stm32wl: exclude backup preferences via MESHTASTIC_EXCLUDE_BACKUP

backup.proto requires 2 LittleFS blocks (4 KB) and is only written on an
explicit admin command. On a flash-constrained node with 12 usable blocks,
this is headroom better preserved for normal operation. Guard the three
AdminModule case handlers and NodeDB declarations/implementations behind
#if !MESHTASTIC_EXCLUDE_BACKUP, matching the pattern used by existing
MESHTASTIC_EXCLUDE_* flags throughout the codebase.

Signed-off-by: Andrew Yong <me@ndoo.sg>

Author: ndoo

src/mesh/NodeDB.cpp

@@ -2190,6 +2190,7 @@ bool NodeDB::checkLowEntropyPublicKey(const meshtastic_Config_SecurityConfig_pub
 }
 #endif
 
+#if !MESHTASTIC_EXCLUDE_BACKUP
 bool NodeDB::backupPreferences(meshtastic_AdminMessage_BackupLocation location)
 {
     bool success = false;
@@ -2277,6 +2278,7 @@ bool NodeDB::restorePreferences(meshtastic_AdminMessage_BackupLocation location,
 #endif
     return success;
 }
+#endif // !MESHTASTIC_EXCLUDE_BACKUP
 
 /// Record an error that should be reported via analytics
 void recordCriticalError(meshtastic_CriticalErrorCode code, uint32_t address, const char *filename)

src/mesh/NodeDB.h

@@ -102,7 +102,9 @@ static constexpr const char *configFileName = "/prefs/config.proto";
 static constexpr const char *uiconfigFileName = "/prefs/uiconfig.proto";
 static constexpr const char *moduleConfigFileName = "/prefs/module.proto";
 static constexpr const char *channelFileName = "/prefs/channels.proto";
+#if !MESHTASTIC_EXCLUDE_BACKUP
 static constexpr const char *backupFileName = "/backups/backup.proto";
+#endif
 
 /// Given a node, return how many seconds in the past (vs now) that we last heard from it
 uint32_t sinceLastSeen(const meshtastic_NodeInfoLite *n);
@@ -316,9 +318,11 @@ class NodeDB
     bool checkLowEntropyPublicKey(const meshtastic_Config_SecurityConfig_public_key_t &keyToTest);
 #endif
 
+#if !MESHTASTIC_EXCLUDE_BACKUP
     bool backupPreferences(meshtastic_AdminMessage_BackupLocation location);
     bool restorePreferences(meshtastic_AdminMessage_BackupLocation location,
                             int restoreWhat = SEGMENT_CONFIG | SEGMENT_MODULECONFIG | SEGMENT_DEVICESTATE | SEGMENT_CHANNELS);
+#endif
 
     /// Notify observers of changes to the DB
     void notifyObservers(bool forceUpdate = false)
@@ -331,9 +335,11 @@ class NodeDB
   private:
     bool duplicateWarned = false;
     bool localPositionUpdatedSinceBoot = false;
-    uint32_t lastNodeDbSave = 0;    // when we last saved our db to flash
+    uint32_t lastNodeDbSave = 0; // when we last saved our db to flash
+#if !MESHTASTIC_EXCLUDE_BACKUP
     uint32_t lastBackupAttempt = 0; // when we last tried a backup automatically or manually
-    uint32_t lastSort = 0;          // When last sorted the nodeDB
+#endif
+    uint32_t lastSort = 0; // When last sorted the nodeDB
     /// Find a node in our DB, create an empty NodeInfoLite if missing
     meshtastic_NodeInfoLite *getOrCreateMeshNode(NodeNum n);
 

src/modules/AdminModule.cpp

@@ -499,6 +499,7 @@ bool AdminModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshta
 #endif
         break;
     }
+#if !MESHTASTIC_EXCLUDE_BACKUP
     case meshtastic_AdminMessage_backup_preferences_tag: {
         LOG_INFO("Client requesting to backup preferences");
         if (nodeDB->backupPreferences(r->backup_preferences)) {
@@ -535,6 +536,7 @@ bool AdminModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshta
 #endif
         break;
     }
+#endif // !MESHTASTIC_EXCLUDE_BACKUP
     case meshtastic_AdminMessage_send_input_event_tag: {
         LOG_INFO("Client requesting to send input event");
         handleSendInputEvent(r->send_input_event);

variants/stm32/stm32.ini

@@ -25,6 +25,7 @@ build_flags =
   -DMESHTASTIC_EXCLUDE_BLUETOOTH=1
   -DMESHTASTIC_EXCLUDE_WIFI=1
   -DMESHTASTIC_EXCLUDE_TZ=1 ; Exclude TZ to save some flash space.
+  -DMESHTASTIC_EXCLUDE_BACKUP=1 ; Backup preferences require 2 flash blocks (4 KB); not useful on a flash-constrained node.
   -DSERIAL_RX_BUFFER_SIZE=256 ; For GPS - the default of 64 is too small.
   -DHAS_SCREEN=0 ; Always disable screen for STM32, it is not supported.
   ;-DPIO_FRAMEWORK_ARDUINO_NANOLIB_FLOAT_PRINTF ; Enable this if enabling debugg logging. It is REQUIRED for at least traceroute debug prints - without it the length returned by printf ends up uninitialized.