TreeGrid#getDataProvider().refreshItem(parent, true); does not remove expanded state if item does not have any children anymore

[randomuser1231232]

Description of the bug

TreeGrid#getDataProvider().refreshItem(parent, true); does not remove expanded state if item does not have any children anymore.

Used Dataprovider: AbstractBackEndHierarchicalDataProvider

Expected behavior

Remove expanded state for item after TreeGrid#getDataProvider().refreshItem(parent, true) if item does not have any children anymore.

Minimal reproducible example

@Route
public class MainView extends VerticalLayout {

    public MainView() {
        final var treegrid = new TestTreeGrid();
        final var addButton = new Button("add");
        addButton.addClickListener(buttonClickEvent -> {
            for (UUID item : treegrid.getSelectedItems()) {
                treegrid.add(item, UUID.randomUUID());
                treegrid.add(item, UUID.randomUUID());
            }
        });
        final var deleteButton = new Button("delete children");
        deleteButton.addClickListener(buttonClickEvent -> {
            for (UUID item : treegrid.getSelectedItems()) {
                treegrid.deleteChildren(item);
            }
        });

        this.add(addButton, deleteButton, treegrid);
    }
}

public class TestTreeGrid extends TreeGrid<UUID> {

    private final Map<UUID, List<UUID>> childMap;

    public TestTreeGrid() {
        UUID root = UUID.randomUUID();
        childMap = new HashMap<>();
        this.setWidth(600, Unit.PIXELS);
        this.setHeight(800, Unit.PIXELS);

        addHierarchyColumn(i -> i);
        setDataProvider(new AbstractBackEndHierarchicalDataProvider<UUID, Object>() {
            @Override
            protected Stream<UUID> fetchChildrenFromBackEnd(HierarchicalQuery<UUID, Object> query) {
                if (query.getParent() == null) {
                    return Stream.of(root);
                }
                return childMap.get(query.getParent()).stream();
            }

            @Override
            public int getChildCount(HierarchicalQuery<UUID, Object> query) {
                if (query.getParent() == null) {
                    return 1;
                }
                return childMap.get(query.getParent()).size();
            }

            @Override
            public boolean hasChildren(UUID item) {
                return childMap.containsKey(item) && !childMap.get(item).isEmpty();
            }
        });
    }

    public void add(UUID parent, UUID child) {
        var children = this.childMap.get(parent);
        if (children == null) {
            children = new ArrayList<>();
        }
        children.add(child);
        childMap.put(parent, children);

        this.expand(parent);
        this.getDataProvider().refreshItem(parent, true);
        this.select(child);
    }

    public void deleteChildren(UUID parent) {
        var children = this.childMap.get(parent);
        if (children == null || children.isEmpty()) {
            return;
        }
        children.clear();

        this.getDataProvider().refreshItem(parent, true);
    }

}

vaadin-grid::part(expanded-row-cell) {
  background-color: green;
}

1. select root
2. add children
3. remove children
4. css above is still applied to cells

Versions

• Vaadin / Flow version:24.6.5

[tepi]

Not 100% sure if this is a bug or not. To me it seems the expanded/collapsed state and existence of children are independent state-like properties of a parent node, so doing this in your example code at least 'fixes' the issue for this case:

public void deleteChildren(UUID parent) {
    var children = this.childMap.get(parent);
    if (children == null || children.isEmpty()) {
        return;
    }
    children.clear();
    this.collapse(parent); // <-- collapse the parent node
    this.getDataProvider().refreshItem(parent, true);
}

[tepi]

Tagging as waiting for author since I think the author might have some more input on this issue.