fix: clear exception flag on disconnect future if its also sent to handlers (#281)

src/dbus_fast/aio/message_bus.py

@@ -1,5 +1,6 @@
 import array
 import asyncio
+import contextlib
 import logging
 import socket
 from collections import deque
@@ -522,6 +523,8 @@ class MessageBus(BaseMessageBus):
         except Exception:
             logging.warning("could not remove message writer", exc_info=True)
 
+        had_handlers = bool(self._method_return_handlers or self._user_message_handlers)
+
         super()._finalize(err)
 
         if self._disconnect_future.done():
@@ -529,6 +532,14 @@ class MessageBus(BaseMessageBus):
 
         if err and not self._user_disconnect:
             _future_set_exception(self._disconnect_future, err)
+            # If this happens during a reply, the message handlers
+            # will have the exception set and wait_for_disconnect will
+            # never be called so we need to manually set the exception
+            # as retrieved to avoid asyncio warnings when the future
+            # is garbage collected.
+            if had_handlers:
+                with contextlib.suppress(Exception):
+                    self._disconnect_future.exception()
         else:
             _future_set_result(self._disconnect_future, None)
 

tests/test_aio_low_level.py

@@ -44,6 +44,25 @@ async def test_standard_interfaces():
     bus.disconnect()
 
 
+@pytest.mark.asyncio
+async def test_error_handling():
+    bus = await MessageBus().connect()
+    msg = Message(
+        destination="org.freedesktop.DBus",
+        path="/org/freedesktop/DBus",
+        interface="org.freedesktop.DBus",
+        member="InvalidMember",
+        serial=bus.next_serial(),
+    )
+    reply = await bus.call(msg)
+
+    assert reply.message_type == MessageType.ERROR
+    assert reply.reply_serial == msg.serial
+    assert reply.signature == "s"
+
+    bus.disconnect()
+
+
 @pytest.mark.asyncio
 async def test_sending_messages_between_buses():
     bus1 = await MessageBus().connect()