Reset HierarchicalDataCommunicator on changes (#9275)

Reset HDC when encountering unexpected changes in the data.

Additionally this patch fixes an issue with client and server caches
getting out of sync during resets.

2 files changed, 210 insertions, 0 deletions

diff --git a/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchy.java b/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchy.java
new file mode 100644
index 0000000000..c7943524e4
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchy.java
@@ -0,0 +1,89 @@
+package com.vaadin.tests.components.treegrid;
+
+import java.util.stream.Stream;
+
+import com.vaadin.data.HierarchyData;
+import com.vaadin.data.ValueProvider;
+import com.vaadin.data.provider.HierarchicalQuery;
+import com.vaadin.data.provider.InMemoryHierarchicalDataProvider;
+import com.vaadin.server.SerializablePredicate;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.TreeGrid;
+
+public class TreeGridChangingHierarchy extends AbstractTestUI {
+
+    private static class TestDataProvider
+            extends InMemoryHierarchicalDataProvider<String> {
+
+        private HierarchyData<String> hierarchyData;
+
+        public TestDataProvider(HierarchyData<String> hierarchyData) {
+            super(hierarchyData);
+            this.hierarchyData = hierarchyData;
+        }
+
+        @Override
+        public boolean hasChildren(String item) {
+            if (!hierarchyData.contains(item)) {
+                return false;
+            }
+            return super.hasChildren(item);
+        }
+
+        @Override
+        public Stream<String> fetchChildren(
+                HierarchicalQuery<String, SerializablePredicate<String>> query) {
+            if (!hierarchyData.contains(query.getParent())) {
+                return Stream.empty();
+            }
+            return super.fetchChildren(query);
+        }
+    }
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        HierarchyData<String> data = new HierarchyData<>();
+        data.addItems(null, "a", "b", "c").addItem("b", "b/a");
+
+        TreeGrid<String> grid = new TreeGrid<>();
+        grid.setDataProvider(new TestDataProvider(data));
+        grid.addColumn(ValueProvider.identity());
+
+        Button btn = new Button("add items to a and refresh");
+        btn.addClickListener(event -> {
+            data.addItems("a", "a/a", "a/b");
+            grid.getDataProvider().refreshItem("a");
+        });
+        Button btn2 = new Button("add items to a/a and refresh");
+        btn2.addClickListener(event -> {
+            data.addItems("a/a", "a/a/a", "a/a/c").addItem("a/a/a", "a/a/a/a");
+            grid.getDataProvider().refreshItem("a/a");
+        });
+        Button btn3 = new Button("remove a/a");
+        btn3.addClickListener(event -> {
+            data.removeItem("a/a");
+        });
+        Button btn4 = new Button("remove children of a/a");
+        btn4.addClickListener(event -> {
+            data.removeItem("a/a/a");
+            data.removeItem("a/a/c");
+        });
+        Button btn5 = new Button("remove a");
+        btn5.addClickListener(event -> {
+            data.removeItem("a");
+        });
+        Button btn6 = new Button("remove children of a");
+        btn6.addClickListener(event -> {
+            data.removeItem("a/a");
+            data.removeItem("a/b");
+        });
+        Button btn7 = new Button("remove children of a/a/a");
+        btn7.addClickListener(event -> {
+            data.removeItem("a/a/a/a");
+        });
+
+        addComponents(grid, btn, btn2, btn3, btn4, btn5, btn6, btn7);
+    }
+}
diff --git a/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchyTest.java b/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchyTest.java
new file mode 100644
index 0000000000..89273af661
--- /dev/null
+++ b/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridChangingHierarchyTest.java
@@ -0,0 +1,121 @@
+package com.vaadin.tests.components.treegrid;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.openqa.selenium.By;
