Fix crash at shutdown if multiple windows are open

The issue is that the window actions were explicitly made children of
the ActionManager, but ActionManager is deleted earlier than the windows
closed at shutdown.

Change WindowList from a bunch of static data to an object with a
lifetime and make it own the actions itself.

Fix-up of 1b0d6e3c26 which started
deleting the actions in the first place.

Fixes: QTCREATORBUG-21221
Change-Id: I2e335887fa4b85b29bdaa2c908ec643b6abf3231
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/coreplugin/windowsupport.cpp

@@ -44,11 +44,7 @@
 namespace Core {
 namespace Internal {
 
-
-QMenu *WindowList::m_dockMenu = nullptr;
-QList<QWidget *> WindowList::m_windows;
-QList<QAction *> WindowList::m_windowActions;
-QList<Id> WindowList::m_windowActionIds;
+Q_GLOBAL_STATIC(WindowList, m_windowList)
 
 WindowSupport::WindowSupport(QWidget *window, const Context &context)
     : QObject(window),
@@ -80,7 +76,7 @@ WindowSupport::WindowSupport(QWidget *window, const Context &context)
     ActionManager::registerAction(m_toggleFullScreenAction, Constants::TOGGLE_FULLSCREEN, context);
     connect(m_toggleFullScreenAction, &QAction::triggered, this, &WindowSupport::toggleFullScreen);
 
-    WindowList::addWindow(window);
+    m_windowList->addWindow(window);
 
     connect(ICore::instance(), &ICore::coreAboutToClose, this, [this]() { m_shutdown = true; });
 }
@@ -95,7 +91,7 @@ WindowSupport::~WindowSupport()
         }
         ActionManager::unregisterAction(m_toggleFullScreenAction, Constants::TOGGLE_FULLSCREEN);
         ICore::removeContextObject(m_contextObject);
-        WindowList::removeWindow(m_window);
+        m_windowList->removeWindow(m_window);
     }
 }
 
@@ -117,12 +113,12 @@ bool WindowSupport::eventFilter(QObject *obj, QEvent *event)
         }
         updateFullScreenAction();
     } else if (event->type() == QEvent::WindowActivate) {
-        WindowList::setActiveWindow(m_window);
+        m_windowList->setActiveWindow(m_window);
     } else if (event->type() == QEvent::Hide) {
         // minimized windows are hidden, but we still want to show them
-        WindowList::setWindowVisible(m_window, m_window->isMinimized());
+        m_windowList->setWindowVisible(m_window, m_window->isMinimized());
     } else if (event->type() == QEvent::Show) {
-        WindowList::setWindowVisible(m_window, true);
+        m_windowList->setWindowVisible(m_window, true);
     }
     return false;
 }
@@ -151,6 +147,11 @@ void WindowSupport::updateFullScreenAction()
     }
 }
 
+WindowList::~WindowList()
+{
+    qDeleteAll(m_windowActions);
+}
+
 void WindowList::addWindow(QWidget *window)
 {
 #ifdef Q_OS_OSX
@@ -163,16 +164,16 @@ void WindowList::addWindow(QWidget *window)
     m_windows.append(window);
     Id id = Id("QtCreator.Window.").withSuffix(m_windows.size());
     m_windowActionIds.append(id);
-    auto action = new QAction(window->windowTitle(), ActionManager::instance());
+    auto action = new QAction(window->windowTitle());
     m_windowActions.append(action);
-    QObject::connect(action, &QAction::triggered, [action]() { WindowList::activateWindow(action); });
+    QObject::connect(action, &QAction::triggered, [action, this]() { activateWindow(action); });
     action->setCheckable(true);
     action->setChecked(false);
     Command *cmd = ActionManager::registerAction(action, id);
     cmd->setAttribute(Command::CA_UpdateText);
     ActionManager::actionContainer(Constants::M_WINDOW)->addAction(cmd, Constants::G_WINDOW_LIST);
     action->setVisible(window->isVisible() || window->isMinimized()); // minimized windows are hidden but should be shown
-    QObject::connect(window, &QWidget::windowTitleChanged, [window]() { WindowList::updateTitle(window); });
+    QObject::connect(window, &QWidget::windowTitleChanged, [window, this]() { updateTitle(window); });
     if (m_dockMenu)
         m_dockMenu->addAction(action);
     if (window->isActiveWindow())

src/plugins/coreplugin/windowsupport.h

@@ -41,19 +41,21 @@ namespace Internal {
 class WindowList
 {
 public:
-    static void addWindow(QWidget *window);
-    static void removeWindow(QWidget *window);
-    static void setActiveWindow(QWidget *window);
-    static void setWindowVisible(QWidget *window, bool visible);
+    ~WindowList();
+
+    void addWindow(QWidget *window);
+    void removeWindow(QWidget *window);
+    void setActiveWindow(QWidget *window);
+    void setWindowVisible(QWidget *window, bool visible);
 
 private:
-    static void activateWindow(QAction *action);
-    static void updateTitle(QWidget *window);
+    void activateWindow(QAction *action);
+    void updateTitle(QWidget *window);
 
-    static QMenu *m_dockMenu;
-    static QList<QWidget *> m_windows;
-    static QList<QAction *> m_windowActions;
-    static QList<Id> m_windowActionIds;
+    QMenu *m_dockMenu = nullptr;
+    QList<QWidget *> m_windows;
+    QList<QAction *> m_windowActions;
+    QList<Id> m_windowActionIds;
 };
 
 class WindowSupport : public QObject