.Net: OpenAI V2 Bugfix for Streaming Asynchronous Filter Results (#8422)

### Motivation and Context

Resolve #8407
 
### Description

Add temporary bugfix for error described in below issues:

- #8407
- openai/openai-dotnet#198
- Added UnitTest to ensure expected behavior.

### Contribution Checklist

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

dotnet/src/Connectors/Connectors.AzureOpenAI.UnitTests/Services/AzureOpenAIChatCompletionServiceTests.cs

@@ -415,6 +415,66 @@ public async Task GetStreamingTextContentsWorksCorrectlyAsync()
         Assert.Equal("Stop", enumerator.Current.Metadata?["FinishReason"]);
     }
 
+    [Fact]
+    public async Task GetStreamingChatContentsWithAsynchronousFilterWorksCorrectlyAsync()
+    {
+        // Arrange
+        var service = new AzureOpenAIChatCompletionService("deployment", "https://endpoint", "api-key", "model-id", this._httpClient);
+        using var stream = new MemoryStream(Encoding.UTF8.GetBytes(AzureOpenAITestHelper.GetTestResponse("chat_completion_streaming_async_filter_response.txt")));
+
+        this._messageHandlerStub.ResponsesToReturn.Add(new HttpResponseMessage(HttpStatusCode.OK)
+        {
+            Content = new StreamContent(stream)
+        });
+
+        // Act & Assert
+        var enumerator = service.GetStreamingChatMessageContentsAsync("Prompt").GetAsyncEnumerator();
+
+#pragma warning disable AOAI001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        await enumerator.MoveNextAsync();
+        var message = enumerator.Current;
+
+        Assert.IsType<StreamingChatCompletionUpdate>(message.InnerContent);
+        var update = (StreamingChatCompletionUpdate)message.InnerContent;
+        var promptResults = update.GetContentFilterResultForPrompt();
+        Assert.Equal(ContentFilterSeverity.Safe, promptResults.Hate.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, promptResults.Sexual.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, promptResults.Violence.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, promptResults.SelfHarm.Severity);
+        Assert.False(promptResults.Jailbreak.Detected);
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+
+        Assert.IsType<StreamingChatCompletionUpdate>(message.InnerContent);
+        update = (StreamingChatCompletionUpdate)message.InnerContent;
+
+        var filterResults = update.GetContentFilterResultForResponse();
+        Assert.Equal(ContentFilterSeverity.Safe, filterResults.Hate.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, filterResults.Sexual.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, filterResults.SelfHarm.Severity);
+        Assert.Equal(ContentFilterSeverity.Safe, filterResults.Violence.Severity);
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+
+        Assert.IsType<StreamingChatCompletionUpdate>(message.InnerContent);
+        update = (StreamingChatCompletionUpdate)message.InnerContent;
+        filterResults = update.GetContentFilterResultForResponse();
+        Assert.False(filterResults.ProtectedMaterialCode.Detected);
+        Assert.False(filterResults.ProtectedMaterialText.Detected);
+#pragma warning restore AOAI001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+    }
+
     [Fact]
     public async Task GetStreamingChatMessageContentsWorksCorrectlyAsync()
     {

dotnet/src/Connectors/Connectors.AzureOpenAI.UnitTests/TestData/chat_completion_streaming_async_filter_response.txt

@@ -0,0 +1,13 @@
+data: {"choices":[],"created":0,"id":"","model":"","object":"","prompt_filter_results":[{"prompt_index":0,"content_filter_results":{"hate":{"filtered":false,"severity":"safe"},"jailbreak":{"filtered":false,"detected":false},"self_harm":{"filtered":false,"severity":"safe"},"sexual":{"filtered":false,"severity":"safe"},"violence":{"filtered":false,"severity":"safe"}}}]}
+
+data: {"choices":[{"delta":{"content":"","role":"assistant"},"finish_reason":null,"index":0,"logprobs":null}],"created":1724860848,"id":"chatcmpl-123","model":"gpt-4o-2024-05-13","object":"chat.completion.chunk","system_fingerprint":"fp_abc28019ad"}
+
+data: {"choices":[{"delta":{"content":"Kindness"},"finish_reason":null,"index":0,"logprobs":null}],"created":1724860848,"id":"chatcmpl-123","model":"gpt-4o-2024-05-13","object":"chat.completion.chunk","system_fingerprint":"fp_abc28019ad"}
+
+data: {"choices":[{"delta":{},"finish_reason":"stop","index":0,"logprobs":null}],"created":1724860848,"id":"chatcmpl-123","model":"gpt-4o-2024-05-13","object":"chat.completion.chunk","system_fingerprint":"fp_abc28019ad"}
+
+data: {"choices":[{"content_filter_offsets":{"check_offset":1576,"start_offset":1576,"end_offset":2318},"content_filter_results":{"hate":{"filtered":false,"severity":"safe"},"self_harm":{"filtered":false,"severity":"safe"},"sexual":{"filtered":false,"severity":"safe"},"violence":{"filtered":false,"severity":"safe"}},"finish_reason":null,"index":0}],"created":0,"id":"","model":"","object":""}
+
+data: {"choices":[{"content_filter_offsets":{"check_offset":1576,"start_offset":1576,"end_offset":2318},"content_filter_results":{"protected_material_code":{"filtered":false,"detected":false},"protected_material_text":{"filtered":false,"detected":false}},"finish_reason":null,"index":0}],"created":0,"id":"","model":"","object":""}
+
+data: [DONE]

