Destroy action-owned submenus

Signed-off-by: Loren Eteval <loren.eteval@proton.me>

Furious/Qt/AGENTS.md

@@ -53,7 +53,9 @@ primitives; pages and services consume them without creating parallel registries
   arbitrary worker calls to the GUI thread; choose an explicit queued owner-thread delivery boundary. A surviving
   Python wrapper can already be natively invalid, so callback freshness and `shiboken6.isValid()` address different
   failure modes. Neither replaces the strong owner required while asynchronous UI remains active.
-- `AppQAction.callback` is strong by design, so the action owner cannot outlive the captured receiver.
+- `AppQAction.callback` is strong by design, so the action owner cannot outlive the captured receiver. An action
+  also owns a submenu supplied without a QWidget parent and schedules its native deletion when the action dies;
+  `QAction.setMenu()` alone does not establish parent ownership. Explicitly parented menus retain their chosen owner.
 - Every `QNetworkReply` has one manager/context owner, one freshness rule, and one terminal deletion path. Request
   context must also be released when native destruction skips `finished`, including manager-first teardown with
   retained Python wrappers. Use the shared network-manager tracking boundary; cleanup must not capture a reply

Furious/Qt/QtGui.py

@@ -147,6 +147,12 @@ class AppQAction(Mixins.QTranslatable, Mixins.ThemeAware, QAction):
             # Create reference
             self._menu = menu
 
+            if menu.parent() is None:
+                # setMenu() associates a submenu without giving it a Qt parent.
+                # This action owns otherwise unparented menus; explicit widget
+                # parents retain their own lifetime. deleteLater is a native slot.
+                self.destroyed.connect(menu.deleteLater)
+
             # Some old version PySide6 does not have setMenu method
             # for QAction. Protect it. Currently only used in TrayIcon
             if hasattr(self, 'setMenu') and useSetMenu:

tests/test_qt_lifetime.py

@@ -220,6 +220,35 @@ class QtLifetimeTest(unittest.TestCase):
 
         self.assertAllDestroyed(references, destroyed, 60)
 
+    def testActionOwnedMenusDieWithActionAndPreserveExplicitOwners(self):
+        """QAction's menu association must not strand an unparented native menu."""
+        references = []
+        destroyed = []
+
+        for explicitOwner in (False, True):
+            for _ in range(30):
+                owner = QWidget()
+                menu = AppQMenu(parent=owner if explicitOwner else None)
+                action = AppQAction('Menu fixture', menu=menu, parent=owner)
+                references.append(weakref.ref(menu))
+                menu.destroyed.connect(lambda *_args: destroyed.append(True))
+
+                action.deleteLater()
+                processQtEvents()
+
+                self.assertFalse(isValid(action))
+                try:
+                    self.assertEqual(isValid(menu), explicitOwner)
+                finally:
+                    if isValid(menu):
+                        menu.deleteLater()
+                    owner.deleteLater()
+                    processQtEvents()
+
+                del action, menu, owner
+
+        self.assertAllDestroyed(references, destroyed, 60)
+
     def testReopenedDialogSurvivesPreviousPresentationCleanup(self):
         """A queued finish must not release the next asynchronous presentation."""
         destroyed = []