Example of patching schema for float Enum query parameters in FastAPI.

patched_schema.py

from enum import Enum

from fastapi import FastAPI, Depends, HTTPException, Query
from pydantic import BaseModel, ValidationError


app = FastAPI()


class Number(float, Enum):
    ten = 10.0
    twelve = 12.0


class MyModel(BaseModel):
    num: Number


async def number_parameter(
    num: float = Query(..., **MyModel.schema()["definitions"]["Number"])
) -> Number:
    try:
        tmp_num = MyModel(num=num)
        return tmp_num.num
    except ValidationError as err:
        # breakpoint()
        raise HTTPException(detail=err.errors(), status_code=400)


# MyModel(num=10.0)  # <- This works!


@app.get("/")
async def root(num: Number = Depends(number_parameter)):
    return {"message": f"Hello {num}"}