feat: deprecate Label and add NativeLabel as replacement

flow-html-components-testbench/src/main/java/com/vaadin/flow/component/html/testbench/LabelElement.java

@@ -22,8 +22,10 @@
  * A TestBench element representing a <code>&lt;label&gt;</code> element.
  *
  * @since 1.0
+ * @deprecated Use {@link NativeLabelElement} instead.
  */
 @Element("label")
+@Deprecated(since = "24.1", forRemoval = true)
 public class LabelElement extends TestBenchElement {
 
 }

flow-html-components-testbench/src/main/java/com/vaadin/flow/component/html/testbench/NativeLabelElement.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2000-2023 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.flow.component.html.testbench;
+
+import com.vaadin.testbench.TestBenchElement;
+import com.vaadin.testbench.elementsbase.Element;
+
+/**
+ * A TestBench element representing a <code>&lt;label&gt;</code> element.
+ *
+ * @since 24.1
+ */
+@Element("label")
+public class NativeLabelElement extends TestBenchElement {
+
+}

flow-html-components/src/main/java/com/vaadin/flow/component/html/Label.java

@@ -17,22 +17,20 @@
 
 import java.util.Optional;
 
+import com.vaadin.flow.component.AttachEvent;
 import com.vaadin.flow.component.Component;
 import com.vaadin.flow.component.Html;
 import com.vaadin.flow.component.HtmlContainer;
 import com.vaadin.flow.component.PropertyDescriptor;
 import com.vaadin.flow.component.PropertyDescriptors;
 import com.vaadin.flow.component.Tag;
+import com.vaadin.flow.shared.Registration;
+import org.slf4j.LoggerFactory;
 
 /**
  * Component for a <code>&lt;label&gt;</code> element, which represents a
  * caption for an item in a user interface.
  * <p>
- * Note that Label components are not meant for loose text in the page - they
- * should be coupled with another component by using the
- * {@link #setFor(Component)} or by adding them to it with the
- * {@link #add(Component...)} method.
- * <p>
  * Clicking on a label automatically transfers the focus to the associated
  * component. This is especially helpful when building forms with
  * {@link Input}s.
@@ -46,12 +44,29 @@
  * @see <a href=
  *      "https://developer.mozilla.org/en-US/docs/Web/HTML/Element/label">https://developer.mozilla.org/en-US/docs/Web/HTML/Element/label</a>
  * @since 1.0
+ * @deprecated Use {@link NativeLabel} instead, if you need the HTML
+ *             <code>&lt;label&gt;</code> element, which is normally not needed
+ *             within a Vaadin Flow application's high-level components. This
+ *             component was deprecated because it was confusing users of
+ *             earlier Vaadin Versions and users migrating from Swing to the
+ *             modern Vaadin Flow Framework. The {@link Label} component /
+ *             <code>&lt;label&gt;</code> element is not meant for loose text in
+ *             the page - it should only be coupled with another component by
+ *             using the {@link #setFor(Component)} or by adding them to it with
+ *             the {@link #add(Component...)} method, for example if you use
+ *             {@link Input}.
+ *
  */
 @Tag(Tag.LABEL)
+@Deprecated(since = "24.1", forRemoval = true)
 public class Label extends HtmlContainer {
     private static final PropertyDescriptor<String, Optional<String>> forDescriptor = PropertyDescriptors
             .optionalAttributeWithDefault("for", "");
 
+    private static Boolean productionMode = null;
+
+    private Registration checkForAttributeOnAttach;
+
     /**
      * Creates a new empty label.
      */
@@ -118,4 +133,55 @@ public void setFor(String forId) {
     public Optional<String> getFor() {
         return get(forDescriptor);
     }
+
+    @Override
+    protected void onAttach(AttachEvent attachEvent) {
+        super.onAttach(attachEvent);
+        if (skipForAttributeCheck(attachEvent)
+                || !attachEvent.isInitialAttach()) {
+            return; // skip check in production so that customer / clients /
+            // ops-teams are not complaining about this warning to the
+            // devs. This should be dealt with by devs in development
+            // mode.
+        }
+        checkForAttributeOnAttach = attachEvent.getUI()
+                .beforeClientResponse(this, ctx -> {
+                    // Label was not associated with a for-attribute
+                    // AND
+                    // Label was not associated by adding a nested component
+                    if (getFor().isEmpty()
+                            && getChildren().findAny().isEmpty()) {
+                        LoggerFactory.getLogger(Label.class.getName()).warn(
+                                "The Label '{}' was not associated with a component. "
+                                        + "Labels should not be used for loose text on the page. "
+                                        + "Consider alternatives like Text, Paragraph, Span or Div. "
+                                        + "See the JavaDocs and Deprecation Warning for more Information.",
+                                getText());
+                    }
+                    checkForAttributeOnAttach.remove();
+                });
+    }
+
+    /**
+     * Checks if the application is running in production mode.
+     * <p>
+     * When unsure, reports that production mode is true so spam-like logging
+     * does not take place in production.
+     *
+     * @return true if in production mode or the mode is unclear, false if in
+     *         development mode
+     **/
+    private static boolean skipForAttributeCheck(AttachEvent attachEvent) {
+        if (productionMode != null) {
+            return productionMode;
+        }
+
+        var session = attachEvent.getSession();
+        if (session == null) {
+            return true;
+        }
+
+        productionMode = session.getConfiguration().isProductionMode();
+        return productionMode;
+    }
 }

flow-html-components/src/main/java/com/vaadin/flow/component/html/NativeLabel.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2000-2023 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.flow.component.html;
+
+import com.vaadin.flow.component.Component;
+import com.vaadin.flow.component.Html;
+import com.vaadin.flow.component.HtmlContainer;
+import com.vaadin.flow.component.PropertyDescriptor;
+import com.vaadin.flow.component.PropertyDescriptors;
+import com.vaadin.flow.component.Tag;
+import java.util.Optional;
+
+/**
+ * Component for a <code>&lt;label&gt;</code> element, which represents a
+ * caption for an input field in a user interface.
+ * <p>
+ * Note that Label components are not meant for loose text in the page - they
+ * should be coupled with another component by using the
+ * {@link #setFor(Component)} or by adding them to it with the
+ * {@link #add(Component...)} method.
+ * <p>
+ * Clicking on a label automatically transfers the focus to the associated
+ * component. This is especially helpful when building forms with
+ * {@link Input}s.
+ * <p>
+ * For adding texts to the page without linking them to other components,
+ * consider using a {@link Span} or a {@link Div} instead. If the text should be
+ * interpreted as HTML, use a {@link Html} (but remember to guard against
+ * cross-site scripting attacks).
+ *
+ * @author Vaadin Ltd
+ * @see <a href=
+ *      "https://developer.mozilla.org/en-US/docs/Web/HTML/Element/label">https://developer.mozilla.org/en-US/docs/Web/HTML/Element/label</a>
+ * @since 24.1
+ */
+@Tag(Tag.LABEL)
+public class NativeLabel extends HtmlContainer {
+    private static final PropertyDescriptor<String, Optional<String>> forDescriptor = PropertyDescriptors
+            .optionalAttributeWithDefault("for", "");
+
+    /**
+     * Creates a new empty label.
+     */
+    public NativeLabel() {
+        super();
+    }
+
+    /**
+     * Creates a new label with the given text content.
+     *
+     * @param text
+     *            the text content
+     */
+    public NativeLabel(String text) {
+        this();
+        setText(text);
+    }
+
+    /**
+     * Sets the component that this label describes. The component (or its id)
+     * should be defined in case the described component is not an ancestor of
+     * the label.
+     * <p>
+     * The provided component must have an id set. This component will still use
+     * the old id if the id of the provided component is changed after this
+     * method has been called.
+     *
+     * @param forComponent
+     *            the component that this label describes, not <code>null</code>
+     *            , must have an id
+     * @throws IllegalArgumentException
+     *             if the provided component has no id
+     */
+    public void setFor(Component forComponent) {
+        if (forComponent == null) {
+            throw new IllegalArgumentException(
+                    "The provided component cannot be null");
+        }
+        setFor(forComponent.getId()
+                .orElseThrow(() -> new IllegalArgumentException(
+                        "The provided component must have an id")));
+    }
+
+    /**
+     * Sets the id of the component that this label describes. The id should be
+     * defined in case the described component is not an ancestor of the label.
+     *
+     * @param forId
+     *            the id of the described component, or <code>null</code> if
+     *            there is no value
+     */
+    public void setFor(String forId) {
+        set(forDescriptor, forId);
+    }
+
+    /**
+     * Gets the id of the component that this label describes.
+     *
+     * @see #setFor(String)
+     *
+     * @return an optional id of the described component, or an empty optional
+     *         if the attribute has not been set
+     */
+    public Optional<String> getFor() {
+        return get(forDescriptor);
+    }
+}

flow-html-components/src/test/java/com/vaadin/flow/component/html/HtmlComponentSmokeTest.java

