fix: 'disconnect_slot' has to be symmetric with 'connect_slot' regarding QtThreadSafeCallback

bec_widgets/utils/bec_dispatcher.py

@@ -129,7 +129,15 @@ class BECDispatcher:
         self._slots[slot].update(set(topics_str))
 
     def disconnect_slot(self, slot: Callable, topics: Union[str, list]):
-        self.client.connector.unregister(topics, cb=slot)
+        # find the right slot to disconnect from ;
+        # slot callbacks are wrapped in QtThreadSafeCallback objects,
+        # but the slot we receive here is the original callable
+        for connected_slot in self._slots:
+            if connected_slot.cb == slot:
+                break
+        else:
+            return
+        self.client.connector.unregister(topics, cb=connected_slot)
         topics_str, _ = self.client.connector._convert_endpointinfo(topics)
         self._slots[slot].difference_update(set(topics_str))
         if not self._slots[slot]:

tests/unit_tests/test_bec_dispatcher.py

@@ -1,4 +1,5 @@
 # pylint: disable = no-name-in-module,missing-class-docstring, missing-module-docstring
+import threading
 import time
 from unittest import mock
 
@@ -13,8 +14,9 @@ from bec_widgets.utils.bec_dispatcher import QtRedisConnector
 
 
 @pytest.fixture
-def bec_dispatcher_w_connector(bec_dispatcher, topics_msg_list):
+def bec_dispatcher_w_connector(bec_dispatcher, topics_msg_list, send_msg_event):
     def pubsub_msg_generator():
+        send_msg_event.wait()
         for topic, msg in topics_msg_list:
             yield {"channel": topic.encode(), "pattern": None, "data": msg}
         while True:
@@ -33,6 +35,11 @@ def bec_dispatcher_w_connector(bec_dispatcher, topics_msg_list):
 dummy_msg = MsgpackSerialization.dumps(ScanMessage(point_id=0, scan_id="0", data={}))
 
 
+@pytest.fixture
+def send_msg_event():
+    return threading.Event()
+
+
 @pytest.mark.parametrize(
     "topics_msg_list",
     [
@@ -43,7 +50,7 @@ dummy_msg = MsgpackSerialization.dumps(ScanMessage(point_id=0, scan_id="0", data
         )
     ],
 )
-def test_dispatcher_disconnect_all(bec_dispatcher_w_connector, qtbot):
+def test_dispatcher_disconnect_all(bec_dispatcher_w_connector, qtbot, send_msg_event):
     bec_dispatcher = bec_dispatcher_w_connector
     cb1 = mock.Mock(spec=[])
     cb2 = mock.Mock(spec=[])
@@ -53,7 +60,81 @@ def test_dispatcher_disconnect_all(bec_dispatcher_w_connector, qtbot):
     bec_dispatcher.connect_slot(cb2, "topic2")
     bec_dispatcher.connect_slot(cb2, "topic3")
     assert len(bec_dispatcher.client.connector._topics_cb) == 3
+    send_msg_event.set()
+    qtbot.wait(10)
+    assert cb1.call_count == 2
+    assert cb2.call_count == 2
 
     bec_dispatcher.disconnect_all()
 
     assert len(bec_dispatcher.client.connector._topics_cb) == 0
+
+
+@pytest.mark.parametrize(
+    "topics_msg_list",
+    [
+        (
+            ("topic1", dummy_msg),
+            ("topic2", dummy_msg),
+        )
+    ],
+)
+def test_dispatcher_disconnect_one(bec_dispatcher_w_connector, qtbot, send_msg_event):
+    # test for BEC issue #276
+    bec_dispatcher = bec_dispatcher_w_connector
+    cb1 = mock.Mock(spec=[])
+    cb2 = mock.Mock(spec=[])
+
+    bec_dispatcher.connect_slot(cb1, "topic1")
+    bec_dispatcher.connect_slot(cb2, "topic2")
+    assert len(bec_dispatcher.client.connector._topics_cb) == 2
+    bec_dispatcher.disconnect_slot(cb1, "topic1")
+    assert len(bec_dispatcher.client.connector._topics_cb) == 1
+
+    send_msg_event.set()
+    qtbot.wait(10)
+    assert cb1.call_count == 0
+    cb2.assert_called_once()
+
+
+@pytest.mark.parametrize("topics_msg_list", [(("topic1", dummy_msg),)])
+def test_dispatcher_2_cb_same_topic(bec_dispatcher_w_connector, qtbot, send_msg_event):
+    # test for BEC issue #276
+    bec_dispatcher = bec_dispatcher_w_connector
+    cb1 = mock.Mock(spec=[])
+    cb2 = mock.Mock(spec=[])
+
+    bec_dispatcher.connect_slot(cb1, "topic1")
+    bec_dispatcher.connect_slot(cb2, "topic1")
+    assert len(bec_dispatcher.client.connector._topics_cb) == 1
+    bec_dispatcher.disconnect_slot(cb1, "topic1")
+
+    send_msg_event.set()
+    qtbot.wait(10)
+    assert cb1.call_count == 0
+    cb2.assert_called_once()
+
+
+@pytest.mark.parametrize(
+    "topics_msg_list",
+    [
+        (
+            ("topic1", dummy_msg),
+            ("topic2", dummy_msg),
+        )
+    ],
+)
+def test_dispatcher_2_topic_same_cb(bec_dispatcher_w_connector, qtbot, send_msg_event):
+    # test for BEC issue #276
+    bec_dispatcher = bec_dispatcher_w_connector
+    cb1 = mock.Mock(spec=[])
+
+    bec_dispatcher.connect_slot(cb1, "topic1")
+    bec_dispatcher.connect_slot(cb1, "topic2")
+    assert len(bec_dispatcher.client.connector._topics_cb) == 2
+    bec_dispatcher.disconnect_slot(cb1, "topic1")
+    assert len(bec_dispatcher.client.connector._topics_cb) == 1
+
+    send_msg_event.set()
+    qtbot.wait(10)
+    cb1.assert_called_once()