fix: Respect send_feature_flags when local eval is enabled

Author: dustinbyrne

posthog/client.py

@@ -679,15 +679,6 @@ def capture(
                     f"[FEATURE FLAGS] Unable to get feature variants: {e}"
                 )
 
-        elif self.feature_flags and event != "$feature_flag_called":
-            # Local evaluation is enabled, flags are loaded, so try and get all flags we can without going to the server
-            feature_variants = self.get_all_flags(
-                distinct_id,
-                groups=(groups or {}),
-                disable_geoip=disable_geoip,
-                only_evaluate_locally=True,
-            )
-
         for feature, variant in (feature_variants or {}).items():
             extra_properties[f"$feature/{feature}"] = variant
 

posthog/test/test_client.py

@@ -409,7 +409,9 @@ def test_basic_capture_with_locally_evaluated_feature_flags(self, patch_flags):
             )
             client.feature_flags = [multivariate_flag, basic_flag, false_flag]
 
-            msg_uuid = client.capture("python test event", distinct_id="distinct_id")
+            msg_uuid = client.capture(
+                "python test event", distinct_id="distinct_id", send_feature_flags=True
+            )
             self.assertIsNotNone(msg_uuid)
             self.assertFalse(self.failed)
 
@@ -565,6 +567,7 @@ def test_dont_override_capture_with_local_flags(self, patch_flags):
                 "python test event",
                 distinct_id="distinct_id",
                 properties={"$feature/beta-feature-local": "my-custom-variant"},
+                send_feature_flags=True,
             )
             self.assertIsNotNone(msg_uuid)
             self.assertFalse(self.failed)
@@ -746,6 +749,88 @@ def test_basic_capture_with_feature_flags_switched_off_doesnt_send_them(
 
             self.assertEqual(patch_flags.call_count, 0)
 
+    @mock.patch("posthog.client.flags")
+    def test_capture_with_send_feature_flags_false_and_local_evaluation_doesnt_send_flags(
+        self, patch_flags
+    ):
+        """Test that send_feature_flags=False with local evaluation enabled does NOT send flags"""
+        patch_flags.return_value = {"featureFlags": {"beta-feature": "remote-variant"}}
+
+        multivariate_flag = {
+            "id": 1,
+            "name": "Beta Feature",
+            "key": "beta-feature-local",
+            "active": True,
+            "rollout_percentage": 100,
+            "filters": {
+                "groups": [
+                    {
+                        "rollout_percentage": 100,
+                    },
+                ],
+                "multivariate": {
+                    "variants": [
+                        {
+                            "key": "first-variant",
+                            "name": "First Variant",
+                            "rollout_percentage": 50,
+                        },
+                        {
+                            "key": "second-variant",
+                            "name": "Second Variant",
+                            "rollout_percentage": 50,
+                        },
+                    ]
+                },
+            },
+        }
+        simple_flag = {
+            "id": 2,
+            "name": "Simple Flag",
+            "key": "simple-flag",
+            "active": True,
+            "filters": {
+                "groups": [
+                    {
+                        "rollout_percentage": 100,
+                    }
+                ],
+            },
+        }
+
+        with mock.patch("posthog.client.batch_post") as mock_post:
+            client = Client(
+                FAKE_TEST_API_KEY,
+                on_error=self.set_fail,
+                personal_api_key=FAKE_TEST_API_KEY,
+                sync_mode=True,
+            )
+            client.feature_flags = [multivariate_flag, simple_flag]
+
+            msg_uuid = client.capture(
+                "python test event",
+                distinct_id="distinct_id",
+                send_feature_flags=False,
+            )
+            self.assertIsNotNone(msg_uuid)
+            self.assertFalse(self.failed)
+
+            # Get the enqueued message from the mock
+            mock_post.assert_called_once()
+            batch_data = mock_post.call_args[1]["batch"]
+            msg = batch_data[0]
+
+            self.assertEqual(msg["event"], "python test event")
+            self.assertEqual(msg["distinct_id"], "distinct_id")
+
+            # CRITICAL: Verify local flags are NOT included in the event
+            self.assertNotIn("$feature/beta-feature-local", msg["properties"])
+            self.assertNotIn("$feature/simple-flag", msg["properties"])
+            self.assertNotIn("$active_feature_flags", msg["properties"])
+
+            # CRITICAL: Verify the /flags API was NOT called
+            self.assertEqual(patch_flags.call_count, 0)
+
     @mock.patch("posthog.client.flags")
     def test_capture_with_send_feature_flags_true_and_local_evaluation_uses_local_flags(
         self, patch_flags