From 47f5e050565e054fb804f11d84fe4ccba4c8f7bb Mon Sep 17 00:00:00 2001
From: Sanjay Santhanam <51058514+Sanjays2402@users.noreply.github.com>
Date: Tue, 21 Jul 2026 02:26:57 -0700
Subject: [PATCH] fix: preserve LaunchDarkly boolean defaults

Resolve boolean flag defaults from the served fallthrough or off variation instead of the LaunchDarkly on toggle. Add focused coverage for both inverted cases.
---
 api/integrations/launch_darkly/services.py    | 14 ++++-
 .../launch_darkly/test_services.py            | 57 +++++++++++++++++++
 2 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/api/integrations/launch_darkly/services.py b/api/integrations/launch_darkly/services.py
index 9c33997bb588..5a432b4c7a79 100644
--- a/api/integrations/launch_darkly/services.py
+++ b/api/integrations/launch_darkly/services.py
@@ -665,11 +665,23 @@ def _create_boolean_feature_states_with_segments_identities(
 ) -> None:
     for ld_environment_key, environment in environments_by_ld_environment_key.items():
         ld_flag_config = ld_flag["environments"][ld_environment_key]
+        is_flag_on = ld_flag_config["on"]
+        variation_idx = (
+            ld_flag_config.get("fallthrough", {}).get("variation")
+            if is_flag_on
+            else ld_flag_config.get("offVariation")
+        )
+        enabled = is_flag_on
+        if variation_idx is not None:
+            variation_value = ld_flag["variations"][variation_idx]["value"]
+            if isinstance(variation_value, bool):
+                enabled = variation_value
+
         feature_state, _ = FeatureState.objects.update_or_create(
             feature=feature,
             feature_segment=None,
             environment=environment,
-            defaults={"enabled": ld_flag_config["on"]},
+            defaults={"enabled": enabled},
         )
 
         FeatureStateValue.objects.update_or_create(
diff --git a/api/tests/unit/integrations/launch_darkly/test_services.py b/api/tests/unit/integrations/launch_darkly/test_services.py
index 251bbc6b6761..5378288b4139 100644
--- a/api/tests/unit/integrations/launch_darkly/test_services.py
+++ b/api/tests/unit/integrations/launch_darkly/test_services.py
@@ -2,6 +2,7 @@
 import io
 import json
 from operator import attrgetter
+from typing import cast
 from unittest.mock import MagicMock
 
 import pytest
@@ -17,8 +18,10 @@
 from environments.identities.traits.models import Trait
 from environments.models import Environment
 from features.models import Feature, FeatureState
+from integrations.launch_darkly import types as ld_types
 from integrations.launch_darkly.models import LaunchDarklyImportRequest
 from integrations.launch_darkly.services import (
+    _create_boolean_feature_states_with_segments_identities,
     _serialize_variation_value,
     create_import_request,
     process_import_request,
@@ -263,6 +266,60 @@ def test_process_import_request__success__expected_status(  # type: ignore[no-un
     [tag.label for tag in tagged_feature.tags.all()] == ["testtag", "testtag2"]
 
 
+@pytest.mark.parametrize(
+    ("is_on", "default_config", "expected_enabled"),
+    [
+        (True, {"fallthrough": {"variation": 1}}, False),
+        (False, {"offVariation": 0}, True),
+    ],
+)
+def test_create_boolean_feature_states__served_variation__sets_expected_state(
+    is_on: bool,
+    default_config: dict[str, object],
+    expected_enabled: bool,
+    mocker: MockerFixture,
+) -> None:
+    # Given
+    ld_flag = cast(
+        ld_types.FeatureFlag,
+        {
+            "kind": "boolean",
+            "variations": [{"value": True}, {"value": False}],
+            "environments": {
+                "test": {
+                    "on": is_on,
+                    **default_config,
+                }
+            },
+        },
+    )
+    environment = cast(Environment, MagicMock(spec=Environment))
+    feature_state = MagicMock(spec=FeatureState)
+    feature_state_manager = mocker.patch(
+        "integrations.launch_darkly.services.FeatureState.objects.update_or_create",
+        return_value=(feature_state, True),
+    )
+    mocker.patch(
+        "integrations.launch_darkly.services.FeatureStateValue.objects.update_or_create"
+    )
+    mocker.patch("integrations.launch_darkly.services._import_targets")
+    mocker.patch("integrations.launch_darkly.services._import_rules")
+
+    # When
+    _create_boolean_feature_states_with_segments_identities(
+        import_request=MagicMock(spec=LaunchDarklyImportRequest),
+        ld_flag=ld_flag,
+        feature=MagicMock(spec=Feature),
+        environments_by_ld_environment_key={"test": environment},
+        segments_by_ld_key={},
+    )
+
+    # Then
+    assert feature_state_manager.call_args.kwargs["defaults"] == {
+        "enabled": expected_enabled
+    }
+
+
 @pytest.mark.django_db(transaction=True)
 def test_process_import_request__already_completed__does_not_reprocess(
     ld_client_class_mock: MagicMock,