innov
/
django1
1
0
Fork 0
Code Issues Pull Requests 1 Projects Releases Wiki Activity

Fixed #6707 -- Added RelatedManager.set() and made descriptors' __set__ use it. 

Thanks Anssi Kääriäinen, Carl Meyer, Collin Anderson, and Tim Graham for the reviews.
This commit is contained in:
Loic Bistuer 2015-01-30 01:15:27 +07:00
parent 49516f7158
commit 71ada3a8e6
10 changed files with 350 additions and 100 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
django/contrib/contenttypes/fields.py
View File

@ -436,16 +436,8 @@ class ReverseGenericRelatedObjectsDescriptor(object):
return manager
def __set__(self, instance, value):
# Force evaluation of `value` in case it's a queryset whose
# value could be affected by `manager.clear()`. Refs #19816.
value = tuple(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)
manager.set(value)
def create_generic_related_manager(superclass):
@ -561,6 +553,31 @@ def create_generic_related_manager(superclass):
obj.delete()
_clear.alters_data = True
def set(self, objs, **kwargs):
clear = kwargs.pop('clear', False)
db = router.db_for_write(self.model, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
if clear:
# Force evaluation of `objs` in case it's a queryset whose value
# could be affected by `manager.clear()`. Refs #19816.
objs = tuple(objs)
self.clear()
self.add(*objs)
else:
old_objs = set(self.using(db).all())
new_objs = []
for obj in objs:
if obj in old_objs:
old_objs.remove(obj)
else:
new_objs.append(obj)
self.remove(*old_objs)
self.add(*new_objs)
set.alters_data = True
def create(self, **kwargs):
kwargs[self.content_type_field_name] = self.content_type
kwargs[self.object_id_field_name] = self.pk_val

102
django/db/models/fields/related.py
View File

@ -796,6 +796,34 @@ def create_foreign_related_manager(superclass, rel_field, rel_model):
obj.save(update_fields=[rel_field.name])
_clear.alters_data = True
def set(self, objs, **kwargs):
clear = kwargs.pop('clear', False)
if rel_field.null:
db = router.db_for_write(self.model, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
if clear:
# Force evaluation of `objs` in case it's a queryset whose value
# could be affected by `manager.clear()`. Refs #19816.
objs = tuple(objs)
self.clear()
self.add(*objs)
else:
old_objs = set(self.using(db).all())
new_objs = []
for obj in objs:
if obj in old_objs:
old_objs.remove(obj)
else:
new_objs.append(obj)
self.remove(*old_objs)
self.add(*new_objs)
else:
self.add(*objs)
set.alters_data = True
return RelatedManager
@ -815,18 +843,8 @@ class ForeignRelatedObjectsDescriptor(object):
return self.related_manager_cls(instance)
def __set__(self, instance, value):
# Force evaluation of `value` in case it's a queryset whose
# value could be affected by `manager.clear()`. Refs #19816.
value = tuple(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:
manager.clear()
manager.add(*value)
manager.set(value)
@cached_property
def related_manager_cls(self):
@ -1002,6 +1020,43 @@ def create_many_related_manager(superclass, rel):
model=self.model, pk_set=None, using=db)
clear.alters_data = True
def set(self, objs, **kwargs):
if not rel.through._meta.auto_created:
opts = self.through._meta
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)
)
clear = kwargs.pop('clear', False)
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
if clear:
# Force evaluation of `objs` in case it's a queryset whose value
# could be affected by `manager.clear()`. Refs #19816.
objs = tuple(objs)
self.clear()
self.add(*objs)
else:
old_ids = set(self.using(db).values_list(self.target_field.related_field.attname, flat=True))
new_objs = []
for obj in objs:
fk_val = (self.target_field.get_foreign_related_value(obj)[0]
if isinstance(obj, self.model) else obj)
if fk_val in old_ids:
old_ids.remove(fk_val)
else:
new_objs.append(obj)
self.remove(*old_ids)
self.add(*new_objs)
set.alters_data = True
def create(self, **kwargs):
# This check needs to be done here, since we can't later remove this
# from the method lookup table, as we do with add and remove.
@ -1181,22 +1236,8 @@ class ManyRelatedObjectsDescriptor(object):
return manager
def __set__(self, instance, value):
if not self.related.field.rel.through._meta.auto_created:
opts = self.related.field.rel.through._meta
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)
)
# Force evaluation of `value` in case it's a queryset whose
# value could be affected by `manager.clear()`. Refs #19816.
value = tuple(value)
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)
manager.set(value)
class ReverseManyRelatedObjectsDescriptor(object):
@ -1251,15 +1292,8 @@ class ReverseManyRelatedObjectsDescriptor(object):
"intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name)
)
# Force evaluation of `value` in case it's a queryset whose
# value could be affected by `manager.clear()`. Refs #19816.
value = tuple(value)
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)
manager.set(value)
class ForeignObjectRel(object):

