Nullpointer when using Azure Open AI and streaming

[berjanjonker]

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Bug description While using the AzureOpenAI chat client streaming won't work. It gets into this nullpointer. When I subscribe and print out the .content() Flux; I noticed that the last received token is null.

2025-04-10 17:38:22.611 [http-nio-8080-exec-7] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet].log - Servlet.service() for servlet [dispatcherServlet] threw exception java.lang.NullPointerException: Cannot invoke "com.azure.ai.openai.models.ChatResponseMessage.getToolCalls()" because "responseMessage" is null at org.springframework.ai.azure.openai.AzureOpenAiChatModel.buildGeneration(AzureOpenAiChatModel.java:498) Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: Assembly trace from producer [reactor.core.publisher.FluxMapFuseable] : reactor.core.publisher.Flux.map(Flux.java:6588) org.springframework.ai.azure.openai.AzureOpenAiChatModel.lambda$internalStream$13(AzureOpenAiChatModel.java:381)

Environment Spring-AI 1.0.0-M6 Chat Model: Azure OpenAI

Steps to reproduce chatClient.prompt().user("How are you?").stream().content().doOnEach(data -> System.out.println(data.get()));

//output How can I assist you today ? null

Expected behavior AzureOpenAiChatModel should be null safe or null values should be filtered out.

Minimal Complete Reproducible example See above. When I switch to another vendor like Anthrophic the result is as expected (without a null at the end of the stream)