Could not derive type of path parameter "id" but the path fragment is "pk" ?

[eLvErDe]

Hello,

Could you help me understanding why spectacular says that ?

I have the following code snippets:

group_preference_multi_by_id = SelfGroupMultiPreferenceViewSet.as_view({
    "get": "retrieve",
    "put": "update",
    "delete": "destroy",
})

group_preference_urlpatterns = [
    path(
        "api/preferences/multi/by-group/<path:group>/<path:application>/<path:preference>/<int:pk>/",
        group_preference_multi_by_id,
        name="multi_preferences_by_given_group_by_id",
    ),
]

But the generated OpenAPI route uses "id" instead of "pk" and keep warning me that type could not be infered (and defaults to string while being actually integer).

Thanks in advance,

[tfranzel]

Hi @eLvErDe,

this is a remnant of the base implementation. pk is coerced to id by a function belonging to DRF. there is even a DRF schema settings for that:

https://www.django-rest-framework.org/api-guide/settings/#schema_coerce_path_pk
https://github.com/encode/django-rest-framework/blob/bb795674f86828fc5f15d6d61501cc781811e053/rest_framework/schemas/generators.py#L210

typing path params should always work, but due to the pk coercion it fails here. the code is looking for id (but pk was typed in the path). i guess this counts as a bug.

however, this is usually not a problem as the type of pk/id is then retrieved from the model of the viewset, but i guess your SelfGroupMultiPreferenceViewSet is not a ModelViewSet or even a GenericAPIView.

[tfranzel]

@eLvErDe does this fix work for you?

[eLvErDe]

@tfranzel Can you wait until thursday ?

[tfranzel]

normally yes but the fix is on master and i need to do a fast minor release, due to an unrelated bug in swagger ui. would be much appreciated if you could check it beforehand.

[eLvErDe]

Ok, give me half an hour

[eLvErDe]

Yes it works for me, warning is gone, path parameter is typed as integer and API is still working, so I guess your patch is OK, thanks :-)

[tfranzel]

thanks so much for doing it so quickly! release will happen very soon.