From f97e82bdb61377eaa10b992296ccd45f9e58286f Mon Sep 17 00:00:00 2001
From: mortysean <yuxiaohuang2004@gmail.com>
Date: Tue, 20 Oct 2026 21:29:23 +0800
Subject: [PATCH] fix: reject conflicting golden tokens and structured output
 constraints

---
 deepinfer/sampling_params.py                  |  3 ++
 .../engine/test_sampling_params_golden_so.py  | 28 +++++++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 tests/engine/test_sampling_params_golden_so.py

diff --git a/deepinfer/sampling_params.py b/deepinfer/sampling_params.py
index 0d03690..74bec2c 100644
--- a/deepinfer/sampling_params.py
+++ b/deepinfer/sampling_params.py
@@ -62,6 +62,9 @@ class SamplingParams:
     ) -> None:
         del logprobs
 
+        if so_args is not None and golden_token_ids is not None:
+            raise ValueError("golden_token_ids cannot be combined with structured output constraints (so_args)")
+
         self.temperature = temperature
         self.top_p = top_p
         self.top_k = top_k
diff --git a/tests/engine/test_sampling_params_golden_so.py b/tests/engine/test_sampling_params_golden_so.py
new file mode 100644
index 0000000..942ef87
--- /dev/null
+++ b/tests/engine/test_sampling_params_golden_so.py
@@ -0,0 +1,28 @@
+import pytest
+
+from deepinfer.sampling_params import SamplingParams
+
+
+def test_golden_tokens_conflict_with_structured_output() -> None:
+    with pytest.raises(ValueError, match="cannot be combined"):
+        SamplingParams(
+            golden_token_ids=[2],
+            so_args={
+                "schema_type": "regex",
+                "schema": "[0-9]+",
+            },
+        )
+
+
+def test_golden_tokens_without_structured_output() -> None:
+    params = SamplingParams(golden_token_ids=[2])
+    assert params.golden_token_ids == [2]
+
+
+def test_structured_output_without_golden_tokens() -> None:
+    so_args = {
+        "schema_type": "regex",
+        "schema": "[0-9]+",
+    }
+    params = SamplingParams(so_args=so_args)
+    assert params.so_args == so_args