Method prepareShutdown

src/gui/PanadapterStack.cpp:837–886

}

void PanadapterStack::prepareShutdown()
{
    if (m_shutdownPrepared) {
        return;
    }
    m_shutdownPrepared = true;

    setShuttingDown(true);
    saveFloatingState();

    // Explicitly delete floating windows rather than calling close().
    // close() without WA_DeleteOnClose only hides the window, leaving it alive
    // as a Qt::Window child of MainWindow.  When MainWindow's QWidget::~QWidget()
    // later tears down its QRhi, Qt fires the QRhiWidgetPrivate cleanup callbacks
    // for those still-parented-but-hidden floating windows in an order that can
    // invalidate QRhiWidgetPrivate before the callback returns → crash at 0x1e2.
    // Deleting fw explicitly runs QRhiWidget::~QRhiWidget() → removeCleanupCallback
    // while the QRhi is still valid, so no stale callbacks remain when MainWindow
    // tears down (#2495 exit crash on macOS).
    const QList<QString> floatingIds = m_floatingWindows.keys();
    for (const QString& panId : floatingIds) {
        PanFloatingWindow* fw = m_floatingWindows.take(panId);
        if (!fw) continue;
        fw->saveWindowGeometry();
        if (PanadapterApplet* applet = fw->applet()) {
            if (SpectrumWidget* sw = applet->spectrumWidget()) {
                sw->prepareForShutdown();
            }
        }
        m_pans.remove(panId);
        delete fw;
    }

    // Explicitly delete docked applets so ~QRhiWidget() runs (and calls
    // removeCleanupCallback) while MainWindow's QRhi is still alive.
    // If we leave applets alive, Qt's destructor chain for QWidget destroys
    // the QRhi *before* ~QObject()::deleteChildren() deletes the child
    // SpectrumWidgets — QRhi::runCleanup() then fires against QRhiWidgetPrivate
    // objects that are still live but have internal Qt fields in a stale state
    // → crash at $0_cleanup +24 on exit (#2495 macOS).
    const QList<QString> dockedIds = m_pans.keys();
    for (const QString& panId : dockedIds) {
        PanadapterApplet* applet = m_pans.take(panId);
        if (!applet) continue;
        if (SpectrumWidget* sw = applet->spectrumWidget()) {
            sw->prepareForShutdown();
        }
        delete applet;
    }
}

void PanadapterStack::saveFloatingState() const
{