Fix potential invalid index when restoring layout

We save the index of each FloatingWindow when saving a layout,
but when restoring we might not want to restore all FloatingWindows,
for example, if we use a LayoutSaver with another affinity.

So, the index in Position::deserialize() should be a index to
LayoutSaver::Layout::floatingWindows, and not to DockRegistry::self()->floatingWindows()
since the later might be smaller.

Author: iamsergio

Diff for: src/LayoutSaver.cpp

@@ -258,14 +258,15 @@ bool LayoutSaver::restoreLayout(const QByteArray &data)
     }
 
     // 2. Restore FloatingWindows
-    for (const LayoutSaver::FloatingWindow &fw : qAsConst(layout.floatingWindows)) {
+    for (LayoutSaver::FloatingWindow &fw : layout.floatingWindows) {
         if (!d->matchesAffinity(fw.affinities))
             continue;
 
         MainWindowBase *parent = fw.parentIndex == -1 ? nullptr
                                                       : DockRegistry::self()->mainwindows().at(fw.parentIndex);
 
         auto floatingWindow = Config::self().frameworkWidgetFactory()->createFloatingWindow(parent);
+        fw.floatingWindowInstance = floatingWindow;
         d->deserializeWindowGeometry(fw, floatingWindow);
         if (!floatingWindow->deserialize(fw)) {
             qWarning() << Q_FUNC_INFO << "Failed to deserialize floating window";
@@ -471,6 +472,19 @@ LayoutSaver::MainWindow LayoutSaver::Layout::mainWindowForIndex(int index) const
     return mainWindows.at(index);
 }
 
+LayoutSaver::FloatingWindow LayoutSaver::Layout::floatingWindowForIndex(int index) const
+{
+    if (index < 0 || index >= floatingWindows.size())
+        return {};
+
+    return floatingWindows.at(index);
+}
+
+FloatingWindow *LayoutSaver::Layout::floatingWindowInstanceForIndex(int index) const
+{
+    return floatingWindowForIndex(index).floatingWindowInstance;
+}
+
 QStringList LayoutSaver::Layout::mainWindowNames() const
 {
     QStringList names;

Diff for: src/LayoutSaver_p.h

@@ -36,6 +36,8 @@
 
 namespace KDDockWidgets {
 
+class FloatingWindow;
+
 template <typename T>
 typename T::List fromVariantList(const QVariantList &listV)
 {
@@ -233,6 +235,9 @@ struct LayoutSaver::FloatingWindow
     int screenIndex;
     QSize screenSize;  // for relative-size restoring
     bool isVisible = true;
+
+    // The instance that was created during a restore:
+    KDDockWidgets::FloatingWindow *floatingWindowInstance = nullptr;
 };
 
 struct LayoutSaver::MainWindow
@@ -313,6 +318,8 @@ struct LayoutSaver::Layout
     static LayoutSaver::Layout* s_currentLayoutBeingRestored;
 
     LayoutSaver::MainWindow mainWindowForIndex(int index) const;
+    LayoutSaver::FloatingWindow floatingWindowForIndex(int index) const;
+    KDDockWidgets::FloatingWindow* floatingWindowInstanceForIndex(int index) const;
 
     QStringList mainWindowNames() const;
     QStringList dockWidgetNames() const;

Diff for: src/private/Position.cpp

@@ -126,9 +126,8 @@ void Position::deserialize(const LayoutSaver::Position &lp)
             if (index == -1) {
                 continue; // Skip
             } else {
-                const auto floatingWindows = DockRegistry::self()->floatingWindows();
-                if (index >= 0 && index < floatingWindows.size()) {
-                    FloatingWindow *fw = floatingWindows.at(index);
+                FloatingWindow *fw = LayoutSaver::Layout::s_currentLayoutBeingRestored->floatingWindowInstanceForIndex(index);
+                if (fw) {
                     layout = fw->multiSplitter();
                 } else {
                     qWarning() << "Invalid floating window position to restore" << index;