Commit 1abd1776 authored by Aymeric Augustin's avatar Aymeric Augustin
Browse files

[1.8.x] Fixed #25160 (again) -- Moved data loss check on reverse relations. 

Moved data loss check when assigning to a reverse one-to-one relation on
an unsaved instance to Model.save(). This is exactly the same change as
e4b813c0 but for reverse relations.

Backport of c3904deb from master
parent a0ce708c

django/db/models/fields/related.py

+0 −6
Original line number Diff line number Diff line
@@ -506,12 +506,6 @@ class SingleRelatedObjectDescriptor(object): 
                    raise ValueError('Cannot assign "%r": the current database router prevents this relation.' % value)



        related_pk = tuple(getattr(instance, field.attname) for field in self.related.field.foreign_related_fields)

        if None in related_pk:

            raise ValueError(

                'Cannot assign "%r": "%s" instance isn\'t saved in the database.' %

                (value, instance._meta.object_name)

            )



        # Set the value of the related field to the value of the related object's related field

        for index, field in enumerate(self.related.field.local_related_fields):

            setattr(value, field.attname, related_pk[index])

docs/releases/1.8.5.txt

+4 −0
Original line number Diff line number Diff line
@@ -39,3 +39,7 @@ Bugfixes 


* Fixed custom queryset chaining with ``values()`` and ``values_list()``

  (:ticket:`20625`).



* Moved the :ref:`unsaved model instance assignment data loss check

  <unsaved-model-instance-check-18>` on reverse relations to ``Model.save()``

  (:ticket:`25160`).

docs/releases/1.8.txt

+3 −0
Original line number Diff line number Diff line
@@ -701,6 +701,9 @@ Assigning unsaved objects to relations raises an error 
        ...

        ValueError: save() prohibited to prevent data loss due to unsaved related object 'author'.



    A similar check on assignment to reverse one-to-one relations was removed

    in Django 1.8.5.



Assigning unsaved objects to a :class:`~django.db.models.ForeignKey`,

:class:`~django.contrib.contenttypes.fields.GenericForeignKey`, and

:class:`~django.db.models.OneToOneField` now raises a :exc:`ValueError`.

tests/one_to_one/tests.py

+7 −5
Original line number Diff line number Diff line
@@ -371,13 +371,15 @@ class OneToOneTests(TestCase): 
        """

        p = Place()

        b = UndergroundBar.objects.create()

        msg = (

            'Cannot assign "<UndergroundBar: UndergroundBar object>": "Place" '

            'instance isn\'t saved in the database.'

        )



        # Assigning a reverse relation on an unsaved object is allowed.

        p.undergroundbar = b



        # However saving the object is not allowed.

        msg = "save() prohibited to prevent data loss due to unsaved related object 'place'."

        with self.assertNumQueries(0):

            with self.assertRaisesMessage(ValueError, msg):

                p.undergroundbar = b

                b.save()



    def test_nullable_o2o_delete(self):

        u = UndergroundBar.objects.create(place=self.p1)