Primitives.String.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     /*public class CharPropertyConverter : JsonPropertyConverter<char>
     {
-        public override char Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override char Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return reader.ParseChar();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, char value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, char value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -23,7 +23,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class StringPropertyConverter : JsonPropertyConverter<string>
     {
-        public override string Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override string Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -33,7 +33,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected String");
             return reader.ParseString();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, string value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, string value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);

src/Discord.Net.Serialization/Json/Converters/Primitives.Unsigned.cs

@@ -4,7 +4,7 @@ namespace Discord.Serialization.Json.Converters
 {
     public class UInt8PropertyConverter : JsonPropertyConverter<byte>
     {
-        public override byte Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override byte Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseUInt8();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, byte value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, byte value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -23,7 +23,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class UInt16PropertyConverter : JsonPropertyConverter<ushort>
     {
-        public override ushort Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override ushort Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -31,7 +31,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseUInt16();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, ushort value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, ushort value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -42,7 +42,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class UInt32PropertyConverter : JsonPropertyConverter<uint>
     {
-        public override uint Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override uint Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -50,7 +50,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseUInt32();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, uint value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, uint value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value);
@@ -61,7 +61,7 @@ namespace Discord.Serialization.Json.Converters
 
     public class UInt64PropertyConverter : JsonPropertyConverter<ulong>
     {
-        public override ulong Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public override ulong Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             if (isTopLevel)
                 reader.Read();
@@ -69,7 +69,7 @@ namespace Discord.Serialization.Json.Converters
                 throw new SerializationException("Bad input, expected Number or String");
             return reader.ParseUInt64();
         }
-        public override void Write(PropertyMap map, object model, ref JsonWriter writer, ulong value, string key)
+        public override void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, ulong value, string key)
         {
             if (key != null)
                 writer.WriteAttribute(key, value.ToString());

src/Discord.Net.Serialization/Json/Converters/Struct.cs

@@ -12,7 +12,7 @@ namespace Discord.Serialization.Json.Converters
             _map = serializer.MapModel<T>();
         }
 
-        public T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel)
+        public T Read(ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel)
         {
             var subModel = new T();
 
@@ -32,7 +32,7 @@ namespace Discord.Serialization.Json.Converters
             }
             throw new SerializationException("Bad input, expected EndObject");
         }
-        public void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key)
+        public void Write(ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key)
         {
             if (key != null)
                 writer.WriteObjectStart(key);

src/Discord.Net.Serialization/Json/IJsonPropertyConverter.cs

@@ -1,26 +0,0 @@
-using System.Text.Json;
-
-namespace Discord.Serialization.Json
-{
-    public abstract class JsonPropertyConverter<T> : IJsonPropertyReader<T>, IJsonPropertyWriter<T>, IJsonPropertyWriter
-    {
-        public abstract T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel);
-        public abstract void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key);
-
-        void IJsonPropertyWriter.Write(PropertyMap map, object model, ref JsonWriter writer, object value, string key)
-            => Write(map, model, ref writer, (T)value, key);
-    }
-
-    public interface IJsonPropertyReader<out T>
-    {
-        T Read(PropertyMap map, object model, ref JsonReader reader, bool isTopLevel);
-    }
-    public interface IJsonPropertyWriter<in T>
-    {
-        void Write(PropertyMap map, object model, ref JsonWriter writer, T value, string key);
-    }
-    public interface IJsonPropertyWriter
-    {
-        void Write(PropertyMap map, object model, ref JsonWriter writer, object value, string key);
-    }
-}

