✨ Support Python internal description on Pydantic model's docstring

[Kludex]

Problem

Currently, on FastAPI endpoint functions we can document for OpenAPI description/Swagger and for internal Python purposes:

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()

@app.get("/")
def useful():
    """My description.
    \f
    Internal documentation.
    """
    ...

On Swagger we'll have:

When documenting models, it doesn't have the same behavior:

from enum import Enum
from fastapi import FastAPI

class Banana(str, Enum):
    """My description.
    \f
    Internal documentation.
    """
    HAHA = "haha"
    HOHO = "hoho"

app = FastAPI()

@app.get("/")
def useful(banana: Banana):
    ...

On Swagger, we'll have:

Solution

The proposed two lines of code on this PR, makes it possible to have the same behavior as the endpoint description:

It follows the same idea as:

fastapi/fastapi/routing.py

Line 350 in 10397dd

self.description = self.description.split("\f")[0]

Related issues

• Should Feed Escape work in Pydantic Models #3024

Questions & Alternatives

• Should Pydantic handle this on the model_process_schema() function instead?

[Kludex]

Do you guys have an opinion on this? @PrettyWood @samuelcolvin

[github-actions]

📝 Docs preview for commit 00da79c at: https://606608e5d9c9b620c64fe21f--fastapi.netlify.app

[codecov]

Codecov Report

Merging #3032 (00becde) into master (b1d0f1e) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #3032   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          538       538           
  Lines        13870     13872    +2     
=========================================
+ Hits         13870     13872    +2     

Impacted Files	Coverage Δ
fastapi/utils.py	100.00% <100.00%> (ø)

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[github-actions]

📝 Docs preview for commit 1c93179 at: https://60660aa9f6c5301f7f6c8b97--fastapi.netlify.app

[killswitch-GUI]

Just bumping.

[killswitch-GUI]

@Kludex Think this one will make it in?

[Kludex]

I don't know. 😗

[github-actions]

📝 Docs preview for commit 00becde at: https://6311f9a78e0d811162b5915a--fastapi.netlify.app

[tiangolo]

Awesome, thanks @Kludex! 🍰

[killswitch-GUI]

@tiangolo and @Kludex thanks for helping fix this! The team will be thankful!

[Kludex]

@tiangolo Even if coverage didn't drop, Kludex forgot to add a test case for this, jfyk.

[tiangolo]

Thanks! We can probably add a test in another PR.