Add test when simple view is interpreted as list view

[tsouvarev]

Spectacular uses is_list_view to determine whether view is listing or not. If it is then response is wrapped in array and operation ID has suffix _list.

is_list_view has some heuristics, and the last of them is to explode route and check if the last part is dynamic parameter like {id}.

So, if you have APIView with route that doesn't end with such parameter, you will end up with response serializer wrapped with array just because of the failed heuristic.

[tsouvarev]

Diff of generated schema with reference file is the following:

 openapi: 3.0.3
  info:
    title: ''
    version: 0.0.0
  paths:
    /{id}/test/:
      get:
-       operationId: test_list
?                         ^ ^^
+       operationId: test_retrieve
?                         ^^^^ ^^^
        description: ''
        parameters:
        - in: path
          name: id
          schema:
            type: integer
          required: true
        tags:
        - test
        security:
        - {}
        responses:
          '200':
            content:
              application/json:
                schema:
-                 type: array
-                 items:
-                   $ref: '#/components/schemas/Alpha'
? --
+                 $ref: '#/components/schemas/Alpha'
            description: ''
- components:
    schemas:
      Alpha:
        type: object
        properties:
          field_a:
            type: string
          field_b:
            type: integer
        required:
        - field_a
        - field_b

[tfranzel]

yes indeed that is a bug from the old code. i knew that was gonna pop up eventually. i already marked the spot with a todo that this is probably not gonna cover all cases. so now we have it. i'll have a look and refactor that broken heuristic.

[MissiaL]

Now I have stopped switching the schema to the 3.0 due to this problem :-(

I learned a little how the drf_yasg handles this situation.
One could look at this code
https://github.com/axnsan12/drf-yasg/blob/master/src/drf_yasg/inspectors/view.py#L216

[tfranzel]

hi @MissiaL, thanks for the info. i had a look at yasg and they are also using a heuristic in the end: https://github.com/axnsan12/drf-yasg/blob/9ccf24c27ad46db4f566170553d49d687b6d21d6/src/drf_yasg/utils.py#L211

but apparently a slightly better one. however, this heuristic also breaks down occasionally. we have seen that in our own usage of yasg.

i'm actively on it and almost have a "as good as it gets" solution. by tomorrow i will have something to look at.

[tfranzel]

sry for the delay but i couldn't find the time earlier. so i tried something different here. this is really one of the more tricky parts.

• viewsets: more or less easy via introspection
• apiviews: there are no actions so no clue there. only thing you can rely on are annotation. the indication for list view is intialize serilizer like @extend_schema(responses=FooSerializer(many=True)). i believe this is also more consise than FooSerializer() for list=False

default for the new is_list_view is False as it makes more sense imho. i think it is still not 100% satisfactory but I don't see how to make it significantly better.

@tsouvarev i refactored the test into 2 separate test that explicitly only check this as the other test was already quite large.

@MissiaL let me know if that works for you now.

[MissiaL]

It works perfect! Thanks!