39
docs/ref/models/relations.txt
View File

@ -135,12 +135,31 @@ Related objects reference
:class:`~django.db.models.ForeignKey`\s where ``null=True`` and it also
accepts the ``bulk`` keyword argument.
.. method:: set(objs, clear=False)
.. versionadded:: 1.9
Replace the set of related objects::
>>> new_list = [obj1, obj2, obj3]
>>> e.related_set.set(new_list)
This method accepts a ``clear`` argument to control how to perform the
operation. If ``False`` (the default), the elements missing from the
new set are removed using ``remove()`` and only the new ones are added.
If ``clear=True``, the ``clear()`` method is called instead and the
whole set is added at once.
Note that since ``set()`` is a compound operation, it is subject to
race conditions. For instance, new objects may be added to the database
in between the call to ``clear()`` and the call to ``add()``.
.. note::
Note that ``add()``, ``create()``, ``remove()``, and ``clear()`` all
apply database changes immediately for all types of related fields. In
other words, there is no need to call ``save()`` on either end of the
relationship.
Note that ``add()``, ``create()``, ``remove()``, ``clear()``, and
``set()`` all apply database changes immediately for all types of
related fields. In other words, there is no need to call ``save()``
on either end of the relationship.
Also, if you are using :ref:`an intermediate model
<intermediary-manytomany>` for a many-to-many relationship, some of the
@ -158,6 +177,12 @@ new iterable of objects to it::
>>> e.related_set = new_list
If the foreign key relationship has ``null=True``, then the related manager
will first call ``clear()`` to disassociate any existing objects in the related
set before adding the contents of ``new_list``. Otherwise the objects in
``new_list`` will be added to the existing related object set.
will first disassociate any existing objects in the related set before adding
the contents of ``new_list``. Otherwise the objects in ``new_list`` will be
added to the existing related object set.
.. versionchanged:1.9
In earlier versions, direct assignment used to perform ``clear()`` followed
by ``add()``. It now performs a ``set()`` with the keyword argument
``clear=False``.

