feat: remove serde flatten of reference limitation

[markhilb]

Don't see why this is a problem.
Correct me if i'm wrong.

[kurtbuilds]

It's been a while since I looked at this, but I believe the issue is the Baz schema that the reference refers to is never added to the spec.

Maybe that's ok? Or it prints a warning? But silently creating an invalid spec feels wrong.

[markhilb]

I'm not sure which spec you mean.
If you mean Foo::schema, then Baz is not added regardless of whether it is flattened or not.
If you mean the openapi spec of a Server then it is added.

use actix_web::web::Json;
use oasgen::{OaSchema, Server, oasgen};
use serde::Serialize;

#[derive(OaSchema, Serialize)]
pub struct Baz {
    value: i32,
}

#[derive(OaSchema, Serialize)]
pub struct Bar {
    baz: Baz,
}

#[derive(OaSchema, Serialize)]
pub struct Foo {
    #[serde(flatten)]
    flattened: Bar,
}

#[oasgen]
async fn foo() -> Json<Foo> {
    todo!()
}

fn main() {
    let server = Server::actix().get("/foo", foo);

    let schema = serde_yaml::to_string(&Foo::schema()).unwrap();
    let spec = serde_yaml::to_string(&server.openapi).unwrap();

    println!("{schema}");
    println!();
    println!("{spec}");
}

type: object
properties:
  baz:
    $ref: '#/components/schemas/Baz'
required:
- baz


openapi: 3.0.3
info:
  title: ''
  version: ''
paths:
  /foo:
    get:
      operationId: foo
      responses:
        '200':
          description: ''
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Foo'
components:
  schemas:
    Bar:
      type: object
      properties:
        baz:
          $ref: '#/components/schemas/Baz'
      required:
      - baz
    Baz:
      type: object
      properties:
        value:
          type: integer
      required:
      - value
    Foo:
      type: object
      properties:
        baz:
          $ref: '#/components/schemas/Baz'
      required:
      - baz