Custom auth dependency can not execute with cython

[SolardiaX]

First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to FastAPI but to Pydantic.
• I already checked if it is not related to FastAPI but to Swagger UI.
• I already checked if it is not related to FastAPI but to ReDoc.

Commit to Help

• I commit to help with one of those options 👆

Example Code

## test.py

from typing import Any, Dict, Optional, cast

from fastapi import Depends, FastAPI, Request, Response, status
from fastapi.exceptions import HTTPException
from fastapi.security import OAuth2
from fastapi.security.oauth2 import OAuthFlowsModel
from fastapi.security.utils import get_authorization_scheme_param


class MyOAuth2PasswordBearer(OAuth2):
    def __init__(
            self,
            tokenUrl: str,
            scheme_name: Optional[str] = None,
            scopes: Optional[Dict[str, str]] = None,
            description: Optional[str] = None,
            auto_error: bool = True,
    ):
        if not scopes:
            scopes = {}
        flows = OAuthFlowsModel(
            password=cast(Any, {"tokenUrl": tokenUrl, "scopes": scopes})
        )
        super().__init__(
            flows=flows,
            scheme_name=scheme_name,
            description=description,
            auto_error=auto_error,
        )

    async def __call__(self, request: Request) -> Optional[str]:
        authorization = request.headers.get("Authorization")
        scheme, param = get_authorization_scheme_param(authorization)
        if not authorization or scheme.lower() != "bearer":
            if self.auto_error:
                raise HTTPException(
                    status_code=status.HTTP_401_UNAUTHORIZED,
                    detail="Not authenticated",
                    headers={"WWW-Authenticate": "Bearer"},
                )
            else:
                return None
        return param

    async def logout(self, request: Request, response: Response):
        pass


oauth2_scheme = MyOAuth2PasswordBearer(tokenUrl="token")


def init():
    app = FastAPI()

    @app.post("/logout", response_class=Response, dependencies=[Depends(oauth2_scheme)])
    async def logout(request: Request, response: Response):
        await oauth2_scheme.logout(request, response)

        response.status_code = status.HTTP_200_OK
        return response

    return app


## setup.py

from distutils.core import setup

from Cython.Build import cythonize


setup(name='Hello world',
      ext_modules=cythonize("test.py"))

Description

The code can run with any problem with pure python.

Run python setup.py build_ext to compile the test.py to test.so
Run uvicorn test:init
Failed with pydantic.errors.PydanticUndefinedAnnotation: name 'Request' is not defined

If remove call method, it’s ok again.

Operating System

Linux, macOS

Operating System Details

No response

FastAPI Version

0.103.0

Pydantic Version

2.3.0

Python Version

3.11

Additional Context

No response

[SolardiaX]

After a hard deep dive debug, I think this issue is caused by the change of/from python 3.10 with annotation future as default.
To fix it and support cython with python version above 3.10, just change the usage of inspect.signature with set argument eval_str=True in fastapi/dependencies/utils.py:

def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
    signature = inspect.signature(call, eval_str=True)
    ...

referrences:

• https://stackoverflow.com/questions/72510518/inspect-parameter-annotation-method-returns-a-string-for-imported-methods-vs-a
• https://bugs.python.org/issue43355

[Kludex]

I'm going to remove the "marked as answer" so I can come back to this later. I usually ignore discussions that were marked as answered. FYI

[jkunzler0]

Thank you for figuring out this solution.

This comment, #9085 (comment), provides an alternative solution.

