Commit 48cf7516 authored by Simon Charette's avatar Simon Charette
Browse files

[1.9.x] Fixed #26186 -- Documented how app relative relationships of abstract models behave. 

This partially reverts commit bc7d201b.

Thanks Tim for the review.

Refs #25858.

Backport of 0223e213 from master
parent e9234569

django/db/models/fields/related.py

+6 −15
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ from .reverse_related import ( 
RECURSIVE_RELATIONSHIP_CONSTANT = 'self'





def resolve_relation(scope_model, relation, resolve_recursive_relationship=True):

def resolve_relation(scope_model, relation):

    """

    Transform relation into a model or fully-qualified model string of the form

    "app_label.ModelName", relative to scope_model.
@@ -55,10 +55,11 @@ def resolve_relation(scope_model, relation, resolve_recursive_relationship=True) 
    """

    # Check for recursive relations

    if relation == RECURSIVE_RELATIONSHIP_CONSTANT:

        if resolve_recursive_relationship:

        relation = scope_model



    # Look for an "app.Model" relation

    elif isinstance(relation, six.string_types) and '.' not in relation:

    if isinstance(relation, six.string_types):

        if "." not in relation:

            relation = "%s.%s" % (scope_model._meta.app_label, relation)



    return relation
@@ -303,11 +304,6 @@ class RelatedField(Field): 
                field.remote_field.model = related

                field.do_related_class(related, model)

            lazy_related_operation(resolve_related_class, cls, self.remote_field.model, field=self)

        else:

            # Bind a lazy reference to the app in which the model is defined.

            self.remote_field.model = resolve_relation(

                cls, self.remote_field.model, resolve_recursive_relationship=False

            )



    def get_forward_related_filter(self, obj):

        """
@@ -1584,11 +1580,6 @@ class ManyToManyField(RelatedField): 
                lazy_related_operation(resolve_through_model, cls, self.remote_field.through, field=self)

            elif not cls._meta.swapped:

                self.remote_field.through = create_many_to_many_intermediary_model(self, cls)

        else:

            # Bind a lazy reference to the app in which the model is defined.

            self.remote_field.through = resolve_relation(

                cls, self.remote_field.through, resolve_recursive_relationship=False

            )



        # Add the descriptor for the m2m relation.

        setattr(cls, self.name, ManyToManyDescriptor(self.remote_field, reverse=False))

docs/ref/models/fields.txt

+29 −0
Original line number Diff line number Diff line
@@ -1155,6 +1155,35 @@ you can use the name of the model, rather than the model object itself:: 
        # ...

        pass



Relationships defined this way on :ref:`abstract models

<abstract-base-classes>` are resolved when the model is subclassed as a

concrete model and are not relative to the abstract model's ``app_label``:



.. snippet::

    :filename: products/models.py



    from django.db import models



    class AbstractCar(models.Model):

        manufacturer = models.ForeignKey('Manufacturer', on_delete=models.CASCADE)



        class Meta:

            abstract = True



.. snippet::

    :filename: production/models.py



    from django.db import models

    from products.models import AbstractCar



    class Manufacturer(models.Model):

        pass



    class Car(AbstractCar):

        pass



    # Car.manufacturer will point to `production.Manufacturer` here.



To refer to models defined in another application, you can explicitly specify

a model with the full application label. For example, if the ``Manufacturer``

model above is defined in another application called ``production``, you'd

docs/releases/1.9.3.txt

+4 −0
Original line number Diff line number Diff line
@@ -52,3 +52,7 @@ Bugfixes 


* Prevented ``ContentTypeManager`` instances from sharing their cache

  (:ticket:`26286`).



* Reverted a change in Django 1.9.2 (:ticket:`25858`) that prevented relative

  lazy relationships defined on abstract models to be resolved according to

  their concrete model's ``app_label`` (:ticket:`26186`).

tests/model_fields/tests.py

+38 −28
Original line number Diff line number Diff line
@@ -251,25 +251,30 @@ class ForeignKeyTests(test.TestCase): 
    def test_abstract_model_app_relative_foreign_key(self):

        test_apps = Apps(['model_fields', 'model_fields.tests'])



        class Refered(models.Model):

            class Meta:

                apps = test_apps

                app_label = 'model_fields'



        class AbstractReferent(models.Model):

            reference = models.ForeignKey('Refered', on_delete=models.CASCADE)



            class Meta:

                apps = test_apps

                app_label = 'model_fields'

                abstract = True



        def assert_app_model_resolved(label):

            class Refered(models.Model):

                class Meta:

                    apps = test_apps

                    app_label = label



            class ConcreteReferent(AbstractReferent):

                class Meta:

                    apps = test_apps

                app_label = 'tests'

                    app_label = label



            self.assertEqual(ConcreteReferent._meta.get_field('reference').related_model, Refered)



        assert_app_model_resolved('model_fields')

        assert_app_model_resolved('tests')





class ManyToManyFieldTests(test.SimpleTestCase):

    def test_abstract_model_pending_operations(self):
@@ -295,34 +300,39 @@ class ManyToManyFieldTests(test.SimpleTestCase): 
    def test_abstract_model_app_relative_foreign_key(self):

        test_apps = Apps(['model_fields', 'model_fields.tests'])



        class Refered(models.Model):

        class AbstractReferent(models.Model):

            reference = models.ManyToManyField('Refered', through='Through')



            class Meta:

                apps = test_apps

                app_label = 'model_fields'

                abstract = True



        class Through(models.Model):

            refered = models.ForeignKey('Refered', on_delete=models.CASCADE)

            referent = models.ForeignKey('tests.ConcreteReferent', on_delete=models.CASCADE)



        def assert_app_model_resolved(label):

            class Refered(models.Model):

                class Meta:

                    apps = test_apps

                app_label = 'model_fields'

                    app_label = label



        class AbstractReferent(models.Model):

            reference = models.ManyToManyField('Refered', through='Through')

            class Through(models.Model):

                refered = models.ForeignKey('Refered', on_delete=models.CASCADE)

                referent = models.ForeignKey('ConcreteReferent', on_delete=models.CASCADE)



                class Meta:

                app_label = 'model_fields'

                abstract = True

                    apps = test_apps

                    app_label = label



            class ConcreteReferent(AbstractReferent):

                class Meta:

                    apps = test_apps

                app_label = 'tests'

                    app_label = label



            self.assertEqual(ConcreteReferent._meta.get_field('reference').related_model, Refered)

            self.assertEqual(ConcreteReferent.reference.through, Through)



        assert_app_model_resolved('model_fields')

        assert_app_model_resolved('tests')





class TextFieldTests(test.TestCase):

    def test_to_python(self):