Add NativeAOT testapp project for M.E.AI (#5573)

* Add NativeAOT testapp project for M.E.AI

* Address PR feedback

src/Libraries/Microsoft.Extensions.AI.AzureAIInference/JsonContext.cs

@@ -48,11 +48,11 @@ private static JsonSerializerOptions CreateDefaultToolJsonOptions()
     {
         // If reflection-based serialization is enabled by default, use it, as it's the most permissive in terms of what it can serialize,
         // and we want to be flexible in terms of what can be put into the various collections in the object model.
-        // Otherwise, use the source-generated options to enable Native AOT.
+        // Otherwise, use the source-generated options to enable trimming and Native AOT.
 
         if (JsonSerializer.IsReflectionEnabledByDefault)
         {
-            // Keep in sync with the JsonSourceGenerationOptions on JsonContext below.
+            // Keep in sync with the JsonSourceGenerationOptions attribute on JsonContext above.
             JsonSerializerOptions options = new(JsonSerializerDefaults.Web)
             {
                 TypeInfoResolver = new DefaultJsonTypeInfoResolver(),

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs

@@ -3,11 +3,13 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.Json;
 using System.Text.Json.Serialization;
+using System.Text.Json.Serialization.Metadata;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Shared.Diagnostics;
@@ -587,10 +589,9 @@ private sealed class OpenAIChatToolJson
                         string? result = resultContent.Result as string;
                         if (result is null && resultContent.Result is not null)
                         {
-                            JsonSerializerOptions options = ToolCallJsonSerializerOptions ?? JsonContext.Default.Options;
                             try
                             {
-                                result = JsonSerializer.Serialize(resultContent.Result, options.GetTypeInfo(typeof(object)));
+                                result = JsonSerializer.Serialize(resultContent.Result, JsonContext.GetTypeInfo(typeof(object), ToolCallJsonSerializerOptions));
                             }
                             catch (NotSupportedException)
                             {
@@ -617,7 +618,9 @@ private sealed class OpenAIChatToolJson
                             ChatToolCall.CreateFunctionToolCall(
                                 callRequest.CallId,
                                 callRequest.Name,
-                                BinaryData.FromObjectAsJson(callRequest.Arguments, ToolCallJsonSerializerOptions)));
+                                new(JsonSerializer.SerializeToUtf8Bytes(
+                                    callRequest.Arguments,
+                                    JsonContext.GetTypeInfo(typeof(IDictionary<string, object?>), ToolCallJsonSerializerOptions)))));
                     }
                 }
 
@@ -670,8 +673,53 @@ private static FunctionCallContent ParseCallContentFromBinaryData(BinaryData ut8
             argumentParser: static json => JsonSerializer.Deserialize(json, JsonContext.Default.IDictionaryStringObject)!);
 
     /// <summary>Source-generated JSON type information.</summary>
+    [JsonSourceGenerationOptions(JsonSerializerDefaults.Web,
+        UseStringEnumConverter = true,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+        WriteIndented = true)]
     [JsonSerializable(typeof(OpenAIChatToolJson))]
     [JsonSerializable(typeof(IDictionary<string, object?>))]
     [JsonSerializable(typeof(JsonElement))]
-    private sealed partial class JsonContext : JsonSerializerContext;
+    private sealed partial class JsonContext : JsonSerializerContext
+    {
+        /// <summary>Gets the <see cref="JsonSerializerOptions"/> singleton used as the default in JSON serialization operations.</summary>
+        private static readonly JsonSerializerOptions _defaultToolJsonOptions = CreateDefaultToolJsonOptions();
+
+        /// <summary>Gets JSON type information for the specified type.</summary>
+        /// <remarks>
+        /// This first tries to get the type information from <paramref name="firstOptions"/>,
+        /// falling back to <see cref="_defaultToolJsonOptions"/> if it can't.
+        /// </remarks>
+        public static JsonTypeInfo GetTypeInfo(Type type, JsonSerializerOptions? firstOptions) =>
+            firstOptions?.TryGetTypeInfo(type, out JsonTypeInfo? info) is true ?
+                info :
+                _defaultToolJsonOptions.GetTypeInfo(type);
+
+        /// <summary>Creates the default <see cref="JsonSerializerOptions"/> to use for serialization-related operations.</summary>
+        [UnconditionalSuppressMessage("AotAnalysis", "IL3050", Justification = "DefaultJsonTypeInfoResolver is only used when reflection-based serialization is enabled")]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026", Justification = "DefaultJsonTypeInfoResolver is only used when reflection-based serialization is enabled")]
+        private static JsonSerializerOptions CreateDefaultToolJsonOptions()
+        {
+            // If reflection-based serialization is enabled by default, use it, as it's the most permissive in terms of what it can serialize,
+            // and we want to be flexible in terms of what can be put into the various collections in the object model.
+            // Otherwise, use the source-generated options to enable trimming and Native AOT.
+
+            if (JsonSerializer.IsReflectionEnabledByDefault)
+            {
+                // Keep in sync with the JsonSourceGenerationOptions attribute on JsonContext above.
+                JsonSerializerOptions options = new(JsonSerializerDefaults.Web)
+                {
+                    TypeInfoResolver = new DefaultJsonTypeInfoResolver(),
+                    Converters = { new JsonStringEnumConverter() },
+                    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+                    WriteIndented = true,
+                };
+
+                options.MakeReadOnly();
+                return options;
+            }
+
+            return Default.Options;
+        }
+    }
 }

