"Options" fails on a many-relational field

[hiaselhans]

i have a field as follows:

sessions = serializers.HyperlinkedRelatedField(many=True,
                                                   read_only=True,
                                                   view_name="session-detail",
                                                   allow_null=True)

similar to http://www.django-rest-framework.org/api-guide/relations/#hyperlinkedrelatedfield
when running an OPTIONS request i get the following TypeError:

Traceback:
File "/usr/lib/python3.4/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/usr/lib/python3.4/site-packages/django/views/decorators/csrf.py" in wrapped_view
  58.         return view_func(*args, **kwargs)
File "/usr/lib/python3.4/site-packages/rest_framework/viewsets.py" in view
  85.             return self.dispatch(request, *args, **kwargs)
File "/usr/lib/python3.4/site-packages/rest_framework/views.py" in dispatch
  451.             response = self.handle_exception(exc)
File "/usr/lib/python3.4/site-packages/rest_framework/views.py" in dispatch
  448.             response = handler(request, *args, **kwargs)
File "/usr/lib/python3.4/site-packages/rest_framework/views.py" in options
  462.         data = self.metadata_class().determine_metadata(request, self)
File "/usr/lib/python3.4/site-packages/rest_framework/metadata.py" in determine_metadata
  64.             actions = self.determine_actions(request, view)
File "/usr/lib/python3.4/site-packages/rest_framework/metadata.py" in determine_actions
  90.                 actions[method] = self.get_serializer_info(serializer)
File "/usr/lib/python3.4/site-packages/rest_framework/metadata.py" in get_serializer_info
  107.             for field_name, field in serializer.fields.items()
File "/usr/lib/python3.4/site-packages/rest_framework/metadata.py" in <listcomp>
  107.             for field_name, field in serializer.fields.items()
File "/usr/lib/python3.4/site-packages/rest_framework/metadata.py" in get_field_info
  130.         if hasattr(field, 'choices'):
File "/usr/lib/python3.4/site-packages/rest_framework/relations.py" in choices
  382.             for item in iterable

Exception Type: TypeError at /api/gliders/
Exception Value: 'NoneType' object is not iterable

[xordoquy]

Looks like #2674