fix: migrate the unique_id of the service entities (#1778)

The description of the service was appended to the unique_id of the service
entities without a migration step, so the entities registered before that
change were replaced by new ones. The entity_id of the new entity is
different, which silently breaks every automation, script and dashboard
referring to the old one.

Look up the entities that are still registered under the old unique_id when
the entry is set up, and rewrite it in place. The entity_id is left
untouched, so nothing referring to it has to be updated.

The lookup is keyed on the unique_id only and scoped to the config entry, and
nothing is written when the current unique_id is already registered, so it is
idempotent and cannot replace an entity that is in use. An entity that cannot
be migrated is reported and skipped, the others are still migrated.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

custom_components/xiaomi_home/__init__.py

@@ -84,6 +84,52 @@ async def async_setup(hass: HomeAssistant, hass_config: dict) -> bool:
     return True
 
 
+def migrate_service_unique_id(
+    er: entity_registry.EntityRegistry,
+    er_entries: dict[str, entity_registry.RegistryEntry],
+    device: MIoTDevice, spec: MIoTSpecService
+) -> bool:
+    """Migrate the unique_id of a service entity registered by a previous
+    version of the integration.
+
+    Only the unique_id is rewritten, the entity_id is left untouched so that
+    the automations, scripts and dashboards referring to it keep working.
+
+    Return False when a legacy entity was found but could not be migrated.
+    """
+    unique_id = device.gen_service_entity_id(
+        ha_domain=DOMAIN, siid=spec.iid, description=spec.description)
+    if unique_id in er_entries:
+        # Already up to date. A legacy entity left over from the format change
+        # may still be registered, it is not removed here since that would
+        # also drop the name, area and aliases set by the user.
+        return True
+    legacy_unique_id: Optional[str] = next(
+        (legacy_unique_id
+         for legacy_unique_id in device.gen_service_entity_id_legacy(
+             ha_domain=DOMAIN, siid=spec.iid)
+         if legacy_unique_id in er_entries),
+        None)
+    if not legacy_unique_id:
+        # A newly added entity
+        return True
+    entity_id = er_entries[legacy_unique_id].entity_id
+    try:
+        er.async_update_entity(entity_id, new_unique_id=unique_id)
+    except ValueError as error:
+        # The unique_id is registered by another config entry, which happens
+        # when the same device is shared between two Xiaomi accounts
+        _LOGGER.warning(
+            'migrate unique_id failed, %s, %s, %s',
+            error, entity_id, unique_id)
+        return False
+    er_entries[unique_id] = er_entries.pop(legacy_unique_id)
+    _LOGGER.info(
+        'migrate unique_id, %s, %s -> %s',
+        entity_id, legacy_unique_id, unique_id)
+    return True
+
+
 async def async_setup_entry(
     hass: HomeAssistant, config_entry: ConfigEntry
 ) -> bool:
@@ -127,6 +173,13 @@ async def async_setup_entry(
         await manufacturer.init_async()
         miot_devices: list[MIoTDevice] = []
         er = entity_registry.async_get(hass=hass)
+        # Index the registered entities by unique_id, used to migrate the
+        # entities registered by a previous version of the integration
+        er_entries: dict[str, entity_registry.RegistryEntry] = {
+            entry.unique_id: entry
+            for entry in entity_registry.async_entries_for_config_entry(
+                registry=er, config_entry_id=entry_id)}
+        migrate_failed: int = 0
         for did, info in miot_client.device_list.items():
             spec_instance = await spec_parser.parse(urn=info['urn'])
             if not isinstance(spec_instance, MIoTSpecInstance):
@@ -140,6 +193,16 @@ async def async_setup_entry(
                 spec_instance=spec_instance)
             miot_devices.append(device)
             device.spec_transform()
+            # Migrate the unique_id of the entities registered by a previous
+            # version of the integration
+            for entities in device.entity_list.values():
+                for entity in entities:
+                    if not isinstance(entity.spec, MIoTSpecService):
+                        continue
+                    if not migrate_service_unique_id(
+                            er=er, er_entries=er_entries, device=device,
+                            spec=entity.spec):
+                        migrate_failed += 1
             # Remove filter entities and non-standard entities
             for platform in SUPPORTED_PLATFORMS:
                 # ONLY support filter spec service translate entity
@@ -236,6 +299,12 @@ async def async_setup_entry(
                     if er.async_get(entity_id_or_uuid=entity_id):
                         er.async_remove(entity_id=entity_id)
 
+        if migrate_failed:
+            _LOGGER.warning(
+                'unique_id migration skipped, %s entities may show up as new '
+                'entities while the old ones become unavailable',
+                migrate_failed)
+
         hass.data[DOMAIN]['devices'][config_entry.entry_id] = miot_devices
         await hass.config_entries.async_forward_entry_setups(
             config_entry, SUPPORTED_PLATFORMS)