Fix via_device race in elkm1 (#177714)

homeassistant/components/elkm1/__init__.py

@@ -26,7 +26,7 @@ from homeassistant.const import (
 )
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import ConfigEntryNotReady
-from homeassistant.helpers import config_validation as cv
+from homeassistant.helpers import config_validation as cv, device_registry as dr
 from homeassistant.helpers.event import async_track_time_interval
 from homeassistant.helpers.typing import ConfigType
 from homeassistant.util.network import is_ip_address
@@ -58,6 +58,7 @@ from .discovery import (
     async_trigger_discovery,
     async_update_entry_from_discovery,
 )
+from .entity import create_elk_system_device_info
 from .models import ELKM1Data
 from .services import async_setup_services
 
@@ -308,6 +309,13 @@ async def async_setup_entry(hass: HomeAssistant, entry: ElkM1ConfigEntry) -> boo
         keypads={},
     )
 
+    # Register the ElkM1 system device before forwarding platforms so entities
+    # on any platform can deterministically resolve it as their via_device.
+    dr.async_get(hass).async_get_or_create(
+        config_entry_id=entry.entry_id,
+        **create_elk_system_device_info(elk, prefix, entry.unique_id),
+    )
+
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
 
     return True

homeassistant/components/elkm1/entity.py

@@ -10,6 +10,7 @@ from elkm1_lib.elk import Elk
 
 from homeassistant.const import ATTR_CONNECTIONS
 from homeassistant.core import callback
+from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.device_registry import CONNECTION_NETWORK_MAC, DeviceInfo
 from homeassistant.helpers.entity import Entity
 
@@ -47,6 +48,23 @@ def create_elk_entities(
     return entities
 
 
+def create_elk_system_device_info(elk: Elk, prefix: str, mac: str | None) -> DeviceInfo:
+    """Return the device info for the ElkM1 system device."""
+    device_name = "ElkM1"
+    if prefix:
+        device_name += f" {prefix}"
+    device_info = DeviceInfo(
+        identifiers={(DOMAIN, f"{prefix}_system")},
+        manufacturer="ELK Products, Inc.",
+        model="M1",
+        name=device_name,
+        sw_version=elk.panel.elkm1_version,
+    )
+    if mac:
+        device_info[ATTR_CONNECTIONS] = {(CONNECTION_NETWORK_MAC, mac)}
+    return device_info
+
+
 def generate_unique_id(prefix: str, element: Element) -> str:
     """Generate a unique id."""
     # unique_id starts with elkm1_ iff there is no prefix
@@ -128,10 +146,16 @@ class ElkEntity(Entity):
     @override
     def device_info(self) -> DeviceInfo:
         """Device info connecting via the ElkM1 system."""
+        config_entry = self.platform.config_entry
+        assert config_entry
         return DeviceInfo(
             name=self._element.name,
             identifiers={(DOMAIN, self._unique_id)},
-            via_device=(DOMAIN, f"{self._prefix}_system"),
+            via_device_id=dr.async_get_device_id_by_identifier(
+                self.hass,
+                (DOMAIN, f"{self._prefix}_system"),
+                config_entry_id=config_entry.entry_id,
+            ),
         )
 
 
@@ -142,16 +166,4 @@ class ElkAttachedEntity(ElkEntity):
     @override
     def device_info(self) -> DeviceInfo:
         """Device info for the underlying ElkM1 system."""
-        device_name = "ElkM1"
-        if self._prefix:
-            device_name += f" {self._prefix}"
-        device_info = DeviceInfo(
-            identifiers={(DOMAIN, f"{self._prefix}_system")},
-            manufacturer="ELK Products, Inc.",
-            model="M1",
-            name=device_name,
-            sw_version=self._elk.panel.elkm1_version,
-        )
-        if self._mac:
-            device_info[ATTR_CONNECTIONS] = {(CONNECTION_NETWORK_MAC, self._mac)}
-        return device_info
+        return create_elk_system_device_info(self._elk, self._prefix, self._mac)

tests/components/elkm1/test_init.py

@@ -0,0 +1,92 @@
+"""Tests for the Elk-M1 Control init."""
+
+from unittest.mock import MagicMock, patch
+
+from homeassistant.components.elkm1.const import DOMAIN
+from homeassistant.config_entries import ConfigEntryState
+from homeassistant.const import CONF_HOST, CONF_PASSWORD, CONF_PREFIX, CONF_USERNAME
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers import device_registry as dr
+
+from . import MOCK_MAC, _patch_discovery, mock_elk
+
+from tests.common import MockConfigEntry
+
+
+def _mocked_elk_with_light() -> MagicMock:
+    """Return a mocked Elk that exposes a single PLC light and nothing else."""
+    light = MagicMock()
+    light.index = 0
+    light.name = "Test Light"
+    light.default_name.return_value = "test_light"
+    light.configured = True
+    light.status = 0
+    light.as_dict.return_value = {}
+
+    elk = mock_elk(sync_complete=True)
+    elk.is_connected.return_value = True
+    for collection in (
+        "areas",
+        "tasks",
+        "counters",
+        "keypads",
+        "zones",
+        "outputs",
+        "settings",
+        "thermostats",
+    ):
+        setattr(elk, collection, [])
+    elk.lights = [light]
+    # The panel sensor is an attached entity; skip it so the only registered
+    # device besides the system device is the light's own (via_device) device.
+    elk.panel.configured = False
+    elk.panel.elkm1_version = "1.0.0"
+    elk.panel.temperature_units = "F"
+    return elk
+
+
+async def test_light_via_device_links_to_system_device(
+    hass: HomeAssistant, device_registry: dr.DeviceRegistry
+) -> None:
+    """A child (light) device links to the system device registered at setup.
+
+    With auto configure and only a light present, no sibling attached entity
+    creates the system device, so the link resolves only because setup
+    registers the system device before platforms are forwarded.
+    """
+    config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={
+            CONF_HOST: "elks://1.2.3.4",
+            CONF_USERNAME: "user",
+            CONF_PASSWORD: "pass",
+            CONF_PREFIX: "",
+            "auto_configure": True,
+        },
+        unique_id=MOCK_MAC,
+    )
+    config_entry.add_to_hass(hass)
+
+    with (
+        _patch_discovery(),
+        patch(
+            "homeassistant.components.elkm1.Elk",
+            return_value=_mocked_elk_with_light(),
+        ),
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.LOADED
+
+    system_device = device_registry.async_get_device_by_identifier(
+        (DOMAIN, "_system"), config_entry.entry_id
+    )
+    assert system_device is not None
+    assert system_device.name == "ElkM1"
+
+    light_device = device_registry.async_get_device_by_identifier(
+        (DOMAIN, "elkm1_test_light"), config_entry.entry_id
+    )
+    assert light_device is not None
+    assert light_device.via_device_id == system_device.id