Call error handler for exceptions in UI.init() (#8055)

Fixes #4995

2 files changed, 198 insertions, 3 deletions

diff --git a/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java b/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
index f66dbe4107..aa167d137f 100644
--- a/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
+++ b/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
@@ -211,10 +211,17 @@ public abstract class UIInitHandler extends SynchronizedRequestHandler {
         // Set thread local here so it is available in init
         UI.setCurrent(ui);
 
-        ui.doInit(request, uiId.intValue(), embedId);
-
+        Exception initException = null;
+        try {
+            ui.doInit(request, uiId.intValue(), embedId);
+        } catch (Exception e) {
+            initException = e;
+        }
         session.addUI(ui);
-
+        if (initException != null) {
+            ui.getSession().getCommunicationManager()
+                    .handleConnectorRelatedException(ui, initException);
+        }
         // Warn if the window can't be preserved
         if (embedId == null
                 && vaadinService.preserveUIOnRefresh(provider, event)) {
diff --git a/server/src/test/java/com/vaadin/server/communication/ServletUIInitHandlerTest.java b/server/src/test/java/com/vaadin/server/communication/ServletUIInitHandlerTest.java
new file mode 100644
index 0000000000..6c61922307
--- /dev/null
+++ b/server/src/test/java/com/vaadin/server/communication/ServletUIInitHandlerTest.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright 2000-2016 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.server.communication;
+
+import java.io.IOException;
+import java.util.Properties;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import com.vaadin.server.DefaultDeploymentConfiguration;
+import com.vaadin.server.ErrorEvent;
+import com.vaadin.server.ErrorHandler;
+import com.vaadin.server.LegacyCommunicationManager;
+import com.vaadin.server.MockServletConfig;
+import com.vaadin.server.UIClassSelectionEvent;
+import com.vaadin.server.UICreateEvent;
+import com.vaadin.server.UIProvider;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinServlet;
+import com.vaadin.server.VaadinServletRequest;
+import com.vaadin.server.VaadinServletResponse;
+import com.vaadin.server.VaadinServletService;
+import com.vaadin.tests.util.AlwaysLockedVaadinSession;
+import com.vaadin.ui.UI;
+
+public class ServletUIInitHandlerTest {
+
+    public static class CommunicationMock {
+
+        public final UI ui;
+        public final ServletConfig servletConfig;
+        public final VaadinServlet servlet;
+        public final DefaultDeploymentConfiguration deploymentConfiguration;
+        public final VaadinServletService service;
+        public final AlwaysLockedVaadinSession session;
+
+        public CommunicationMock(final UI ui) throws Exception {
+            servletConfig = new MockServletConfig();
+            servlet = new VaadinServlet();
+            servlet.init(servletConfig);
+
+            deploymentConfiguration = new DefaultDeploymentConfiguration(
+                    UI.class, new Properties());
+
+            service = new VaadinServletService(servlet,
+                    deploymentConfiguration);
+            session = new AlwaysLockedVaadinSession(service);
+            LegacyCommunicationManager communicationManager = new LegacyCommunicationManager(
+                    session);
+            session.setCommunicationManager(communicationManager);
+            session.setConfiguration(deploymentConfiguration);
+            session.addUIProvider(new UIProvider() {
+
+                @Override
+                public Class<? extends UI> getUIClass(
+                        UIClassSelectionEvent event) {
+                    return ui.getClass();
+                }
+
+                @Override
+                public UI createInstance(UICreateEvent event) {
+                    return ui;
+                }
+            });
+            this.ui = ui;
+        }
+
+        public VaadinRequest createInitRequest() {
+            return new VaadinServletRequest(
+                    Mockito.mock(HttpServletRequest.class), service) {
+                @Override
+                public String getMethod() {
+                    return "POST";
+                }
+
+                @Override
+                public String getParameter(String name) {
+                    if (UIInitHandler.BROWSER_DETAILS_PARAMETER.equals(name)) {
+                        return "1";
+                    }
+                    return super.getParameter(name);
+                }
+
+            };
+        }
+
+    }
+
+    @Test
+    public void errorHandlerForInitException() throws Exception {
+        final AtomicInteger pre = new AtomicInteger(0);
+        final AtomicInteger errorHandlerCalls = new AtomicInteger(0);
+
+        UI ui = new UI() {
+            @Override
+            protected void init(VaadinRequest request) {
+                pre.incrementAndGet();
+                throw new RuntimeException("Exception produced in init()");
+            }
+        };
+
+        ui.setErrorHandler(new ErrorHandler() {
+            @Override
+            public void error(ErrorEvent event) {
+                errorHandlerCalls.incrementAndGet();
+            }
+        });
+
+        CommunicationMock mock = new CommunicationMock(ui);
+        VaadinRequest initRequest = mock.createInitRequest();
+
+        ServletUIInitHandler servletUIInitHandler = new ServletUIInitHandler();
+        servletUIInitHandler.handleRequest(mock.session, initRequest,
+                new VaadinServletResponse(
+                        Mockito.mock(HttpServletResponse.class), mock.service) {
+                    @Override
+                    public ServletOutputStream getOutputStream()
+                            throws IOException {
+                        return new ServletOutputStream() {
+                            @Override
+                            public void write(int b) throws IOException {
+                            }
+                        };
+                    }
+                });
+
+        Assert.assertEquals(1, pre.getAndIncrement());
+        Assert.assertEquals(1, errorHandlerCalls.getAndIncrement());
+        Assert.assertEquals(mock.session, ui.getSession());
+    }
+
+    @Test
+    public void initExceptionNoErrorHandler() throws Exception {
+        final AtomicInteger pre = new AtomicInteger(0);
+
+        UI ui = new UI() {
+            @Override
+            protected void init(VaadinRequest request) {
+                pre.incrementAndGet();
+                throw new RuntimeException("Exception produced in init()");
+            }
+        };
+
+        CommunicationMock mock = new CommunicationMock(ui);
+        VaadinRequest initRequest = mock.createInitRequest();
+
+        ServletUIInitHandler servletUIInitHandler = new ServletUIInitHandler();
+        servletUIInitHandler.handleRequest(mock.session, initRequest,
+                new VaadinServletResponse(
+                        Mockito.mock(HttpServletResponse.class), mock.service) {
+                    @Override
+                    public ServletOutputStream getOutputStream()
+                            throws IOException {
+                        return new ServletOutputStream() {
+                            @Override
+                            public void write(int b) throws IOException {
+                            }
+                        };
+                    }
+                });
+
+        Assert.assertEquals(1, pre.getAndIncrement());
+        // Default error handler only logs the exception
+        Assert.assertEquals(mock.session, ui.getSession());
+    }
+
+}