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[4.1.x] Fixed #33984 -- Reverted "Fixed #32980 -- Made models cache related managers." 

This reverts 4f8c7fd9d9 and adds
two regression tests:
- test_related_manager_refresh(), and
- test_create_copy_with_m2m().

Thanks joeli for the report.
Backport of 5e0aa362d9 from main
This commit is contained in:
Mariusz Felisiak 2022-09-30 18:18:33 +02:00
parent ecf6506f44
commit 7a1675806a
12 changed files with 47 additions and 176 deletions
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8
django/contrib/contenttypes/fields.py
View File

@ -552,14 +552,6 @@ class ReverseGenericManyToOneDescriptor(ReverseManyToOneDescriptor):
self.rel,
)
@cached_property
def related_manager_cache_key(self):
# By default, GenericRel instances will be marked as hidden unless
# related_query_name is given (their accessor name being "+" when
# hidden), which would cause multiple GenericRelations declared on a
# single model to collide, so always use the remote field's name.
return self.field.get_cache_name()
def create_generic_related_manager(superclass, rel):
"""

27
django/db/models/base.py
View File

@ -434,18 +434,11 @@ class ModelBase(type):
return cls._meta.default_manager
class ModelStateCacheDescriptor:
"""
Upon first access, replace itself with an empty dictionary on the instance.
"""
def __set_name__(self, owner, name):
self.attribute_name = name
class ModelStateFieldsCacheDescriptor:
def __get__(self, instance, cls=None):
if instance is None:
return self
res = instance.__dict__[self.attribute_name] = {}
res = instance.fields_cache = {}
return res
@ -458,20 +451,7 @@ class ModelState:
# explicit (non-auto) PKs. This impacts validation only; it has no effect
# on the actual save.
adding = True
fields_cache = ModelStateCacheDescriptor()
related_managers_cache = ModelStateCacheDescriptor()
def __getstate__(self):
state = self.__dict__.copy()
if "fields_cache" in state:
state["fields_cache"] = self.fields_cache.copy()
# Manager instances stored in related_managers_cache won't necessarily
# be deserializable if they were dynamically created via an inner
# scope, e.g. create_forward_many_to_many_manager() and
# create_generic_related_manager().
if "related_managers_cache" in state:
state["related_managers_cache"] = {}
return state
fields_cache = ModelStateFieldsCacheDescriptor()
class Model(metaclass=ModelBase):
@ -633,6 +613,7 @@ class Model(metaclass=ModelBase):
"""Hook to allow choosing the attributes to pickle."""
state = self.__dict__.copy()
state["_state"] = copy.copy(state["_state"])
state["_state"].fields_cache = state["_state"].fields_cache.copy()
# memoryview cannot be pickled, so cast it to bytes and store
# separately.
_memoryview_attrs = []

26
django/db/models/fields/related_descriptors.py
View File

@ -561,14 +561,6 @@ class ReverseManyToOneDescriptor:
self.rel = rel
self.field = rel.field
@cached_property
def related_manager_cache_key(self):
# Being able to access the manager instance precludes it from being
# hidden. The rel's accessor name is used to allow multiple managers
# to the same model to coexist. e.g. post.attached_comment_set and
# post.attached_link_set are separately cached.
return self.rel.get_cache_name()
@cached_property
def related_manager_cls(self):
related_model = self.rel.related_model
@ -590,11 +582,8 @@ class ReverseManyToOneDescriptor:
"""
if instance is None:
return self
key = self.related_manager_cache_key
instance_cache = instance._state.related_managers_cache
if key not in instance_cache:
instance_cache[key] = self.related_manager_cls(instance)
return instance_cache[key]
return self.related_manager_cls(instance)
def _get_set_deprecation_msg_params(self):
return (
@ -913,17 +902,6 @@ class ManyToManyDescriptor(ReverseManyToOneDescriptor):
reverse=self.reverse,
)
@cached_property
def related_manager_cache_key(self):
if self.reverse:
# Symmetrical M2Ms won't have an accessor name, but should never
# end up in the reverse branch anyway, as the related_name ends up
# being hidden, and no public manager is created.
return self.rel.get_cache_name()
else:
# For forward managers, defer to the field name.
return self.field.get_cache_name()
def _get_set_deprecation_msg_params(self):
return (
"%s side of a many-to-many set"

4
docs/releases/4.1.2.txt
View File

@ -43,3 +43,7 @@ Bugfixes
* Fixed a regression in Django 4.1 that caused a crash for :class:`View`
subclasses with asynchronous handlers when handling non-allowed HTTP methods
(:ticket:`34062`).
* Reverted caching related managers for ``ForeignKey``, ``ManyToManyField``,
and ``GenericRelation`` that caused the incorrect refreshing of related
objects (:ticket:`33984`).

