Homekit should skip devices that are missing in device registry (#35857)

* Homekit should skip devices that are missing in device registry

* Add test for this failure state

tests/components/homekit/test_homekit.py

@@ -913,3 +913,83 @@ def _write_data(path: str, data: Dict) -> None:
     if not os.path.isdir(os.path.dirname(path)):
         os.makedirs(os.path.dirname(path))
     json_util.save_json(path, data)
+
+
+async def test_homekit_ignored_missing_devices(
+    hass, hk_driver, debounce_patcher, device_reg, entity_reg
+):
+    """Test HomeKit handles a device in the entity registry but missing from the device registry."""
+    entry = await async_init_integration(hass)
+
+    homekit = HomeKit(
+        hass,
+        None,
+        None,
+        None,
+        {},
+        {"light.demo": {}},
+        DEFAULT_SAFE_MODE,
+        advertise_ip=None,
+        interface_choice=None,
+        entry_id=entry.entry_id,
+    )
+    homekit.driver = hk_driver
+    homekit._filter = Mock(return_value=True)
+    homekit.bridge = HomeBridge(hass, hk_driver, "mock_bridge")
+
+    config_entry = MockConfigEntry(domain="test", data={})
+    config_entry.add_to_hass(hass)
+    device_entry = device_reg.async_get_or_create(
+        config_entry_id=config_entry.entry_id,
+        sw_version="0.16.0",
+        model="Powerwall 2",
+        manufacturer="Tesla",
+        connections={(device_registry.CONNECTION_NETWORK_MAC, "12:34:56:AB:CD:EF")},
+    )
+
+    entity_reg.async_get_or_create(
+        "binary_sensor",
+        "powerwall",
+        "battery_charging",
+        device_id=device_entry.id,
+        device_class=DEVICE_CLASS_BATTERY_CHARGING,
+    )
+    entity_reg.async_get_or_create(
+        "sensor",
+        "powerwall",
+        "battery",
+        device_id=device_entry.id,
+        device_class=DEVICE_CLASS_BATTERY,
+    )
+    light = entity_reg.async_get_or_create(
+        "light", "powerwall", "demo", device_id=device_entry.id
+    )
+
+    # Delete the device to make sure we fallback
+    # to using the platform
+    device_reg.async_remove_device(device_entry.id)
+
+    hass.states.async_set(light.entity_id, STATE_ON)
+
+    def _mock_get_accessory(*args, **kwargs):
+        return [None, "acc", None]
+
+    with patch.object(homekit.bridge, "add_accessory"), patch(
+        f"{PATH_HOMEKIT}.show_setup_message"
+    ), patch(f"{PATH_HOMEKIT}.get_accessory") as mock_get_acc, patch(
+        "pyhap.accessory_driver.AccessoryDriver.start"
+    ):
+        await homekit.async_start()
+    await hass.async_block_till_done()
+
+    mock_get_acc.assert_called_with(
+        hass,
+        hk_driver,
+        ANY,
+        ANY,
+        {
+            "platform": "Tesla Powerwall",
+            "linked_battery_charging_sensor": "binary_sensor.powerwall_battery_charging",
+            "linked_battery_sensor": "sensor.powerwall_battery",
+        },
+    )