Merge fix/improve-error-logging: Human-readable MQTT errors

- Initialize _mqtt_bridge and _web_config to nullptr in declarations
- Add destructor to clean up dynamically allocated objects
- Initialize _last_mqtt_stats to 0 in declaration
- Fix WiFiState/NetworkState enum mismatch in getWiFiStatus()

While embedded firmware typically runs forever (making these not
critical leaks), proper cleanup enables testing and prevents
static analyzer warnings.

src/MQTTBridge.cpp

@@ -17,6 +17,7 @@ MQTTBridge::MQTTBridge(INetworkManager* network, mesh::PacketManager* mgr, mesh:
       _last_status_publish(0),
       _last_stats_publish(0),
       _connected_since(0),
+      _current_backoff_ms(BACKOFF_MIN_MS),
       _messages_sent(0),
       _messages_received(0),
       _reconnect_count(0),
@@ -81,7 +82,8 @@ void MQTTBridge::loop() {
 
   switch (_state) {
     case MQTTState::DISCONNECTED:
-      if (millis() - _last_connect_attempt > 5000) {
+      // Use exponential backoff for reconnection attempts
+      if (millis() - _last_connect_attempt > _current_backoff_ms) {
         attemptConnection();
       }
       break;
@@ -94,6 +96,7 @@ void MQTTBridge::loop() {
         _state = MQTTState::DISCONNECTED;
         Serial.println("[MQTT] Connection lost");
         _last_connect_attempt = millis();
+        // Don't reset backoff on connection loss - broker might be down
       } else {
         _mqtt_client.loop();
 
@@ -105,7 +108,8 @@ void MQTTBridge::loop() {
       break;
 
     case MQTTState::ERROR:
-      if (millis() - _last_connect_attempt > 30000) {
+      // Use backoff for error recovery too
+      if (millis() - _last_connect_attempt > _current_backoff_ms) {
         _state = MQTTState::DISCONNECTED;
       }
       break;
@@ -135,7 +139,8 @@ void MQTTBridge::attemptConnection() {
   _state = MQTTState::CONNECTING;
   _last_connect_attempt = millis();
 
-  Serial.printf("[MQTT] Connecting to %s:%d...\n", _config.broker, _config.port);
+  Serial.printf("[MQTT] Connecting to %s:%d (backoff=%lums)...\n",
+                _config.broker, _config.port, _current_backoff_ms);
 
   String client_id = String(_config.client_id);
   if (client_id.length() == 0) {
@@ -158,6 +163,8 @@ void MQTTBridge::attemptConnection() {
     _state = MQTTState::CONNECTED;
     _connected_since = millis();
     _reconnect_count++;
+    // Reset backoff on successful connection
+    _current_backoff_ms = BACKOFF_MIN_MS;
     Serial.println("[MQTT] Connected!");
 
     subscribeToCommands();
@@ -170,6 +177,10 @@ void MQTTBridge::attemptConnection() {
     Serial.printf("[MQTT] Broker: %s:%d, User: %s\n", _config.broker, _config.port,
                   strlen(_config.user) > 0 ? _config.user : "(none)");
     _state = MQTTState::ERROR;
+
+    // Exponential backoff: double the delay (up to max)
+    _current_backoff_ms = min(_current_backoff_ms * BACKOFF_MULTIPLIER, BACKOFF_MAX_MS);
+    Serial.printf("[MQTTS] Next retry in %lums\n", _current_backoff_ms);
   }
 }
 

src/MQTTBridge.h

@@ -85,6 +85,12 @@ private:
   unsigned long _last_stats_publish;
   unsigned long _connected_since;
 
+  // Exponential backoff for reconnection
+  static constexpr uint32_t BACKOFF_MIN_MS = 1000;      // Start at 1 second
+  static constexpr uint32_t BACKOFF_MAX_MS = 60000;     // Max 60 seconds
+  static constexpr uint32_t BACKOFF_MULTIPLIER = 2;     // Double each attempt
+  uint32_t _current_backoff_ms;
+
   uint32_t _messages_sent;
   uint32_t _messages_received;
   uint32_t _reconnect_count;

src/MyMesh.cpp

@@ -733,6 +733,21 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.adc_multiplier = 0.0f; // 0.0f means use default board multiplier
 }
 
