Solve Modbus reload issue (#82253)

fixes undefined

homeassistant/components/modbus/__init__.py

@@ -386,4 +386,3 @@ async def async_reset_platform(hass: HomeAssistant, integration_name: str) -> No
     hubs = hass.data[DOMAIN]
     for name in hubs:
         await hubs[name].async_close()
-    del hass.data[DOMAIN]

homeassistant/components/modbus/modbus.py

@@ -132,6 +132,12 @@ async def async_modbus_setup(
 
     await async_setup_reload_service(hass, DOMAIN, [DOMAIN])
 
+    if DOMAIN in hass.data and config[DOMAIN] == []:
+        hubs = hass.data[DOMAIN]
+        for name in hubs:
+            if not await hubs[name].async_setup():
+                return False
+
     hass.data[DOMAIN] = hub_collect = {}
     for conf_hub in config[DOMAIN]:
         my_hub = ModbusHub(hass, conf_hub)