QMenu: guard for destruction when emitting action signals

If a slot connected to a QMenu-action destroys the QMenu, then
we must not touch data members in subsequent code, and instead return
immediately.

We cannot use QBoolBlocker here, as that would reset the data
member of QMenuPrivate even when trying to return early.

Fixes: QTBUG-106718
Change-Id: I6b5ea471b1bf1f9864e1384382100f8f6c01346f
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
(cherry picked from commit 52ce4d2d29db8a44fa2fa817cab9ebe969db082e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 31 insertions, 3 deletions

diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index ac474c9bab..861af005e5 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -1387,9 +1387,18 @@ bool QMenuPrivate::mouseEventTaken(QMouseEvent *e)
 void QMenuPrivate::activateCausedStack(const QList<QPointer<QWidget>> &causedStack, QAction *action,
                                        QAction::ActionEvent action_e, bool self)
 {
-    QBoolBlocker guard(activationRecursionGuard);
+    Q_Q(QMenu);
+    // can't use QBoolBlocker here
+    const bool activationRecursionGuardReset = activationRecursionGuard;
+    activationRecursionGuard = true;
+    QPointer<QMenu> guard(q);
     if (self)
         action->activate(action_e);
+    if (!guard)
+        return;
+    auto boolBlocker = qScopeGuard([this, activationRecursionGuardReset]{
+        activationRecursionGuard = activationRecursionGuardReset;
+    });
 
     for(int i = 0; i < causedStack.size(); ++i) {
         QPointer<QWidget> widget = causedStack.at(i);
@@ -1465,9 +1474,10 @@ void QMenuPrivate::activateAction(QAction *action, QAction::ActionEvent action_e
 #endif
     }
 
-
+    QPointer<QMenu> thisGuard(q);
     activateCausedStack(causedStack, action, action_e, self);
-
+    if (!thisGuard)
+        return;
 
     if (action_e == QAction::Hover) {
 #if QT_CONFIG(accessibility)
diff --git a/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp b/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
index 31a3addd44..a7563bfa26 100644
--- a/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
+++ b/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
@@ -110,6 +110,7 @@ private slots:
     void tearOffMenuNotDisplayed();
     void QTBUG_61039_menu_shortcuts();
     void screenOrientationChangedCloseMenu();
+    void deleteWhenTriggered();
 
 protected slots:
     void onActivated(QAction*);
@@ -2011,5 +2012,22 @@ void tst_QMenu::screenOrientationChangedCloseMenu()
      QTRY_COMPARE(menu.isVisible(),false);
 }
 
+/*
+    Verify that deleting the menu in a slot connected to an
+    action's triggered signal doesn't crash.
+    QTBUG-106718
+*/
+void tst_QMenu::deleteWhenTriggered()
+{
+    QPointer<QMenu> menu = new QMenu;
+    QAction *action = menu->addAction("Action", [&menu]{
+        delete menu;
+    });
+    menu->popup(QGuiApplication::primaryScreen()->availableGeometry().center());
+    menu->setActiveAction(action);
+    QTest::keyClick(menu, Qt::Key_Return);
+    QTRY_VERIFY(!menu);
+}
+
 QTEST_MAIN(tst_QMenu)
 #include "tst_qmenu.moc"