24
docs/releases/1.9.txt
View File

@ -127,7 +127,10 @@ Management Commands
Models
^^^^^^
* ...
* Added the :meth:`RelatedManager.set()
<django.db.models.fields.related.RelatedManager.set()>` method to the related
managers created by ``ForeignKey``, ``GenericForeignKey``, and
``ManyToManyField``.
Signals
^^^^^^^
@ -192,6 +195,25 @@ used by the egg loader to detect if setuptools was installed. The ``is_usable``
attribute is now removed and the egg loader instead fails at runtime if
setuptools is not installed.
Related set direct assignment
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:ref:`Direct assignment <direct-assignment>`) used to perform a ``clear()``
followed by a call to ``add()``. This caused needlessly large data changes
and prevented using the :data:`~django.db.models.signals.m2m_changed` signal
to track individual changes in many-to-many relations.
Direct assignment now relies on the the new
:meth:`django.db.models.fields.related.RelatedManager.set()` method on
related managers which by default only processes changes between the
existing related set and the one that's newly assigned. The previous behavior
can be restored by replacing direct assignment by a call to ``set()`` with
the keyword argument ``clear=True``.
``ModelForm``, and therefore ``ModelAdmin``, internally rely on direct
assignment for many-to-many relations and as a consequence now use the new
behavior.
Miscellaneous
~~~~~~~~~~~~~

3
docs/topics/db/queries.txt
View File

@ -1190,6 +1190,9 @@ be found in the :doc:`related objects reference </ref/models/relations>`.
``clear()``
Removes all objects from the related object set.
``set(objs)``
Replace the set of related objects.
To assign the members of a related set in one fell swoop, just assign to it
from any iterable object. The iterable can contain object instances, or just
a list of primary key values. For example::

52
tests/generic_relations/tests.py
View File

@ -246,6 +246,58 @@ class GenericRelationsTests(TestCase):
self.comp_func
)
def test_set(self):
bacon = Vegetable.objects.create(name="Bacon", is_yucky=False)
fatty = bacon.tags.create(tag="fatty")
salty = bacon.tags.create(tag="salty")
bacon.tags.set([fatty, salty])
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
"<TaggedItem: salty>",
])
bacon.tags.set([fatty])
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
])
bacon.tags.set([])
self.assertQuerysetEqual(bacon.tags.all(), [])
bacon.tags.set([fatty, salty], clear=True)
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
"<TaggedItem: salty>",
])
bacon.tags.set([fatty], clear=True)
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
])
bacon.tags.set([], clear=True)
self.assertQuerysetEqual(bacon.tags.all(), [])
def test_assign(self):
bacon = Vegetable.objects.create(name="Bacon", is_yucky=False)
fatty = bacon.tags.create(tag="fatty")
salty = bacon.tags.create(tag="salty")
bacon.tags = [fatty, salty]
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
"<TaggedItem: salty>",
])
bacon.tags = [fatty]
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
])
bacon.tags = []
self.assertQuerysetEqual(bacon.tags.all(), [])
def test_assign_with_queryset(self):
# Ensure that querysets used in reverse GFK assignments are pre-evaluated
# so their value isn't affected by the clearing operation in

98
tests/m2m_signals/tests.py
View File

@ -252,6 +252,38 @@ class ManyToManySignalsTest(TestCase):
# direct assignment clears the set first, then adds
self.vw.default_parts = [self.wheelset, self.doors, self.engine]
expected_messages.append({
'instance': self.vw,
'action': 'pre_remove',
'reverse': False,
'model': Part,
'objects': [p6],
})
expected_messages.append({
'instance': self.vw,
'action': 'post_remove',
'reverse': False,
'model': Part,
'objects': [p6],
})
expected_messages.append({
'instance': self.vw,
'action': 'pre_add',
'reverse': False,
'model': Part,
'objects': [self.doors, self.engine, self.wheelset],
})
expected_messages.append({
