[Bug] GPT request failed: Error code: 400 - Cannot read properties of null (reading 'type')

运行环境：

OS: Debian GNU/Linux forky/sid (forky) x86_64
Kernel: Linux 6.19.10+deb14-amd64
CPU: Intel(R) Xeon(R) E5-2680 v4 (28) @ 3.30 GHz
GPU: AMD Radeon RX 590 GME [Discrete]

问题描述：

使用videoLingo调用LM-Studio-0.4.9-1-x64本地运行gemma-4-e4b-it的api服务时出现

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 5/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 6/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 1/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 1/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 2/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 3/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 4/5

GPT request failed: Error code: 400 - {'error': "Cannot read properties of null (reading 'type')"}, retry: 5/5 

lm_studio的日志：
2026-04-04 18:37:33 [DEBUG]

Received request: POST to /v1/chat/completions with body  {

"messages": [

{

"role": "user",

"content": "This is a test, response 'message':'success' in json format."

}

],

"model": "gemma-4-e4b-it",

"response_format": null

} 

发现lm_studio不能处理response_format为null的请求。
core/utils/ask_gpt.py中第60行
response_format = {"type": "json_object"} if resp_type == "json" and load_key("api.llm_support_json") else None
不满足条件时response_format就会变成null,导致400错误。

可能的解决办法：

动态构建 params 字典，不满足条件时，不应包含response_format字段。

Start in core/utils/ask_gpt.py around line 60 and inspect how the request parameters are assembled. Reproduce the request with LM Studio using the reported configuration, then verify that requests sent without JSON response support omit response_format rather than sending it as null.