Use ErrorContent in OpenAIResponseChatClient (#6231)

* Use ErrorContent in OpenAIResponseChatClient

* Address feedback

Author: stephentoub

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

@@ -2,8 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
-using System.Text.Json.Serialization;
-using Microsoft.Shared.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.Extensions.AI;
 
@@ -16,33 +15,33 @@ namespace Microsoft.Extensions.AI;
 public class ErrorContent : AIContent
 {
     /// <summary>The error message.</summary>
-    private string _message;
+    private string? _message;
 
-    /// <summary>Initializes a new instance of the <see cref="ErrorContent"/> class with the specified message.</summary>
-    /// <param name="message">The message to store in this content.</param>
-    [JsonConstructor]
-    public ErrorContent(string message)
+    /// <summary>Initializes a new instance of the <see cref="ErrorContent"/> class with the specified error message.</summary>
+    /// <param name="message">The error message to store in this content.</param>
+    public ErrorContent(string? message)
     {
-        _message = Throw.IfNull(message);
+        _message = message;
     }
 
     /// <summary>Gets or sets the error message.</summary>
+    [AllowNull]
     public string Message
     {
-        get => _message;
-        set => _message = Throw.IfNull(value);
+        get => _message ?? string.Empty;
+        set => _message = value;
     }
 
-    /// <summary>Gets or sets the error code.</summary>
+    /// <summary>Gets or sets an error code associated with the error.</summary>
     public string? ErrorCode { get; set; }
 
-    /// <summary>Gets or sets the error details.</summary>
+    /// <summary>Gets or sets additional details about the error.</summary>
     public string? Details { get; set; }
 
     /// <summary>Gets a string representing this instance to display in the debugger.</summary>
     [DebuggerBrowsable(DebuggerBrowsableState.Never)]
     private string DebuggerDisplay =>
-        $"Error = {Message}" +
-        (ErrorCode is not null ? $" ({ErrorCode})" : string.Empty) +
-        (Details is not null ? $" - {Details}" : string.Empty);
+        $"Error = \"{Message}\"" +
+        (!string.IsNullOrWhiteSpace(ErrorCode) ? $" ({ErrorCode})" : string.Empty) +
+        (!string.IsNullOrWhiteSpace(Details) ? $" - \"{Details}\"" : string.Empty);
 }

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

@@ -132,6 +132,11 @@ public async Task<ChatResponse> GetResponseAsync(
                         break;
                 }
             }
+
+            if (openAIResponse.Error is { } error)
+            {
+                message.Contents.Add(new ErrorContent(error.Message) { ErrorCode = error.Code });
+            }
         }
 
         return response;
@@ -246,6 +251,24 @@ public async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(
 
                     break;
                 }
+
+                case StreamingResponseErrorUpdate errorUpdate:
+                    yield return new ChatResponseUpdate
+                    {
+                        CreatedAt = createdAt,
+                        MessageId = lastMessageId,
+                        ModelId = modelId,
+                        ResponseId = responseId,
+                        Contents =
+                        [
+                            new ErrorContent(errorUpdate.Message)
+                            {
+                                ErrorCode = errorUpdate.Code,
+                                Details = errorUpdate.Param,
+                            }
+                        ],
+                    };
+                    break;
             }
         }
     }

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

@@ -8,6 +8,19 @@ namespace Microsoft.Extensions.AI;
 
 public class ErrorContentTests
 {
+    [Fact]
+    public void Constructor_NormalizesNullToEmpty()
+    {
+        ErrorContent content = new(null!);
+        Assert.Empty(content.Message);
+
+        content.Message = "test";
+        Assert.Equal("test", content.Message);
+
+        content.Message = null!;
+        Assert.Empty(content.Message);
+    }
+
     [Fact]
     public void Constructor_ShouldInitializeProperties()
     {