OpenAI function calling broken since 3.19.0

[garraflavatra]

Hi, it seems that since v3.19.0, the function parameter chunks fetched using the completions API of the synchronous OpenAI API wrapper with stream=True are duplicated, resulting in invalid JSON, e.g. {"{"processprocess_id_id":2}:2} instead of just {"process_id":2}. The "normal" responses work fine though.

I use the following logic to concatenate the chunks, which worked before v3.19.0:

final_tool_calls = {}

for chunk in response:
    delta = chunk.choices[0].delta

    if delta.tool_calls:
        for tool_call in delta.tool_calls:
            index = tool_call.index

            if index not in final_tool_calls:
                final_tool_calls[index] = tool_call

            final_tool_calls[index].function.arguments += tool_call.function.arguments

I suppose the following line causes the issue. It does exactly the same as my code, including manipulating the original function object. Maybe that should be cloned first?

posthog-python/posthog/ai/openai/openai.py

Line 139 in 8331af7

accumulated_tools[index].function.arguments += tool_call.function.arguments