Cover for Postgres' physical ordering

Author: emyller

api/segments/models.py

@@ -302,9 +302,7 @@ def deep_clone(self, cloned_segment: Segment) -> "SegmentRule":
 
 
 class ConditionManager(SoftDeleteExportableManager):
-    def get_queryset(
-        self,
-    ) -> models.QuerySet["Condition"]:
+    def get_queryset(self) -> models.QuerySet["Condition"]:
         # Effectively `Condition.Meta.ordering = ("id",) if ... else ()`,
         # but avoid the weirdness of a setting-dependant migration
         # and having to reload everything in tests

api/tests/unit/segments/test_unit_segments_models.py

@@ -1,13 +1,74 @@
 from unittest.mock import PropertyMock
 
 import pytest
+from django.db import transaction
 from flag_engine.segments.constants import EQUAL, PERCENTAGE_SPLIT
+from pytest_django.fixtures import SettingsWrapper
 from pytest_mock import MockerFixture
 
 from segments.models import Condition, Segment, SegmentRule
 from segments.services import SegmentCloneService
 
 
+@pytest.mark.django_db(transaction=True)
+def test__ConditionManager__get_queryset__explicit_ordering_disabled__cant_guarantee_condition_ordering(
+    segment_rule: SegmentRule,
+    settings: SettingsWrapper,
+) -> None:
+    # Given
+    settings.SEGMENT_RULES_CONDITIONS_EXPLICIT_ORDERING_ENABLED = False
+    with transaction.atomic():
+        condition1 = Condition.objects.create(
+            rule=segment_rule,
+            property="condition1",
+            operator=EQUAL,
+            value="original1",
+        )
+        condition2 = Condition.objects.create(
+            rule=segment_rule,
+            property="condition1",
+            operator=EQUAL,
+            value="original2",
+        )
+    with transaction.atomic():
+        condition1.value = "updated1"
+        condition1.save()  # UPDATE causes the condition1 tuple to be the most recent physically
+
+    # When
+    conditions = Condition.objects.filter(rule=segment_rule)
+
+    # Then
+    assert list(conditions) == [condition2, condition1]
+
+
+def test__ConditionManager__get_queryset__explicit_ordering_enabled__orders_conditions_by_id(
+    segment_rule: SegmentRule,
+    settings: SettingsWrapper,
+) -> None:
+    # Given
+    settings.SEGMENT_RULES_CONDITIONS_EXPLICIT_ORDERING_ENABLED = True
+    condition1 = Condition.objects.create(
+        rule=segment_rule,
+        property="condition1",
+        operator=EQUAL,
+        value="original1",
+    )
+    condition2 = Condition.objects.create(
+        rule=segment_rule,
+        property="condition1",
+        operator=EQUAL,
+        value="original2",
+    )
+    condition1.value = "updated1"
+    condition1.save()  # Update leads to physical reordering of tuples
+
+    # When
+    conditions = Condition.objects.filter(rule=segment_rule)
+
+    # Then
+    assert list(conditions) == [condition1, condition2]
+
+
 def test_get_segment_returns_parent_segment_for_nested_rule(
     segment: Segment,
 ) -> None: