Fix NPE on column width detection in TreeTable and RowGenerator (#19437)

Change-Id: I7ed03d34124dda839bddc2507274a63b1e22f05f

client/src/com/vaadin/client/ui/VScrollTable.java

@@ -5307,9 +5307,13 @@ public class VScrollTable extends FlowPanel implements HasWidgets,
                 for (Widget row : renderedRows) {
                     if (!(row instanceof VScrollTableGeneratedRow)) {
                         TableRowElement tr = row.getElement().cast();
-                        Element wrapperdiv = tr.getCells().getItem(columnIndex)
-                                .getFirstChildElement().cast();
-                        return wrapperdiv.getOffsetWidth();
+                        // Spanned rows might cause an NPE.
+                        if (columnIndex < tr.getChildCount()) {
+                            Element wrapperdiv = tr.getCells()
+                                    .getItem(columnIndex)
+                                    .getFirstChildElement().cast();
+                            return wrapperdiv.getOffsetWidth();
+                        }
                     }
                 }
                 return 0;

uitest/src/com/vaadin/tests/components/treetable/TreeTableRowGenerator.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.components.treetable;
+
+import com.vaadin.data.Item;
+import com.vaadin.data.util.HierarchicalContainer;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Table;
+import com.vaadin.ui.TreeTable;
+
+public class TreeTableRowGenerator extends AbstractTestUI {
+    public static final String COLUMN_A = "first";
+    public static final String COLUMN_B = "second";
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        TreeTable treeTable = new TreeTable();
+
+        final HierarchicalContainer hierarchicalContainer = new HierarchicalContainer();
+        hierarchicalContainer.addContainerProperty(COLUMN_A, String.class, "");
+        hierarchicalContainer.addContainerProperty(COLUMN_B, String.class, "");
+
+        Item it = hierarchicalContainer.addItem(0);
+        it.getItemProperty(COLUMN_A).setValue("row 1 column a");
+        it.getItemProperty(COLUMN_B).setValue("row 1 column b");
+        hierarchicalContainer.setChildrenAllowed(0, true);
+
+        Item it2 = hierarchicalContainer.addItem(1);
+        it2.getItemProperty(COLUMN_A).setValue("row 2 column a");
+        it2.getItemProperty(COLUMN_B).setValue("row 2 column b");
+        hierarchicalContainer.setChildrenAllowed(1, false);
+
+        hierarchicalContainer.setParent(1, 0);
+
+        treeTable.setRowGenerator(new Table.RowGenerator() {
+            @Override
+            public Table.GeneratedRow generateRow(Table table, Object itemId) {
+                if (table instanceof TreeTable
+                        && ((TreeTable) table).areChildrenAllowed(itemId)) {
+                    return new Table.GeneratedRow("Spanned Row");
+                } else {
+                    return null;
+                }
+            }
+        });
+
+        treeTable.setContainerDataSource(hierarchicalContainer);
+        treeTable.setSizeFull();
+        addComponent(treeTable);
+    }
+}

uitest/src/com/vaadin/tests/components/treetable/TreeTableRowGeneratorTest.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.components.treetable;
+
+import org.junit.Test;
+
+import com.vaadin.tests.tb3.SingleBrowserTest;
+
+public class TreeTableRowGeneratorTest extends SingleBrowserTest {
+
+    @Test
+    public void testNoExceptionOnRender() {
+        setDebug(true);
+        openTestURL();
+
+        assertNoErrorNotifications();
+    }
+}