Mark the FunctionCall/ResultContent.Exception properties as [JsonIgnore]

Given implementation details of the JSON source generator today, even with the converter applied to these properties, code is still being generated for Exception, leading to unsuppressable trimmer warnings.

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionCallContent.cs

@@ -49,11 +49,11 @@ public FunctionCallContent(string callId, string name, IDictionary<string, objec
     /// Gets or sets any exception that occurred while mapping the original function call data to this class.
     /// </summary>
     /// <remarks>
-    /// When an instance of <see cref="FunctionCallContent"/> is serialized using <see cref="JsonSerializer"/>, any exception
-    /// stored in this property will be serialized as a string. When deserialized, the string will be converted back to an instance
-    /// of the base <see cref="Exception"/> type. As such, consumers shouldn't rely on the exact type of the exception stored in this property.
+    /// This property is for information purposes only. The <see cref="Exception"/> is not serialized as part of serializing
+    /// instances of this class with <see cref="JsonSerializer"/>; as such, upon deserialization, this property will be <see langword="null"/>.
+    /// Consumers should not rely on <see langword="null"/> indicating success. 
     /// </remarks>
-    [JsonConverter(typeof(FunctionCallExceptionConverter))]
+    [JsonIgnore]
     public Exception? Exception { get; set; }
 
     /// <summary>Gets a string representing this instance to display in the debugger.</summary>

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionResultContent.cs

@@ -20,25 +20,30 @@ public sealed class FunctionResultContent : AIContent
     /// </summary>
     /// <param name="callId">The function call ID for which this is the result.</param>
     /// <param name="name">The function name that produced the result.</param>
-    /// <param name="result">The function call result.</param>
-    /// <param name="exception">Any exception that occurred when invoking the function.</param>
+    /// <param name="result">
+    /// This may be <see langword="null"/> if the function returned <see langword="null"/>, if the function was void-returning
+    /// and thus had no result, or if the function call failed. Typically, however, in order to provide meaningfully representative
+    /// information to an AI service, a human-readable representation of those conditions should be supplied.
+    /// </param>
     [JsonConstructor]
-    public FunctionResultContent(string callId, string name, object? result = null, Exception? exception = null)
+    public FunctionResultContent(string callId, string name, object? result)
     {
         CallId = Throw.IfNull(callId);
         Name = Throw.IfNull(name);
         Result = result;
-        Exception = exception;
     }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="FunctionResultContent"/> class.
     /// </summary>
     /// <param name="functionCall">The function call for which this is the result.</param>
-    /// <param name="result">The function call result.</param>
-    /// <param name="exception">Any exception that occurred when invoking the function.</param>
-    public FunctionResultContent(FunctionCallContent functionCall, object? result = null, Exception? exception = null)
-        : this(Throw.IfNull(functionCall).CallId, functionCall.Name, result, exception)
+    /// <param name="result">
+    /// This may be <see langword="null"/> if the function returned <see langword="null"/>, if the function was void-returning
+    /// and thus had no result, or if the function call failed. Typically, however, in order to provide meaningfully representative
+    /// information to an AI service, a human-readable representation of those conditions should be supplied.
+    /// </param>
+    public FunctionResultContent(FunctionCallContent functionCall, object? result)
+        : this(Throw.IfNull(functionCall).CallId, functionCall.Name, result)
     {
     }
 
@@ -59,17 +64,22 @@ public FunctionResultContent(FunctionCallContent functionCall, object? result =
     /// <summary>
     /// Gets or sets the result of the function call, or a generic error message if the function call failed.
     /// </summary>
+    /// <remarks>
+    /// This may be <see langword="null"/> if the function returned <see langword="null"/>, if the function was void-returning
+    /// and thus had no result, or if the function call failed. Typically, however, in order to provide meaningfully representative
+    /// information to an AI service, a human-readable representation of those conditions should be supplied.
+    /// </remarks>
     public object? Result { get; set; }
 
