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	Fields inherited from abstract base classes may be overridden like any other Python attribute. Inheriting from multiple models/classes with the same attribute name will follow the MRO.
		
			
				
	
	
		
			355 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			355 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| from __future__ import unicode_literals
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| 
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| from django.contrib.contenttypes.fields import (
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|     GenericForeignKey, GenericRelation,
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| )
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| from django.contrib.contenttypes.models import ContentType
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| from django.core.checks import Error
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| from django.core.exceptions import FieldDoesNotExist, FieldError
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| from django.db import models
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| from django.test import TestCase
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| from django.test.utils import isolate_apps
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| 
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| 
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| @isolate_apps('model_inheritance')
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| class AbstractInheritanceTests(TestCase):
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|     def test_single_parent(self):
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|         class AbstractBase(models.Model):
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|             name = models.CharField(max_length=30)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class AbstractDescendant(AbstractBase):
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|             name = models.CharField(max_length=50)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class DerivedChild(AbstractBase):
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|             name = models.CharField(max_length=50)
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| 
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|         class DerivedGrandChild(AbstractDescendant):
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|             pass
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| 
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|         self.assertEqual(AbstractDescendant._meta.get_field('name').max_length, 50)
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|         self.assertEqual(DerivedChild._meta.get_field('name').max_length, 50)
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|         self.assertEqual(DerivedGrandChild._meta.get_field('name').max_length, 50)
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| 
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|     def test_multiple_parents_mro(self):
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|         class AbstractBaseOne(models.Model):
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|             class Meta:
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|                 abstract = True
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| 
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|         class AbstractBaseTwo(models.Model):
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|             name = models.CharField(max_length=30)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class DescendantOne(AbstractBaseOne, AbstractBaseTwo):
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|             class Meta:
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|                 abstract = True
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| 
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|         class DescendantTwo(AbstractBaseOne, AbstractBaseTwo):
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|             name = models.CharField(max_length=50)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Derived(DescendantOne, DescendantTwo):
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|             pass
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| 
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|         self.assertEqual(DescendantOne._meta.get_field('name').max_length, 30)
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|         self.assertEqual(DescendantTwo._meta.get_field('name').max_length, 50)
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|         self.assertEqual(Derived._meta.get_field('name').max_length, 50)
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| 
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|     def test_multiple_inheritance_cannot_shadow_concrete_inherited_field(self):
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|         class ConcreteParent(models.Model):
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|             name = models.CharField(max_length=255)
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| 
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|         class AbstractParent(models.Model):
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|             name = models.IntegerField()
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class FirstChild(ConcreteParent, AbstractParent):
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|             pass
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| 
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|         class AnotherChild(AbstractParent, ConcreteParent):
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|             pass
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| 
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|         self.assertIsInstance(FirstChild._meta.get_field('name'), models.CharField)
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|         self.assertEqual(
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|             AnotherChild.check(),
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|             [Error(
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|                 "The field 'name' clashes with the field 'name' "
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|                 "from model 'model_inheritance.concreteparent'.",
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|                 obj=AnotherChild._meta.get_field('name'),
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|                 id="models.E006",
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|             )]
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|         )
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| 
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|     def test_virtual_field(self):
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|         class RelationModel(models.Model):
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|             content_type = models.ForeignKey(ContentType, models.CASCADE)
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|             object_id = models.PositiveIntegerField()
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|             content_object = GenericForeignKey('content_type', 'object_id')
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| 
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|         class RelatedModelAbstract(models.Model):
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|             field = GenericRelation(RelationModel)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class ModelAbstract(models.Model):
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|             field = models.CharField(max_length=100)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class OverrideRelatedModelAbstract(RelatedModelAbstract):
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|             field = models.CharField(max_length=100)
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| 
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|         class ExtendModelAbstract(ModelAbstract):
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|             field = GenericRelation(RelationModel)
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| 
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|         self.assertIsInstance(OverrideRelatedModelAbstract._meta.get_field('field'), models.CharField)
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|         self.assertIsInstance(ExtendModelAbstract._meta.get_field('field'), GenericRelation)
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| 
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|     def test_cannot_override_indirect_abstract_field(self):
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|         class AbstractBase(models.Model):
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|             name = models.CharField(max_length=30)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class ConcreteDescendant(AbstractBase):
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|             pass
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| 
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|         msg = (
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|             "Local field 'name' in class 'Descendant' clashes with field of "
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|             "the same name from base class 'ConcreteDescendant'."
