I guess something changed in the way DRF 3 includes default many-to-many fields forModelSerializer, because as soon as I upgraded I got this unhelpful stack-trace:

Traceback:File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/django/core/handlers/base.py" in get_response  111.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/django/views/decorators/csrf.py" in wrapped_view  57.         return view_func(*args, **kwargs)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/viewsets.py" in view  85.             return self.dispatch(request, *args, **kwargs)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/views.py" in dispatch  407.             response = self.handle_exception(exc)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/views.py" in dispatch  404.             response = handler(request, *args, **kwargs)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/mixins.py" in list  46.         return Response(serializer.data)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in data  422.         ret = super(Serializer, self).dataFile "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in data  177.                 self._data = self.to_representation(self.instance)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in to_representation  391.                 ret[field.field_name] = field.to_representation(attribute)File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in to_representation  524.             self.child.to_representation(item) for item in iterableFile "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in <listcomp>  524.             self.child.to_representation(item) for item in iterableFile "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in to_representation  384.         fields = [field for field in self.fields.values() if not field.write_only]File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in fields  277.             for key, value in self.get_fields().items():File "/Users/maryokhin/.virtualenvs/backend-drf3/lib/python3.4/site-packages/rest_framework/serializers.py" in get_fields  846.                     fields.remove(field_name)Exception Type: ValueError at /channels/Exception Value: list.remove(x): x not in list

Before I had to exclude this field specifically, now it's not even there.

Assert fields inexclude are model fields

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lovelydinosaur commentedDec 18, 2014

Before I had to exclude this field specifically, now it's not even there.

Sorry could you give the context for what code is giving you this stacktrace?

What's the most minimal example of a model and serializer that reproduces it?

lovelydinosaur added the Needs information label

Dec 18, 2014

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maryokhin commentedDec 18, 2014

classChannel(models.Model):name=models.CharField(max_length=128)classSubscription(models.Model):channel=models.ForeignKey(Channel,related_name='subscribers')

classChannelSerializer(ModelSerializer):classMeta():model=Channelexclude= ('subscribers', )

Here I would have something like the following:

exclude= ('subscribers',)field_name='subscribers'fields= ['id','name']

Ithink that I had reverse relationships populated on 2.4.4, which is why I excluded it.

In any case, if it's a field name not in the ones that the serializer has (default or declared) it'll spill an unfriendly stack trace when trying to remove it.

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lovelydinosaur commentedDec 18, 2014

Okay, reverse relationships are not (have never been) included by default, so you don't need to do this, but we should clearly be more graceful in this case.

lovelydinosaur added Enhancement and removed Needs information labels

Dec 18, 2014

lovelydinosaur added this to the3.0.3 Release milestone

Dec 18, 2014

lovelydinosaur added a commit that referenced this pull request

Dec 18, 2014

Merge pull request#2319from maryokhin/master

e0096fe

Assert fields in `exclude` are model fields

lovelydinosaur merged commite0096fe intoencode:master

Dec 18, 2014

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lovelydinosaur commentedDec 18, 2014

Thanks!

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maryokhin commentedDec 19, 2014

I just realized that a long time agoSubscription model was a many-to-manythrough model, that was probably why it was added to the serializer as a forward relation. Then that changed to a regular many-to-many model, was still excluded, 2.4.4 did't care, 3.0 loudly failed.