     /// <summary>
     /// Gets or sets an exception that occurred if the function call failed.
     /// </summary>
     /// <remarks>
-    /// When an instance of <see cref="FunctionResultContent"/> is serialized using <see cref="JsonSerializer"/>, any exception
-    /// stored in this property will be serialized as a string. When deserialized, the string will be converted back to an instance
-    /// of the base <see cref="Exception"/> type. As such, consumers shouldn't rely on the exact type of the exception stored in this property.
+    /// This property is for information purposes only. The <see cref="Exception"/> is not serialized as part of serializing
+    /// instances of this class with <see cref="JsonSerializer"/>; as such, upon deserialization, this property will be <see langword="null"/>.
+    /// Consumers should not rely on <see langword="null"/> indicating success. 
     /// </remarks>
-    [JsonConverter(typeof(FunctionCallExceptionConverter))]
+    [JsonIgnore]
     public Exception? Exception { get; set; }
 
     /// <summary>Gets a string representing this instance to display in the debugger.</summary>

src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs

@@ -521,7 +521,7 @@ FunctionResultContent CreateFunctionResultContent(FunctionInvocationResult resul
                 functionResult = message;
             }
 
-            return new FunctionResultContent(result.CallContent.CallId, result.CallContent.Name, functionResult, result.Exception);
+            return new(result.CallContent.CallId, result.CallContent.Name, functionResult) { Exception = result.Exception };
         }
     }
 

src/Libraries/Microsoft.Extensions.AI/JsonDefaults.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using System.Text.Json.Serialization.Metadata;
@@ -16,6 +17,8 @@ internal static partial class JsonDefaults
     public static JsonSerializerOptions Options { get; } = CreateDefaultOptions();
 
     /// <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 CreateDefaultOptions()
     {
         // If reflection-based serialization is enabled by default, use it, as it's the most permissive in terms of what it can serialize,
@@ -28,9 +31,7 @@ private static JsonSerializerOptions CreateDefaultOptions()
             var options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
             {
                 DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
-#pragma warning disable IL3050, IL2026 // only used when reflection-based serialization is enabled
                 TypeInfoResolver = new DefaultJsonTypeInfoResolver(),
-#pragma warning restore IL3050, IL2026
             };
 
             options.MakeReadOnly();

src/Libraries/Microsoft.Extensions.AI/Microsoft.Extensions.AI.csproj

@@ -18,11 +18,6 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <!-- TEMPORARY UNTIL JSON SOURCE GENERATOR ISSUE CAN BE SORTED OUT -->
-    <NoWarn>$(NoWarn);IL2026</NoWarn>
-  </PropertyGroup>
-
   <PropertyGroup>
     <InjectSharedCollectionExtensions>true</InjectSharedCollectionExtensions>
     <InjectSharedEmptyCollections>true</InjectSharedEmptyCollections>

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests..cs

@@ -5,9 +5,6 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
-#if NET
-using System.Runtime.ExceptionServices;
-#endif
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using System.Threading;
@@ -84,48 +81,6 @@ public void Constructor_PropsRoundtrip()
         Assert.Same(e, c.Exception);
     }
 
