fix(device_input): ensure callback is removed after cleanup

bec_widgets/widgets/control/device_input/device_combobox/device_combobox.py

@@ -489,14 +489,17 @@ class DeviceComboBox(BECWidget, QComboBox):
             action: Device update action emitted by BEC.
             content: Device update payload. Currently unused.
         """
+        if self._callback_id is None or getattr(self, "_destroyed", False):
+            return
         if action in ["add", "remove", "reload"]:
             self.device_config_update.emit()
 
     def cleanup(self):
         """Cleanup the widget."""
         if self._callback_id is not None:
-            self.bec_dispatcher.client.callbacks.remove(self._callback_id)
+            callback_id = self._callback_id
             self._callback_id = None
+            self.bec_dispatcher.client.callbacks.remove(callback_id)
         super().cleanup()
 
     def get_current_device(self) -> object:

bec_widgets/widgets/control/device_input/signal_combobox/signal_combobox.py

@@ -594,8 +594,9 @@ class SignalComboBox(BECWidget, QComboBox):
     def cleanup(self):
         """Cleanup the widget."""
         if self._device_update_register is not None:
-            self.bec_dispatcher.client.callbacks.remove(self._device_update_register)
+            callback_id = self._device_update_register
             self._device_update_register = None
+            self.bec_dispatcher.client.callbacks.remove(callback_id)
         super().cleanup()
 
     @staticmethod

tests/unit_tests/test_device_input_widgets.py

@@ -139,6 +139,23 @@ def test_device_input_combobox_cleanup_unregisters_callback(qtbot, mocked_client
         assert widget._callback_id is None
 
 
+def test_device_input_combobox_cleanup_clears_callback_before_unregister(qtbot, mocked_client):
+    widget = DeviceComboBox(client=mocked_client)
+    qtbot.addWidget(widget)
+    callback_id = widget._callback_id
+
+    def assert_callback_cleared(removed_callback_id):
+        assert removed_callback_id == callback_id
+        assert widget._callback_id is None
+
+    with mock.patch.object(
+        mocked_client.callbacks, "remove", side_effect=assert_callback_cleared
+    ) as remove_mock:
+        widget.cleanup()
+
+    remove_mock.assert_called_once_with(callback_id)
+
+
 def test_get_device_from_input_combobox_init(device_input_combobox):
     device_input_combobox.setCurrentIndex(0)
     device_text = device_input_combobox.currentText()

tests/unit_tests/test_device_signal_input.py

@@ -196,6 +196,41 @@ def test_device_signal_input_base_cleanup(qtbot, mocked_client):
         assert widget._device_update_register is None
 
 
+def test_signal_combobox_cleanup_clears_callback_before_unregister(qtbot, mocked_client):
+    widget = create_widget(qtbot=qtbot, widget=SignalComboBox, client=mocked_client)
+    callback_id = widget._device_update_register
+
+    def assert_callback_cleared(removed_callback_id):
+        assert removed_callback_id == callback_id
+        assert widget._device_update_register is None
+
+    with mock.patch.object(
+        mocked_client.callbacks, "remove", side_effect=assert_callback_cleared
+    ) as remove_mock:
+        widget.cleanup()
+
+    remove_mock.assert_called_once_with(callback_id)
+
+
+def test_signal_combobox_cleanup_blocks_in_flight_device_update(qtbot, mocked_client):
+    widget = create_widget(qtbot=qtbot, widget=SignalComboBox, client=mocked_client)
+    callback_id = widget._device_update_register
+
+    def trigger_in_flight_update(_):
+        widget.update_signals_from_filters("reload", {})
+
+    with (
+        mock.patch.object(
+            mocked_client.callbacks, "remove", side_effect=trigger_in_flight_update
+        ) as remove_mock,
+        mock.patch.object(widget, "_set_signal_groups") as set_signal_groups,
+    ):
+        widget.cleanup()
+
+    remove_mock.assert_called_once_with(callback_id)
+    set_signal_groups.assert_not_called()
+
+
 def test_signal_combobox_device_update_ignores_update_action(qtbot, mocked_client):
     widget = create_widget(qtbot=qtbot, widget=SignalComboBox, client=mocked_client)