Fix Matter device ID for non-bridged composed device (#118256)

homeassistant/components/matter/helpers.py

@@ -59,12 +59,12 @@ def get_device_id(
 ) -> str:
     """Return HA device_id for the given MatterEndpoint."""
     operational_instance_id = get_operational_instance_id(server_info, endpoint.node)
-    # Append endpoint ID if this endpoint is a bridged or composed device
-    if endpoint.is_composed_device:
-        compose_parent = endpoint.node.get_compose_parent(endpoint.endpoint_id)
-        assert compose_parent is not None
-        postfix = str(compose_parent.endpoint_id)
-    elif endpoint.is_bridged_device:
+    # if this is a composed device we need to get the compose parent
+    # example: Philips Hue motion sensor on Hue Hub (bridged to Matter)
+    if compose_parent := endpoint.node.get_compose_parent(endpoint.endpoint_id):
+        endpoint = compose_parent
+    if endpoint.is_bridged_device:
+        # Append endpoint ID if this endpoint is a bridged device
         postfix = str(endpoint.endpoint_id)
     else:
         # this should be compatible with previous versions

tests/components/matter/test_adapter.py

@@ -172,6 +172,20 @@ async def test_node_added_subscription(
     assert entity_state
 
 
+async def test_device_registry_single_node_composed_device(
+    hass: HomeAssistant,
+    matter_client: MagicMock,
+) -> None:
+    """Test that a composed device within a standalone node only creates one HA device entry."""
+    await setup_integration_with_node_fixture(
+        hass,
+        "air-purifier",
+        matter_client,
+    )
+    dev_reg = dr.async_get(hass)
+    assert len(dev_reg.devices) == 1
+
+
 async def test_get_clean_name_() -> None:
     """Test get_clean_name helper.