Implemented serialization for `MetadataOverride`. Deserialization is broken (converter is never called)

LLama/Abstractions/IModelParams.cs

@@ -5,7 +5,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
-using LLama.Common;
 using LLama.Native;
 
 namespace LLama.Abstractions
@@ -110,6 +109,7 @@ namespace LLama.Abstractions
         }
     }
 
+
     /// <summary>
     /// A fixed size array to set the tensor splits across multiple GPUs
     /// </summary>
@@ -204,6 +204,7 @@ namespace LLama.Abstractions
         }
     }
 
+
     /// <summary>
     /// An override for a single key/value pair in model metadata
     /// </summary>
@@ -243,57 +244,92 @@ namespace LLama.Abstractions
             return new BoolOverride(key, value);
         }
 
-        internal abstract void Write(ref LLamaModelMetadataOverride dest);
-
         /// <summary>
         /// Get the key being overriden by this override
         /// </summary>
         public abstract string Key { get; init; }
 
+        internal abstract LLamaModelKvOverrideType Type { get; }
+
+        internal abstract void WriteValue(ref LLamaModelMetadataOverride dest);
+
+        internal abstract void WriteValue(Utf8JsonWriter writer, JsonSerializerOptions options);
+
         private record IntOverride(string Key, int Value) : MetadataOverride
         {
-            internal override void Write(ref LLamaModelMetadataOverride dest)
+            internal override LLamaModelKvOverrideType Type => LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_INT;
+
+            internal override void WriteValue(ref LLamaModelMetadataOverride dest)
             {
-                dest.Tag = LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_INT;
                 dest.IntValue = Value;
             }
+
+            internal override void WriteValue(Utf8JsonWriter writer, JsonSerializerOptions options)
+            {
+                writer.WriteNumberValue(Value);
+            }
         }
 
         private record FloatOverride(string Key, float Value) : MetadataOverride
         {
-            internal override void Write(ref LLamaModelMetadataOverride dest)
+            internal override LLamaModelKvOverrideType Type => LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_FLOAT;
+
+            internal override void WriteValue(ref LLamaModelMetadataOverride dest)
             {
-                dest.Tag = LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_FLOAT;
                 dest.FloatValue = Value;
             }
+
+            internal override void WriteValue(Utf8JsonWriter writer, JsonSerializerOptions options)
+            {
+                writer.WriteNumberValue(Value);
+            }
         }
 
         private record BoolOverride(string Key, bool Value) : MetadataOverride
         {
-            internal override void Write(ref LLamaModelMetadataOverride dest)
+            internal override LLamaModelKvOverrideType Type => LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_BOOL;
+
+            internal override void WriteValue(ref LLamaModelMetadataOverride dest)
             {
-                dest.Tag = LLamaModelKvOverrideType.LLAMA_KV_OVERRIDE_BOOL;
                 dest.BoolValue = Value ? -1 : 0;
             }
+
+            internal override void WriteValue(Utf8JsonWriter writer, JsonSerializerOptions options)
+            {
+                writer.WriteBooleanValue(Value);
+            }
         }
     }
 
+    /// <summary>
+    /// A JSON converter for <see cref="MetadataOverride"/>
+    /// </summary>
     public class MetadataOverrideConverter
         : JsonConverter<MetadataOverride>
     {
+        /// <inheritdoc/>
+        public override bool CanConvert(Type typeToConvert)
+        {
+            return typeof(MetadataOverride).IsAssignableFrom(typeToConvert);
+        }
+
         /// <inheritdoc/>
         public override MetadataOverride Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            throw new NotImplementedException();
-            //var arr = JsonSerializer.Deserialize<float[]>(ref reader, options) ?? Array.Empty<float>();
-            //return new TensorSplitsCollection(arr);
+            throw new NotImplementedException("for some reason this is never called!");
         }
 
         /// <inheritdoc/>
         public override void Write(Utf8JsonWriter writer, MetadataOverride value, JsonSerializerOptions options)
         {
-            throw new NotImplementedException();
-            //JsonSerializer.Serialize(writer, value.Splits, options);
+            writer.WriteStartObject();
+            {
+                writer.WriteString("Key", value.Key);
+                writer.WriteNumber("Type", (int)value.Type);
+                writer.WritePropertyName("Value");
+                value.WriteValue(writer, options);
+            }
+            writer.WriteEndObject();
         }
     }
 }

LLama/Extensions/IModelParamsExtensions.cs

@@ -57,10 +57,12 @@ public static class IModelParamsExtensions
             for (var i = 0; i < @params.MetadataOverrides.Count; i++)
             {
                 var item = @params.MetadataOverrides[i];
-                var native = new LLamaModelMetadataOverride();
+                var native = new LLamaModelMetadataOverride
+                {
+                    Tag = item.Type
+                };
 
-                // Init value and tag
-                item.Write(ref native);
+                item.WriteValue(ref native);
 
                 // Convert key to bytes
                 unsafe