get_schema returns "description" as "The type of the None singleton"

[sparrowt]

Describe the bug

Calling get_schema on a drf_spectacular.generators.SchemaGenerator sometimes returns a schema with a very odd description string of "The type of the None singleton."

{
  "openapi": "3.0.3",
  "info": {
    ...
  },
  "paths": {
    ...
    "/myapi/v1/thing/lookup/{lookup}/": {
      "get": {
        "operationId": "thing_lookup_retrieve",
        "description": "The type of the None singleton.",
        "parameters": [
          {
            ...

This first occurred when upgrading from Python 3.12 to 3.13 although I haven't yet 100% convinced myself that the python version is the cause (we had to upgrade several other unrelated-as-far-as-I-can-see packages to get 3.13 support) but certainly the drf-spectacular version remains unchanged at drf-spectacular==0.26.2.

To Reproduce

It's a private project however the rough shape of the view code in question is like this:

class LookupView(generics.RetrieveAPIView):
    permission_classes = [...]
    authentication_classes = [...]
    action = "lookup"

    lookup_field = "xyz__iexact"
    lookup_url_kwarg = "lookup"


class ThingLookupView(LookupView):
    queryset = Thing.objects.all()
    serializer_class = ThingSerializer

However I have stepped through in a debugger to get_description and observed that in this case action_or_method == None and thus action_doc ends up as "The type of the None singleton."

Expected behavior

The "description" should continue to be omitted, as it was before.

[robberwick]

It looks like this is as a result of the addition of a bunch of docstrings in python 3.13, and the fix for it landed in #1381

[ldjacobs]

Any chance we could get an official release that includes this fix? There hasn't been a release since November.

[tfranzel]

good stuff. sorry, i have been very busy with work recently. I'm trying to catch up on the backlog as soon as possible.