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Code Issues 32 Releases Wiki Activity

Fixed #35405 -- Converted get_cache_name into a cached property in FieldCacheMixin.

Browse Source 
FieldCacheMixin is used by related fields to track their cached values.
This work migrates get_cache_name() to be a cached property to optimize
performance by reducing unnecessary function calls when working with
related fields, given that its value remains constant.

Co-authored-by: Simon Charette <charette.s@gmail.com>
Co-authored-by: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com>
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
This commit is contained in:
Adam Johnson
2024-05-03 17:18:06 +01:00
committed by nessita
parent 15fff62d5d
commit b9838c65ec
8 changed files with 117 additions and 14 deletions
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3
django/contrib/contenttypes/fields.py
View File

@@ -140,7 +140,8 @@ class GenericForeignKey(FieldCacheMixin, Field):
else:
return []
def get_cache_name(self):
@cached_property
def cache_name(self):
return self.name
def get_content_type(self, obj=None, id=None, using=None, model=None):

33
django/db/models/fields/mixins.py
View File

@@ -1,31 +1,52 @@
import warnings
from django.core import checks
from django.utils.deprecation import RemovedInDjango60Warning
from django.utils.functional import cached_property
NOT_PROVIDED = object()
class FieldCacheMixin:
"""Provide an API for working with the model's fields value cache."""
"""
An API for working with the model's fields value cache.
Subclasses must set self.cache_name to a unique entry for the cache -
typically the field’s name.
"""
# RemovedInDjango60Warning.
def get_cache_name(self):
raise NotImplementedError
def get_cached_value(self, instance, default=NOT_PROVIDED):
@cached_property
def cache_name(self):
# RemovedInDjango60Warning: when the deprecation ends, replace with:
# raise NotImplementedError
cache_name = self.get_cache_name()
warnings.warn(
f"Override {self.__class__.__qualname__}.cache_name instead of "
"get_cache_name().",
RemovedInDjango60Warning,
)
return cache_name
def get_cached_value(self, instance, default=NOT_PROVIDED):
try:
return instance._state.fields_cache[cache_name]
return instance._state.fields_cache[self.cache_name]
except KeyError:
if default is NOT_PROVIDED:
raise
return default
def is_cached(self, instance):
return self.get_cache_name() in instance._state.fields_cache
return self.cache_name in instance._state.fields_cache
def set_cached_value(self, instance, value):
instance._state.fields_cache[self.get_cache_name()] = value
instance._state.fields_cache[self.cache_name] = value
def delete_cached_value(self, instance):
del instance._state.fields_cache[self.get_cache_name()]
del instance._state.fields_cache[self.cache_name]
class CheckFieldDefaultMixin:

3
django/db/models/fields/related.py
View File

@@ -509,7 +509,8 @@ class RelatedField(FieldCacheMixin, Field):
)
return target_fields[0]
def get_cache_name(self):
@cached_property
def cache_name(self):
return self.name

10
django/db/models/fields/related_descriptors.py
View File

@@ -210,7 +210,7 @@ class ForwardManyToOneDescriptor:
rel_obj_attr,
instance_attr,
True,
self.field.get_cache_name(),
self.field.cache_name,
False,
)
@@ -486,7 +486,7 @@ class ReverseOneToOneDescriptor:
rel_obj_attr,
instance_attr,
True,
self.related.get_cache_name(),
self.related.cache_name,
False,
)
@@ -744,7 +744,7 @@ def create_reverse_many_to_one_manager(superclass, rel):
def _remove_prefetched_objects(self):
try:
self.instance._prefetched_objects_cache.pop(
self.field.remote_field.get_cache_name()
self.field.remote_field.cache_name
)
except (AttributeError, KeyError):
pass # nothing to clear from cache
@@ -760,7 +760,7 @@ def create_reverse_many_to_one_manager(superclass, rel):
)
try:
return self.instance._prefetched_objects_cache[
self.field.remote_field.get_cache_name()
self.field.remote_field.cache_name
]
except (AttributeError, KeyError):
queryset = super().get_queryset()
@@ -798,7 +798,7 @@ def create_reverse_many_to_one_manager(superclass, rel):
if not self.field.is_cached(rel_obj):
instance = instances_dict[rel_obj_attr(rel_obj)]
setattr(rel_obj, self.field.name, instance)
cache_name = self.field.remote_field.get_cache_name()
cache_name = self.field.remote_field.cache_name
return queryset, rel_obj_attr, instance_attr, False, cache_name, False
def add(self, *objs, bulk=True):

