[Bug]: `DjangoOpenAPIResponse` no longer type compatible with `unmarshal_response`

[jceipek]

Actual Behavior

There is a type error here when using werkzeug Version 3.1.2 or newer:

from django.conf import settings
from openapi_core import unmarshal_response
from openapi_core.contrib.django import DjangoOpenAPIRequest, DjangoOpenAPIResponse

def test(openapi_request: DjangoOpenAPIRequest, openapi_response: DjangoOpenAPIResponse):
        return unmarshal_response(
            request=openapi_request,
            response=openapi_response, # type error on this line
            spec=settings.OPENAPI_SPEC,
        )

Expected Behavior

No type errors in the provided sample code.

Steps to Reproduce

Typecheck the provided sample code using mypy.

OpenAPI Core Version

3.0.0

OpenAPI Core Integration

django

Affected Area(s)

casting, dependencies, unmarshalling

References

• https://.com/pallets/werkzeug/blob/main/CHANGES.rst#version-312
• MutableMapping cannot be instantiated from Headers pallets/werkzeug#2989

Anything else we need to know?

werkzeug Version 3.1.2 changed the definition of Headers because it isn't technically a MutableMapping.

The Response protocol in openapi_core here has Mapping[str, Any]:

openapi-core/openapi_core/protocols.py

Lines 122 to 123 in b8f0644

	@property
	def headers(self) -> Mapping[str, Any]: ...

DjangoOpenAPIResponse has headers typed as Headers from werkzeug:

openapi-core/openapi_core/contrib/django/responses.py

Lines 33 to 35 in b8f0644

	@property
	def headers(self) -> Headers:
	return Headers(self.response.headers.items())

Since these are no longer compatible, unmarshal_response can no longer accept DjangoOpenAPIResponse as a response parameter without failing typechecking.

Would you like to implement a fix?

None

[andersk]

MockResponse is also incompatible with Response for the same reason.

openapi-core/openapi_core/testing/responses.py

Line 20 in b8f0644

self.headers = Headers(headers or {})

[LewisCowlesMotive]

What if I were to use a protocol with a generic? Could we have that just wrap the werkzeug nonsense?