qml: add busy property on QETxFinalizer for guarding re-entry while background job

is running

Author: accumulator

electrum/gui/qml/components/ConfirmTxDialog.qml

@@ -324,7 +324,7 @@ ElDialog {
                         ? qsTr('Finalize...')
                         : qsTr('Pay...')
                 icon.source: '../../icons/confirmed.png'
-                enabled: finalizer.valid
+                enabled: finalizer.valid && !finalizer.busy
                 onClicked: confirmed()
             }
         }

electrum/gui/qml/qetxfinalizer.py

@@ -448,6 +448,7 @@ def __init__(
         self._extraFee = QEAmount()
         self._canRbf = False
         self._swapStatusMsg = ''
+        self._busy = False
         self.swap_task: Future = None
 
         self.swapAvailabilityChanged.connect(self.on_swap_availability_changed, Qt.ConnectionType.QueuedConnection)
@@ -489,6 +490,17 @@ def amount(self, amount: QEAmount):
             self._amount.copyFrom(amount)
             self.amountChanged.emit()
 
+    busyChanged = pyqtSignal()
+    @pyqtProperty(bool, notify=busyChanged)
+    def busy(self) -> bool:
+        return self._busy
+
+    @busy.setter
+    def busy(self, busy: bool):
+        if self._busy != busy:
+            self._busy = busy
+            self.busyChanged.emit()
+
     effectiveAmountChanged = pyqtSignal()
     @pyqtProperty(QEAmount, notify=effectiveAmountChanged)
     def effectiveAmount(self):
@@ -642,6 +654,10 @@ def signAndSend(self):
             self._logger.debug('no valid tx')
             return
 
+        if self.busy:
+            self._logger.debug('busy')
+            return
+
         tx = self._tx
 
         if self.f_accept:
@@ -659,6 +675,8 @@ def _send_with_swap_change(self, tx):
         assert self._wallet.wallet.lnworker
         assert tx.get_dummy_output(DummyAddress.SWAP)
 
+        self.busy = True
+
         async def handle_swap_task():
             try:
                 swap_dummy_output = tx.get_dummy_output(DummyAddress.SWAP)
@@ -717,6 +735,7 @@ async def handle_swap_task():
             finally:
                 # ensures that swap_task is always set None if transport closes
                 self.swap_task = None
+                self.busy = False
 
         self.swap_task = asyncio.run_coroutine_threadsafe(handle_swap_task(), get_asyncio_loop())