From 74e04c07bd7530d8984bce690ed999b331f93c92 Mon Sep 17 00:00:00 2001
From: Josh Hawkins <32435876+hawkeye217@users.noreply.github.com>
Date: Sun, 1 Mar 2026 08:00:06 -0600
Subject: [PATCH] ensure deep_merge replaces existing list values when override
 is true

---
 frigate/test/http_api/test_http_app.py | 29 ++++++++++++++++++++++++++
 frigate/test/test_config.py            | 16 ++++++++++++++
 frigate/util/builtin.py                |  5 ++++-
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/frigate/test/http_api/test_http_app.py b/frigate/test/http_api/test_http_app.py
index b04b1cf55..bf8e9c72a 100644
--- a/frigate/test/http_api/test_http_app.py
+++ b/frigate/test/http_api/test_http_app.py
@@ -22,3 +22,32 @@ class TestHttpApp(BaseTestHttp):
             response = client.get("/stats")
             response_json = response.json()
             assert response_json == self.test_stats
+
+    def test_config_set_in_memory_replaces_objects_track_list(self):
+        self.minimal_config["cameras"]["front_door"]["objects"] = {
+            "track": ["person", "car"],
+        }
+        app = super().create_app()
+        app.config_publisher = Mock()
+
+        with AuthTestClient(app) as client:
+            response = client.put(
+                "/config/set",
+                json={
+                    "requires_restart": 0,
+                    "skip_save": True,
+                    "update_topic": "config/cameras/front_door/objects",
+                    "config_data": {
+                        "cameras": {
+                            "front_door": {
+                                "objects": {
+                                    "track": ["person"],
+                                }
+                            }
+                        }
+                    },
+                },
+            )
+
+            assert response.status_code == 200
+            assert app.frigate_config.cameras["front_door"].objects.track == ["person"]
diff --git a/frigate/test/test_config.py b/frigate/test/test_config.py
index 98799fcf0..e903c2ac3 100644
--- a/frigate/test/test_config.py
+++ b/frigate/test/test_config.py
@@ -151,6 +151,22 @@ class TestConfig(unittest.TestCase):
         frigate_config = FrigateConfig(**config)
         assert "dog" in frigate_config.cameras["back"].objects.track
 
+    def test_deep_merge_override_replaces_list_values(self):
+        base = {"objects": {"track": ["person", "face"]}}
+        update = {"objects": {"track": ["person"]}}
+
+        merged = deep_merge(base, update, override=True)
+
+        assert merged["objects"]["track"] == ["person"]
+
+    def test_deep_merge_merge_lists_still_appends(self):
+        base = {"track": ["person"]}
+        update = {"track": ["face"]}
+
+        merged = deep_merge(base, update, override=True, merge_lists=True)
+
+        assert merged["track"] == ["person", "face"]
+
     def test_override_birdseye(self):
         config = {
             "mqtt": {"host": "mqtt"},
diff --git a/frigate/util/builtin.py b/frigate/util/builtin.py
index bcdc2feda..aa2417a5c 100644
--- a/frigate/util/builtin.py
+++ b/frigate/util/builtin.py
@@ -84,7 +84,8 @@ def deep_merge(dct1: dict, dct2: dict, override=False, merge_lists=False) -> dic
     """
     :param dct1: First dict to merge
     :param dct2: Second dict to merge
-    :param override: if same key exists in both dictionaries, should override? otherwise ignore. (default=True)
+    :param override: if same key exists in both dictionaries, should override? otherwise ignore.
+    :param merge_lists: if True, lists will be merged.
     :return: The merge dictionary
     """
     merged = copy.deepcopy(dct1)
@@ -96,6 +97,8 @@ def deep_merge(dct1: dict, dct2: dict, override=False, merge_lists=False) -> dic
             elif isinstance(v1, list) and isinstance(v2, list):
                 if merge_lists:
                     merged[k] = v1 + v2
+                elif override:
+                    merged[k] = copy.deepcopy(v2)
             else:
                 if override:
                     merged[k] = copy.deepcopy(v2)