dotnet/src/Connectors/Connectors.OpenAI/Core/ClientCore.ChatCompletion.cs

@@ -416,24 +416,26 @@ internal async IAsyncEnumerable<OpenAIStreamingChatMessageContent> GetStreamingC
 
                         var openAIStreamingChatMessageContent = new OpenAIStreamingChatMessageContent(chatCompletionUpdate, 0, targetModel, metadata);
 
-                        foreach (var functionCallUpdate in chatCompletionUpdate.ToolCallUpdates)
+                        if (openAIStreamingChatMessageContent.ToolCallUpdates is not null)
                         {
-                            // Using the code below to distinguish and skip non - function call related updates.
-                            // The Kind property of updates can't be reliably used because it's only initialized for the first update.
-                            if (string.IsNullOrEmpty(functionCallUpdate.Id) &&
-                                string.IsNullOrEmpty(functionCallUpdate.FunctionName) &&
-                                string.IsNullOrEmpty(functionCallUpdate.FunctionArgumentsUpdate))
+                            foreach (var functionCallUpdate in openAIStreamingChatMessageContent.ToolCallUpdates!)
                             {
-                                continue;
-                            }
+                                // Using the code below to distinguish and skip non - function call related updates.
+                                // The Kind property of updates can't be reliably used because it's only initialized for the first update.
+                                if (string.IsNullOrEmpty(functionCallUpdate.Id) &&
+                                    string.IsNullOrEmpty(functionCallUpdate.FunctionName) &&
+                                    string.IsNullOrEmpty(functionCallUpdate.FunctionArgumentsUpdate))
+                                {
+                                    continue;
+                                }
 
-                            openAIStreamingChatMessageContent.Items.Add(new StreamingFunctionCallUpdateContent(
-                                callId: functionCallUpdate.Id,
-                                name: functionCallUpdate.FunctionName,
-                                arguments: functionCallUpdate.FunctionArgumentsUpdate,
-                                functionCallIndex: functionCallUpdate.Index));
+                                openAIStreamingChatMessageContent.Items.Add(new StreamingFunctionCallUpdateContent(
+                                    callId: functionCallUpdate.Id,
+                                    name: functionCallUpdate.FunctionName,
+                                    arguments: functionCallUpdate.FunctionArgumentsUpdate,
+                                    functionCallIndex: functionCallUpdate.Index));
+                            }
                         }
-
                         streamedContents?.Add(openAIStreamingChatMessageContent);
                         yield return openAIStreamingChatMessageContent;
                     }

dotnet/src/Connectors/Connectors.OpenAI/Core/OpenAIStreamingChatMessageContent.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using System.Text;
 using Microsoft.SemanticKernel.ChatCompletion;
@@ -33,17 +34,38 @@ internal OpenAIStreamingChatMessageContent(
         string modelId,
         IReadOnlyDictionary<string, object?>? metadata = null)
         : base(
-            chatUpdate.Role.HasValue ? new AuthorRole(chatUpdate.Role.Value.ToString()) : null,
+            null,
             null,
             chatUpdate,
             choiceIndex,
             modelId,
             Encoding.UTF8,
             metadata)
     {
-        this.ToolCallUpdates = chatUpdate.ToolCallUpdates;
-        this.FinishReason = chatUpdate.FinishReason;
-        this.Items = CreateContentItems(chatUpdate.ContentUpdate);
+        try
+        {
+            this.FinishReason = chatUpdate.FinishReason;
+
+            if (chatUpdate.Role.HasValue)
+            {
+                this.Role = new AuthorRole(chatUpdate.Role.ToString()!);
+            }
+
+            if (chatUpdate.ToolCallUpdates is not null)
+            {
+                this.ToolCallUpdates = chatUpdate.ToolCallUpdates;
+            }
+
+            if (chatUpdate.ContentUpdate is not null)
+            {
+                this.Items = CreateContentItems(chatUpdate.ContentUpdate);
+            }
+        }
+        catch (NullReferenceException)
+        {
+            // Temporary bugfix for: https://github.com/openai/openai-dotnet/issues/198
+            // TODO: Remove this try-catch block once the bug is fixed.
+        }
     }
 
     /// <summary>