3
docs/releases/4.1.txt
View File

@ -530,7 +530,8 @@ Miscellaneous
* Related managers for :class:`~django.db.models.ForeignKey`,
:class:`~django.db.models.ManyToManyField`, and
:class:`~django.contrib.contenttypes.fields.GenericRelation` are now cached
on the :class:`~django.db.models.Model` instance to which they belong.
on the :class:`~django.db.models.Model` instance to which they belong. *This
change was reverted in Django 4.1.2.*
* The Django test runner now returns a non-zero error code for unexpected
successes from tests marked with :py:func:`unittest.expectedFailure`.

16
tests/custom_managers/models.py
View File

@ -164,22 +164,6 @@ class Book(models.Model):
base_manager_name = "annotated_objects"
class ConfusedBook(models.Model):
title = models.CharField(max_length=50)
author = models.CharField(max_length=30)
favorite_things = GenericRelation(
Person,
content_type_field="favorite_thing_type",
object_id_field="favorite_thing_id",
)
less_favorite_things = GenericRelation(
FunPerson,
content_type_field="favorite_thing_type",
object_id_field="favorite_thing_id",
related_query_name="favorite_things",
)
class FastCarManager(models.Manager):
def get_queryset(self):
return super().get_queryset().filter(top_speed__gt=150)

76
tests/custom_managers/tests.py
View File

@ -4,7 +4,6 @@ from django.test import TestCase
from .models import (
Book,
Car,
ConfusedBook,
CustomManager,
CustomQuerySet,
DeconstructibleCustomManager,
@ -196,10 +195,6 @@ class CustomManagerTests(TestCase):
ordered=False,
)
def test_fk_related_manager_reused(self):
self.assertIs(self.b1.favorite_books, self.b1.favorite_books)
self.assertIn("favorite_books", self.b1._state.related_managers_cache)
def test_gfk_related_manager(self):
Person.objects.create(
first_name="Bugs", last_name="Bunny", fun=True, favorite_thing=self.b1
@ -248,67 +243,6 @@ class CustomManagerTests(TestCase):
ordered=False,
)
def test_gfk_related_manager_reused(self):
self.assertIs(
self.b1.fun_people_favorite_things,
self.b1.fun_people_favorite_things,
)
self.assertIn(
"fun_people_favorite_things",
self.b1._state.related_managers_cache,
)
def test_gfk_related_manager_not_reused_when_alternate(self):
self.assertIsNot(
self.b1.favorite_things(manager="fun_people"),
self.b1.favorite_things(manager="fun_people"),
)
def test_gfk_related_manager_no_overlap_when_not_hidden(self):
"""
If a GenericRelation defines a related_query_name (and thus the
related_name) which shadows another GenericRelation, it should not
cause those separate managers to clash.
"""
book = ConfusedBook.objects.create(
title="How to program",
author="Rodney Dangerfield",
)
person = Person.objects.create(
first_name="Bugs",
last_name="Bunny",
fun=True,
favorite_thing=book,
)
fun_person = FunPerson.objects.create(
first_name="Droopy",
last_name="Dog",
fun=False,
favorite_thing=book,
)
# The managers don't collide in the internal cache.
self.assertIsNot(book.favorite_things, book.less_favorite_things)
self.assertIs(book.favorite_things, book.favorite_things)
self.assertIs(book.less_favorite_things, book.less_favorite_things)
# Both managers are cached separately despite the collision in names.
self.assertIn("favorite_things", book._state.related_managers_cache)
self.assertIn("less_favorite_things", book._state.related_managers_cache)
# "less_favorite_things" isn't available as a reverse related manager,
# so never ends up in the cache.
self.assertQuerysetEqual(fun_person.favorite_things.all(), [book])
with self.assertRaises(AttributeError):
fun_person.less_favorite_things
self.assertIn("favorite_things", fun_person._state.related_managers_cache)
self.assertNotIn(
"less_favorite_things",
fun_person._state.related_managers_cache,
)
# The GenericRelation doesn't exist for Person, only FunPerson, so the
# exception prevents the cache from being polluted.
with self.assertRaises(AttributeError):
person.favorite_things
self.assertNotIn("favorite_things", person._state.related_managers_cache)
def test_m2m_related_manager(self):
bugs = Person.objects.create(first_name="Bugs", last_name="Bunny", fun=True)
self.b1.authors.add(bugs)
@ -355,16 +289,6 @@ class CustomManagerTests(TestCase):
ordered=False,
)
def test_m2m_related_forward_manager_reused(self):
self.assertIs(self.b1.authors, self.b1.authors)
self.assertIn("authors", self.b1._state.related_managers_cache)
def test_m2m_related_revers_manager_reused(self):
bugs = Person.objects.create(first_name="Bugs", last_name="Bunny")
self.b1.authors.add(bugs)
self.assertIs(bugs.books, bugs.books)
self.assertIn("books", bugs._state.related_managers_cache)
def test_removal_through_default_fk_related_manager(self, bulk=True):
bugs = FunPerson.objects.create(
first_name="Bugs", last_name="Bunny", fun=True, favorite_book=self.b1

