tomchristie/django-rest-framework — pull request #1528 by rolandkal (2014-04-13 02:34:15+00:00)
Title: Added null value for list.

No ValidationError raised, If "many=True" and "required=True" are set on PrimaryKerRelatedField.

````python
class CompanySerializer(serializers.ModelSerializer):
groups = serializer.PrimaryKeyRelatedField(many=True, required=True)
class Meta:
model = Company
````

These PUT requests should raise a ValidationError as no groups defined.
````
{"name":"Company Name Ltd.","groups":[]}
{"name":"Company Name Ltd."}
````

Expected error:
````
{"groups": ["This field is required."]}
````