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import sys
import pytest
from django.db import models
from djangoproject.social.models import User
from tests.factories import UserFactory
pytestmark = pytest.mark.django_db
def test_handles_calling_queryset_many_times():
UserFactory.create()
user = User.objects.prefetch_related("posts").all()[0]
for _ in range(sys.getrecursionlimit() + 1):
# this should *not* raise a recursion error
list(user.posts.all())
def test_handles_empty_querysets():
User.objects.none().first()
def test_handles_get_with_values():
user = UserFactory.create()
User.objects.filter(pk=user.pk).values("username").get()
class CustomEqualityModel(models.Model):
"""Model that implements custom equality checking using related fields"""
name: models.CharField = models.CharField(max_length=100)
relation: models.ForeignKey[
"CustomEqualityModel", "CustomEqualityModel"
] = models.ForeignKey(
"self", null=True, on_delete=models.CASCADE, related_name="related"
)
def __eq__(self, other: object) -> bool:
if not isinstance(other, CustomEqualityModel):
return NotImplemented
# Explicitly access relation to trigger potential recursion
my_rel = self.relation
other_rel = other.relation
return my_rel == other_rel and self.name == other.name
class Meta:
app_label = "social"
def test_handles_custom_equality_with_relations():
"""
Ensure model equality comparisons don't cause infinite recursion
when __eq__ methods access related fields. This is important because
Django's lazy loading could trigger repeated relation lookups during
equality checks.
"""
# Create test instances
base = CustomEqualityModel.objects.create(name="base")
obj1 = CustomEqualityModel.objects.create(name="test1", relation=base)
obj2 = CustomEqualityModel.objects.create(name="test1", relation=base)
obj3 = CustomEqualityModel.objects.create(name="test2", relation=base)
assert obj1 == obj1 # Same object
assert obj1 == obj2 # Different objects, same values
assert obj1 != obj3 # Different values
result = CustomEqualityModel.objects.filter(name="test1").first()
assert result is not None
_ = result.relation
def test_handles_nested_relation_equality():
"""
Ensure deep relation traversal works correctly without infinite recursion.
This is particularly important for models that compare relations in their
equality checks, as each comparison could potentially trigger a chain of
database lookups through the relationship tree.
"""
root = CustomEqualityModel.objects.create(name="root")
middle = CustomEqualityModel.objects.create(name="middle", relation=root)
leaf1 = CustomEqualityModel.objects.create(name="leaf", relation=middle)
leaf2 = CustomEqualityModel.objects.create(name="leaf", relation=middle)
assert leaf1 == leaf2
assert leaf1.relation == leaf2.relation
result = CustomEqualityModel.objects.filter(name="leaf").first()
assert result is not None
_ = result.relation.relation
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