22
tests/m2m_regress/tests.py
View File

@ -39,14 +39,6 @@ class M2MRegressionTests(TestCase):
self.assertSequenceEqual(e1.topics.all(), [t1])
self.assertSequenceEqual(e1.related.all(), [t2])
def test_m2m_managers_reused(self):
s1 = SelfRefer.objects.create(name="s1")
e1 = Entry.objects.create(name="e1")
self.assertIs(s1.references, s1.references)
self.assertIs(s1.related, s1.related)
self.assertIs(e1.topics, e1.topics)
self.assertIs(e1.related, e1.related)
def test_internal_related_name_not_in_error_msg(self):
# The secret internal related names for self-referential many-to-many
# fields shouldn't appear in the list when an error is made.
@ -79,6 +71,20 @@ class M2MRegressionTests(TestCase):
w.save()
w.delete()
def test_create_copy_with_m2m(self):
t1 = Tag.objects.create(name="t1")
Entry.objects.create(name="e1")
entry = Entry.objects.first()
entry.topics.set([t1])
old_topics = entry.topics.all()
entry.pk = None
entry._state.adding = True
entry.save()
entry.topics.set(old_topics)
entry = Entry.objects.get(pk=entry.pk)
self.assertCountEqual(entry.topics.all(), old_topics)
self.assertSequenceEqual(entry.topics.all(), [t1])
def test_add_m2m_with_base_class(self):
# Regression for #11956 -- You can add an object to a m2m with the
# base class without causing integrity errors

19
tests/many_to_many/tests.py
View File

@ -92,6 +92,25 @@ class ManyToManyTests(TestCase):
a5.authors.remove(user_2.username)
self.assertSequenceEqual(a5.authors.all(), [])
def test_related_manager_refresh(self):
user_1 = User.objects.create(username="Jean")
user_2 = User.objects.create(username="Joe")
self.a3.authors.add(user_1.username)
self.assertSequenceEqual(user_1.article_set.all(), [self.a3])
# Change the username on a different instance of the same user.
user_1_from_db = User.objects.get(pk=user_1.pk)
self.assertSequenceEqual(user_1_from_db.article_set.all(), [self.a3])
user_1_from_db.username = "Paul"
self.a3.authors.set([user_2.username])
user_1_from_db.save()
# Assign a different article.
self.a4.authors.add(user_1_from_db.username)
self.assertSequenceEqual(user_1_from_db.article_set.all(), [self.a4])
# Refresh the instance with an evaluated related manager.
user_1.refresh_from_db()
self.assertEqual(user_1.username, "Paul")
self.assertSequenceEqual(user_1.article_set.all(), [self.a4])
def test_add_remove_invalid_type(self):
msg = "Field 'id' expected a number but got 'invalid'."
for method in ["add", "remove"]:

5
tests/model_inheritance_regress/tests.py
View File

@ -416,11 +416,6 @@ class ModelInheritanceTest(TestCase):
parties = list(p4.bachelorparty_set.all())
self.assertEqual(parties, [bachelor, messy_parent])
def test_abstract_base_class_m2m_relation_inheritance_manager_reused(self):
p1 = Person.objects.create(name="Alice")
self.assertIs(p1.birthdayparty_set, p1.birthdayparty_set)
self.assertIs(p1.bachelorparty_set, p1.bachelorparty_set)
def test_abstract_verbose_name_plural_inheritance(self):
"""
verbose_name_plural correctly inherited from ABC if inheritance chain

9
tests/model_regress/test_state.py
View File

@ -1,12 +1,7 @@
from django.db.models.base import ModelState, ModelStateCacheDescriptor
from django.db.models.base import ModelState, ModelStateFieldsCacheDescriptor
from django.test import SimpleTestCase
class ModelStateTests(SimpleTestCase):
def test_fields_cache_descriptor(self):
self.assertIsInstance(ModelState.fields_cache, ModelStateCacheDescriptor)
def test_related_managers_descriptor(self):
self.assertIsInstance(
ModelState.related_managers_cache, ModelStateCacheDescriptor
)
self.assertIsInstance(ModelState.fields_cache, ModelStateFieldsCacheDescriptor)

8
tests/prefetch_related/tests.py
View File

@ -1353,14 +1353,6 @@ class ForeignKeyToFieldTest(TestCase):
],
)
def test_m2m_manager_reused(self):
author = Author.objects.prefetch_related(
"favorite_authors",
"favors_me",
).first()
self.assertIs(author.favorite_authors, author.favorite_authors)
self.assertIs(author.favors_me, author.favors_me)
class LookupOrderingTest(TestCase):
"""