fix: remove duplicate global nWalletBackups variable

Remove the unused global nWalletBackups from util/system and use
CWallet::nWalletBackups everywhere. Qt and CoinJoin code now access
the backup status through the interfaces::Wallet::getWalletBackupStatus()
method instead of directly accessing wallet internals.

This fixes a bug where the global was never updated from its initial
value of 10, causing Qt/CoinJoin to see incorrect backup status.

Author: UdjinM6

src/coinjoin/client.cpp

@@ -724,7 +724,7 @@ bool CCoinJoinClientManager::CheckAutomaticBackup()
     // We don't need auto-backups for descriptor wallets
     if (!m_wallet->IsLegacy()) return true;
 
-    switch (nWalletBackups) {
+    switch (CWallet::nWalletBackups) {
     case 0:
         strAutoDenomResult = _("Automatic backups disabled") + Untranslated(", ") + _("no mixing available.");
         WalletCJLogPrint(m_wallet, "CCoinJoinClientManager::CheckAutomaticBackup -- %s\n", strAutoDenomResult.original);

src/interfaces/wallet.h

@@ -108,6 +108,10 @@ class Wallet
     //! Get the number of keys since the last auto backup
     virtual int64_t getKeysLeftSinceAutoBackup() = 0;
 
+    //! Get wallet backup status
+    //! Returns: 1..20 = number of backups to keep, 0 = disabled, -1 = error, -2 = locked
+    virtual int getWalletBackupStatus() = 0;
+
     //! Get wallet name.
     virtual std::string getWalletName() = 0;
 

src/qt/overviewpage.cpp

@@ -498,9 +498,10 @@ void OverviewPage::coinJoinStatus(bool fForce)
     if (!fForce && (clientModel->node().shutdownRequested() || !clientModel->masternodeSync().isBlockchainSynced())) return;
 
     // Disable any PS UI for masternode or when autobackup is disabled or failed for whatever reason
-    if (clientModel->node().isMasternode() || nWalletBackups <= 0) {
+    int backupStatus = walletModel->wallet().getWalletBackupStatus();
+    if (clientModel->node().isMasternode() || backupStatus <= 0) {
         DisableCoinJoinCompletely();
-        if (nWalletBackups <= 0) {
+        if (backupStatus <= 0) {
             ui->labelCoinJoinEnabled->setToolTip(tr("Automatic backups are disabled, no mixing available!"));
         }
         return;
@@ -595,7 +596,7 @@ void OverviewPage::coinJoinStatus(bool fForce)
 
     // Warn user that wallet is running out of keys
     // NOTE: we do NOT warn user and do NOT create autobackups if mixing is not running
-    if (walletModel->wallet().isLegacy() && nWalletBackups > 0 && walletModel->getKeysLeftSinceAutoBackup() < COINJOIN_KEYS_THRESHOLD_WARNING) {
+    if (walletModel->wallet().isLegacy() && walletModel->wallet().getWalletBackupStatus() > 0 && walletModel->getKeysLeftSinceAutoBackup() < COINJOIN_KEYS_THRESHOLD_WARNING) {
         QSettings settings;
         if(settings.value("fLowKeysWarning").toBool()) {
             QString strWarn =   tr("Very low number of keys left since last automatic backup!") + "<br><br>" +
@@ -639,7 +640,8 @@ void OverviewPage::coinJoinStatus(bool fForce)
     ui->labelCoinJoinEnabled->setText(strEnabled);
 
     if (walletModel->wallet().isLegacy()) {
-        if(nWalletBackups == -1) {
+        int backupStatus = walletModel->wallet().getWalletBackupStatus();
+        if (backupStatus == -1) {
             // Automatic backup failed, nothing else we can do until user fixes the issue manually
             DisableCoinJoinCompletely();
 
@@ -649,7 +651,7 @@ void OverviewPage::coinJoinStatus(bool fForce)
             ui->labelCoinJoinEnabled->setToolTip(strError);
 
             return;
-        } else if(nWalletBackups == -2) {
+        } else if (backupStatus == -2) {
             // We were able to create automatic backup but keypool was not replenished because wallet is locked.
             QString strWarning = tr("WARNING! Failed to replenish keypool, please unlock your wallet to do so.");
             ui->labelCoinJoinEnabled->setToolTip(strWarning);
@@ -754,7 +756,7 @@ void OverviewPage::DisableCoinJoinCompletely()
 
     ui->toggleCoinJoin->setText("(" + tr("Disabled") + ")");
     ui->frameCoinJoin->setEnabled(false);
-    if (nWalletBackups <= 0) {
+    if (walletModel && walletModel->wallet().getWalletBackupStatus() <= 0) {
         ui->labelCoinJoinEnabled->setText("<span style='" + GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR) + "'>(" + tr("Disabled") + ")</span>");
     }
     walletModel->coinJoin()->stopMixing();

src/util/system.cpp

@@ -78,15 +78,6 @@ const int64_t nStartupTime = GetTime();
 //Dash only features
 const std::string gCoinJoinName = "CoinJoin";
 
-/**
-    nWalletBackups:
-        1..10   - number of automatic backups to keep
-        0       - disabled by command-line
-        -1      - disabled because of some error during run-time
-        -2      - disabled because wallet was locked and we were not able to replenish keypool
-*/
-int nWalletBackups = 10;
-
 const char * const BITCOIN_CONF_FILENAME = "dash.conf";
 const char * const BITCOIN_SETTINGS_FILENAME = "settings.json";
 

src/util/system.h

@@ -35,7 +35,6 @@
 
 //Dash only features
 
-extern int nWalletBackups;
 extern const std::string gCoinJoinName;
 
 class UniValue;

src/wallet/interfaces.cpp

@@ -181,6 +181,7 @@ class WalletImpl : public Wallet
         return m_wallet->AutoBackupWallet(wallet_path, error_string, warnings);
     }
     int64_t getKeysLeftSinceAutoBackup() override { return m_wallet->nKeysLeftSinceAutoBackup; }
+    int getWalletBackupStatus() override { return CWallet::nWalletBackups; }
     std::string getWalletName() override { return m_wallet->GetName(); }
     util::Result<CTxDestination> getNewDestination(const std::string& label) override
     {