.Net: AzureOpenAI Connector - Bugfix AsyncFilter Null Reference Excep…

…tion when using Function Calling. (#8654)

### Motivation and Context

Closes #8629 

Workaround BugFix for issue in OpenAI SDK:

- openai/openai-dotnet#198

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

@@ -544,6 +544,98 @@ public async Task GetStreamingChatMessageContentsWithFunctionCallAsync()
         Assert.Equal(2, functionCallCount);
     }
 
+    [Fact]
+    public async Task GetStreamingChatMessageContentsWithFunctionCallAsyncFilterAsync()
+    {
+        // Arrange
+        int functionCallCount = 0;
+
+        var kernel = Kernel.CreateBuilder().Build();
+        var function1 = KernelFunctionFactory.CreateFromMethod((string location) =>
+        {
+            functionCallCount++;
+            return "Some weather";
+        }, "GetCurrentWeather");
+
+        var function2 = KernelFunctionFactory.CreateFromMethod((string argument) =>
+        {
+            functionCallCount++;
+            throw new ArgumentException("Some exception");
+        }, "FunctionWithException");
+
+        kernel.Plugins.Add(KernelPluginFactory.CreateFromFunctions("MyPlugin", [function1, function2]));
+
+        var service = new AzureOpenAIChatCompletionService("deployment", "https://endpoint", "api-key", "model-id", this._httpClient, this._mockLoggerFactory.Object);
+        var settings = new AzureOpenAIPromptExecutionSettings() { ToolCallBehavior = ToolCallBehavior.AutoInvokeKernelFunctions };
+
+        using var response1 = new HttpResponseMessage(HttpStatusCode.OK) { Content = AzureOpenAITestHelper.GetTestResponseAsStream("chat_completion_streaming_multiple_function_calls_test_async_filter_response.txt") };
+        using var response2 = new HttpResponseMessage(HttpStatusCode.OK) { Content = AzureOpenAITestHelper.GetTestResponseAsStream("chat_completion_streaming_test_response.txt") };
+
+        this._messageHandlerStub.ResponsesToReturn = [response1, response2];
+
+        // Act & Assert
+        var enumerator = service.GetStreamingChatMessageContentsAsync([], settings, kernel).GetAsyncEnumerator();
+        await enumerator.MoveNextAsync();
+        var message = enumerator.Current;
+
+        Assert.IsType<StreamingChatCompletionUpdate>(message.InnerContent);
+        var update = (StreamingChatCompletionUpdate)message.InnerContent;
+#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.
+        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;
+        Assert.Equal("Test chat streaming response", message.Content);
+        Assert.Equal("ToolCalls", message.Metadata?["FinishReason"]);
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+        Assert.Equal("ToolCalls", message.Metadata?["FinishReason"]);
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+        Assert.Equal("ToolCalls", message.Metadata?["FinishReason"]);
+
+        await enumerator.MoveNextAsync();
+        message = enumerator.Current;
+        Assert.Equal("ToolCalls", message.Metadata?["FinishReason"]);
+
+        // Async Filter Final Chunks
+        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);
+
+        // Keep looping until the end of stream
+        while (await enumerator.MoveNextAsync())
+        {
+        }
+
+        Assert.Equal(2, functionCallCount);
+#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 GetStreamingChatMessageContentsWithFunctionCallMaximumAutoInvokeAttemptsAsync()
     {

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

@@ -0,0 +1,15 @@
+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: {"id":"response-id","object":"chat.completion.chunk","created":1704212243,"model":"gpt-4","system_fingerprint":null,"choices":[{"index":0,"delta":{"role":"assistant","content":"Test chat streaming response","tool_calls":[{"index":0,"id":"1","type":"function","function":{"name":"MyPlugin-GetCurrentWeather","arguments":"{\n\"location\": \"Boston, MA\"\n}"}}]},"finish_reason":"tool_calls"}]}
+
+data: {"id":"response-id","object":"chat.completion.chunk","created":1704212243,"model":"gpt-4","system_fingerprint":null,"choices":[{"index":0,"delta":{"role":"assistant","content":"Test chat streaming response","tool_calls":[{"index":1,"id":"2","type":"function","function":{"name":"MyPlugin-FunctionWithException","arguments":"{\n\"argument\": \"value\"\n}"}}]},"finish_reason":"tool_calls"}]}
+
+data: {"id":"response-id","object":"chat.completion.chunk","created":1704212243,"model":"gpt-4","system_fingerprint":null,"choices":[{"index":0,"delta":{"role":"assistant","content":"Test chat streaming response","tool_calls":[{"index":2,"id":"3","type":"function","function":{"name":"MyPlugin-NonExistentFunction","arguments":"{\n\"argument\": \"value\"\n}"}}]},"finish_reason":"tool_calls"}]}
+
+data: {"id":"response-id","object":"chat.completion.chunk","created":1704212243,"model":"gpt-4","system_fingerprint":null,"choices":[{"index":0,"delta":{"role":"assistant","content":"Test chat streaming response","tool_calls":[{"index":3,"id":"4","type":"function","function":{"name":"MyPlugin-InvalidArguments","arguments":"invalid_arguments_format"}}]},"finish_reason":"tool_calls"}]}
+
+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

@@ -401,15 +401,22 @@ internal async IAsyncEnumerable<OpenAIStreamingChatMessageContent> GetStreamingC
                         // If we're intending to invoke function calls, we need to consume that function call information.
                         if (toolCallingConfig.AutoInvoke)
                         {
-                            foreach (var contentPart in chatCompletionUpdate.ContentUpdate)
+                            try
                             {
-                                if (contentPart.Kind == ChatMessageContentPartKind.Text)
+                                foreach (var contentPart in chatCompletionUpdate.ContentUpdate)
                                 {
-                                    (contentBuilder ??= new()).Append(contentPart.Text);
+                                    if (contentPart.Kind == ChatMessageContentPartKind.Text)
+                                    {
+                                        (contentBuilder ??= new()).Append(contentPart.Text);
+                                    }
                                 }
+                                OpenAIFunctionToolCall.TrackStreamingToolingUpdate(chatCompletionUpdate.ToolCallUpdates, ref toolCallIdsByIndex, ref functionNamesByIndex, ref functionArgumentBuildersByIndex);
+                            }
+                            catch (NullReferenceException)
+                            {
+                                // Temporary workaround for OpenAI SDK Bug here: https://github.com/openai/openai-dotnet/issues/198
+                                // TODO: Remove this try-catch block once the bug is fixed.
                             }
-
-                            OpenAIFunctionToolCall.TrackStreamingToolingUpdate(chatCompletionUpdate.ToolCallUpdates, ref toolCallIdsByIndex, ref functionNamesByIndex, ref functionArgumentBuildersByIndex);
                         }
 
                         var openAIStreamingChatMessageContent = new OpenAIStreamingChatMessageContent(chatCompletionUpdate, 0, targetModel, metadata);

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

@@ -63,7 +63,7 @@ internal OpenAIStreamingChatMessageContent(
         }
         catch (NullReferenceException)
         {
-            // Temporary bugfix for: https://github.com/openai/openai-dotnet/issues/198
+            // Temporary workaround for OpenAI SDK Bug here: https://github.com/openai/openai-dotnet/issues/198
             // TODO: Remove this try-catch block once the bug is fixed.
         }
     }