From 4a1ac4784a3fde4c580443ffd299789e1561c958 Mon Sep 17 00:00:00 2001
From: f321x <f@f321x.com>
Date: Sun, 20 Jul 2025 17:28:10 +0200
Subject: [PATCH] qml: catch exceptions in QESwapHelper transport_task

Adds an on_done_callback to the QESwapHelper.transport_task future
to prevent the task from swallowing exceptions by retrieving exceptions
and calling `util.send_exception_to_crash_reporter` with them.
---
 electrum/gui/qml/qeswaphelper.py | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/electrum/gui/qml/qeswaphelper.py b/electrum/gui/qml/qeswaphelper.py
index bcc1a8e65..80dede72b 100644
--- a/electrum/gui/qml/qeswaphelper.py
+++ b/electrum/gui/qml/qeswaphelper.py
@@ -12,7 +12,7 @@ from electrum.bitcoin import DummyAddress
 from electrum.logging import get_logger
 from electrum.transaction import PartialTxOutput, PartialTransaction
 from electrum.util import (NotEnoughFunds, NoDynamicFeeEstimates, profiler, get_asyncio_loop, age,
-                           wait_for2)
+                           wait_for2, send_exception_to_crash_reporter)
 from electrum.submarine_swaps import NostrTransport, SwapServerTransport, pubkey_to_rgb_color
 from electrum.fee_policy import FeePolicy
 
@@ -24,6 +24,7 @@ from .qewallet import QEWallet
 from .util import QtEventListener, qt_event_listener
 
 if TYPE_CHECKING:
+    import concurrent.futures
     from electrum.submarine_swaps import SwapOffer
 
 
@@ -200,7 +201,6 @@ class QESwapHelper(AuthMixin, QObject, QtEventListener):
     def on_destroy(self):
         if self.transport_task is not None:
             self.transport_task.cancel()
-            self.transport_task = None
         self.unregister_callbacks()
 
     walletChanged = pyqtSignal()
@@ -457,17 +457,19 @@ class QESwapHelper(AuthMixin, QObject, QtEventListener):
                             self.offersUpdated.emit()
                     await asyncio.sleep(1)
 
-        async def handle_swap_transport(transport: SwapServerTransport):
-            # ensures that swap_transport is always set None if transport closes
-            try:
-                await swap_transport_task(transport)
-            finally:
-                self.swap_transport = None
+        def transport_closed_cb(fut: 'concurrent.futures.Future'):
+            self.transport_task = None
+            if fut.cancelled():
+                return
+            exc = fut.exception()
+            if exc:
+                send_exception_to_crash_reporter(exc)
 
         self.transport_task = asyncio.run_coroutine_threadsafe(
-            handle_swap_transport(swap_transport),
+            swap_transport_task(swap_transport),
             get_asyncio_loop()
         )
+        self.transport_task.add_done_callback(transport_closed_cb)
 
     @pyqtSlot()
     def npubSelectionCancelled(self):