[Wallet] Use RBF by default in QT only

GUI wallet uses RBF by default, regardless of -walletrbf.

RPC and debug console in the GUI remain unchanged; they don't
use RBF by default, unless launched with -walletrbf=1.

doc/release-notes.md

@@ -67,6 +67,14 @@ Due to a backward-incompatible change in the wallet database, wallets created
 with version 0.16.0 will be rejected by previous versions. Also, version 0.16.0
 will only create hierarchical deterministic (HD) wallets.
 
+Replace-By-Fee by default in GUI
+--------------------------------
+The send screen now uses BIP-125 RBF by default, regardless of `-walletrbf`.
+There is a checkbox to mark the transaction as final.
+
+The RPC default remains unchanged: to use RBF, launch with `-walletrbf=1` or
+use the `replaceable` argument for individual transactions.
+
 Custom wallet directories
 ---------------------
 The ability to specify a directory other than the default data directory in which to store

src/qt/forms/sendcoinsdialog.ui

@@ -1108,10 +1108,10 @@
            <item>
             <widget class="QCheckBox" name="optInRBF">
              <property name="text">
-              <string>Allow increasing fee</string>
+              <string>Enable Replace-By-Fee</string>
              </property>
              <property name="toolTip">
-              <string>This allows you to increase the fee later if the transaction takes a long time to confirm. This will also cause the recommended fee to be lower. ("Replace-By-Fee", BIP 125)</string>
+              <string>With Replace-By-Fee (BIP-125) you can increase a transaction's fee after it is sent. Without this, a higher fee may be recommended to compensate for increased transaction delay risk.</string>
              </property>
             </widget>
            </item>

src/qt/sendcoinsdialog.cpp

@@ -184,7 +184,7 @@ void SendCoinsDialog::setModel(WalletModel *_model)
         updateSmartFeeLabel();
 
         // set default rbf checkbox state
-        ui->optInRBF->setCheckState(model->getDefaultWalletRbf() ? Qt::Checked : Qt::Unchecked);
+        ui->optInRBF->setCheckState(Qt::Checked);
 
         // set the smartfee-sliders default value (wallets default conf.target or last stored value)
         QSettings settings;
@@ -342,12 +342,14 @@ void SendCoinsDialog::on_sendButton_clicked()
     questionString.append(QString("<span style='font-size:10pt;font-weight:normal;'><br />(=%2)</span>")
         .arg(alternativeUnits.join(" " + tr("or") + "<br />")));
 
-    if (ui->optInRBF->isChecked())
-    {
     questionString.append("<hr /><span>");
-        questionString.append(tr("You can increase the fee later (signals Replace-By-Fee)."));
+    if (ui->optInRBF->isChecked()) {
-        questionString.append("</span>");
+        questionString.append(tr("You can increase the fee later (signals Replace-By-Fee, BIP-125)."));
+    } else {
+        questionString.append(tr("Not signalling Replace-By-Fee, BIP-125."));
     }
+    questionString.append("</span>");
+
 
     SendConfirmationDialog confirmationDialog(tr("Confirm send coins"),
         questionString.arg(formatted.join("<br />")), SEND_CONFIRM_DELAY, this);

src/qt/walletmodel.cpp

@@ -737,8 +737,3 @@ int WalletModel::getDefaultConfirmTarget() const
 {
     return nTxConfirmTarget;
 }
-
-bool WalletModel::getDefaultWalletRbf() const
-{
-    return fWalletRbf;
-}

src/qt/walletmodel.h

@@ -216,8 +216,6 @@ public:
 
     int getDefaultConfirmTarget() const;
 
-    bool getDefaultWalletRbf() const;
-
 private:
     CWallet *wallet;
     bool fHaveWatchOnly;

src/wallet/init.cpp

@@ -31,7 +31,7 @@ std::string GetWalletHelpString(bool showDebug)
     strUsage += HelpMessageOpt("-salvagewallet", _("Attempt to recover private keys from a corrupt wallet on startup"));
     strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
     strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
-    strUsage += HelpMessageOpt("-walletrbf", strprintf(_("Send transactions with full-RBF opt-in enabled (default: %u)"), DEFAULT_WALLET_RBF));
+    strUsage += HelpMessageOpt("-walletrbf", strprintf(_("Send transactions with full-RBF opt-in enabled (RPC only, default: %u)"), DEFAULT_WALLET_RBF));
     strUsage += HelpMessageOpt("-upgradewallet", _("Upgrade wallet to latest format on startup"));
     strUsage += HelpMessageOpt("-wallet=<file>", _("Specify wallet file (within data directory)") + " " + strprintf(_("(default: %s)"), DEFAULT_WALLET_DAT));
     strUsage += HelpMessageOpt("-walletbroadcast", _("Make the wallet broadcast transactions") + " " + strprintf(_("(default: %u)"), DEFAULT_WALLETBROADCAST));