+
+import com.vaadin.testbench.elements.ButtonElement;
+import com.vaadin.testbench.elements.TreeGridElement;
+import com.vaadin.tests.tb3.SingleBrowserTest;
+
+public class TreeGridChangingHierarchyTest extends SingleBrowserTest {
+
+    private TreeGridElement grid;
+    private ButtonElement addItemsToABtn;
+    private ButtonElement addItemsToAABtn;
+    private ButtonElement removeAABtn;
+    private ButtonElement removeChildrenOfAABtn;
+    private ButtonElement removeABtn;
+    private ButtonElement removeChildrenOfABtn;
+    private ButtonElement removeChildrenOfAAABtn;
+
+    @Before
+    public void before() {
+        setDebug(true);
+        openTestURL();
+        grid = $(TreeGridElement.class).first();
+        addItemsToABtn = $(ButtonElement.class).get(0);
+        addItemsToAABtn = $(ButtonElement.class).get(1);
+        removeAABtn = $(ButtonElement.class).get(2);
+        removeChildrenOfAABtn = $(ButtonElement.class).get(3);
+        removeABtn = $(ButtonElement.class).get(4);
+        removeChildrenOfABtn = $(ButtonElement.class).get(5);
+        removeChildrenOfAAABtn = $(ButtonElement.class).get(6);
+    }
+
+    @After
+    public void after() {
+        assertNoErrorNotifications();
+        assertFalse(isElementPresent(By.className("v-errorindicator")));
+    }
+
+    @Test
+    public void removing_items_from_hierarchy() {
+        addItemsToABtn.click();
+        addItemsToAABtn.click();
+        grid.expandWithClick(0);
+        grid.expandWithClick(1);
+        grid.collapseWithClick(0);
+        removeAABtn.click();
+        // Item removed from hierarchy. when encountering less children than
+        // expected, should reset:
+        grid.expandWithClick(0);
+        // expand "a" after the reset:
+        grid.expandWithClick(0);
+        // "a/a" should be removed from a's children:
+        assertEquals("a/b", grid.getCell(1, 0).getText());
+    }
+
+    @Test
+    public void removing_all_children_from_item() {
+        addItemsToABtn.click();
+        assertTrue(grid.isRowCollapsed(0, 0));
+        // drop added children from backing data source
+        removeChildrenOfABtn.click();
+        // changes are not refreshed, thus the row should still appear as
+        // collapsed
+        assertTrue(grid.isRowCollapsed(0, 0));
+        // when encountering 0 children, will reset
+        grid.expandWithClick(0);
+        assertEquals(3, grid.getRowCount());
+        assertFalse(grid.hasExpandToggle(0, 0));
+        // verify other items still expand/collapse correctly:
+        grid.expandWithClick(1);
+        assertEquals("b/a", grid.getCell(2, 0).getText());
+        assertEquals(4, grid.getRowCount());
+        grid.collapseWithClick(1);
+        assertEquals("c", grid.getCell(2, 0).getText());
+        assertEquals(3, grid.getRowCount());
+    }
+
+    @Test
+    public void removal_of_deeply_nested_items() {
+        addItemsToABtn.click();
+        addItemsToAABtn.click();
+        grid.expandWithClick(0);
+        grid.expandWithClick(1);
+        grid.expandWithClick(2);
+        removeChildrenOfAAABtn.click();
+        grid.collapseWithClick(1);
+        // reset should get triggered here
+        grid.expandWithClick(1);
+        grid.expandWithClick(0);
+        grid.expandWithClick(1);
+        assertEquals("a/a/a", grid.getCell(2, 0).getText());
+        assertFalse(grid.hasExpandToggle(2, 0));
+    }
+
+    @Test
+    public void changing_selection_from_selected_removed_item() {
+        addItemsToABtn.click();
+        grid.expandWithClick(0);
+        grid.getCell(1, 0).click();
+        removeChildrenOfABtn.click();
+        grid.collapseWithClick(0);
+        grid.getCell(1, 0).click();
+        assertTrue(grid.getRow(1).isSelected());
+    }
+
+    @Test
+    public void remove_item_from_root() {
+        addItemsToABtn.click();
+        removeABtn.click();
+        grid.expandWithClick(0);
+        assertEquals("b", grid.getCell(0, 0).getText());
+    }
+}