From 45c00daa1baec019c45e98e2b41f3e26965bddba Mon Sep 17 00:00:00 2001
From: Liangsheng Yin <hnyls2002@gmail.com>
Date: Sun, 2 Aug 2026 23:55:06 -0700
Subject: [PATCH] [misc] Deep-merge nested config overrides and parse request
 bodies with orjson (#33351)

---
 python/sglang/srt/entrypoints/http_server.py  | 28 +++++++++++++++++++
 .../srt/utils/hf_transformers/config.py       | 10 ++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/python/sglang/srt/entrypoints/http_server.py b/python/sglang/srt/entrypoints/http_server.py
index 5962f1edc..74bd711ec 100644
--- a/python/sglang/srt/entrypoints/http_server.py
+++ b/python/sglang/srt/entrypoints/http_server.py
@@ -42,6 +42,7 @@ from typing import (
 
 import aiohttp
 import numpy as np
+import orjson
 import requests
 import uvicorn
 import uvloop
@@ -60,6 +61,7 @@ from fastapi import (
 from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import ORJSONResponse, Response, StreamingResponse
+from fastapi.routing import APIRoute
 
 from sglang.srt.configs.embedding_model_spec import resolved_embedding_plan
 from sglang.srt.constants import HEALTH_CHECK_RID_PREFIX
@@ -427,10 +429,33 @@ async def lifespan(fast_api_app: FastAPI):
 
 
 # Fast API
+class ORJSONRequest(Request):
+    """Request whose ``json()`` uses orjson, for the tens-of-MB multimodal
+    bodies FastAPI would otherwise hand to stdlib json. Stricter than stdlib
+    on bare NaN/Infinity and >64-bit ints: those now 400 instead of parsing.
+    """
+
+    async def json(self) -> Any:
+        if not hasattr(self, "_json"):
+            self._json = orjson.loads(await self.body())
+        return self._json
+
+
+class ORJSONRoute(APIRoute):
+    def get_route_handler(self):
+        original_handler = super().get_route_handler()
+
+        async def custom_handler(request: Request):
+            return await original_handler(ORJSONRequest(request.scope, request.receive))
+
+        return custom_handler
+
+
 app = FastAPI(
     lifespan=lifespan,
     openapi_url=None if get_bool_env_var("DISABLE_OPENAPI_DOC") else "/openapi.json",
 )
+app.router.route_class = ORJSONRoute
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["*"],
@@ -449,10 +474,13 @@ if envs.SGLANG_ENABLE_REQUEST_DECOMPRESSION.get():
 # Include routers
 from sglang.srt.entrypoints.v1_loads import router as v1_loads_router
 
+# route_class is per-router, so included routers need it set too.
+v1_loads_router.route_class = ORJSONRoute
 app.include_router(v1_loads_router)
 
 from sglang.srt.entrypoints.elastic_ep import router as elastic_ep_router
 
+elastic_ep_router.route_class = ORJSONRoute
 app.include_router(elastic_ep_router)
 
 
diff --git a/python/sglang/srt/utils/hf_transformers/config.py b/python/sglang/srt/utils/hf_transformers/config.py
index c5cb120b8..1c26fbeeb 100644
--- a/python/sglang/srt/utils/hf_transformers/config.py
+++ b/python/sglang/srt/utils/hf_transformers/config.py
@@ -254,7 +254,15 @@ def get_config(
     )
 
     if model_override_args:
-        config.update(model_override_args)
+        # A plain update() setattrs a dict-valued override straight onto the
+        # config, so '{"text_config": {...}}' on a VLM would replace the whole
+        # sub-config with a dict and break attribute access downstream.
+        for key, value in model_override_args.items():
+            current = getattr(config, key, None)
+            if isinstance(value, dict) and isinstance(current, PretrainedConfig):
+                current.update(value)
+            else:
+                setattr(config, key, value)
 
     if is_gguf:
         if config.model_type not in MODEL_FOR_CAUSAL_LM_MAPPING_NAMES: