allow address creation beyond gap limit in GUI. fixes #512

gui/qt/main_window.py

@@ -40,6 +40,7 @@ from electrum import Transaction
 from electrum import mnemonic
 from electrum import util, bitcoin, commands, Interface, Wallet
 from electrum import SimpleConfig, Wallet, WalletStorage
+from electrum import Imported_Wallet
 
 from amountedit import AmountEdit, BTCAmountEdit, MyLineEdit
 from network_dialog import NetworkDialog
@@ -681,7 +682,7 @@ class ElectrumWindow(QMainWindow):
         self.save_request_button.clicked.connect(self.save_payment_request)
         grid.addWidget(self.save_request_button, 3, 1)
         clear_button = QPushButton(_('New'))
-        clear_button.clicked.connect(self.clear_receive_tab)
+        clear_button.clicked.connect(self.new_receive_address)
         grid.addWidget(clear_button, 3, 2)
         grid.setRowStretch(4, 1)
 
@@ -739,6 +740,22 @@ class ElectrumWindow(QMainWindow):
         self.wallet.storage.put('receive_requests', self.receive_requests)
         self.update_receive_tab()
 
+    def new_receive_address(self):
+        domain = self.wallet.get_account_addresses(self.current_account, include_change=False)
+        for addr in domain:
+            if not self.wallet.address_is_old(addr) and addr not in self.receive_requests.keys():
+                break
+        else:
+            if isinstance(self.wallet, Imported_Wallet):
+                self.show_message(_('No more addresses in your wallet.'))
+                return
+            if not self.question(_("Warning: The next address will not be recovered automatically if you restore your wallet from seed; you may need to add it manually.\n\nThis occurs because you have too many unused addresses in your wallet. To avoid this situation, use the existing addresses first.\n\nCreate anyway?")):
+                return
+            addr = self.wallet.create_new_address(self.current_account, False)
+        self.receive_address_e.setText(addr)
+        self.receive_message_e.setText('')
+        self.receive_amount_e.setAmount(None)
+
     def clear_receive_tab(self):
         self.receive_requests = self.wallet.storage.get('receive_requests',{}) 
         domain = self.wallet.get_account_addresses(self.current_account, include_change=False)
@@ -746,7 +763,7 @@ class ElectrumWindow(QMainWindow):
             if not self.wallet.address_is_old(addr) and addr not in self.receive_requests.keys():
                 break
         else:
-            addr = ""
+            addr = ''
         self.receive_address_e.setText(addr)
         self.receive_message_e.setText('')
         self.receive_amount_e.setAmount(None)