[BUG] openapi.json throws error when generated with nested models

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Example Code

from typing import List, Dict, Tuple

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()

class Answers(BaseModel):
    answers: Dict[str, List[Tuple[str, float]]] = {}

@app.get("/qa", response_model=Answers)
async def qatask(request: str):
    return Answers()

if __name__ == "__main__":
    import uvicorn
    uvicorn.run("bugfind:app", host="0.0.0.0", port=5000, reload=True,
                workers=1)  # , debug=True)

Description

open http://localhost:5000/docs or http://localhost:5000/openapi.json and you will see the error in the logs.

Operating System

Linux

Operating System Details

ubuntu 20.04

FastAPI Version

0.68.1

Python Version

3.8.10

Additional Context

There was a bug #383 a while ago reporting the same problem but closed. This new issue here is in order to reopen that bug as it still isn’t solved or reappeared since then. Fell free to close this new issue and reopen the old bug if that is preferred.

this is the error:

Traceback (most recent call last):
  File "//home/name/.local/lib/python3.8/site-packages/uvicorn/protocols/http/h11_impl.py", line 373, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File "//home/name/.local/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
    return await self.app(scope, receive, send)
  File "//home/name/.local/lib/python3.8/site-packages/fastapi/applications.py", line 208, in __call__
    await super().__call__(scope, receive, send)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/applications.py", line 112, in __call__
    await self.middleware_stack(scope, receive, send)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 181, in __call__
    raise exc from None
  File "//home/name/.local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 159, in __call__
    await self.app(scope, receive, _send)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/exceptions.py", line 82, in __call__
    raise exc from None
  File "//home/name/.local/lib/python3.8/site-packages/starlette/exceptions.py", line 71, in __call__
    await self.app(scope, receive, sender)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/routing.py", line 580, in __call__
    await route.handle(scope, receive, send)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/routing.py", line 241, in handle
    await self.app(scope, receive, send)
  File "//home/name/.local/lib/python3.8/site-packages/starlette/routing.py", line 52, in app
    response = await func(request)
  File "//home/name/.local/lib/python3.8/site-packages/fastapi/applications.py", line 161, in openapi
    return JSONResponse(self.openapi())
  File "//home/name/.local/lib/python3.8/site-packages/fastapi/applications.py", line 136, in openapi
    self.openapi_schema = get_openapi(
  File "//home/name/.local/lib/python3.8/site-packages/fastapi/openapi/utils.py", line 410, in get_openapi
    return jsonable_encoder(OpenAPI(**output), by_alias=True, exclude_none=True)  # type: ignore
  File "pydantic/main.py", line 406, in pydantic.main.BaseModel.__init__
pydantic.error_wrappers.ValidationError: 4 validation errors for OpenAPI
components -> schemas -> Answers -> properties -> answers -> additionalProperties -> items -> items
  value is not a valid dict (type=type_error.dict)
components -> schemas -> Answers -> properties -> answers -> additionalProperties -> $ref
  field required (type=value_error.missing)
components -> schemas -> Answers -> properties -> answers -> additionalProperties
  value could not be parsed to a boolean (type=type_error.bool)
components -> schemas -> Answers -> $ref
  field required (type=value_error.missing)

[tiangolo]

It seems this is a duplicate of https://github.com/tiangolo/fastapi/issues/3665

In short, it should be fixed by FastAPI 0.73.0, released in the next hours. 🎉

For more info, read the last comment in that issue: https://github.com/tiangolo/fastapi/issues/3665#issuecomment-1019579214

And the comment in the PR: https://github.com/tiangolo/fastapi/pull/3874#issuecomment-1019578028

[github-actions[bot]]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.