drf-spectacular not working when versioning is used (No operations defined in spec!) - django-rest-framework

Question

Some weeks ago I installed drf-spectacular. Everything was working properly until I enabled versioning in DRF (Django Rest Framework).
I implemented AcceptHeaderVersioning and it was working correctly. But then I realized Swagger wasn't showing the endpoints at /docs/ and this message was shown: "No operations defined in spec!".
If I comment DEFAULT_VERSIONING_CLASS line in REST_FRAMEWORK settings, all endpoint are correctly shown in Swagger docs page (/docs/). However, it breaks my versioning: request.version = None.
I tested with AcceptHeaderVersioning, as well as with URLPathVersioning and NamespaceVersioning. Same result for all of them.
I read that AcceptHeaderVersioning was implemented a year ago. Link to the commit here.
But I also read that it was planned to change modify_for_versioning function and it could affect header versioning. Link to the function in plumbing module, here and conversation here. In fact, a lot of changes have been made to the module the last year, check here.
These are my DRF settings:
REST_FRAMEWORK = {
# Auth
'DEFAULT_AUTHENTICATION_CLASSES': [
'rest_framework.authentication.TokenAuthentication',
],
# Swagger/docs
'DEFAULT_SCHEMA_CLASS': 'drf_spectacular.openapi.AutoSchema',
# Pagination
'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
'PAGE_SIZE': 5,
# Testing
'TEST_REQUEST_DEFAULT_FORMAT': 'json',
# Versioning
# https://www.django-rest-framework.org/api-guide/versioning/#configuring-the-versioning-scheme
'DEFAULT_VERSIONING_CLASS': 'rest_framework.versioning.AcceptHeaderVersioning',
'DEFAULT_VERSION': None,
'ALLOWED_VERSIONS': None,
'VERSION_PARAM': 'version',
}
Question
Any idea of what I'm doing wrong? Any recommendation to make both work together (versioning and swagger)? Any suggestions?
And BTW (this is secondary and not the main question): Is it possible to launch drf-spectacular tests into my own project?
Thanks in advance!

Answer 1

Question 1: Versioning works just fine. This is a common mistake. When SpectacularAPIView is versioned with AcceptHeaderVersioning (via DEFAULT_VERSIONING_CLASS), the request that fetches the schema from SpectacularAPIView likely does not contain the version header, and thus you only get unversioned endpoints (in your case none).
Either explicitly request a versioned schema with /api/schema?version=v2 or set version manually with
path('api/schema/', SpectacularAPIView.as_view(api_version='v2'), name='schema'),
FAQ entry
Where the magic happens and the order in which versions are used.
Question 2: The python wheels do not include the tests. For that you would need to install the source package: https://pypi.org/project/drf-spectacular/#files