Fix race condition between rendering TreeGrid and setting up headers (#9105)

* Fix race condition between rendering Grid and setting up headers
* Remove Grid default headers when initializing the widget
* Fix header clean up, add null check to select all checkbox

2 files changed, 38 insertions, 0 deletions

diff --git a/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInit.java b/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInit.java
new file mode 100644
index 0000000000..fa9ff25b45
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInit.java
@@ -0,0 +1,23 @@
+package com.vaadin.tests.components.treegrid;
+
+import com.vaadin.annotations.Widgetset;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.TreeGrid;
+import com.vaadin.ui.renderers.ComponentRenderer;
+
+@Widgetset("com.vaadin.DefaultWidgetSet")
+public class TreeGridNoHeaderOnInit extends AbstractTestUI {
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        TreeGrid<String> grid = new TreeGrid<>();
+        grid.addColumn(Object::toString).setCaption("toString with Caption");
+        grid.addColumn(t -> new Label(t), new ComponentRenderer());
+        grid.setItems("Foo", "Bar", "Baz");
+        grid.removeHeaderRow(0);
+        grid.appendFooterRow();
+        addComponent(grid);
+    }
+}
diff --git a/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInitTest.java b/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInitTest.java
new file mode 100644
index 0000000000..c9463e519f
--- /dev/null
+++ b/uitest/src/test/java/com/vaadin/tests/components/treegrid/TreeGridNoHeaderOnInitTest.java
@@ -0,0 +1,15 @@
+package com.vaadin.tests.components.treegrid;
+
+import org.junit.Test;
+
+import com.vaadin.tests.tb3.SingleBrowserTest;
+
+public class TreeGridNoHeaderOnInitTest extends SingleBrowserTest {
+
+    @Test
+    public void no_exception_thrown() {
+        setDebug(true);
+        openTestURL();
+        assertNoErrorNotifications();
+    }
+}