fix: publish offline status and reconnect when mqtt.iata changes

docs/custom-cli.md

@@ -51,7 +51,7 @@ Notes:
 - `letsmesh-eu` and `letsmesh-us` remain off by default unless already configured in saved prefs
 - if `mqtt.iata` is `UNSET`, `eastmesh-au`, `letsmesh-eu`, and `letsmesh-us` will not connect even if they are toggled on
 - turning off a connected broker publishes a retained MQTT status update with `"status":"offline"` before the client disconnects
-- changing `mqtt.iata` away from a configured value also publishes retained offline status to the old status topic before switching topics
+- changing `mqtt.iata` away from a configured value also publishes retained offline status to the old status topic, restarts connected broker clients, and reconnects under the new topic path
 
 Legacy dotted aliases are also accepted:
 

docs/web-panel.md

@@ -222,7 +222,7 @@ Notes:
 - the current MQTT server states are loaded when the page opens
 - you can toggle each MQTT server on or off from this panel
 - turning off a connected MQTT server publishes retained offline status before the client disconnects
-- changing `mqtt.iata` away from a configured value publishes retained offline status to the old status topic before the new topic is used
+- changing `mqtt.iata` away from a configured value publishes retained offline status to the old status topic, restarts connected broker clients, and reconnects under the new topic path
 - if all three servers are enabled at once, the panel shows a warning recommending two at most
 
 ## `/stats` Overview

release-notes.yml

@@ -570,7 +570,7 @@ releases:
         text: "Published explicit retained offline status before a connected broker is toggled off, matching operator expectations without relying on last-will behavior that only fires on unclean disconnects."
       - type: fixed
         area: mqtt
-        text: "Published retained offline status to the old status topic before `mqtt.iata` changes, preventing stale online status from remaining under the previous IATA path."
+        text: "Published retained offline status to the old status topic before `mqtt.iata` changes, then restarted connected broker clients so they reconnect and publish online status under the new IATA path."
       - type: docs
         area: mqtt
         text: "Updated the CLI and web-panel docs to describe retained offline status publishing for broker toggles and IATA changes."

src/helpers/mqtt/MQTTUplink.cpp

@@ -1164,17 +1164,30 @@ bool MQTTUplink::setIata(const char* iata) {
   for (size_t i = 0; cleaned[i] != 0; ++i) {
     cleaned[i] = toupper(static_cast<unsigned char>(cleaned[i]));
   }
-  if (strcmp(cleaned, _prefs.iata) != 0 && !isUnsetIataValue(_prefs.iata)) {
+  bool changed = strcmp(cleaned, _prefs.iata) != 0;
+  if (changed && !isUnsetIataValue(_prefs.iata)) {
     publishStatus(false);
   }
   if (strcmp(cleaned, MQTT_UNSET_IATA) == 0) {
     StrHelper::strncpy(_prefs.iata, MQTT_UNSET_IATA, sizeof(_prefs.iata));
     refreshIdentityStrings();
-    return savePrefs();
+    bool saved = savePrefs();
+    if (changed) {
+      for (BrokerState& broker : _brokers) {
+        destroyBroker(broker);
+      }
+    }
+    return saved;
   }
   StrHelper::strncpy(_prefs.iata, cleaned, sizeof(_prefs.iata));
   refreshIdentityStrings();
-  return savePrefs();
+  bool saved = savePrefs();
+  if (changed) {
+    for (BrokerState& broker : _brokers) {
+      destroyBroker(broker);
+    }
+  }
+  return saved;
 }
 
 bool MQTTUplink::setOwnerPublicKey(const char* owner_public_key) {