Fix: Prevent NPE with autoUpload=false and multiple files are being u…

…ploaded (#919)

Fixes: vaadin/vaadin-upload#358

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/pom.xml

@@ -93,6 +93,11 @@
             <groupId>com.vaadin</groupId>
             <artifactId>flow-polymer-template</artifactId>
         </dependency>
+ 		<dependency>
+			<groupId>javax.servlet</groupId>
+			<artifactId>javax.servlet-api</artifactId>
+			<scope>provided</scope>
+		</dependency>
     </dependencies>
     <build>
         <plugins>

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/main/java/com/vaadin/flow/component/upload/tests/it/NonImmediateUploadView.java

@@ -0,0 +1,31 @@
+package com.vaadin.flow.component.upload.tests.it;
+
+import com.vaadin.flow.component.AttachEvent;
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.html.Span;
+import com.vaadin.flow.component.upload.Upload;
+import com.vaadin.flow.component.upload.receivers.MultiFileMemoryBuffer;
+import com.vaadin.flow.router.Route;
+
+@Route("vaadin-upload/non-immediate-upload")
+public class NonImmediateUploadView extends Div {
+
+    private Span result = new Span("No errors");
+
+    public NonImmediateUploadView() {
+        result.setId("error-handler-message");
+
+        MultiFileMemoryBuffer buffer = new MultiFileMemoryBuffer();
+        Upload upload = new Upload(buffer);
+        upload.setAutoUpload(false);
+        add(upload, result);
+    }
+
+    @Override
+    public void onAttach(AttachEvent attachEvent) {
+        attachEvent.getUI().getSession().setErrorHandler(event -> {
+            result.setText("There was an error");
+            event.getThrowable().printStackTrace();
+        });
+    }
+}

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/test/java/com/vaadin/flow/component/upload/tests/NonImmediateUploadIT.java

@@ -0,0 +1,65 @@
+package com.vaadin.flow.component.upload.tests;
+
+import java.io.File;
+
+import org.junit.Assert;
+import org.junit.AssumptionViolatedException;
+import org.junit.Before;
+import org.junit.Test;
+import org.openqa.selenium.WebElement;
+
+import com.vaadin.flow.component.upload.testbench.UploadElement;
+import com.vaadin.flow.testutil.TestPath;
+import com.vaadin.testbench.TestBenchElement;
+
+@TestPath("vaadin-upload/non-immediate-upload")
+public class NonImmediateUploadIT extends AbstractUploadIT {
+
+    @Before
+    public void init() {
+        if (getRunLocallyBrowser() == null) {
+            // Multiple file upload does not work with Remotewebdriver
+            // and autoUpload=false
+            // Related to
+            // https://github.com/SeleniumHQ/selenium/issues/7408
+            throw new AssumptionViolatedException(
+                    "Skipped <Multiple file upload does not work with Remotewebdriver>");
+        }
+    }
+
+    @Test
+    public void uploadMultipleFiles_shouldNotThrowException_onStart()
+            throws Exception {
+        uploadMultipleFiles_shouldNotThrowException("start-button");
+    }
+
+    @Test
+    public void uploadMultipleFiles_shouldNotThrowException_onRemove()
+            throws Exception {
+        uploadMultipleFiles_shouldNotThrowException("clear-button");
+    }
+
+    private void uploadMultipleFiles_shouldNotThrowException(String buttonType)
+            throws Exception {
+        open();
+        File file1 = createTempFile();
+        File file2 = createTempFile();
+        UploadElement upload = $(UploadElement.class).waitForFirst();
+        WebElement input = getInput(upload);
+        fillPathToUploadInput(input, file1.getPath(), file2.getPath());
+        WebElement button = findButtonInVaadinUploadFile(upload, buttonType);
+        button.click();
+        TestBenchElement element = $("span").id("error-handler-message");
+        Assert.assertEquals("No errors", element.getText());
+    }
+
+    private WebElement findButtonInVaadinUploadFile(UploadElement upload,
+            String buttonType) {
+        final String QUERY = String.format(
+                "return arguments[0]"
+                        + ".shadowRoot.querySelector('vaadin-upload-file')"
+                        + ".shadowRoot.querySelector('[part=\"%s\"]')",
+                buttonType);
+        return (WebElement) getCommandExecutor().executeScript(QUERY, upload);
+    }
+}

vaadin-upload-flow-parent/vaadin-upload-flow/src/main/java/com/vaadin/flow/component/upload/Upload.java

@@ -88,8 +88,12 @@ public Upload() {
         DomEventListener allFinishedListener = e -> {
             JsonArray files = e.getEventData().getArray(elementFiles);
 
-            boolean isUploading = IntStream.range(0, files.length()).anyMatch(
-                    index -> files.getObject(index).getBoolean("uploading"));
+            boolean isUploading = IntStream.range(0, files.length())
+                    .anyMatch(index -> {
+                        final String KEY = "uploading";
+                        JsonObject object = files.getObject(index);
+                        return object.hasKey(KEY) && object.getBoolean(KEY);
+                    });
 
             if (this.uploading && !isUploading) {
                 this.fireAllFinish();