Fixed #17673 -- Forbid field shadowing. (ee9fcb16) · Commits · Dom Sekotill / django

django/db/models/base.py

+61 −2

Original line number	Diff line number	Diff line
		@@ -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.

django/db/models/fields/init.py

+21 −2

Original line number	Diff line number	Diff line
		@@ -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 []

docs/releases/1.7.txt

+6 −0

Original line number	Diff line number	Diff line
		@@ -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

tests/invalid_models_tests/test_models.py

+130 −20

Original line number	Diff line number	Diff line
		@@ -191,48 +191,158 @@ class UniqueTogetherTests(IsolatedModelsTestCase):
		self.assertEqual(errors, expected)


		class OtherModelTests(IsolatedModelsTestCase):
		class FieldNamesTests(IsolatedModelsTestCase):

		def test_unique_primary_key(self):
		def test_ending_with_underscore(self):
		class Model(models.Model):
		id = models.IntegerField(primary_key=False)
		field_ = models.CharField(max_length=10)
		m2m_ = models.ManyToManyField('self')

		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',
		'Field names must not end with underscores.',
		hint=None,
		obj=Model._meta.get_field('field_'),
		id='E001',
		),
		Error(
		'Field "id" has column name "id" that is already used.',
		'Field names must not end with underscores.',
		hint=None,
		obj=Model,
		obj=Model._meta.get_field('m2m_'),
		id='E001',
		),
		]
		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_field_names_ending_with_underscore(self):
		def test_pk(self):
		class Model(models.Model):
		field_ = models.CharField(max_length=10)
		m2m_ = models.ManyToManyField('self')
		pk = models.IntegerField()

		errors = Model.check()
		expected = [
		Error(
		'Field names must not end with underscores.',
		'Cannot use "pk" as a field name since it is a reserved name.',
		hint=None,
		obj=Model._meta.get_field('field_'),
		id='E001',
		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(
		'Field names must not end with underscores.',
		('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=Model._meta.get_field('m2m_'),
		id='E001',
		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)

tests/model_inheritance/models.py

+0 −4

Original line number	Diff line number	Diff line
		@@ -45,10 +45,6 @@ class Student(CommonInfo):
		pass


		class StudentWorker(Student, Worker):
		pass


		#
		# Abstract base classes with related models
		#