macOS: Fix native dangling menu still visible on screen and crash

If the parent window gets destroyed while a QtQuick Controls menu is open
the macOS native platform menu is not dismissed and you see a blank
gray rectangle without any text.
Also, at this point the QQmlEngine was already destroyed but it's still
present on the call stack, so you get a crash when the stack unwinds to
the original right mouse click that created the context menu.

Change-Id: I638b0de13734815995d2994e6dd6603bcb0ebefc
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>

2 files changed, 19 insertions, 0 deletions

diff --git a/src/controls/qquickmenu.cpp b/src/controls/qquickmenu.cpp
index b725bbbf..3c243ba3 100644
--- a/src/controls/qquickmenu.cpp
+++ b/src/controls/qquickmenu.cpp
@@ -436,6 +436,10 @@ void QQuickMenu1::__popup(const QRectF &targetRect, int atItemIndex, MenuType me
     // parentWindow may not be a QQuickWindow (happens when using QQuickWidget)
 
     if (m_platformMenu) {
+        if (m_windowConnection)
+            QObject::disconnect(m_windowConnection);
+        m_windowConnection = connect(parentWindow, &QWindow::visibleChanged, this,
+                                     &QQuickMenu1::platformMenuWindowVisibleChanged, Qt::UniqueConnection);
         QRectF globalTargetRect = targetRect.translated(m_xOffset, m_yOffset);
         if (visualItem()) {
             if (qGuiApp->isRightToLeft()) {
@@ -565,6 +569,19 @@ void QQuickMenu1::windowVisibleChanged(bool v)
     }
 }
 
+void QQuickMenu1::platformMenuWindowVisibleChanged(bool visible)
+{
+    if (!visible) {
+        if (m_windowConnection) {
+            QObject::disconnect(m_windowConnection);
+            m_windowConnection = QMetaObject::Connection();
+        }
+        if (m_platformMenu) {
+            m_platformMenu->dismiss();
+        }
+    }
+}
+
 void QQuickMenu1::clearPopupWindow()
 {
     m_popupWindow = 0;
diff --git a/src/controls/qquickmenu_p.h b/src/controls/qquickmenu_p.h
index 576ae5fd..8510efbe 100644
--- a/src/controls/qquickmenu_p.h
+++ b/src/controls/qquickmenu_p.h
@@ -165,6 +165,7 @@ protected Q_SLOTS:
 
     void updateText();
     void windowVisibleChanged(bool);
+    void platformMenuWindowVisibleChanged(bool);
 
 private:
     QQuickWindow *findParentWindow();
@@ -205,6 +206,7 @@ private:
     QFont m_font;
     int m_triggerCount;
     bool m_proxy;
+    QMetaObject::Connection m_windowConnection;
 };
 
 QT_END_NAMESPACE