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|         )
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|         with self.assertRaisesMessage(FieldError, msg):
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|             class Descendant(ConcreteDescendant):
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|                 name = models.IntegerField()
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| 
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|     def test_override_field_with_attr(self):
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|         class AbstractBase(models.Model):
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|             first_name = models.CharField(max_length=50)
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|             last_name = models.CharField(max_length=50)
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|             middle_name = models.CharField(max_length=30)
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|             full_name = models.CharField(max_length=150)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Descendant(AbstractBase):
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|             middle_name = None
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| 
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|             def full_name(self):
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|                 return self.first_name + self.last_name
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| 
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|         with self.assertRaises(FieldDoesNotExist):
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|             Descendant._meta.get_field('middle_name')
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| 
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|         with self.assertRaises(FieldDoesNotExist):
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|             Descendant._meta.get_field('full_name')
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| 
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|     def test_overriding_field_removed_by_concrete_model(self):
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|         class AbstractModel(models.Model):
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|             foo = models.CharField(max_length=30)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class RemovedAbstractModelField(AbstractModel):
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|             foo = None
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| 
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|         class OverrideRemovedFieldByConcreteModel(RemovedAbstractModelField):
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|             foo = models.CharField(max_length=50)
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| 
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|         self.assertEqual(OverrideRemovedFieldByConcreteModel._meta.get_field('foo').max_length, 50)
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| 
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|     def test_shadowed_fkey_id(self):
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|         class Foo(models.Model):
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|             pass
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| 
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|         class AbstractBase(models.Model):
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|             foo = models.ForeignKey(Foo, models.CASCADE)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Descendant(AbstractBase):
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|             foo_id = models.IntegerField()
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| 
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|         self.assertEqual(
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|             Descendant.check(),
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|             [Error(
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|                 "The field 'foo_id' clashes with the field 'foo' "
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|                 "from model 'model_inheritance.descendant'.",
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|                 obj=Descendant._meta.get_field('foo_id'),
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|                 id='models.E006',
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|             )]
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|         )
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| 
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|     def test_shadow_related_name_when_set_to_none(self):
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|         class AbstractBase(models.Model):
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|             bar = models.IntegerField()
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Foo(AbstractBase):
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|             bar = None
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|             foo = models.IntegerField()
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| 
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|         class Bar(models.Model):
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|             bar = models.ForeignKey(Foo, models.CASCADE, related_name='bar')
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| 
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|         self.assertEqual(Bar.check(), [])
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| 
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|     def test_reverse_foreign_key(self):
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|         class AbstractBase(models.Model):
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|             foo = models.CharField(max_length=100)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Descendant(AbstractBase):
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|             pass
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| 
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|         class Foo(models.Model):
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|             foo = models.ForeignKey(Descendant, models.CASCADE, related_name='foo')
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| 
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|         self.assertEqual(
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|             Foo._meta.get_field('foo').check(),
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|             [
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|                 Error(
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|                     "Reverse accessor for 'Foo.foo' clashes with field name 'Descendant.foo'.",
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|                     hint=(
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|                         "Rename field 'Descendant.foo', or add/change a related_name "
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|                         "argument to the definition for field 'Foo.foo'."
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|                     ),
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|                     obj=Foo._meta.get_field('foo'),
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|                     id='fields.E302',
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|                 ),
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|                 Error(
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|                     "Reverse query name for 'Foo.foo' clashes with field name 'Descendant.foo'.",
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|                     hint=(
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|                         "Rename field 'Descendant.foo', or add/change a related_name "
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|                         "argument to the definition for field 'Foo.foo'."
