[BUG] Pydantic schema is using a higher version json schema than open api

[shughes-uk]

Describe the bug
It seems pydantic is generating schema in line with the latest json schema draft, but openapi expects an older version.
This issue has some info, and fastapi appears to have solved it but it might be worth solving this in ninja too.

pydantic/pydantic#1164

The outcome of this at the moment is codegen tools for openapi do not work correctly with ninja produced openapi docs.

swagger codegen simply silently fails, https://github.com/openapi-generators/openapi-python-client explodes

The type causing the issue is used as part of the default pagination decorator so I imagine this applies to most ninja users.

[vitalik]

Hi @shughes-uk

do you have some simple snippet that can be used to reproduce this bug ?

[shughes-uk]

Example api with paginate

from django.contrib import admin
from django.urls import path
from ninja import NinjaAPI, Schema
from ninja.pagination import paginate

api = NinjaAPI()


@api.get("/add")
@paginate
def add(request, a: int, b: int, **kwargs):
    return [{"result": a + b}]


urlpatterns = [
    path("admin/", admin.site.urls),
    path("api/", api.urls),
]

Running

python manage.py runserver &
pip openapi-python-client
openapi-python-client generate --url http://127.0.0.1:8000/api/openapi.json

Running this outputs

Error(s) encountered while generating, client was not created

Failed to parse OpenAPI document

3 validation errors for OpenAPI
paths -> /api/add -> get -> parameters -> 3 -> schema -> $ref
  field required (type=value_error.missing)
paths -> /api/add -> get -> parameters -> 3 -> schema -> exclusiveMinimum
  value could not be parsed to a boolean (type=type_error.bool)
paths -> /api/add -> get -> parameters -> 3 -> $ref
  field required (type=value_error.missing)

It's a little obtuse but those errors are from their pydantic representation of the openapi schema.

This issue over on fast-api may be more helpful than the issue I linked in the ticket tiangolo/fastapi#3541

[vitalik]

@shughes-uk this is fixed in 0.18+