Merge de8742116a into d34dfc3fac

rest_framework/fields.py

@@ -429,6 +429,11 @@ class ModelField(WritableField):
             "type": self.model_field.get_internal_type()
         }
 
+    def validate(self, value):
+        super(ModelField, self).validate(value)
+        if value is None and not self.model_field.null:
+            raise ValidationError(self.error_messages['invalid'])
+
 
 ##### Typed Fields #####
 
@@ -474,10 +479,7 @@ class CharField(WritableField):
             self.validators.append(validators.MaxLengthValidator(max_length))
 
     def from_native(self, value):
-        if isinstance(value, six.string_types):
+        if value in validators.EMPTY_VALUES:
-            return value
-
-        if value is None:
             return ''
 
         return smart_text(value)

rest_framework/relations.py

@@ -33,7 +33,7 @@ class RelatedField(WritableField):
     many_widget = widgets.SelectMultiple
     form_field_class = forms.ChoiceField
     many_form_field_class = forms.MultipleChoiceField
-    null_values = (None, '', 'None')
+    null_values = (None, '', 'None', [], (), {})
 
     cache_choices = False
     empty_label = None
@@ -182,7 +182,7 @@ class RelatedField(WritableField):
         if value in self.null_values:
             if self.required:
                 raise ValidationError(self.error_messages['required'])
-            into[(self.source or field_name)] = None
+            into[(self.source or field_name)] = [] if self.many else None
         elif self.many:
             into[(self.source or field_name)] = [self.from_native(item) for item in value]
         else:

rest_framework/serializers.py

@@ -18,6 +18,7 @@ import types
 from decimal import Decimal
 from django.contrib.contenttypes.generic import GenericForeignKey
 from django.core.paginator import Page
+from django.core.exceptions import ObjectDoesNotExist
 from django.db import models
 from django.forms import widgets
 from django.utils.datastructures import SortedDict
@@ -912,9 +913,19 @@ class ModelSerializer(Serializer):
 
         for field_name, field in self.fields.items():
             field_name = field.source or field_name
+
+            # PY3 compat problem with ManyToManyField & OneToOneField
+            # hasattr in PY2 catches all exceptions, but in PY3 it only looks
+            # for AttributeError
+            # @see: https://code.djangoproject.com/ticket/22839
+            try:
+                field_exists = hasattr(instance, field_name)
+            except (AttributeError, ValueError, ObjectDoesNotExist):
+                field_exists = False
+
             if field_name in exclusions \
                 and not field.read_only \
-                and (field.required or hasattr(instance, field_name)) \
+                and (field.required or field_exists) \
                 and not isinstance(field, Serializer):
                 exclusions.remove(field_name)
         return exclusions

rest_framework/tests/models.py

@@ -52,7 +52,7 @@ class CallableDefaultValueModel(RESTFrameworkModel):
 
 
 class ManyToManyModel(RESTFrameworkModel):
-    rel = models.ManyToManyField(Anchor, help_text='Some help text.')
+    rel = models.ManyToManyField(Anchor, help_text='Some help text.', blank=True)
 
 
 class ReadOnlyManyToManyModel(RESTFrameworkModel):

rest_framework/tests/test_relations.py

@@ -3,6 +3,7 @@ General tests for relational fields.
 """
 from __future__ import unicode_literals
 from django import get_version
+from django.core.exceptions import ValidationError
 from django.db import models
 from django.test import TestCase
 from django.utils import unittest
@@ -43,12 +44,27 @@ class TestManyRelatedMixin(TestCase):
 
         https://github.com/tomchristie/django-rest-framework/pull/632
         '''
-        field = serializers.RelatedField(many=True, read_only=False)
+        field = serializers.RelatedField(many=True, read_only=False, required=False)
 
         into = {}
         field.field_from_native({}, None, 'field_name', into)
         self.assertEqual(into['field_name'], [])
 
+    def test_missing_required_many_to_many_related_field(self):
+        '''
+        Missing but required many-to-many relationship should cause
+        ValidationError
+        '''
+        field = serializers.RelatedField(many=True, read_only=False)
+
+        into = {}
+        self.assertRaises(
+            ValidationError,
+            field.field_from_native,
+            {}, None, 'field_name', into
+        )
+        self.assertDictEqual(into, {})
+
 
 # Regression tests for #694 (`source` attribute on related fields)