src/Discord.Net.Serialization/Json/JsonPropertyConverter.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Text.Json;
+
+namespace Discord.Serialization.Json
+{
+    public abstract class JsonPropertyConverter<T> : IJsonPropertyReader<T>, IJsonPropertyWriter<T>, IJsonPropertyWriter
+    {
+        public abstract T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel);
+        public abstract void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key);
+
+        void IJsonPropertyWriter.Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, object value, string key)
+            => Write(serializer, modelMap, propMap, model, ref writer, (T)value, key);
+
+        protected void RaiseUnmappedProperty(Serializer serializer, ModelMap modelMap, ReadOnlyBuffer<byte> propertyKey)
+            => serializer.RaiseUnknownProperty(modelMap.Path, propertyKey);
+        protected void RaiseUnmappedProperty(Serializer serializer, ModelMap modelMap, ReadOnlySpan<byte> propertyKey)
+            => serializer.RaiseUnknownProperty(modelMap.Path, propertyKey);
+        protected void RaiseModelError(Serializer serializer, PropertyMap propMap, Exception ex)
+            => serializer.RaiseModelError(propMap.Path, ex);
+    }
+
+    public interface IJsonPropertyReader<out T>
+    {
+        T Read(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonReader reader, bool isTopLevel);
+    }
+    public interface IJsonPropertyWriter<in T>
+    {
+        void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, T value, string key);
+    }
+    public interface IJsonPropertyWriter
+    {
+        void Write(Serializer serializer, ModelMap modelMap, PropertyMap propMap, object model, ref JsonWriter writer, object value, string key);
+    }
+}

src/Discord.Net.Serialization/Json/JsonPropertyMap.cs

@@ -9,36 +9,38 @@ namespace Discord.Serialization.Json
         string Key { get; }
         ReadOnlyBuffer<byte> Utf8Key { get; }
 
-        void Write(TModel model, ref JsonWriter writer);
-        void Read(TModel model, ref JsonReader reader);
+        void Write(Serializer serializer, TModel model, ref JsonWriter writer);
+        void Read(Serializer serializer, TModel model, ref JsonReader reader);
     }
 
     internal class JsonPropertyMap<TModel, TValue> : PropertyMap<TModel, TValue>, IJsonPropertyMap<TModel>
     {
+        private readonly ModelMap _modelMap;
         private readonly JsonPropertyConverter<TValue> _converter;
         private readonly Func<TModel, TValue> _getFunc;
         private readonly Action<TModel, TValue> _setFunc;
 
-        public JsonPropertyMap(Serializer serializer, PropertyInfo propInfo, JsonPropertyConverter<TValue> converter)
-            : base(serializer, propInfo)
+        public JsonPropertyMap(Serializer serializer, ModelMap modelMap, PropertyInfo propInfo, JsonPropertyConverter<TValue> converter)
+            : base(serializer, modelMap, propInfo)
         {
+            _modelMap = modelMap;
             _converter = converter;
 
             _getFunc = propInfo.GetMethod.CreateDelegate(typeof(Func<TModel, TValue>)) as Func<TModel, TValue>;
             _setFunc = propInfo.SetMethod.CreateDelegate(typeof(Action<TModel, TValue>)) as Action<TModel, TValue>;
         }
 
-        public void Read(TModel model, ref JsonReader reader)
+        public void Read(Serializer serializer, TModel model, ref JsonReader reader)
         {
-            var value = _converter.Read(this, model, ref reader, true);
+            var value = _converter.Read(serializer, _modelMap, this, model, ref reader, true);
             _setFunc(model, value);
         }
-        public void Write(TModel model, ref JsonWriter writer)
+        public void Write(Serializer serializer, TModel model, ref JsonWriter writer)
         {
             var value = _getFunc(model);
             if (value == null && ExcludeNull)
                 return;
-            _converter.Write(this, model, ref writer, value, Key);
+            _converter.Write(serializer, _modelMap, this, model, ref writer, value, Key);
         }
     }
 }

src/Discord.Net.Serialization/Json/JsonSerializer.cs

@@ -18,10 +18,10 @@ namespace Discord.Serialization.Json
             where TConverter : JsonPropertyConverter<TValue>
             => AddConverter(typeof(TValue), typeof(TConverter), condition);
 
