Made Root.getCurrent() work in LoginForm LoginListener (#9372)

server/src/com/vaadin/ui/LoginForm.java

@@ -99,6 +99,9 @@ public class LoginForm extends CustomComponent {
                 throws IOException {
             String requestPathInfo = request.getRequestPathInfo();
             if ("/loginHandler".equals(requestPathInfo)) {
+                // Ensure Root.getCurrent() works in listeners
+                Root.setCurrent(getRoot());
+
                 response.setCacheTime(-1);
                 response.setContentType("text/html; charset=utf-8");
                 response.getWriter()

tests/testbench/com/vaadin/tests/components/loginform/LoginFormRootInLoginHandler.java

@@ -0,0 +1,52 @@
+package com.vaadin.tests.components.loginform;
+
+import com.vaadin.tests.components.TestBase;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.LoginForm;
+import com.vaadin.ui.LoginForm.LoginEvent;
+import com.vaadin.ui.LoginForm.LoginListener;
+import com.vaadin.ui.Root;
+
+public class LoginFormRootInLoginHandler extends TestBase {
+
+    @Override
+    protected void setup() {
+        LoginForm lf = new LoginForm();
+        lf.addListener(new LoginListener() {
+
+            @Override
+            public void onLogin(LoginEvent event) {
+                Root r1 = Root.getCurrent();
+                if (r1 != null) {
+                    addComponent(new Label("Root.getCurrent().data: "
+                            + r1.getData()));
+                } else {
+                    addComponent(new Label("Root.getCurrent() is null"));
+                }
+                Root r2 = ((LoginForm) event.getSource()).getRoot();
+                if (r2 != null) {
+                    addComponent(new Label("event.getSource().data: "
+                            + r2.getData()));
+                } else {
+                    addComponent(new Label(
+                            "event.getSource().getRoot() is null"));
+                }
+            }
+        });
+        addComponent(lf);
+        getLayout().getRoot().setData("This root");
+    }
+
+    @Override
+    protected String getDescription() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    protected Integer getTicketNumber() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}