← oracle_full

fastapi_14297

failed WRONG_FIX UNSUBMITTED wrong_fix_unsubmitted(None) · None tool calls · 0 s · fastapi/fastapi

Task input

🐛 Fix optional sequence handling in `serialize sequence value` with Pydantic V2

Currently the following test code leads to `TypeError: issubclass() arg 1 must be a class` (with Python 3.14 error is different, but the root cause is the same):

```py
from typing import List, Optional

from fastapi import FastAPI, File
from fastapi.testclient import TestClient

app = FastAPI()


@app.post("/files")
async def upload_files(files: Optional[List[bytes]] = File(None)):
    if files is None:
        return {"files_count": 0}
    return {"files_count": len(files), "sizes": [len(f) for f in files]}


def test_optional_bytes_list():
    client = TestClient(app)
    response = client.post(
        "/files",
        files=[("files", b"content1"), ("files", b"content2")],
    )
    assert response.status_code == 200
    assert response.json() == {"files_count": 2, "sizes": [8, 8]}
```

This is because for optional sequence the `origin_type` in the following line is `Union`:

https://github.com/fastapi/fastapi/blob/972a967d5d3fa24d450637c36c6b7ad1f1d8c1b6/fastapi/_compat/v2.py#L374

So, we need to unwrap that `Uinion`, take non-None type from its arguments and use it as `origin_type`

Tool calls (0)

Patch

--- a/fastapi/_compat/v2.py
+++ b/fastapi/_compat/v2.py
@@ -371,6 +371,13 @@ def copy_field_info(*, field_info: FieldInfo, annotation: Any) -> FieldInfo:
 
 def serialize_sequence_value(*, field: ModelField, value: Any) -> Sequence[Any]:
     origin_type = get_origin(field.field_info.annotation) or field.field_info.annotation
+    if origin_type is Union:  # Handle optional sequences
+        union_args = get_args(field.field_info.annotation)
+        for union_arg in union_args:
+            if union_arg is type(None):
+                continue
+            origin_type = get_origin(union_arg) or union_arg
+            break
     assert issubclass(origin_type, shared.sequence_types)  # type: ignore[arg-type]
     return shared.sequence_annotation_to_type[origin_type](value)  # type: ignore[no-any-return]
 

Test output

==================================== ERRORS ====================================
______________ ERROR collecting tests/test_optional_file_list.py _______________
tests/test_optional_file_list.py:9: in <module>
    @app.post("/files")
     ^^^^^^^^^^^^^^^^^^
fastapi/routing.py:1078: in decorator
    self.add_api_route(
fastapi/routing.py:1017: in add_api_route
    route = route_class(
fastapi/routing.py:636: in __init__
    self.dependant = get_dependant(
fastapi/dependencies/utils.py:259: in get_dependant
    param_details = analyze_param(
fastapi/dependencies/utils.py:496: in analyze_param
    ensure_multipart_is_installed()
fastapi/dependencies/utils.py:121: in ensure_multipart_is_installed
    raise RuntimeError(multipart_not_installed_error) from None
E   RuntimeError: Form data requires "python-multipart" to be installed. 
E   You can install "python-multipart" with: 
E   
E   pip install python-multipart
=============================== warnings summary ===============================
../../../../../../../Users/jp/repos/kaggle-gemini-coding-agent-post-training/.envs/overlays/starlette-0.50.0-py3-none-any/starlette/testclient.py:45
  /Users/jp/repos/kaggle-gemini-coding-agent-post-training/.envs/overlays/starlette-0.50.0-py3-none-any/starlette/testclient.py:45: DeprecationWarning: The anyio.abc.BlockingPortal alias is deprecated, use anyio.from_thread.BlockingPortal instead.
    _PortalFactoryType = Callable[[], AbstractContextManager[anyio.abc.BlockingPortal]]

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
1 warning, 1 error in 0.63s