class SomeCustomClass(BaseModel):
        model_config = {"arbitrary_types_allowed": True}

        a_uuid: MyUuid

        @field_serializer("a_uuid")
        def serialize_a_uuid(self, v):
            return str(v)

    @app.get("/get_custom_class")
    def return_some_user():
        # Test that the fix also works for custom pydantic classes

Example:

    Source (English):

        «««
        <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel docs</a>
        »»»

    Result (German):

        «««
        <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel-Dokumentation</a>
        »»»

as-is, including the `hashed_password`. To fix this, the declared `response_model` is cloned, if it is a Pydantic model class (or contains Pydantic model classes in it, e.g. in a `List[Item]`), the Pydantic model class(es) will be a different one (the "cloned" one). So, an object that is a subclass won't simply pass the validation and returned as-is, because it is no longer a sub-class of the cloned `response_model`. Instead, a new Pydantic model object will be created with the contents of the returned...

WebSocketErrorModel: type[BaseModel] = create_model("WebSocket")


class FastAPIError(RuntimeError):
    """
    A generic, FastAPI-specific error.
    """


class DependencyScopeError(FastAPIError):
    """
    A dependency declared that it depends on another dependency with an invalid
    (narrower) scope.
    """


class ValidationException(Exception):
    def __init__(
        self,

            else:
                # It would probably make more sense for all response classes to have an
                # explicit default status_code, and to extract it from them, instead of
                # doing this inspection tricks, that would probably be in the future
                # TODO: probably make status_code a default class attribute for all
                # responses in Starlette

@pytest.fixture(name="client")
def get_client():
    from pydantic import BaseModel, ValidationInfo, field_validator

    app = FastAPI()

    class ModelB(BaseModel):
        username: str

    class ModelC(ModelB):
        password: str

    class ModelA(BaseModel):
        name: str
        description: Optional[str] = None
        foo: ModelB
        tags: dict[str, str] = {}

# =====================================================================================
# Without aliases


@app.get("/optional-str")
async def read_optional_str(p: Optional[str] = None):
    return {"p": p}


class QueryModelOptionalStr(BaseModel):
    p: Optional[str] = None


@app.get("/model-optional-str")
async def read_model_optional_str(p: Annotated[QueryModelOptionalStr, Query()]):
    return {"p": p.p}

# Without aliases


@app.get("/required-str")
async def read_required_str(p: Annotated[str, Cookie()]):
    return {"p": p}


class CookieModelRequiredStr(BaseModel):
    p: str


@app.get("/model-required-str")
async def read_model_required_str(p: Annotated[CookieModelRequiredStr, Cookie()]):
    return {"p": p.p}

def client_fixture() -> TestClient:
    from pydantic import BaseModel

    class Address(BaseModel):
        """
        This is a public description of an Address
        \f
        You can't see this part of the docstring, it's private!
        """

        line_1: str
        city: str
        state_province: str

    class Facility(BaseModel):
        id: str
        address: Address

    app = FastAPI()

# Without aliases


@app.post("/required-list-str", operation_id="required_list_str")
async def read_required_list_str(p: Annotated[list[str], Form()]):
    return {"p": p}


class FormModelRequiredListStr(BaseModel):
    p: list[str]


@app.post("/model-required-list-str", operation_id="model_required_list_str")
def read_model_required_list_str(p: Annotated[FormModelRequiredListStr, Form()]):