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Fixed #17673 -- Forbid field shadowing. 

Thanks Anssi Kääriäinen for the suggestion.
This commit is contained in:
Christopher Medrela 2014-02-07 22:34:56 +01:00 committed by Tim Graham
parent f5123c7291
commit ee9fcb1672
6 changed files with 223 additions and 65 deletions
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61
django/db/models/base.py
View File

@ -1055,7 +1055,11 @@ class Model(six.with_metaclass(ModelBase)):
if not cls._meta.swapped:
errors.extend(cls._check_fields(**kwargs))
errors.extend(cls._check_m2m_through_same_relationship())
errors.extend(cls._check_id_field())
clash_errors = cls._check_id_field() + cls._check_field_name_clashes()
errors.extend(clash_errors)
# If there are field name clashes, hide consequent column name
# clashes.
if not clash_errors:
errors.extend(cls._check_column_name_clashes())
errors.extend(cls._check_index_together())
errors.extend(cls._check_unique_together())
@ -1175,6 +1179,61 @@ class Model(six.with_metaclass(ModelBase)):
else:
return []
@classmethod
def _check_field_name_clashes(cls):
""" Ref #17673. """
errors = []
used_fields = {} # name or attname -> field
# Check that multi-inheritance doesn't cause field name shadowing.
for parent in cls._meta.parents:
for f in parent._meta.local_fields:
clash = used_fields.get(f.name) or used_fields.get(f.attname) or None
if clash:
errors.append(
checks.Error(
('The field "%s" from parent model '
'%s clashes with the field "%s" '
'from parent model %s.') % (
clash.name, clash.model._meta,
f.name, f.model._meta
),
hint=None,
obj=cls,
id='E053',
)
)
used_fields[f.name] = f
used_fields[f.attname] = f
# Check that fields defined in the model don't clash with fields from
# parents.
for f in cls._meta.local_fields:
clash = used_fields.get(f.name) or used_fields.get(f.attname) or None
# Note that we may detect clash between user-defined non-unique
# field "id" and automatically added unique field "id", both
# defined at the same model. This special case is considered in
# _check_id_field and here we ignore it.
id_conflict = (f.name == "id" and
clash and clash.name == "id" and clash.model == cls)
if clash and not id_conflict:
errors.append(
checks.Error(
('The field clashes with the field "%s" '
'from model %s.') % (
clash.name, clash.model._meta
),
hint=None,
obj=f,
id='E054',
)
)
used_fields[f.name] = f
used_fields[f.attname] = f
return errors
@classmethod
def _check_column_name_clashes(cls):
# Store a list of column names which have already been used by other fields.

23
django/db/models/fields/__init__.py
View File

@ -191,8 +191,9 @@ class Field(RegisterLookupMixin):
return errors
def _check_field_name(self):
""" Check if field name is valid (i. e. not ending with an underscore).
"""
""" Check if field name is valid, i.e. 1) does not end with an
underscore, 2) does not contain "__" and 3) is not "pk". """
if self.name.endswith('_'):
return [
checks.Error(
@ -202,6 +203,24 @@ class Field(RegisterLookupMixin):
id='E001',
)
]
elif '__' in self.name:
return [
checks.Error(
'Field names must not contain "__".',
hint=None,
obj=self,
id='E052',
)
]
elif self.name == 'pk':
return [
checks.Error(
'Cannot use "pk" as a field name since it is a reserved name.',
hint=None,
obj=self,
id='E051',
)
]
else:
return []

6
docs/releases/1.7.txt
View File

@ -1068,6 +1068,12 @@ Miscellaneous
which does allow primary keys with value 0. It only forbids *autoincrement*
primary keys with value 0.
* Shadowing model fields defined in a parent model has been forbidden as this
creates amiguity in the expected model behavior. In addition, any clashing
fields in the model inheritance hierarchy results in a system check error.
For example, if you use multi-inheritance, you need to define custom primary
key fields on parent models, otherwise the default ``id`` fields will clash.
.. _deprecated-features-1.7:
Features deprecated in 1.7