+MyMesh::~MyMesh() {
+  // Clean up dynamically allocated resources
+#ifdef WITH_MQTT
+  delete _web_config;
+  _web_config = nullptr;
+  delete _mqtt_bridge;
+  _mqtt_bridge = nullptr;
+#endif
+
+#ifdef WITH_ETHERNET
+  delete _mqtt_bridge;
+  _mqtt_bridge = nullptr;
+#endif
+}
+
 void MyMesh::begin(FILESYSTEM *fs) {
   mesh::Mesh::begin();
   _fs = fs;

src/MyMesh.h

@@ -125,21 +125,21 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
 
 #ifdef WITH_MQTT
   WiFiManager _wifi_mgr;
-  MQTTBridge* _mqtt_bridge;
-  WebConfig* _web_config;
+  MQTTBridge* _mqtt_bridge = nullptr;
+  WebConfig* _web_config = nullptr;
   WiFiConfig _wifi_config;
   MQTTConfig _mqtt_config;
-  unsigned long _last_mqtt_stats;
+  unsigned long _last_mqtt_stats = 0;
 
   void initMQTT();
 #endif
 
 #ifdef WITH_ETHERNET
   EthernetManager _eth_mgr;
-  MQTTBridge* _mqtt_bridge;
+  MQTTBridge* _mqtt_bridge = nullptr;
   MQTTConfig _mqtt_config;
   EthernetConfig _eth_config;
-  unsigned long _last_mqtt_stats;
+  unsigned long _last_mqtt_stats = 0;
 
   void initEthernet();
 #endif
@@ -196,6 +196,7 @@ protected:
 
 public:
   MyMesh(mesh::MainBoard& board, mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::MeshTables& tables);
+  ~MyMesh();  // Clean up dynamically allocated resources
 
   void begin(FILESYSTEM* fs);
 

src/WiFiManager.cpp

@@ -10,6 +10,7 @@ WiFiManager::WiFiManager()
       _retry_count(0),
       _initialized(false) {
   memset(&_config, 0, sizeof(_config));
+  memset(_cached_ssid, 0, sizeof(_cached_ssid));
 }
 
 void WiFiManager::begin(const WiFiConfig& config) {
@@ -82,6 +83,9 @@ void WiFiManager::loop() {
         _state = WiFiState::CONNECTED;
         _connected_since = millis();
         _retry_count = 0;
+        // Cache SSID to avoid dangling pointer from WiFi.SSID().c_str()
+        strncpy(_cached_ssid, WiFi.SSID().c_str(), sizeof(_cached_ssid) - 1);
+        _cached_ssid[sizeof(_cached_ssid) - 1] = '\0';
         Serial.printf("[WiFi] Connected! IP: %s, RSSI: %d dBm\n",
                       WiFi.localIP().toString().c_str(), WiFi.RSSI());
       } else if (status == WL_NO_SSID_AVAIL) {
@@ -184,6 +188,9 @@ void WiFiManager::startAPMode() {
 
   if (success) {
     _state = WiFiState::AP_MODE;
+    // Cache AP SSID to avoid dangling pointer
+    strncpy(_cached_ssid, ap_ssid.c_str(), sizeof(_cached_ssid) - 1);
+    _cached_ssid[sizeof(_cached_ssid) - 1] = '\0';
     Serial.printf("[WiFi] AP started: SSID='%s', IP=%s\n",
                   ap_ssid.c_str(), WiFi.softAPIP().toString().c_str());
   } else {
@@ -221,10 +228,8 @@ int32_t WiFiManager::getRSSI() const {
 }
 
 const char* WiFiManager::getSSID() const {
-  if (_state == WiFiState::CONNECTED) {
-    return WiFi.SSID().c_str();
-  } else if (_state == WiFiState::AP_MODE) {
-    return WiFi.softAPSSID().c_str();
+  if (_state == WiFiState::CONNECTED || _state == WiFiState::AP_MODE) {
+    return _cached_ssid;
   }
   return "";
 }
@@ -264,10 +269,8 @@ NetworkState WiFiManager::getState() const {
 }
 
 const char* WiFiManager::getConnectionName() const {
-  if (_state == WiFiState::CONNECTED) {
-    return WiFi.SSID().c_str();
-  } else if (_state == WiFiState::AP_MODE) {
-    return WiFi.softAPSSID().c_str();
+  if (_state == WiFiState::CONNECTED || _state == WiFiState::AP_MODE) {
+    return _cached_ssid;
   }
   return "Not connected";
 }

src/WiFiManager.h

@@ -61,6 +61,7 @@ private:
   unsigned long _connected_since;
   uint8_t _retry_count;
   bool _initialized;
+  char _cached_ssid[33];  // Cached SSID to avoid dangling pointer from WiFi.SSID().c_str()
 
   void attemptConnection();
   void checkConnection();