-        protected override PropertyMap CreatePropertyMap<TModel, TValue>(PropertyInfo propInfo)
+        protected override PropertyMap CreatePropertyMap<TModel, TValue>(ModelMap modelMap, PropertyInfo propInfo)
         {
             var converter = (JsonPropertyConverter<TValue>)GetConverter(typeof(TValue), propInfo);
-            return new JsonPropertyMap<TModel, TValue>(this, propInfo, converter);
+            return new JsonPropertyMap<TModel, TValue>(this, modelMap, propInfo, converter);
         }
         
         public TModel Read<TModel>(Utf8String str)
@@ -32,14 +32,16 @@ namespace Discord.Serialization.Json
             if (!reader.Read())
                 return default;
             var converter = GetConverter(typeof(TModel)) as JsonPropertyConverter<TModel>;
-            return converter.Read(null, null, ref reader, false);
+            //Don't wrap this. We should throw an exception if we cant create the model.
+            return converter.Read(this, null, null, null, ref reader, false);
         }
 
         public override void Write<TModel>(ArrayFormatter stream, TModel model)
         {
             var writer = new JsonWriter(stream);
             var converter = GetConverter(typeof(TModel)) as JsonPropertyConverter<TModel>;
-            converter.Write(null, null, ref writer, model, null);
+            //Don't wrap this, always throw exceptions on Write.
+            converter.Write(this, null, null, null, ref writer, model, null);
         }
     }
 }

src/Discord.Net.Serialization/ModelMap.cs

@@ -1,22 +1,28 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
 
 namespace Discord.Serialization
 {
-    public class ModelMap<TModel>
-        where TModel : class, new()
+    public class ModelMap
     {
-        private BufferDictionary<PropertyMap> _propDict;
+        private readonly List<PropertyMap> _propList;
+        private readonly BufferDictionary<PropertyMap> _propDict;
 
+        public string Path { get; }
         public bool HasDynamics { get; }
-        public PropertyMap[] Properties { get; }
+        public IReadOnlyList<PropertyMap> Properties => _propList;
 
-        public ModelMap(Serializer serializer, TypeInfo type, List<PropertyMap> properties)
+        internal ModelMap(string path)
         {
-            Properties = properties.ToArray();
-            _propDict = new BufferDictionary<PropertyMap>(properties.ToDictionary(x => x.Utf8Key));
+            Path = path;
+            _propList = new List<PropertyMap>();
+            _propDict = new BufferDictionary<PropertyMap>();
+        }
+
+        internal void AddProperty(PropertyMap propMap)
+        {
+            _propList.Add(propMap);
+            _propDict.Add(propMap.Utf8Key, propMap);
         }
 
         public bool TryGetProperty(ReadOnlyBuffer<byte> key, out PropertyMap value)

src/Discord.Net.Serialization/PropertyMap.cs

@@ -11,18 +11,19 @@ namespace Discord.Serialization
         public string Key { get; }
         public ReadOnlyBuffer<byte> Utf8Key { get; }
         public string Name { get; }
+        public string Path { get; }
 
         public bool ExcludeNull { get; }
 
-        public PropertyMap(Serializer serializer, PropertyInfo propInfo)
+        internal PropertyMap(Serializer serializer, PropertyInfo propInfo, ModelMap modelMap)
         {
             Name = propInfo.Name;
+            Path = $"{modelMap.Path}.{propInfo.Name}";
 
             var attr = propInfo.GetCustomAttribute<ModelPropertyAttribute>();
             Key = attr.Key ?? propInfo.Name;
             Utf8Key = new ReadOnlyBuffer<byte>(new Utf8String(Key).Bytes.ToArray());
             ExcludeNull = attr.ExcludeNull;
-
         }
         
         public abstract object GetDynamicConverter(object model, bool throwOnMissing);
@@ -54,11 +55,10 @@ namespace Discord.Serialization
                 => _group?.GetDynamicConverter(_getWrappedSelectorFunc, model);
         }
         
-        private readonly Delegate _getSelectorFunc, _getWrappedSelectorFunc;
         private readonly IReadOnlyList<Selector> _selectors;
 
-        public PropertyMap(Serializer serializer, PropertyInfo propInfo)
-            : base(serializer, propInfo)
+        internal PropertyMap(Serializer serializer, ModelMap modelMap, PropertyInfo propInfo)
+            : base(serializer, propInfo, modelMap)
         {
             _selectors = propInfo.GetCustomAttributes<ModelSelectorAttribute>()
                 .Select(x =>

src/Discord.Net.Serialization/Serializer.cs

@@ -4,18 +4,21 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using System.Text.Formatting;
+using System.Text.Utf8;
 