'instance': self.vw,
'action': 'post_add',
'reverse': False,
'model': Part,
'objects': [self.doors, self.engine, self.wheelset],
})
self.assertEqual(self.m2m_changed_messages, expected_messages)
# set by clearing.
self.vw.default_parts.set([self.wheelset, self.doors, self.engine], clear=True)
expected_messages.append({
'instance': self.vw,
'action': 'pre_clear',
@ -280,22 +312,28 @@ class ManyToManySignalsTest(TestCase):
})
self.assertEqual(self.m2m_changed_messages, expected_messages)
# set by only removing what's necessary.
self.vw.default_parts.set([self.wheelset, self.doors], clear=False)
expected_messages.append({
'instance': self.vw,
'action': 'pre_remove',
'reverse': False,
'model': Part,
'objects': [self.engine],
})
expected_messages.append({
'instance': self.vw,
'action': 'post_remove',
'reverse': False,
'model': Part,
'objects': [self.engine],
})
self.assertEqual(self.m2m_changed_messages, expected_messages)
# Check that signals still work when model inheritance is involved
c4 = SportsCar.objects.create(name='Bugatti', price='1000000')
c4b = Car.objects.get(name='Bugatti')
c4.default_parts = [self.doors]
expected_messages.append({
'instance': c4,
'action': 'pre_clear',
'reverse': False,
'model': Part,
})
expected_messages.append({
'instance': c4,
'action': 'post_clear',
'reverse': False,
'model': Part,
})
expected_messages.append({
'instance': c4,
'action': 'pre_add',
@ -340,18 +378,6 @@ class ManyToManySignalsTest(TestCase):
)
self.alice.friends = [self.bob, self.chuck]
expected_messages.append({
'instance': self.alice,
'action': 'pre_clear',
'reverse': False,
'model': Person,
})
expected_messages.append({
'instance': self.alice,
'action': 'post_clear',
'reverse': False,
'model': Person,
})
expected_messages.append({
'instance': self.alice,
'action': 'pre_add',
@ -369,18 +395,6 @@ class ManyToManySignalsTest(TestCase):
self.assertEqual(self.m2m_changed_messages, expected_messages)
self.alice.fans = [self.daisy]
expected_messages.append({
'instance': self.alice,
'action': 'pre_clear',
'reverse': False,
'model': Person,
})
expected_messages.append({
'instance': self.alice,
'action': 'post_clear',
'reverse': False,
'model': Person,
})
expected_messages.append({
'instance': self.alice,
'action': 'pre_add',
@ -398,18 +412,6 @@ class ManyToManySignalsTest(TestCase):
self.assertEqual(self.m2m_changed_messages, expected_messages)
self.chuck.idols = [self.alice, self.bob]
expected_messages.append({
'instance': self.chuck,
'action': 'pre_clear',
'reverse': True,
'model': Person,
})
expected_messages.append({
'instance': self.chuck,
'action': 'post_clear',
'reverse': True,
'model': Person,
})
expected_messages.append({
'instance': self.chuck,
'action': 'pre_add',

39
tests/many_to_many/tests.py
View File

@ -332,6 +332,45 @@ class ManyToManyTests(TestCase):
])
self.assertQuerysetEqual(self.a3.publications.all(), [])
def test_set(self):
self.p2.article_set.set([self.a4, self.a3])
self.assertQuerysetEqual(self.p2.article_set.all(),
[
'<Article: NASA finds intelligent life on Earth>',
'<Article: Oxygen-free diet works wonders>',
])
self.assertQuerysetEqual(self.a4.publications.all(),
['<Publication: Science News>'])
self.a4.publications.set([self.p3.id])
self.assertQuerysetEqual(self.p2.article_set.all(),
['<Article: NASA finds intelligent life on Earth>'])
self.assertQuerysetEqual(self.a4.publications.all(),
['<Publication: Science Weekly>'])
self.p2.article_set.set([])
self.assertQuerysetEqual(self.p2.article_set.all(), [])
self.a4.publications.set([])
self.assertQuerysetEqual(self.a4.publications.all(), [])
self.p2.article_set.set([self.a4, self.a3], clear=True)
self.assertQuerysetEqual(self.p2.article_set.all(),
[
'<Article: NASA finds intelligent life on Earth>',
'<Article: Oxygen-free diet works wonders>',
])
self.assertQuerysetEqual(self.a4.publications.all(),
['<Publication: Science News>'])
self.a4.publications.set([self.p3.id], clear=True)
