fix(dock_area): skip superseded deferred layout ratio requests

bec_widgets/widgets/containers/dock_area/basic_dock_area.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import inspect
+import itertools
 from dataclasses import dataclass
 from typing import Any, Callable, Literal, Mapping, Sequence, cast
 
@@ -26,6 +27,11 @@ from bec_widgets.widgets.containers.qt_ads import (
 
 logger = bec_logger.logger
 
+# Dynamic property tagging a splitter with its latest layout-ratio request; deferred applies of
+# older requests compare against it and skip themselves.
+_RATIO_REQUEST_PROPERTY = "_bec_layout_ratio_request"
+_ratio_requests = itertools.count(1)
+
 
 class DockSettingsDialog(QDialog):
     """Generic settings editor shown from dock title bar actions."""
@@ -746,7 +752,9 @@ class DockAreaWidget(BECWidget, QWidget):
 
         The deferred callback is bound to the splitter as context object, so Qt drops it
         if the splitter is deleted (e.g. by ADS while the layout changes) before it runs.
-        While the splitter has no usable size, the ratios wait for its next resize.
+        While the splitter has no usable size, the ratios wait for its next resize. Every request
+        tags the splitter, so a deferred apply of an older request skips itself once a newer one
+        for the same splitter exists.
 
         Args:
             splitter(QtAds.CDockSplitter): Target splitter.
@@ -759,7 +767,12 @@ class DockAreaWidget(BECWidget, QWidget):
         if not ratios:
             return
 
+        request = next(_ratio_requests)
+        splitter.setProperty(_RATIO_REQUEST_PROPERTY, request)
+
         def apply():
+            if splitter.property(_RATIO_REQUEST_PROPERTY) != request:
+                return  # superseded by a newer request for this splitter
             count = splitter.count()
             if count != len(ratios):
                 return

tests/unit_tests/test_dock_area.py

@@ -433,6 +433,12 @@ class TestBasicDockArea:
             def findChildren(self, *_args, **_kwargs):
                 return []
 
+            def setProperty(self, name, value):
+                self.__dict__[name] = value
+
+            def property(self, name):
+                return self.__dict__.get(name)
+
         splitter = DummySplitter()
 
         basic_dock_area._schedule_splitter_weights(splitter, [1, 2, 1])
@@ -647,6 +653,19 @@ class TestBasicDockArea:
         assert left_px > 2 * right_px
         assert root.findChildren(basic_dock_module._ResizeWatcher) == []
 
+    def test_layout_ratios_superseded_request_does_not_apply(self, collapsed_dock_area, qtbot):
+        """An older request still queued when a newer one arrives must not win either."""
+        outer, area, root = collapsed_dock_area
+        area.set_layout_ratios(horizontal=[1, 3])
+        # The area gets its width back between the two queued applies.
+        QTimer.singleShot(0, outer, lambda: outer.setSizes([400, 400]))
+        area.set_layout_ratios(horizontal=[3, 1])
+        qtbot.waitUntil(lambda: root.width() > 0)
+        qtbot.wait(50)
+
+        left_px, right_px = root.sizes()
+        assert left_px > 2 * right_px
+
     def test_first_dock_title_bar_preference_survives_second_dock(self, basic_dock_area):
         first = QWidget(parent=basic_dock_area)
         first.setObjectName("first_panel")