From 213981cef394c6f7603c24b9a51096ffb56f6024 Mon Sep 17 00:00:00 2001
From: Mark Aaron Shirley <maspwr@gmail.com>
Date: Fri, 4 Jan 2013 21:11:03 +0100
Subject: [PATCH] Handle ObjectDoesNotExist exceptions when serializing null
 reverse one-to-one

---
 rest_framework/relations.py              | 10 ++++++++--
 rest_framework/serializers.py            | 17 ++++++++++-------
 rest_framework/tests/models.py           |  5 +++++
 rest_framework/tests/relations_nested.py | 22 +++++++++++++++++++++-
 4 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/rest_framework/relations.py b/rest_framework/relations.py
index 686dcf04e..6c1d4f5ba 100644
--- a/rest_framework/relations.py
+++ b/rest_framework/relations.py
@@ -100,7 +100,10 @@ class RelatedField(WritableField):
     ### Regular serializer stuff...
 
     def field_to_native(self, obj, field_name):
-        value = getattr(obj, self.source or field_name)
+        try:
+            value = getattr(obj, self.source or field_name)
+        except ObjectDoesNotExist:
+            return None
         return self.to_native(value)
 
     def field_from_native(self, data, files, field_name, into):
@@ -202,7 +205,10 @@ class PrimaryKeyRelatedField(RelatedField):
             pk = obj.serializable_value(self.source or field_name)
         except AttributeError:
             # RelatedObject (reverse relationship)
-            obj = getattr(obj, self.source or field_name)
+            try:
+                obj = getattr(obj, self.source or field_name)
+            except ObjectDoesNotExist:
+                return None
             return self.to_native(obj.pk)
         # Forward relationship
         return self.to_native(pk)
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index bd54db4ca..3391a262d 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -293,15 +293,18 @@ class BaseSerializer(Field):
         Override default so that we can apply ModelSerializer as a nested
         field to relationships.
         """
-        if self.source:
-            for component in self.source.split('.'):
-                obj = getattr(obj, component)
+        try:
+            if self.source:
+                for component in self.source.split('.'):
+                    obj = getattr(obj, component)
+                    if is_simple_callable(obj):
+                        obj = obj()
+            else:
+                obj = getattr(obj, field_name)
                 if is_simple_callable(obj):
                     obj = obj()
-        else:
-            obj = getattr(obj, field_name)
-            if is_simple_callable(obj):
-                obj = value()
+        except ObjectDoesNotExist:
+            return None
 
         # If the object has an "all" method, assume it's a relationship
         if is_simple_callable(getattr(obj, 'all', None)):
diff --git a/rest_framework/tests/models.py b/rest_framework/tests/models.py
index 59c350740..34cdbff31 100644
--- a/rest_framework/tests/models.py
+++ b/rest_framework/tests/models.py
@@ -205,3 +205,8 @@ class NullableForeignKeySource(RESTFrameworkModel):
     name = models.CharField(max_length=100)
     target = models.ForeignKey(ForeignKeyTarget, null=True, blank=True,
                                related_name='nullable_sources')
+
+class NullableOneToOneSource(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+    target = models.OneToOneField(ForeignKeyTarget, null=True, blank=True,
+                                  related_name='nullable_source')
diff --git a/rest_framework/tests/relations_nested.py b/rest_framework/tests/relations_nested.py
index 5710c1ef4..808399f74 100644
--- a/rest_framework/tests/relations_nested.py
+++ b/rest_framework/tests/relations_nested.py
@@ -1,7 +1,7 @@
 from django.db import models
 from django.test import TestCase
 from rest_framework import serializers
-from rest_framework.tests.models import ForeignKeyTarget, ForeignKeySource, NullableForeignKeySource
+from rest_framework.tests.models import ForeignKeyTarget, ForeignKeySource, NullableForeignKeySource, NullableOneToOneSource
 
 
 class ForeignKeySourceSerializer(serializers.ModelSerializer):
@@ -28,6 +28,13 @@ class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
         model = NullableForeignKeySource
 
 
+class NullableForeignKeyTargetSerializer(serializers.ModelSerializer):
+    nullable_source = serializers.PrimaryKeyRelatedField()
+
+    class Meta:
+        model = ForeignKeyTarget
+
+
 class ReverseForeignKeyTests(TestCase):
     def setUp(self):
         target = ForeignKeyTarget(name='target-1')
@@ -67,6 +74,10 @@ class NestedNullableForeignKeyTests(TestCase):
     def setUp(self):
         target = ForeignKeyTarget(name='target-1')
         target.save()
+        new_target = ForeignKeyTarget(name='target-2')
+        new_target.save()
+        one_source = NullableOneToOneSource(name='one-source-1', target=target)
+        one_source.save()
         for idx in range(1, 4):
             if idx == 3:
                 target = None
@@ -82,3 +93,12 @@ class NestedNullableForeignKeyTests(TestCase):
             {'id': 3, 'name': u'source-3', 'target': None},
         ]
         self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_retrieve_with_null(self):
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = NullableForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'nullable_source': 1},
+            {'id': 2, 'name': u'target-2', 'nullable_source': None},
+        ]
+        self.assertEquals(serializer.data, expected)