Lab - reload surface mesh with selection

[janetournois]

Issue Details

• Load a surface mesh, and a selection (either from two separate files or stored in one file like .om file format
• make operations (or not)
• click "Reload Item From File"

Depending on the operations scenario, Lab either crashes, or does not reload the selection.

Indeed, in MainWindow.cpp, the function reloadItem() does not take into account the "dependent" items like the selection_item. This should be fixed

Environment

• CGAL version: 6.0.1

[Nerdgirl50]

void MainWindow::reloadItem(Item* item) {
    if (!item) {
        qDebug() << "No item provided for reload.";
        return;
    }

    // Step 1: Identify and store dependent items
    QList<Item*> dependentItems;
    if (item->hasDependencies()) {
        dependentItems = item->getDependencies();
    }

    // Step 2: Reload the main item
    bool reloadSuccessful = item->reloadFromFile();
    if (!reloadSuccessful) {
        qDebug() << "Failed to reload item from file.";
        return;
    }

    // Step 3: Handle dependent items
    for (Item* dependentItem : dependentItems) {
        if (dependentItem) {
            bool dependentReloadSuccessful = dependentItem->reloadFromFile();
            if (!dependentReloadSuccessful) {
                qDebug() << "Failed to reload dependent item:" << dependentItem->name();
                // Optionally, recreate or update dependent items as needed
            }
        }
    }

    // Step 4: Update UI and consistency
    updateUI();
    qDebug() << "Reloaded item and its dependencies successfully.";
}

[chinanuj]

Hello ,

I have just opened PR #9361 to address this bug.

I looked into the patch proposed earlier, but during testing, I found that relying directly on C++ pointers/dependencies during the reload struggles because Scene_polyhedron_selection_item intentionally self-destructs the moment its parent mesh is removed.

To safely bypass this, I implemented a "Cache and Restore" mechanism using Qt's dynamic properties. The system now caches the file paths of any dependent items right before the parent mesh is deleted, and then explicitly restores and reattaches them once the new parent mesh is loaded and highlighted.

I've tested it locally and it successfully reloads surface meshes while keeping the selection intact without crashing.

Hope this solves the issue .