First check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue 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.
• After submitting this, I commit to one of:
  • Read open issues with questions until I find 2 issues where I can help someone and add a comment to help there.
  • I already hit the "watch" button in this repository to receive notifications and I commit to help at least 2 people that ask questions in the future.
  • Implement a Pull Request for a confirmed bug.

Example

Here's a self-contained, minimal, reproducible, example with my use case:

from fastapi import FastAPI
from pydantic import BaseModel

class Test(BaseModel):
    foo: str
    bar: str

class Test2(BaseModel):
    test: Test
    baz: str

app = FastAPI()
@app.get(
    "/",
    response_model=Test2,
    response_model_include={'baz': ..., 'test': {'foo'}},
    response_model_exclude={'test': {'bar'}}
    )
def item():
    return Test2(test=Test(foo="visible field", bar="invisible field"), baz="also visible field")

Description

Dictionary, passed to response_mode_include/exclude casts to set.

• Open the browser and call the endpoint /.
• It returns a JSON with {"baz":"also visible field"}.
• But I expected it to return {"baz":"also visible field", "test": {"foo": "visible field"}}.

Environment

• OS: Windows
• FastAPI Version: 0.60.1
• Python version: Python 3.7.3

Additional context

So, this happens due to cast of include and exclude params to set at https://github.com/tiangolo/fastapi/blob/master/fastapi/encoders.py#L37 and https://github.com/tiangolo/fastapi/blob/master/fastapi/encoders.py#L39.

According to pydantic docs, this is a normal usage of include/exclude.

So, i think, fix can be simple, like appending ... and not isinstance(include, dict) to conditions. But i'm not familiar with fastapi, and not sure that fix can break something.