Pass an adjusted request object to the serializer

closes #7718

CHANGES/plugin_api/7718.feature

@@ -0,0 +1,2 @@
+Enabled plugin writers to retrieve a request object from a serializer when look ups are
+performed from within the task serializer.

pulpcore/app/serializers/task.py

@@ -25,13 +25,24 @@ def to_representation(self, data):
                 return None
         except AttributeError:
             pass
-        viewset = get_viewset_for_model(data.content_object)
 
-        # serializer contains all serialized fields because we are passing
-        # 'None' to the request's context
-        serializer = viewset.serializer_class(data.content_object, context={"request": None})
+        # query parameters can be ignored because we are looking just for 'pulp_href'; still,
+        # we need to use the request object due to contextual references required by some
+        # serializers
+        request = self._get_request_without_query_params()
+
+        viewset = get_viewset_for_model(data.content_object)
+        serializer = viewset.serializer_class(data.content_object, context={"request": request})
         return serializer.data.get("pulp_href")
 
+    def _get_request_without_query_params(self):
+        """Remove all query parameters from the request object."""
+        request = self.context["request"]
+        request.query_params._mutable = True
+        request.query_params.clear()
+        request.query_params._mutable = False
+        return request
+
     class Meta:
         model = models.CreatedResource
         fields = []