From 6104875a2cc797bbd1254aa61f22a9b03d652128 Mon Sep 17 00:00:00 2001
From: Paulo <commonzenpython@gmail.com>
Date: Sun, 27 May 2018 13:48:24 +0200
Subject: [PATCH] Fixed #29230 -- Fixed nested prefetches that clash with
descriptors.
---
django/db/models/query.py | 2 +-
tests/prefetch_related/tests.py | 13 +++++++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/django/db/models/query.py b/django/db/models/query.py
index 1ef20d01d9..5ae451879c 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -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)
diff --git a/tests/prefetch_related/tests.py b/tests/prefetch_related/tests.py
index 5a701bffec..9201ff3853 100644
--- a/tests/prefetch_related/tests.py
+++ b/tests/prefetch_related/tests.py
@@ -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'))