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Fixed transaction handling for a number of operations on related objects. 

Thanks Anssi and Aymeric for the reviews. Refs #21174.
This commit is contained in:
Loic Bistuer 2014-03-30 01:57:28 +07:00
parent 975337e5c3
commit bc9be72bdc
5 changed files with 124 additions and 79 deletions
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7
django/contrib/contenttypes/fields.py
View File

@ -394,6 +394,9 @@ class ReverseGenericRelatedObjectsDescriptor(object):
def __set__(self, instance, value):
manager = self.__get__(instance)
db = router.db_for_write(manager.model, instance=manager.instance)
with transaction.atomic(using=db, savepoint=False):
manager.clear()
for obj in value:
manager.add(obj)
@ -474,6 +477,8 @@ def create_generic_related_manager(superclass):
self.prefetch_cache_name)
def add(self, *objs):
db = router.db_for_write(self.model, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
for obj in objs:
if not isinstance(obj, self.model):
raise TypeError("'%s' instance expected" % self.model._meta.object_name)
@ -498,6 +503,8 @@ def create_generic_related_manager(superclass):
db = router.db_for_write(self.model, instance=self.instance)
queryset = queryset.using(db)
if bulk:
# `QuerySet.delete()` creates its own atomic block which
# contains the `pre_delete` and `post_delete` signal handlers.
queryset.delete()
else:
with transaction.atomic(using=db, savepoint=False):

28
django/db/models/fields/related.py
View File

@ -735,6 +735,7 @@ def create_foreign_related_manager(superclass, rel_field, rel_model):
db = router.db_for_write(self.model, instance=self.instance)
queryset = queryset.using(db)
if bulk:
# `QuerySet.update()` is intrinsically atomic.
queryset.update(**{rel_field.name: None})
else:
with transaction.atomic(using=db, savepoint=False):
@ -763,6 +764,9 @@ class ForeignRelatedObjectsDescriptor(object):
def __set__(self, instance, value):
manager = self.__get__(instance)
db = router.db_for_write(manager.model, instance=manager.instance)
with transaction.atomic(using=db, savepoint=False):
# If the foreign key can support nulls, then completely clear the related set.
# Otherwise, just move the named objects into the set.
if self.related.field.null:
@ -901,6 +905,9 @@ def create_many_related_manager(superclass, rel):
"Cannot use add() on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." %
(opts.app_label, opts.object_name)
)
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
self._add_items(self.source_field_name, self.target_field_name, *objs)
# If this is a symmetrical m2m relation to self, add the mirror entry in the m2m table
@ -920,7 +927,7 @@ def create_many_related_manager(superclass, rel):
def clear(self):
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
signals.m2m_changed.send(sender=self.through, action="pre_clear",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=None, using=db)
@ -990,20 +997,24 @@ def create_many_related_manager(superclass, rel):
)
else:
new_ids.add(obj)
db = router.db_for_write(self.through, instance=self.instance)
vals = self.through._default_manager.using(db).values_list(target_field_name, flat=True)
vals = vals.filter(**{
vals = (self.through._default_manager.using(db)
.values_list(target_field_name, flat=True)
.filter(**{
source_field_name: self.related_val[0],
'%s__in' % target_field_name: new_ids,
})
}))
new_ids = new_ids - set(vals)
with transaction.atomic(using=db, savepoint=False):
if self.reverse or source_field_name == self.source_field_name:
# Don't send the signal when we are inserting the
# duplicate data row for symmetrical reverse entries.
signals.m2m_changed.send(sender=self.through, action='pre_add',
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=new_ids, using=db)
# Add the ones that aren't there already
self.through._default_manager.using(db).bulk_create([
self.through(**{
@ -1037,7 +1048,7 @@ def create_many_related_manager(superclass, rel):
old_ids.add(obj)
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
# Send a signal to the other end if need be.
signals.m2m_changed.send(sender=self.through, action="pre_remove",
instance=self.instance, reverse=self.reverse,
@ -1103,6 +1114,9 @@ class ManyRelatedObjectsDescriptor(object):
raise AttributeError("Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))
manager = self.__get__(instance)
db = router.db_for_write(manager.through, instance=manager.instance)
with transaction.atomic(using=db, savepoint=False):
manager.clear()
manager.add(*value)
@ -1157,9 +1171,13 @@ class ReverseManyRelatedObjectsDescriptor(object):
raise AttributeError("Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))
manager = self.__get__(instance)
# clear() can change expected output of 'value' queryset, we force evaluation
# of queryset before clear; ticket #19816
value = tuple(value)
db = router.db_for_write(manager.through, instance=manager.instance)
with transaction.atomic(using=db, savepoint=False):
manager.clear()
manager.add(*value)

14
docs/releases/1.8.txt
View File

@ -168,7 +168,19 @@ Backwards incompatible changes in 1.8
deprecation timeline for a given feature, its removal may appear as a
backwards incompatible change.
...
* Some operations on related objects such as
:meth:`~django.db.models.fields.related.RelatedManager.add()` or
:ref:`direct assignment<direct-assignment>` ran multiple data modifying
queries without wrapping them in transactions. To reduce the risk of data
corruption, all data modifying methods that affect multiple related objects
(i.e. ``add()``, ``remove()``, ``clear()``, and
:ref:`direct assignment<direct-assignment>`) now perform their data modifying
queries from within a transaction, provided your database supports
transactions.
This has one backwards incompatible side effect, signal handlers triggered
from these methods are now executed within the method's transaction and
any exception in a signal handler will prevent the whole operation.
Miscellaneous
~~~~~~~~~~~~~

3
tests/many_to_many/tests.py
View File

@ -1,5 +1,6 @@
from __future__ import unicode_literals
from django.db import transaction
from django.test import TestCase
from django.utils import six
@ -54,7 +55,9 @@ class ManyToManyTests(TestCase):
# Adding an object of the wrong type raises TypeError
with six.assertRaisesRegex(self, TypeError, "'Publication' instance expected, got <Article.*"):
with transaction.atomic():
a6.publications.add(a5)
# Add a Publication directly via publications.add by using keyword arguments.
a6.publications.create(title='Highlights for Adults')
self.assertQuerysetEqual(a6.publications.all(),

5
tests/multiple_database/tests.py
View File

@ -295,18 +295,22 @@ class QueryTestCase(TestCase):
# Add to an m2m with an object from a different database
with self.assertRaises(ValueError):
with transaction.atomic(using='default'):
marty.book_set.add(dive)
# Set a m2m with an object from a different database
with self.assertRaises(ValueError):
with transaction.atomic(using='default'):
marty.book_set = [pro, dive]
# Add to a reverse m2m with an object from a different database
with self.assertRaises(ValueError):
with transaction.atomic(using='other'):
dive.authors.add(marty)
# Set a reverse m2m with an object from a different database
with self.assertRaises(ValueError):
with transaction.atomic(using='other'):
dive.authors = [mark, marty]
def test_m2m_deletion(self):
@ -762,6 +766,7 @@ class QueryTestCase(TestCase):
# Add to a foreign key set with an object from a different database
with self.assertRaises(ValueError):
with transaction.atomic(using='other'):
dive.reviews.add(review1)
# BUT! if you assign a FK object when the base object hasn't