feat(slot): add 'verify_sender' argument to SafeSlot for sender verification

bec_widgets/utils/error_popups.py

@@ -96,15 +96,33 @@ def SafeSlot(*slot_args, **slot_kwargs):  # pylint: disable=invalid-name
 
     'popup_error' keyword argument can be passed with boolean value if a dialog should pop up,
     otherwise error display is left to the original exception hook
+    'verify_sender' keyword argument can be passed with boolean value if the sender should be verified
+    before executing the slot. If True, the slot will only execute if the sender is a QObject. This is
+    useful to prevent function calls from already deleted objects.
     """
     popup_error = bool(slot_kwargs.pop("popup_error", False))
+    verify_sender = bool(slot_kwargs.pop("verify_sender", False))
 
     def error_managed(method):
         @Slot(*slot_args, **slot_kwargs)
         @functools.wraps(method)
         def wrapper(*args, **kwargs):
             try:
+                if not verify_sender or len(args) == 0:
+                    return method(*args, **kwargs)
+
+                _instance = args[0]
+                if not isinstance(_instance, QObject):
+                    return method(*args, **kwargs)
+                sender = _instance.sender()
+                if sender is None:
+                    logger.info(
+                        f"Sender is None for {method.__module__}.{method.__qualname__}, "
+                        "skipping method call."
+                    )
+                    return
                 return method(*args, **kwargs)
+
             except Exception:
                 slot_name = f"{method.__module__}.{method.__qualname__}"
                 error_msg = traceback.format_exc()

tests/unit_tests/test_error_utils.py

@@ -1,13 +1,11 @@
-import sys
 from unittest.mock import patch
 
 import pytest
-import pytestqt
 from bec_lib.logger import bec_logger
-from qtpy.QtCore import QObject
+from qtpy.QtCore import QObject, Signal
 from qtpy.QtWidgets import QMessageBox
 
-from bec_widgets.utils.error_popups import ErrorPopupUtility, ExampleWidget, SafeProperty
+from bec_widgets.utils.error_popups import ErrorPopupUtility, ExampleWidget, SafeProperty, SafeSlot
 
 
 class TestSafePropertyClass(QObject):
@@ -30,6 +28,32 @@ class TestSafePropertyClass(QObject):
         self._my_value = val
 
 
+class TestSafeSlotEmitter(QObject):
+    test_signal = Signal()
+
+
+class TestSafeSlotClass(QObject):
+    """
+    Test class to demonstrate the use of SafeSlot decorator.
+    """
+
+    def __init__(self, parent=None, signal_obj: TestSafeSlotEmitter | None = None):
+        super().__init__(parent)
+        assert signal_obj is not None, "Signal object must be provided"
+        signal_obj.test_signal.connect(self.method_without_sender_verification)
+        signal_obj.test_signal.connect(self.method_with_sender_verification)
+        self._method_without_verification_called = False
+        self._method_with_verification_called = False
+
+    @SafeSlot()
+    def method_without_sender_verification(self):
+        self._method_without_verification_called = True
+
+    @SafeSlot(verify_sender=True)
+    def method_with_sender_verification(self):
+        self._method_with_verification_called = True
+
+
 @pytest.fixture
 def widget(qtbot):
     test_widget = ExampleWidget()
@@ -147,3 +171,28 @@ def test_safe_property_setter_error(mock_exec, mock_log_error, qtbot, global_pop
     logged_msg = mock_log_error.call_args[0][0]
     assert "SafeProperty error in SETTER" in logged_msg
     assert "ValueError" in logged_msg
+
+
+@pytest.mark.timeout(100)
+def test_safe_slot_emit(qtbot):
+    """
+    Test that the signal is emitted correctly.
+    """
+    signal_obj = TestSafeSlotEmitter()
+    test_obj = TestSafeSlotClass(signal_obj=signal_obj)
+    signal_obj.test_signal.emit()
+
+    qtbot.waitUntil(lambda: test_obj._method_without_verification_called, timeout=1000)
+    qtbot.waitUntil(lambda: test_obj._method_with_verification_called, timeout=1000)
+
+    test_obj.deleteLater()
+
+    test_obj = TestSafeSlotClass(signal_obj=signal_obj)
+    test_obj.method_without_sender_verification()
+    test_obj.method_with_sender_verification()
+
+    assert test_obj._method_without_verification_called is True
+    assert test_obj._method_with_verification_called is False
+
+    test_obj.deleteLater()
+    signal_obj.deleteLater()