 namespace Discord.Serialization
 {
     public abstract class Serializer
     {
-        public event Action<Exception> Error; //TODO: Impl
+        public event Action<string, Exception> ModelError;
+        public event Action<string> UnmappedProperty;
 
         private static readonly MethodInfo _createPropertyMapMethod
             = typeof(Serializer).GetTypeInfo().GetDeclaredMethod(nameof(CreatePropertyMap));
         
         private readonly ConcurrentDictionary<Type, object> _maps;
         private readonly ConverterCollection _converters;
+        private readonly ConcurrentHashSet<string> _unknownProps = new ConcurrentHashSet<string>();
 
         protected Serializer()
             : this(null) { }
@@ -50,16 +53,18 @@ namespace Discord.Serialization
         public ISelectorGroup GetSelectorGroup(Type keyType, string groupKey)
             => _converters.GetSelectorGroup(keyType, groupKey);
 
-        protected internal ModelMap<TModel> MapModel<TModel>()
-            where TModel : class, new()
+        protected internal ModelMap MapModel<TModel>()
         {
             return _maps.GetOrAdd(typeof(TModel), _ =>
             {
                 var type = typeof(TModel).GetTypeInfo();
+                var searchType = type;
                 var properties = new List<PropertyMap>();
-                while (type != null)
+                var map = new ModelMap(type.Name);
+
+                while (searchType != null)
                 {
-                    var propInfos = type.DeclaredProperties
+                    var propInfos = searchType.DeclaredProperties
                         .Where(x => x.CanRead && x.CanWrite)
                         .ToArray();
 
@@ -67,24 +72,68 @@ namespace Discord.Serialization
                     {
                         if (propInfos[i].GetCustomAttribute<ModelPropertyAttribute>() != null)
                         {
-                            var propMap = MapProperty<TModel>(propInfos[i]);
-                            properties.Add(propMap);
+                            var propMap = MapProperty<TModel>(map, propInfos[i]);
+                            map.AddProperty(propMap);
                         }
                     }
 
-                    type = type.BaseType?.GetTypeInfo();
+                    searchType = searchType.BaseType?.GetTypeInfo();
                 }
-                return new ModelMap<TModel>(this, type, properties);
-            }) as ModelMap<TModel>;
+                return map;
+            }) as ModelMap;
         }
 
-        private PropertyMap MapProperty<TModel>(PropertyInfo propInfo)
-            => _createPropertyMapMethod.MakeGenericMethod(typeof(TModel), propInfo.PropertyType).Invoke(this, new object[] { propInfo }) as PropertyMap;
-        protected abstract PropertyMap CreatePropertyMap<TModel, TValue>(PropertyInfo propInfo);
+        private PropertyMap MapProperty<TModel>(ModelMap modelMap, PropertyInfo propInfo)
+            => _createPropertyMapMethod.MakeGenericMethod(typeof(TModel), propInfo.PropertyType).Invoke(this, new object[] { modelMap, propInfo }) as PropertyMap;
+        protected abstract PropertyMap CreatePropertyMap<TModel, TValue>(ModelMap modelMap, PropertyInfo propInfo);
 
         public TModel Read<TModel>(ReadOnlyBuffer<byte> data)
             => Read<TModel>(data.Span);
         public abstract TModel Read<TModel>(ReadOnlySpan<byte> data);
         public abstract void Write<TModel>(ArrayFormatter stream, TModel model);
+
+        internal void RaiseModelError(string path, Exception ex)
+        {
+            if (ModelError != null)
+                ModelError?.Invoke(path, ex);
+        }
+        internal void RaiseModelError(ModelMap modelMap, Exception ex)
+        {
+            if (ModelError != null)
+                ModelError?.Invoke(modelMap.Path, ex);
+        }
+        internal void RaiseModelError(PropertyMap propMap, Exception ex)
+        {
+            if (ModelError != null)
+                ModelError?.Invoke(propMap.Path, ex);
+        }
+
+        internal void RaiseUnmappedProperty(string model, string propertyMap)
+        {
+            if (UnmappedProperty != null)
+            {
+                string path = $"{model}.{propertyMap}";
+                if (_unknownProps.TryAdd(path))
+                    UnmappedProperty?.Invoke(path);
+            }
+        }
+        internal void RaiseUnknownProperty(string model, ReadOnlyBuffer<byte> propertyMap)
+        {
+            if (UnmappedProperty != null)
+            {
+                string path = $"{model}.{new Utf8String(propertyMap.Span).ToString()}";
+                if (_unknownProps.TryAdd(path))
+                    UnmappedProperty?.Invoke(path);
+            }
+        }
+        internal void RaiseUnknownProperty(string model, ReadOnlySpan<byte> propertyMap)
+        {
+            if (UnmappedProperty != null)
+            {
+                string path = $"{model}.{new Utf8String(propertyMap).ToString()}";
+                if (_unknownProps.TryAdd(path))
+                    UnmappedProperty?.Invoke(path);
+            }
+        }
     }
 }

