bridge: call connection_lost "soon"

src/cockpit/channel.py

@@ -366,7 +366,7 @@ class ProtocolChannel(Channel, asyncio.Protocol):
     Otherwise, if the subclass implements .do_open() itself, it is responsible
     for setting up the connection and ensuring that .connection_made() is called.
     """
-    _transport: 'asyncio.Transport | None'
+    _transport: 'asyncio.Transport | None' = None
     _send_pongs: bool = True
     _last_ping: 'JsonObject | None' = None
     _create_transport_task: 'asyncio.Task[asyncio.Transport] | None' = None

src/cockpit/transports.py

@@ -142,7 +142,7 @@ def abort(self, exc: 'Exception | None' = None) -> None:
         self._closing = True
         self._close_reader()
         self._remove_write_queue()
-        self._protocol.connection_lost(exc)
+        self._loop.call_soon(self._protocol.connection_lost, exc)
         self._close()
 
     def can_write_eof(self) -> bool:

test/pytest/test_transport.py

@@ -255,6 +255,10 @@ async def test_cat(self) -> None:
         assert transport.get_returncode() == 0
         assert protocol.sent == protocol.received
         transport.close()
+        # make sure the connection_lost handler isn't called immediately
+        assert protocol.transport is not None
+        # ...but "soon" (in the very next mainloop iteration)
+        await asyncio.sleep(0.01)
         assert protocol.transport is None
 
     @pytest.mark.asyncio
@@ -330,6 +334,10 @@ async def test_broken_pipe(self) -> None:
         # Now let's write to the stdin with the other side closed.
         # This should be enough to immediately disconnect us (EPIPE)
         protocol.write(b'abc')
+        # make sure the connection_lost handler isn't called immediately
+        assert protocol.transport is not None
+        # ...but "soon" (in the very next mainloop iteration)
+        await asyncio.sleep(0.01)
         assert protocol.transport is None
         assert isinstance(protocol.exc, BrokenPipeError)
 
@@ -396,7 +404,11 @@ async def test_simple_close(self) -> None:
         assert protocol.transport
         assert protocol.transport.get_write_buffer_size() == 0
         protocol.transport.close()
-        assert protocol.transport is None  # make sure it closed immediately
+        # make sure the connection_lost handler isn't called immediately
+        assert protocol.transport is not None
+        # ...but "soon" (in the very next mainloop iteration)
+        await asyncio.sleep(0.01)
+        assert protocol.transport is None
         # we have another ref on the transport
         transport.close()  # should be idempotent