Handle changes to source entity in utility_meter (home-assistant#146526)

Author: emontnemery

homeassistant/components/utility_meter/__init__.py

@@ -17,9 +17,11 @@
     entity_registry as er,
 )
 from homeassistant.helpers.device import (
+    async_entity_id_to_device_id,
     async_remove_stale_devices_links_keep_entity_device,
 )
 from homeassistant.helpers.dispatcher import async_dispatcher_send
+from homeassistant.helpers.helper_integration import async_handle_source_entity_changes
 from homeassistant.helpers.typing import ConfigType
 
 from .const import (
@@ -217,6 +219,29 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         )
         return False
 
+    def set_source_entity_id_or_uuid(source_entity_id: str) -> None:
+        hass.config_entries.async_update_entry(
+            entry,
+            options={**entry.options, CONF_SOURCE_SENSOR: source_entity_id},
+        )
+
+    async def source_entity_removed() -> None:
+        # The source entity has been removed, we need to clean the device links.
+        async_remove_stale_devices_links_keep_entity_device(hass, entry.entry_id, None)
+
+    entry.async_on_unload(
+        async_handle_source_entity_changes(
+            hass,
+            helper_config_entry_id=entry.entry_id,
+            set_source_entity_id_or_uuid=set_source_entity_id_or_uuid,
+            source_device_id=async_entity_id_to_device_id(
+                hass, entry.options[CONF_SOURCE_SENSOR]
+            ),
+            source_entity_id_or_uuid=entry.options[CONF_SOURCE_SENSOR],
+            source_entity_removed=source_entity_removed,
+        )
+    )
+
     if not entry.options.get(CONF_TARIFFS):
         # Only a single meter sensor is required
         hass.data[DATA_UTILITY][entry.entry_id][CONF_TARIFF_ENTITY] = None