[felixgao]

I am having a similar problem but this happens within my docker container.
Python 3.11
Fastapi: 0.109.2
Pydantic: 2.6.1

Traceback (most recent call last):
  File "/app/.venv/lib/python3.11/site-packages/pydantic/type_adapter.py", line 207, in __init__
    core_schema = _getattr_no_parents(type, '__pydantic_core_schema__')
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/type_adapter.py", line 98, in _getattr_no_parents
    raise AttributeError(attribute)
AttributeError: __pydantic_core_schema__

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 677, in _resolve_forward_ref
    obj = _typing_extra.eval_type_backport(obj, globalns=self._types_namespace)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_typing_extra.py", line 240, in eval_type_backport
    return typing._eval_type(  # type: ignore
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/typing.py", line 381, in _eval_type
    return t._evaluate(globalns, localns, recursive_guard)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/typing.py", line 891, in _evaluate
    eval(self.__forward_code__, globalns, localns),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 1, in <module>
NameError: name 'Request' is not defined

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/app/.venv/bin/uvicorn", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/main.py", line 418, in main
    run(
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/main.py", line 587, in run
    server.run()
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/server.py", line 62, in run
    return asyncio.run(self.serve(sockets=sockets))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/asyncio/runners.py", line 190, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "uvloop/loop.pyx", line 1517, in uvloop.loop.Loop.run_until_complete
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/server.py", line 69, in serve
    config.load()
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/config.py", line 458, in load
    self.loaded_app = import_from_string(self.app)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/uvicorn/importer.py", line 21, in import_from_string
    module = importlib.import_module(module_str)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/app/app/service/server.py", line 5, in <module>
    app = create_app()
          ^^^^^^^^^^^^
  File "/app/app/service/__init__.py", line 88, in create_app
    from .router import health, ocr
  File "/app/app/service/router/ocr.py", line 41, in <module>
    @router.post("/file")
     ^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/routing.py", line 956, in decorator
    self.add_api_route(
  File "/app/.venv/lib/python3.11/site-packages/fastapi/routing.py", line 895, in add_api_route
    route = route_class(
            ^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/routing.py", line 525, in __init__
    self.dependant = get_dependant(path=self.path_format, call=self.endpoint)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/dependencies/utils.py", line 268, in get_dependant
    sub_dependant = get_param_sub_dependant(
                    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/dependencies/utils.py", line 111, in get_param_sub_dependant
    return get_sub_dependant(
           ^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/dependencies/utils.py", line 147, in get_sub_dependant
    sub_dependant = get_dependant(
                    ^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/dependencies/utils.py", line 261, in get_dependant
    type_annotation, depends, param_field = analyze_param(
                                            ^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/dependencies/utils.py", line 442, in analyze_param
    field = create_response_field(
            ^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/fastapi/utils.py", line 99, in create_response_field
    return ModelField(**kwargs)  # type: ignore[arg-type]
           ^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 6, in __init__
  File "/app/.venv/lib/python3.11/site-packages/fastapi/_compat.py", line 107, in __post_init__
    self._type_adapter: TypeAdapter[Any] = TypeAdapter(
                                           ^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/type_adapter.py", line 209, in __init__
    core_schema = _get_schema(type, config_wrapper, parent_depth=_parent_depth + 1)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/type_adapter.py", line 81, in _get_schema
    schema = gen.generate_schema(type_)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 499, in generate_schema
    schema = self._generate_schema(obj)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 737, in _generate_schema
    schema = self._post_process_generated_schema(self._generate_schema_inner(obj))
                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 744, in _generate_schema_inner
    return self._annotated_schema(obj)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 1675, in _annotated_schema
    source_type, *annotations = self._get_args_resolving_forward_refs(
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 701, in _get_args_resolving_forward_refs
    args = tuple([self._resolve_forward_ref(a) if isinstance(a, ForwardRef) else a for a in args])
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 701, in <listcomp>
    args = tuple([self._resolve_forward_ref(a) if isinstance(a, ForwardRef) else a for a in args])
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.11/site-packages/pydantic/_internal/_generate_schema.py", line 679, in _resolve_forward_ref
    raise PydanticUndefinedAnnotation.from_name_error(e) from e
pydantic.errors.PydanticUndefinedAnnotation: name 'Request' is not defined

The code that causes this is in a file called config.py

# the config is set in the server.py's create_app method.
# see https://fastapi.tiangolo.com/advanced/settings/#settings-in-a-dependency
@lru_cache(maxsize=1)
def get_settings(request: Request) -> SvcSettings:
    return request.app.state.config

If I remove the annotation it works fine.