Unify GSM8K eval path to Chat API for regression CI readiness (#21667)

python/sglang/test/run_eval.py

@@ -62,7 +62,7 @@ def run_eval_once(args, base_url: str, eval_obj: Eval) -> dict:
             extra_body[param_name] = value
 
     common_kwargs = dict(
-        model=args.model,
+        model=getattr(args, "model", None),
         max_tokens=getattr(args, "max_tokens", 2048),
         top_p=getattr(args, "top_p", 1.0),
         base_url=base_url,
@@ -71,7 +71,12 @@ def run_eval_once(args, base_url: str, eval_obj: Eval) -> dict:
 
     api_mode = getattr(args, "api", "chat")
     if api_mode == "completion":
-        sampler = CompletionSampler(**common_kwargs)
+        # Default stop tokens for completion API (matches few_shot_gsm8k behavior)
+        stop = getattr(args, "stop", ["Question", "Assistant:", "<|separator|>"])
+        sampler = CompletionSampler(
+            **common_kwargs,
+            stop=stop,
+        )
     else:
         sampler = ChatCompletionSampler(
             **common_kwargs,
@@ -143,7 +148,7 @@ def run_eval(args):
         categories = args.categories.split(",") if args.categories else None
 
         eval_obj = LongBenchV2Eval(
-            model=args.model,
+            model=getattr(args, "model", None),
             data_source=data_source,
             num_examples=args.num_examples,
             num_threads=args.num_threads,