3
django/db/models/fields/reverse_related.py
View File

@@ -248,7 +248,8 @@ class ForeignObjectRel(FieldCacheMixin):
def path_infos(self):
return self.get_path_info()
def get_cache_name(self):
@cached_property
def cache_name(self):
"""
Return the name of the cache key to use for storing an instance of the
forward model on the reverse model.

2
docs/internals/deprecation.txt
View File

@@ -82,6 +82,8 @@ details on these changes.
* The ``OS_OPEN_FLAGS`` attribute of
:class:`~django.core.files.storage.FileSystemStorage` will be removed.
* The ``get_cache_name()`` method of ``FieldCacheMixin`` will be removed.
.. _deprecation-removed-in-5.1:
5.1

2
docs/releases/5.1.txt
View File

@@ -474,6 +474,8 @@ Miscellaneous
overwriting files in storage, set the new
:attr:`~django.core.files.storage.FileSystemStorage.allow_overwrite` option
to ``True`` instead.
* The ``get_cache_name()`` method of ``FieldCacheMixin`` is deprecated in favor
of the ``cache_name`` cached property.
Features removed in 5.1
=======================

75
tests/model_fields/test_mixins.py Normal file
View File

@@ -0,0 +1,75 @@
from django.db.models.fields.mixins import FieldCacheMixin
from django.test import SimpleTestCase
from django.utils.deprecation import RemovedInDjango60Warning
from django.utils.functional import cached_property
from .models import Foo
# RemovedInDjango60Warning.
class ExampleOld(FieldCacheMixin):
def get_cache_name(self):
return "example"
class Example(FieldCacheMixin):
@cached_property
def cache_name(self):
return "example"
class FieldCacheMixinTests(SimpleTestCase):
def setUp(self):
self.instance = Foo()
self.field = Example()
# RemovedInDjango60Warning: when the deprecation ends, replace with:
# def test_cache_name_not_implemented(self):
# with self.assertRaises(NotImplementedError):
# FieldCacheMixin().cache_name
def test_get_cache_name_not_implemented(self):
with self.assertRaises(NotImplementedError):
FieldCacheMixin().get_cache_name()
# RemovedInDjango60Warning.
def test_get_cache_name_deprecated(self):
msg = "Override ExampleOld.cache_name instead of get_cache_name()."
with self.assertWarnsMessage(RemovedInDjango60Warning, msg):
result = ExampleOld().cache_name
self.assertEqual(result, "example")
def test_cache_name(self):
result = Example().cache_name
self.assertEqual(result, "example")
def test_get_cached_value_missing(self):
with self.assertRaises(KeyError):
self.field.get_cached_value(self.instance)
def test_get_cached_value_default(self):
default = object()
result = self.field.get_cached_value(self.instance, default=default)
self.assertIs(result, default)
def test_get_cached_value_after_set(self):
value = object()
self.field.set_cached_value(self.instance, value)
result = self.field.get_cached_value(self.instance)
self.assertIs(result, value)
def test_is_cached_false(self):
result = self.field.is_cached(self.instance)
self.assertFalse(result)
def test_is_cached_true(self):
self.field.set_cached_value(self.instance, 1)
result = self.field.is_cached(self.instance)
self.assertTrue(result)
def test_delete_cached_value(self):
self.field.set_cached_value(self.instance, 1)
self.field.delete_cached_value(self.instance)
result = self.field.is_cached(self.instance)
self.assertFalse(result)