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.
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Commit to Help

• I commit to help with one of those options 👆

Example Code

from __future__ import annotations
from typing import Annotated
from fastapi import FastAPI, Depends, Request

app = FastAPI()

def get_value() -> str:
    return "injected_value"

class AuthClass:
    def __init__(self, roles: list[str]):
        self.roles = roles

    async def __call__(self, request: Request, dep: Annotated[str, Depends(get_value)]):
        # auth logic here
        return {"dep": dep}

@app.get("/class")
async def with_class(auth: Annotated[dict, Depends(AuthClass(["ADMIN"]))]):
    return auth

Description

pydantic.errors.PydanticUserError: 'TypeAdapter[typing.Annotated[ForwardRef('Request'), Query(PydanticUndefined)]]' is not fully defined

Operating System

Windows

Operating System Details

async def auth_func(request: Request, dep: Annotated[str, Depends(get_value)]):
return {"dep": dep}

FastAPI Version

FastAPI Version: 0.118.0

Pydantic Version

Pydantic Version: 2.11.10

Python Version

Python Version: 3.13.3

Additional Context

I noticed get_typed_signature() in FastAPI uses getattr(call, "globals", {}), which returns {} for callable instances.

Is there a recommended way to make callable class dependencies work with PEP 563 annotations?