src/Libraries/Microsoft.Extensions.AI/Utilities/AIJsonUtilities.Defaults.cs

@@ -23,11 +23,11 @@ private static JsonSerializerOptions CreateDefaultOptions()
     {
         // If reflection-based serialization is enabled by default, use it, as it's the most permissive in terms of what it can serialize,
         // and we want to be flexible in terms of what can be put into the various collections in the object model.
-        // Otherwise, use the source-generated options to enable Native AOT.
+        // Otherwise, use the source-generated options to enable trimming and Native AOT.
 
         if (JsonSerializer.IsReflectionEnabledByDefault)
         {
-            // Keep in sync with the JsonSourceGenerationOptions on JsonContext below.
+            // Keep in sync with the JsonSourceGenerationOptions attribute on JsonContext below.
             JsonSerializerOptions options = new(JsonSerializerDefaults.Web)
             {
                 TypeInfoResolver = new DefaultJsonTypeInfoResolver(),

test/Libraries/Microsoft.Extensions.AI.AotCompatibility.TestApp/Microsoft.Extensions.AI.AotCompatibility.TestApp.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>$(LatestTargetFramework)</TargetFrameworks>
+    <PublishAot>true</PublishAot>
+    <TrimmerSingleWarn>false</TrimmerSingleWarn>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <TrimmerRootAssembly Include="Microsoft.Extensions.AI" />
+    <TrimmerRootAssembly Include="Microsoft.Extensions.AI.Abstractions" />
+    <TrimmerRootAssembly Include="Microsoft.Extensions.AI.Ollama" />
+    <!-- Azure.AI.Inference produces many warnings
+    <TrimmerRootAssembly Include="Microsoft.Extensions.AI.AzureAIInference" />
+    -->
+    <!-- OpenAI produces a few warnings
+    <TrimmerRootAssembly Include="Microsoft.Extensions.AI.OpenAI" />
+    -->
+
+    <TrimmerRootAssembly Update="@(TrimmerRootAssembly)" Path="$(RepoRoot)\src\Libraries\%(Identity)\%(Identity).csproj" />
+    <ProjectReference Include="@(TrimmerRootAssembly->'%(Path)')" />
+  </ItemGroup>
+
+</Project>

test/Libraries/Microsoft.Extensions.AI.AotCompatibility.TestApp/Program.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#pragma warning disable S125 // Remove this commented out code
+
+using Microsoft.Extensions.AI;
+
+// Use types from each library.
+
+// Microsoft.Extensions.AI.Ollama
+using var b = new OllamaChatClient("http://localhost:11434", "llama3.2");
+
+// Microsoft.Extensions.AI.AzureAIInference
+// using var a = new Azure.AI.Inference.ChatCompletionClient(new Uri("http://localhost"), new("apikey")); // uncomment once warnings in Azure.AI.Inference are addressed
+
+// Microsoft.Extensions.AI.OpenAI
+// using var c = new OpenAI.OpenAIClient("apikey").AsChatClient("gpt-4o-mini"); // uncomment once warnings in OpenAI are addressed
+
+// Microsoft.Extensions.AI
+AIFunctionFactory.Create(() => { });
+
+System.Console.WriteLine("Success!");