src/Discord.Net.WebSocket/Audio/AudioClient.cs

@@ -68,10 +68,16 @@ namespace Discord.Audio
             _audioLogger = Discord.LogManager.CreateLogger($"Audio #{clientId}");
 
             _serializer = DiscordVoiceJsonSerializer.Global.CreateScope();
-            _serializer.Error += ex =>
+            if (Discord.LogManager.Level >= LogSeverity.Warning)
             {
-                _audioLogger.WarningAsync("Serializer Error", ex).GetAwaiter().GetResult();
-            };
+                _serializer.ModelError += (path, ex)
+                    => _audioLogger.WarningAsync($"Failed to deserialize {path}", ex).GetAwaiter().GetResult();
+            }
+            if (Discord.LogManager.Level >= LogSeverity.Debug)
+            {
+                _serializer.UnmappedProperty += path
+                    => _audioLogger.DebugAsync($"Unmapped property: {path}");
+            }
 
             ApiClient = new DiscordVoiceApiClient(guild.Id, Discord.WebSocketProvider, Discord.UdpSocketProvider, _serializer);
             ApiClient.SentGatewayMessage += async opCode => await _audioLogger.DebugAsync($"Sent {opCode}").ConfigureAwait(false);

src/Discord.Net.WebSocket/DiscordShardedClient.cs

@@ -56,10 +56,16 @@ namespace Discord.WebSocket
             _connectionGroupLock = new SemaphoreSlim(1, 1);
 
             _serializer = DiscordSocketJsonSerializer.Global.CreateScope();
-            _serializer.Error += ex =>
+            if (config.LogLevel >= LogSeverity.Warning)
             {
-                _restLogger.WarningAsync("Serializer Error", ex).GetAwaiter().GetResult();
-            };
+                _serializer.ModelError += (path, ex)
+                    => _restLogger.WarningAsync($"Failed to deserialize {path}", ex).GetAwaiter().GetResult();
+            }
+            if (config.LogLevel >= LogSeverity.Debug)
+            {
+                _serializer.UnmappedProperty += path
+                    => _restLogger.DebugAsync($"Unmapped property: {path}");
+            }
 
             SetApiClient(new API.DiscordSocketApiClient(config.RestClientProvider, config.WebSocketProvider, DiscordConfig.UserAgent, _serializer));
 

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -88,10 +88,16 @@ namespace Discord.WebSocket
             _gatewayLogger = LogManager.CreateLogger(ShardId == 0 && TotalShards == 1 ? "Gateway" : $"Shard #{ShardId}");
 
             _serializer = DiscordSocketJsonSerializer.Global.CreateScope();
-            _serializer.Error += ex =>
+            if (config.LogLevel >= LogSeverity.Warning)
             {
-                _restLogger.WarningAsync("Serializer Error", ex).GetAwaiter().GetResult();
-            };
+                _serializer.ModelError += (path, ex) 
+                    => _gatewayLogger.WarningAsync($"Failed to deserialize {path}", ex).GetAwaiter().GetResult();
+            }
+            if (config.LogLevel >= LogSeverity.Debug)
+            {
+                _serializer.UnmappedProperty += path
+                    => _gatewayLogger.DebugAsync($"Unmapped property: {path}");
+            }
 
             SetApiClient(new API.DiscordSocketApiClient(config.RestClientProvider, config.WebSocketProvider, DiscordConfig.UserAgent, _serializer, config.GatewayHost, config.DefaultRetryMode));