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Code Issues 25 Releases Wiki Activity

Fixed #29230 -- Fixed nested prefetches that clash with descriptors.

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Paulo 2018-05-27 13:48:24 +02:00 committed by Tim Graham
parent e0ff88be4f
commit 6104875a2c
2 changed files with 14 additions and 1 deletions
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2
django/db/models/query.py
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@ -1568,7 +1568,7 @@ def prefetch_related_objects(model_instances, *related_lookups):
# same relationships to stop infinite recursion. So, if we
# are already on an automatically added lookup, don't add
# the new lookups from relationships we've seen already.
if not (lookup in auto_lookups and descriptor in followed_descriptors):
if not (prefetch_to in done_queries and lookup in auto_lookups and descriptor in followed_descriptors):
done_queries[prefetch_to] = obj_list
new_lookups = normalize_prefetch_lookups(reversed(additional_lookups), prefetch_to)
auto_lookups.update(new_lookups)

13
tests/prefetch_related/tests.py
View File

@ -772,6 +772,19 @@ class CustomPrefetchTests(TestCase):
self.room2_1
)
def test_nested_prefetch_related_with_duplicate_prefetcher(self):
"""
Nested prefetches whose name clashes with descriptor names
(Person.houses here) are allowed.
"""
occupants = Person.objects.prefetch_related(
Prefetch('houses', to_attr='some_attr_name'),
Prefetch('houses', queryset=House.objects.prefetch_related('main_room')),
)
houses = House.objects.prefetch_related(Prefetch('occupants', queryset=occupants))
with self.assertNumQueries(5):
self.traverse_qs(list(houses), [['occupants', 'houses', 'main_room']])
def test_values_queryset(self):
with self.assertRaisesMessage(ValueError, 'Prefetch querysets cannot use values().'):
Prefetch('houses', House.objects.values('pk'))