From 6f1a4721288c10ec0be38dd3bfde335cc4c45d0a Mon Sep 17 00:00:00 2001
From: appel_c <christian.appel@psi.ch>
Date: Tue, 15 Apr 2025 20:17:47 +0200
Subject: [PATCH] fix(on_async_readback): suppress history updates from old
 scan_id

---
 bec_widgets/utils/bec_dispatcher.py            | 9 ++++-----
 bec_widgets/widgets/plots/waveform/waveform.py | 6 ++++++
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/bec_widgets/utils/bec_dispatcher.py b/bec_widgets/utils/bec_dispatcher.py
index 976b70b0..96fdf894 100644
--- a/bec_widgets/utils/bec_dispatcher.py
+++ b/bec_widgets/utils/bec_dispatcher.py
@@ -25,9 +25,9 @@ if TYPE_CHECKING:  # pragma: no cover
 class QtThreadSafeCallback(QObject):
     cb_signal = pyqtSignal(dict, dict)
 
-    def __init__(self, cb):
+    def __init__(self, cb, cb_info: dict | None = None):
         super().__init__()
-        self.topics = None
+        self.cb_info = cb_info
         self.cb = cb
         self.cb_signal.connect(self.cb)
 
@@ -38,7 +38,6 @@ class QtThreadSafeCallback(QObject):
         return id(self.cb)
 
     def __call__(self, msg_content, metadata):
-        logger.info(f"Received message for topic {self.topics}")
         self.cb_signal.emit(msg_content, metadata)
 
 
@@ -138,6 +137,7 @@ class BECDispatcher:
         self,
         slot: Callable,
         topics: Union[EndpointInfo, str, list[Union[EndpointInfo, str]]],
+        cb_info: dict | None = None,
         **kwargs,
     ) -> None:
         """Connect widget's qt slot, so that it is called on new pub/sub topic message.
@@ -147,8 +147,7 @@ class BECDispatcher:
                 the corresponding pub/sub message
             topics (EndpointInfo | str | list): A topic or list of topics that can typically be acquired via bec_lib.MessageEndpoints
         """
-        slot = QtThreadSafeCallback(slot)
-        slot.topics = topics
+        slot = QtThreadSafeCallback(slot, cb_info=cb_info)
         self.client.connector.register(topics, cb=slot, **kwargs)
         topics_str, _ = self.client.connector._convert_endpointinfo(topics)
         self._slots[slot].update(set(topics_str))
diff --git a/bec_widgets/widgets/plots/waveform/waveform.py b/bec_widgets/widgets/plots/waveform/waveform.py
index 3a7fcfcb..d38fb049 100644
--- a/bec_widgets/widgets/plots/waveform/waveform.py
+++ b/bec_widgets/widgets/plots/waveform/waveform.py
@@ -1176,6 +1176,7 @@ class Waveform(PlotBase):
         self.bec_dispatcher.connect_slot(
             self.on_async_readback,
             MessageEndpoints.device_async_readback(self.scan_id, name),
+            cb_info={"scan_id": self.scan_id},
             from_start=True,
         )
         logger.info(f"Setup async curve {name}")
@@ -1199,6 +1200,11 @@ class Waveform(PlotBase):
             msg(dict): Message with the async data.
             metadata(dict): Metadata of the message.
         """
+        sender = self.sender()
+        if sender and hasattr(sender, "cb_info"):
+            scan_id = sender.cb_info.get("scan_id", None)
+            if scan_id != self.scan_id:
+                return  # Ignore messages from other scans
         instruction = metadata.get("async_update", {}).get("type")
         if instruction not in ["add", "add_slice", "replace"]:
             logger.warning(f"Invalid async update instruction: {instruction}")