"type": "missing",
                    "loc": ["header", "x-token"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["header", "x-key"],
                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(

                    "msg": "Field required",
                    "input": {"name": "Foo"},
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", "price"],
                    "msg": "field required",
                    "type": "value_error.missing",

                    "msg": "Field required",
                    "input": {"name": "Foo"},
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", "price"],
                    "msg": "field required",
                    "type": "value_error.missing",

from typing import List

from fastapi import FastAPI
from fastapi._compat import PYDANTIC_V2
from fastapi.testclient import TestClient
from pydantic import BaseModel, ConfigDict, Field

app = FastAPI()


class Model(BaseModel):
    name: str = Field(alias="alias")


class ModelNoAlias(BaseModel):
    name: str

    if PYDANTIC_V2:
        model_config = ConfigDict(
            json_schema_extra={

from .utils import needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    app = FastAPI()

    from pydantic import BaseModel, computed_field

    class Rectangle(BaseModel):
        width: int
        length: int

        @computed_field
        @property
        def area(self) -> int:
            return self.width * self.length

    @app.get("/")
    def read_root() -> Rectangle:

                """
                `username` string. The OAuth2 spec requires the exact field name
                `username`.
                """
            ),
        ],
        password: Annotated[
            str,
            Form(),
            Doc(
                """
                `password` string. The OAuth2 spec requires the exact field name
                `password".
                """
            ),
        ],

    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "missing",
                    "loc": ["query", "needy"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "int_parsing",
                    "loc": ["query", "skip"],

import strawberry
from fastapi import FastAPI
from strawberry.asgi import GraphQL


@strawberry.type
class User:
    name: str
    age: int


@strawberry.type
class Query:
    @strawberry.field
    def user(self) -> User:
        return User(name="Patrick", age=100)


schema = strawberry.Schema(query=Query)


graphql_app = GraphQL(schema)

app = FastAPI()
app.add_route("/graphql", graphql_app)

    {!> ../../../docs_src/response_model/tutorial001_01.py!}
    ```

FastAPI will use this return type to:

* **Validate** the returned data.

```{ .python .annotate hl_lines="1  5  8-11  14-17  23-25  28" }
{!../../../docs_src/dataclasses/tutorial003.py!}
```

1. We still import `field` from standard `dataclasses`.

2. `pydantic.dataclasses` is a drop-in replacement for `dataclasses`.

3. The `Author` dataclass includes a list of `Item` dataclasses.