Fixed #26226 -- Made related managers honor the queryset used for prefetching their results. (c92123cc) · Commits · Dom Sekotill / django

django/contrib/contenttypes/fields.py

+9 −2

Original line number	Diff line number	Diff line
		@@ -521,12 +521,19 @@ def create_generic_related_manager(superclass, rel):
		def __str__(self):
		return repr(self)

		def _apply_rel_filters(self, queryset):
		"""
		Filter the queryset for the instance this manager is bound to.
		"""
		db = self._db or router.db_for_read(self.model, instance=self.instance)
		return queryset.using(db).filter(**self.core_filters)

		def get_queryset(self):
		try:
		return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
		except (AttributeError, KeyError):
		db = self._db or router.db_for_read(self.model, instance=self.instance)
		return super(GenericRelatedObjectManager, self).get_queryset().using(db).filter(**self.core_filters)
		queryset = super(GenericRelatedObjectManager, self).get_queryset()
		return self._apply_rel_filters(queryset)

		def get_prefetch_queryset(self, instances, queryset=None):
		if queryset is None:

django/db/models/fields/related_descriptors.py

+30 −18

Original line number	Diff line number	Diff line
		@@ -502,23 +502,29 @@ def create_reverse_many_to_one_manager(superclass, rel):
		return manager_class(self.instance)
		do_not_call_in_templates = True

		def get_queryset(self):
		try:
		return self.instance._prefetched_objects_cache[self.field.related_query_name()]
		except (AttributeError, KeyError):
		def _apply_rel_filters(self, queryset):
		"""
		Filter the queryset for the instance this manager is bound to.
		"""
		db = self._db or router.db_for_read(self.model, instance=self.instance)
		empty_strings_as_null = connections[db].features.interprets_empty_strings_as_nulls
		qs = super(RelatedManager, self).get_queryset()
		qs._add_hints(instance=self.instance)
		queryset._add_hints(instance=self.instance)
		if self._db:
		qs = qs.using(self._db)
		qs = qs.filter(**self.core_filters)
		queryset = queryset.using(self._db)
		queryset = queryset.filter(**self.core_filters)
		for field in self.field.foreign_related_fields:
		val = getattr(self.instance, field.attname)
		if val is None or (val == '' and empty_strings_as_null):
		return qs.none()
		qs._known_related_objects = {self.field: {self.instance.pk: self.instance}}
		return qs
		return queryset.none()
		queryset._known_related_objects = {self.field: {self.instance.pk: self.instance}}
		return queryset

		def get_queryset(self):
		try:
		return self.instance._prefetched_objects_cache[self.field.related_query_name()]
		except (AttributeError, KeyError):
		queryset = super(RelatedManager, self).get_queryset()
		return self._apply_rel_filters(queryset)

		def get_prefetch_queryset(self, instances, queryset=None):
		if queryset is None:
		@@ -776,15 +782,21 @@ def create_forward_many_to_many_manager(superclass, rel, reverse):
		filters \|= symmetrical_filters
		return filters

		def _apply_rel_filters(self, queryset):
		"""
		Filter the queryset for the instance this manager is bound to.
		"""
		queryset._add_hints(instance=self.instance)
		if self._db:
		queryset = queryset.using(self._db)
		return queryset._next_is_sticky().filter(**self.core_filters)

		def get_queryset(self):
		try:
		return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
		except (AttributeError, KeyError):
		qs = super(ManyRelatedManager, self).get_queryset()
		qs._add_hints(instance=self.instance)
		if self._db:
		qs = qs.using(self._db)
		return qs._next_is_sticky().filter(**self.core_filters)
		queryset = super(ManyRelatedManager, self).get_queryset()
		return self._apply_rel_filters(queryset)

		def get_prefetch_queryset(self, instances, queryset=None):
		if queryset is None:

django/db/models/query.py

+21 −2

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@ from django.db.models.query_utils import (
		)
		from django.db.models.sql.constants import CURSOR
		from django.utils import six, timezone
		from django.utils.deprecation import RemovedInDjango20Warning
		from django.utils.functional import partition
		from django.utils.version import get_version

		@@ -1608,6 +1609,9 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
		msg = 'to_attr={} conflicts with a field on the {} model.'
		raise ValueError(msg.format(to_attr, model.__name__))

		# Whether or not we're prefetching the last part of the lookup.
		leaf = len(lookup.prefetch_through.split(LOOKUP_SEP)) - 1 == level

		for obj in instances:
		instance_attr_val = instance_attr(obj)
		vals = rel_obj_cache.get(instance_attr_val, [])
		@@ -1621,8 +1625,23 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
		setattr(obj, to_attr, vals)
		obj._prefetched_objects_cache[cache_name] = vals
		else:
		# Cache in the QuerySet.all().
		qs = getattr(obj, to_attr).all()
		manager = getattr(obj, to_attr)
		if leaf and lookup.queryset is not None:
		try:
		apply_rel_filter = manager._apply_rel_filters
		except AttributeError:
		warnings.warn(
		"The `%s.%s` class must implement a `_apply_rel_filters()` "
		"method that accepts a `QuerySet` as its single "
		"argument and returns an appropriately filtered version "
		"of it." % (manager.__class__.__module__, manager.__class__.__name__),
		RemovedInDjango20Warning,
		)
		qs = manager.get_queryset()
		else:
		qs = apply_rel_filter(lookup.queryset)
		else:
		qs = manager.get_queryset()
		qs._result_cache = vals
		# We don't want the individual qs doing prefetch_related now,
		# since we have merged this into the current work.

docs/internals/deprecation.txt

+3 −0

Original line number	Diff line number	Diff line
		@@ -144,6 +144,9 @@ details on these changes.
		* The ``__search`` query lookup and the
		``DatabaseOperations.fulltext_search_sql()`` method will be removed.

		* The shim for supporting custom related manager classes without a
		``_apply_rel_filters()`` method will be removed.

		.. _deprecation-removed-in-1.10:

		1.10

docs/releases/1.10.txt

+11 −0

Original line number	Diff line number	Diff line
		@@ -762,6 +762,17 @@ features, is deprecated. Replace it with a custom lookup::
		models.CharField.register_lookup(Search)
		models.TextField.register_lookup(Search)

		Custom manager classes available through ``prefetch_related`` must define a ``_apply_rel_filters()`` method
		-----------------------------------------------------------------------------------------------------------

		If you defined a custom manager class available through
		:meth:`~django.db.models.query.QuerySet.prefetch_related` you must make sure
		it defines a ``_apply_rel_filters()`` method.

		This method must accept a :class:`~django.db.models.query.QuerySet` instance
		as its single argument and return a filtered version of the queryset for the
		model instance the manager is bound to.

		Miscellaneous
		-------------