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|                     ),
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|                     obj=Foo._meta.get_field('foo'),
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|                     id='fields.E303',
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|                 ),
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|             ]
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|         )
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| 
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|     def test_multi_inheritance_field_clashes(self):
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|         class AbstractBase(models.Model):
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|             name = models.CharField(max_length=30)
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class ConcreteBase(AbstractBase):
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|             pass
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| 
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|         class AbstractDescendant(ConcreteBase):
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|             class Meta:
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|                 abstract = True
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| 
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|         class ConcreteDescendant(AbstractDescendant):
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|             name = models.CharField(max_length=100)
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| 
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|         self.assertEqual(
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|             ConcreteDescendant.check(),
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|             [Error(
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|                 "The field 'name' clashes with the field 'name' from "
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|                 "model 'model_inheritance.concretebase'.",
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|                 obj=ConcreteDescendant._meta.get_field('name'),
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|                 id="models.E006",
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|             )]
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|         )
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| 
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|     def test_override_one2one_relation_auto_field_clashes(self):
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|         class ConcreteParent(models.Model):
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|             name = models.CharField(max_length=255)
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| 
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|         class AbstractParent(models.Model):
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|             name = models.IntegerField()
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         msg = (
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|             "Auto-generated field 'concreteparent_ptr' in class 'Descendant' "
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|             "for parent_link to base class 'ConcreteParent' clashes with "
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|             "declared field of the same name."
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|         )
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|         with self.assertRaisesMessage(FieldError, msg):
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|             class Descendant(ConcreteParent, AbstractParent):
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|                 concreteparent_ptr = models.CharField(max_length=30)
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| 
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|     def test_abstract_model_with_regular_python_mixin_mro(self):
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|         class AbstractModel(models.Model):
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|             name = models.CharField(max_length=255)
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|             age = models.IntegerField()
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| 
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|             class Meta:
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|                 abstract = True
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| 
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|         class Mixin(object):
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|             age = None
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| 
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|         class Mixin2(object):
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|             age = 2
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| 
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|         class DescendantMixin(Mixin):
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|             pass
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| 
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|         class ConcreteModel(models.Model):
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|             foo = models.IntegerField()
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| 
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|         class ConcreteModel2(ConcreteModel):
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|             age = models.SmallIntegerField()
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| 
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|         def fields(model):
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|             if not hasattr(model, '_meta'):
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|                 return list()
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|             return list((f.name, f.__class__) for f in model._meta.get_fields())
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| 
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|         model_dict = {'__module__': 'model_inheritance'}
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|         model1 = type(str('Model1'), (AbstractModel, Mixin), model_dict.copy())
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|         model2 = type(str('Model2'), (Mixin2, AbstractModel), model_dict.copy())
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|         model3 = type(str('Model3'), (DescendantMixin, AbstractModel), model_dict.copy())
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|         model4 = type(str('Model4'), (Mixin2, Mixin, AbstractModel), model_dict.copy())
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|         model5 = type(str('Model5'), (Mixin2, ConcreteModel2, Mixin, AbstractModel), model_dict.copy())
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| 
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|         self.assertEqual(
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|             fields(model1),
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|             [('id', models.AutoField), ('name', models.CharField), ('age', models.IntegerField)]
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|         )
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| 
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|         self.assertEqual(fields(model2), [('id', models.AutoField), ('name', models.CharField)])
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|         self.assertEqual(getattr(model2, 'age'), 2)
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| 
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|         self.assertEqual(fields(model3), [('id', models.AutoField), ('name', models.CharField)])
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| 
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|         self.assertEqual(fields(model4), [('id', models.AutoField), ('name', models.CharField)])
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|         self.assertEqual(getattr(model4, 'age'), 2)
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| 
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|         self.assertEqual(
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|             fields(model5),
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|             [
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|                 ('id', models.AutoField), ('foo', models.IntegerField),
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|                 ('concretemodel_ptr', models.OneToOneField),
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|                 ('age', models.SmallIntegerField), ('concretemodel2_ptr', models.OneToOneField),
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|                 ('name', models.CharField),
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|             ]
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|         )
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