-    [Fact]
-    public void ItShouldBeSerializableAndDeserializableWithException()
-    {
-        // Arrange
-        var ex = new InvalidOperationException("hello", new NullReferenceException("bye"));
-#if NET
-        ExceptionDispatchInfo.SetRemoteStackTrace(ex, "stack trace");
-#endif
-        var sut = new FunctionCallContent("callId1", "functionName") { Exception = ex };
-
-        // Act
-        var json = JsonSerializer.SerializeToNode(sut, TestJsonSerializerContext.Default.Options);
-        var deserializedSut = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
-
-        // Assert
-        JsonObject jsonEx = Assert.IsType<JsonObject>(json!["exception"]);
-        Assert.Equal(4, jsonEx.Count);
-        Assert.Equal("System.InvalidOperationException", (string?)jsonEx["className"]);
-        Assert.Equal("hello", (string?)jsonEx["message"]);
-#if NET
-        Assert.StartsWith("stack trace", (string?)jsonEx["stackTraceString"]);
-#endif
-        JsonObject jsonExInner = Assert.IsType<JsonObject>(jsonEx["innerException"]);
-        Assert.Equal(4, jsonExInner.Count);
-        Assert.Equal("System.NullReferenceException", (string?)jsonExInner["className"]);
-        Assert.Equal("bye", (string?)jsonExInner["message"]);
-        Assert.Null(jsonExInner["innerException"]);
-        Assert.Null(jsonExInner["stackTraceString"]);
-
-        Assert.NotNull(deserializedSut);
-        Assert.IsType<Exception>(deserializedSut.Exception);
-        Assert.Equal("hello", deserializedSut.Exception.Message);
-#if NET
-        Assert.StartsWith("stack trace", deserializedSut.Exception.StackTrace);
-#endif
-
-        Assert.IsType<Exception>(deserializedSut.Exception.InnerException);
-        Assert.Equal("bye", deserializedSut.Exception.InnerException.Message);
-        Assert.Null(deserializedSut.Exception.InnerException.StackTrace);
-        Assert.Null(deserializedSut.Exception.InnerException.InnerException);
-    }
-
     [Fact]
     public async Task AIFunctionFactory_ObjectValues_Converted()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionResultContentTests.cs

@@ -12,7 +12,7 @@ public class FunctionResultContentTests
     [Fact]
     public void Constructor_PropsDefault()
     {
-        FunctionResultContent c = new("callId1", "functionName");
+        FunctionResultContent c = new("callId1", "functionName", null);
         Assert.Equal("callId1", c.CallId);
         Assert.Equal("functionName", c.Name);
         Assert.Null(c.RawRepresentation);
@@ -25,36 +25,32 @@ public void Constructor_PropsDefault()
     [Fact]
     public void Constructor_String_PropsRoundtrip()
     {
-        Exception e = new();
-
-        FunctionResultContent c = new("id", "name", "result", e);
+        FunctionResultContent c = new("id", "name", "result");
         Assert.Null(c.RawRepresentation);
         Assert.Null(c.ModelId);
         Assert.Null(c.AdditionalProperties);
         Assert.Equal("name", c.Name);
         Assert.Equal("id", c.CallId);
         Assert.Equal("result", c.Result);
-        Assert.Same(e, c.Exception);
+        Assert.Null(c.Exception);
     }
 
     [Fact]
     public void Constructor_FunctionCallContent_PropsRoundtrip()
     {
-        Exception e = new();
-
-        FunctionResultContent c = new(new FunctionCallContent("id", "name"), "result", e);
+        FunctionResultContent c = new(new FunctionCallContent("id", "name"), "result");
         Assert.Null(c.RawRepresentation);
         Assert.Null(c.ModelId);
         Assert.Null(c.AdditionalProperties);
         Assert.Equal("id", c.CallId);
         Assert.Equal("result", c.Result);
-        Assert.Same(e, c.Exception);
+        Assert.Null(c.Exception);
     }
 
     [Fact]
     public void Constructor_PropsRoundtrip()
     {
-        FunctionResultContent c = new("callId1", "functionName");
+        FunctionResultContent c = new("callId1", "functionName", null);
 
         Assert.Null(c.RawRepresentation);
         object raw = new();
@@ -101,20 +97,4 @@ public void ItShouldBeSerializableAndDeserializable()
         Assert.Equal(sut.CallId, deserializedSut.CallId);
         Assert.Equal(sut.Result, deserializedSut.Result?.ToString());
     }
-
-    [Fact]
-    public void ItShouldBeSerializableAndDeserializableWithException()
-    {
-        // Arrange
-        var sut = new FunctionResultContent("callId1", "functionName") { Exception = new InvalidOperationException("hello") };
-
-        // Act
-        var json = JsonSerializer.Serialize(sut, TestJsonSerializerContext.Default.Options);
-        var deserializedSut = JsonSerializer.Deserialize<FunctionResultContent>(json, TestJsonSerializerContext.Default.Options);
-
-        // Assert
-        Assert.NotNull(deserializedSut);
-        Assert.IsType<Exception>(deserializedSut.Exception);
-        Assert.Contains("hello", deserializedSut.Exception.Message);
-    }
 }