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Refs #34007, Refs #35359 -- Added Q.referenced_based_fields property.
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Thank you to Mariusz Felisiak and Natalia Bidart for the reviews.
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David Sanders authored and sarahboyce committed May 2, 2024
1 parent 39828fa commit 97d48cd
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13 changes: 13 additions & 0 deletions django/db/models/query_utils.py
Original file line number Diff line number Diff line change
Expand Up @@ -175,6 +175,19 @@ def __eq__(self, other):
def __hash__(self):
return hash(self.identity)

@cached_property
def referenced_base_fields(self):
"""
Retrieve all base fields referenced directly or through F expressions
excluding any fields referenced through joins.
"""
# Avoid circular imports.
from django.db.models.sql import query

return {
child.split(LOOKUP_SEP, 1)[0] for child in query.get_children_from_q(self)
}


class DeferredAttribute:
"""
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28 changes: 28 additions & 0 deletions tests/queries/test_q.py
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
)
from django.db.models.expressions import NegatedExpression, RawSQL
from django.db.models.functions import Lower
from django.db.models.lookups import Exact, IsNull
from django.db.models.sql.where import NothingNode
from django.test import SimpleTestCase, TestCase

Expand Down Expand Up @@ -263,6 +264,33 @@ def test_create_helper(self):
Q(*items, _connector=connector),
)

def test_referenced_base_fields(self):
# Make sure Q.referenced_base_fields retrieves all base fields from
# both filters and F expressions.
tests = [
(Q(field_1=1) & Q(field_2=1), {"field_1", "field_2"}),
(
Q(Exact(F("field_3"), IsNull(F("field_4"), True))),
{"field_3", "field_4"},
),
(Q(Exact(Q(field_5=F("field_6")), True)), {"field_5", "field_6"}),
(Q(field_2=1), {"field_2"}),
(Q(field_7__lookup=True), {"field_7"}),
(Q(field_7__joined_field__lookup=True), {"field_7"}),
]
combined_q = Q(1)
combined_q_base_fields = set()
for q, expected_base_fields in tests:
combined_q &= q
combined_q_base_fields |= expected_base_fields
tests.append((combined_q, combined_q_base_fields))
for q, expected_base_fields in tests:
with self.subTest(q=q):
self.assertEqual(
q.referenced_base_fields,
expected_base_fields,
)


class QCheckTests(TestCase):
def test_basic(self):
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