158
tests/invalid_models_tests/test_models.py
View File

@ -191,31 +191,9 @@ class UniqueTogetherTests(IsolatedModelsTestCase):
self.assertEqual(errors, expected)
class OtherModelTests(IsolatedModelsTestCase):
class FieldNamesTests(IsolatedModelsTestCase):
def test_unique_primary_key(self):
class Model(models.Model):
id = models.IntegerField(primary_key=False)
errors = Model.check()
expected = [
Error(
('You cannot use "id" as a field name, because each model '
'automatically gets an "id" field if none of the fields '
'have primary_key=True.'),
hint='Remove or rename "id" field or add primary_key=True to a field.',
obj=Model,
id='E005',
),
Error(
'Field "id" has column name "id" that is already used.',
hint=None,
obj=Model,
)
]
self.assertEqual(errors, expected)
def test_field_names_ending_with_underscore(self):
def test_ending_with_underscore(self):
class Model(models.Model):
field_ = models.CharField(max_length=10)
m2m_ = models.ManyToManyField('self')
@ -237,6 +215,138 @@ class OtherModelTests(IsolatedModelsTestCase):
]
self.assertEqual(errors, expected)
def test_including_separator(self):
class Model(models.Model):
some__field = models.IntegerField()
errors = Model.check()
expected = [
Error(
'Field names must not contain "__".',
hint=None,
obj=Model._meta.get_field('some__field'),
id='E052',
)
]
self.assertEqual(errors, expected)
def test_pk(self):
class Model(models.Model):
pk = models.IntegerField()
errors = Model.check()
expected = [
Error(
'Cannot use "pk" as a field name since it is a reserved name.',
hint=None,
obj=Model._meta.get_field('pk'),
id='E051',
)
]
self.assertEqual(errors, expected)
class ShadowingFieldsTests(IsolatedModelsTestCase):
def test_multiinheritance_clash(self):
class Mother(models.Model):
clash = models.IntegerField()
class Father(models.Model):
clash = models.IntegerField()
class Child(Mother, Father):
# Here we have two clashed: id (automatic field) and clash, because
# both parents define these fields.
pass
errors = Child.check()
expected = [
Error(
('The field "id" from parent model '
'invalid_models_tests.mother clashes with the field "id" '
'from parent model invalid_models_tests.father.'),
hint=None,
obj=Child,
id='E053',
),
Error(
('The field "clash" from parent model '
'invalid_models_tests.mother clashes with the field "clash" '
'from parent model invalid_models_tests.father.'),
hint=None,
obj=Child,
id='E053',
)
]
self.assertEqual(errors, expected)
def test_inheritance_clash(self):
class Parent(models.Model):
f_id = models.IntegerField()
class Target(models.Model):
# This field doesn't result in a clash.
f_id = models.IntegerField()
class Child(Parent):
# This field clashes with parent "f_id" field.
f = models.ForeignKey(Target)
errors = Child.check()
expected = [
Error(
('The field clashes with the field "f_id" '
'from model invalid_models_tests.parent.'),
hint=None,
obj=Child._meta.get_field('f'),
id='E054',
)
]
self.assertEqual(errors, expected)
def test_id_clash(self):
class Target(models.Model):
pass
class Model(models.Model):
fk = models.ForeignKey(Target)
fk_id = models.IntegerField()
errors = Model.check()
expected = [
Error(
('The field clashes with the field "fk" from model '
'invalid_models_tests.model.'),
hint=None,
obj=Model._meta.get_field('fk_id'),
id='E054',
)
]
self.assertEqual(errors, expected)
class OtherModelTests(IsolatedModelsTestCase):
def test_unique_primary_key(self):
invalid_id = models.IntegerField(primary_key=False)
class Model(models.Model):
id = invalid_id
errors = Model.check()
expected = [
Error(
('You cannot use "id" as a field name, because each model '
'automatically gets an "id" field if none of the fields '
'have primary_key=True.'),
hint='Remove or rename "id" field or add primary_key=True to a field.',
obj=Model,
id='E005',
),
]
self.assertEqual(errors, expected)
def test_ordering_non_iterable(self):
class Model(models.Model):
class Meta:

4
tests/model_inheritance/models.py
View File

@ -45,10 +45,6 @@ class Student(CommonInfo):
pass
class StudentWorker(Student, Worker):
pass
#
# Abstract base classes with related models
#

34
tests/model_inheritance/tests.py
View File

@ -10,7 +10,7 @@ from django.utils import six
from .models import (
Chef, CommonInfo, ItalianRestaurant, ParkingLot, Place, Post,
Restaurant, Student, StudentWorker, Supplier, Worker, MixinModel,
Restaurant, Student, Supplier, Worker, MixinModel,
Title, Base, SubBase)
@ -48,38 +48,6 @@ class ModelInheritanceTests(TestCase):
# doesn't exist as a model).
self.assertRaises(AttributeError, lambda: CommonInfo.objects.all())
# A StudentWorker which does not exist is both a Student and Worker
# which does not exist.
self.assertRaises(
Student.DoesNotExist,
StudentWorker.objects.get, pk=12321321
)
self.assertRaises(
Worker.DoesNotExist,
StudentWorker.objects.get, pk=12321321
)
# MultipleObjectsReturned is also inherited.
# This is written out "long form", rather than using __init__/create()
# because of a bug with diamond inheritance (#10808)
sw1 = StudentWorker()
sw1.name = "Wilma"
sw1.age = 35
sw1.save()
sw2 = StudentWorker()
sw2.name = "Betty"
sw2.age = 24
sw2.save()
self.assertRaises(
Student.MultipleObjectsReturned,
StudentWorker.objects.get, pk__lt=sw2.pk + 100
)
self.assertRaises(
Worker.MultipleObjectsReturned,
StudentWorker.objects.get, pk__lt=sw2.pk + 100
)
def test_multiple_table(self):
post = Post.objects.create(title="Lorem Ipsum")
# The Post model has distinct accessors for the Comment and Link models.