use maxint-2 to signal RBF, in order to standardize with Bitcoin Core

gui/kivy/uix/dialogs/tx_dialog.py

@@ -148,7 +148,7 @@ class TxDialog(Factory.Popup):
             self.app.show_error(str(e))
             return
         if is_final:
-            new_tx.set_sequence(0xffffffff)
+            new_tx.set_rbf(False)
         self.tx = new_tx
         self.update()
         self.do_sign()

gui/kivy/uix/screens.py

@@ -284,7 +284,7 @@ class SendScreen(CScreen):
             self.app.show_error(str(e))
             return
         if rbf:
-            tx.set_sequence(0)
+            tx.set_rbf(True)
         fee = tx.get_fee()
         msg = [
             _("Amount to be sent") + ": " + self.app.format_amount_and_units(amount),

gui/qt/main_window.py

@@ -1306,7 +1306,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
 
         use_rbf = self.rbf_checkbox.isChecked()
         if use_rbf:
-            tx.set_sequence(0)
+            tx.set_rbf(True)
 
         if fee < self.wallet.relayfee() * tx.estimated_size() / 1000 and tx.requires_fee(self.wallet):
             self.show_error(_("This transaction requires a higher fee, or it will not be propagated by the network"))
@@ -2823,7 +2823,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
             self.show_error(_('Max fee exceeded'))
             return
         new_tx = self.wallet.cpfp(parent_tx, fee)
-        new_tx.set_sequence(0)
+        new_tx.set_rbf(True)
         self.show_transaction(new_tx)
 
     def bump_fee_dialog(self, tx):
@@ -2860,5 +2860,5 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
             self.show_error(str(e))
             return
         if is_final:
-            new_tx.set_sequence(0xffffffff)
+            new_tx.set_rbf(False)
         self.show_transaction(new_tx)

lib/commands.py

@@ -414,7 +414,7 @@ class Commands:
         coins = self.wallet.get_spendable_coins(domain)
         tx = self.wallet.make_unsigned_transaction(coins, final_outputs, self.config, fee, change_addr)
         if rbf:
-            tx.set_sequence(0)
+            tx.set_rbf(True)
         if not unsigned:
             self.wallet.sign_transaction(tx, self._password)
         return tx

lib/transaction.py

@@ -681,9 +681,10 @@ class Transaction:
         s += int_to_hex(txin.get('sequence', 0xffffffff), 4)
         return s
 
-    def set_sequence(self, n):
+    def set_rbf(self, rbf):
+        nSequence = 0xffffffff - (2 if rbf else 0)
         for txin in self.inputs():
-            txin['sequence'] = n
+            txin['sequence'] = nSequence
 
     def BIP_LI01_sort(self):
         # See https://github.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki