Skip to content

[Bugfix] Replace assert with ValueError for response_format validatio… #35514

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
antonovsergey93 wants to merge 1 commit into from
Closed

[Bugfix] Replace assert with ValueError for response_format validatio… #35514

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions tests/entrypoints/openai/test_chat_error.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,19 @@ async def mock_generate(*args, **kwargs):
assert response.error.code == HTTPStatus.INTERNAL_SERVER_ERROR


def test_json_schema_response_format_missing_schema():
"""When response_format type is 'json_schema' but the json_schema field
is not provided, request construction should raise a validation error
so the API returns 400 instead of 500."""
with pytest.raises(Exception, match="json_schema.*must be provided"):
ChatCompletionRequest(
model=MODEL_NAME,
prompt="Test prompt",
max_tokens=10,
response_format={"type": "json_schema"},
)


@pytest.mark.asyncio
async def test_chat_error_stream():
"""test finish_reason='error' returns 500 InternalServerError (streaming)"""
Expand Down
30 changes: 29 additions & 1 deletion vllm/entrypoints/openai/chat_completion/protocol.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -447,7 +447,7 @@ def to_sampling_params(
structured_outputs_kwargs["json"] = json_schema.json_schema
elif response_format.type == "structural_tag":
structural_tag = response_format
assert structural_tag is not None and isinstance(
Copy link
Copy Markdown
Contributor

@gemini-code-assist gemini-code-assist bot Feb 27, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

high

The assert statement should be replaced with a more appropriate error handling mechanism, such as raising a ValueError or a custom exception, to provide more informative error messages and prevent the server from crashing. This is especially important in production environments.

                raise ValueError("structural_tag cannot be None when response_format type is 'structural_tag'")

assert isinstance(
structural_tag,
(
LegacyStructuralTagResponseFormat,
Expand Down Expand Up @@ -502,6 +502,34 @@ def to_sampling_params(
skip_clone=True, # Created fresh per request, safe to skip clone
)

@model_validator(mode="before")
@classmethod
def validate_response_format(cls, data):
response_format = data.get("response_format")
if response_format is None:
return data

rf_type = (
response_format.get("type")
if isinstance(response_format, dict)
else getattr(response_format, "type", None)
)

if rf_type == "json_schema":
json_schema = (
response_format.get("json_schema")
if isinstance(response_format, dict)
else getattr(response_format, "json_schema", None)
)
if json_schema is None:
raise VLLMValidationError(
"When response_format type is 'json_schema', the "
"'json_schema' field must be provided.",
parameter="response_format",
)

return data

@model_validator(mode="before")
@classmethod
def validate_stream_options(cls, data):
Expand Down