self.assertQuerysetEqual(self.p2.article_set.all(),
['<Article: NASA finds intelligent life on Earth>'])
self.assertQuerysetEqual(self.a4.publications.all(),
['<Publication: Science Weekly>'])
self.p2.article_set.set([], clear=True)
self.assertQuerysetEqual(self.p2.article_set.all(), [])
self.a4.publications.set([], clear=True)
self.assertQuerysetEqual(self.a4.publications.all(), [])
def test_assign(self):
# Relation sets can be assigned. Assignment clears any existing set members
self.p2.article_set = [self.a4, self.a3]

39
tests/many_to_one/tests.py
View File

@ -80,11 +80,49 @@ class ManyToOneTests(TestCase):
"<Article: This is a test>",
])
def test_set(self):
new_article = self.r.article_set.create(headline="John's second story",
pub_date=datetime.date(2005, 7, 29))
new_article2 = self.r2.article_set.create(headline="Paul's story",
pub_date=datetime.date(2006, 1, 17))
# Assign the article to the reporter.
new_article2.reporter = self.r
new_article2.save()
self.assertEqual(repr(new_article2.reporter), "<Reporter: John Smith>")
self.assertEqual(new_article2.reporter.id, self.r.id)
self.assertQuerysetEqual(self.r.article_set.all(), [
"<Article: John's second story>",
"<Article: Paul's story>",
"<Article: This is a test>",
])
self.assertQuerysetEqual(self.r2.article_set.all(), [])
# Set the article back again.
self.r2.article_set.set([new_article, new_article2])
self.assertQuerysetEqual(self.r.article_set.all(), ["<Article: This is a test>"])
self.assertQuerysetEqual(self.r2.article_set.all(),
[
"<Article: John's second story>",
"<Article: Paul's story>",
])
# Funny case - because the ForeignKey cannot be null,
# existing members of the set must remain.
self.r.article_set.set([new_article])
self.assertQuerysetEqual(self.r.article_set.all(),
[
"<Article: John's second story>",
"<Article: This is a test>",
])
self.assertQuerysetEqual(self.r2.article_set.all(), ["<Article: Paul's story>"])
def test_assign(self):
new_article = self.r.article_set.create(headline="John's second story",
pub_date=datetime.date(2005, 7, 29))
new_article2 = self.r2.article_set.create(headline="Paul's story",
pub_date=datetime.date(2006, 1, 17))
# Assign the article to the reporter directly using the descriptor.
new_article2.reporter = self.r
new_article2.save()
@ -96,6 +134,7 @@ class ManyToOneTests(TestCase):
"<Article: This is a test>",
])
self.assertQuerysetEqual(self.r2.article_set.all(), [])
# Set the article back again using set descriptor.
self.r2.article_set = [new_article, new_article2]
self.assertQuerysetEqual(self.r.article_set.all(), ["<Article: This is a test>"])

19
tests/many_to_one_null/tests.py
View File

@ -74,9 +74,26 @@ class ManyToOneNullTests(TestCase):
self.assertRaises(Reporter.DoesNotExist, self.r.article_set.remove, self.a4)
self.assertQuerysetEqual(self.r2.article_set.all(), ['<Article: Fourth>'])
def test_set(self):
# Use manager.set() to allocate ForeignKey. Null is legal, so existing
# members of the set that are not in the assignment set are set to null.
self.r2.article_set.set([self.a2, self.a3])
self.assertQuerysetEqual(self.r2.article_set.all(),
['<Article: Second>', '<Article: Third>'])
# Use manager.set(clear=True)
self.r2.article_set.set([self.a3, self.a4], clear=True)
self.assertQuerysetEqual(self.r2.article_set.all(),
['<Article: Fourth>', '<Article: Third>'])
# Clear the rest of the set
self.r2.article_set.set([])
self.assertQuerysetEqual(self.r2.article_set.all(), [])
self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
['<Article: Fourth>', '<Article: Second>', '<Article: Third>'])
def test_assign_clear_related_set(self):
# Use descriptor assignment to allocate ForeignKey. Null is legal, so
# existing members of set that are not in the assignment set are set null
# existing members of the set that are not in the assignment set are
# set to null.
self.r2.article_set = [self.a2, self.a3]
self.assertQuerysetEqual(self.r2.article_set.all(),
['<Article: Second>', '<Article: Third>'])