@@ -206,6 +206,11 @@ private static boolean isSpecialSetter(Method method) {
                 && method.getParameterTypes()[0] == Component.class) {
             return true;
         }
+        if (method.getDeclaringClass() == NativeLabel.class
+                && method.getName().equals("setFor")
+                && method.getParameterTypes()[0] == Component.class) {
+            return true;
+        }
 
         // Anchor.setTarget(AnchorTargetValue) -
         // https://github.com/vaadin/flow/issues/8346

flow-html-components/src/test/java/com/vaadin/flow/component/html/NativeLabelTest.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2000-2023 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.flow.component.html;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class NativeLabelTest extends ComponentTest {
+
+    // Actual test methods in super class
+
+    @Override
+    protected void addProperties() {
+        addOptionalStringProperty("for");
+    }
+
+    @Test
+    public void setForComponent() {
+        NativeLabel otherComponent = new NativeLabel();
+        otherComponent.setId("otherC");
+        NativeLabel l = (NativeLabel) getComponent();
+        l.setFor(otherComponent);
+        Assert.assertEquals(otherComponent.getId().get(), l.getFor().get());
+    }
+
+}

flow-tests/test-dev-mode/src/main/java/com/vaadin/flow/uitest/ui/frontend/BrowserLoggingView.java

@@ -19,7 +19,7 @@
 import com.vaadin.flow.component.Tag;
 import com.vaadin.flow.component.dependency.JavaScript;
 import com.vaadin.flow.component.html.Div;
-import com.vaadin.flow.component.html.Label;
+import com.vaadin.flow.component.html.NativeLabel;
 import com.vaadin.flow.router.Route;
 import com.vaadin.flow.shared.ui.LoadMode;
 import com.vaadin.flow.uitest.servlet.ViewTestLayout;
@@ -29,7 +29,7 @@
 @JavaScript(value = "./consoleLoggingProxy.js", loadMode = LoadMode.INLINE)
 public class BrowserLoggingView extends Div {
     public BrowserLoggingView() {
-        Label label = new Label("Just a label");
+        NativeLabel label = new NativeLabel("Just a label");
         label.setId("elementId");
         add(label);
     }

flow-tests/test-dev-mode/src/main/java/com/vaadin/flow/uitest/ui/template/AbstractAttachExistingElementByIdTemplate.java

@@ -16,7 +16,7 @@
 package com.vaadin.flow.uitest.ui.template;
 
 import com.vaadin.flow.component.html.Input;
-import com.vaadin.flow.component.html.Label;
+import com.vaadin.flow.component.html.NativeLabel;
 import com.vaadin.flow.component.polymertemplate.EventHandler;
 import com.vaadin.flow.component.polymertemplate.Id;
 import com.vaadin.flow.component.polymertemplate.PolymerTemplate;
@@ -29,7 +29,7 @@ public abstract class AbstractAttachExistingElementByIdTemplate
     private Input input;
 
     @Id("label")
-    private Label label;
+    private NativeLabel label;
 
     protected AbstractAttachExistingElementByIdTemplate(String id) {
         setId(id);

flow-tests/test-dev-mode/src/test/java/com/vaadin/flow/uitest/ui/UrlValidationIT.java

@@ -22,7 +22,7 @@
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.vaadin.flow.component.html.testbench.LabelElement;
+import com.vaadin.flow.component.html.testbench.NativeLabelElement;
 import com.vaadin.flow.testutil.ChromeBrowserTest;
 
 public class UrlValidationIT extends ChromeBrowserTest {
@@ -36,7 +36,8 @@ public void devModeUriValidation_uriWithDirectoryChange_statusForbidden()
             throws Exception {
         // open a view and wait till the expected label is displayed
         open();
-        waitUntil(input -> $(LabelElement.class).id("elementId").isDisplayed());
+        waitUntil(input -> $(NativeLabelElement.class).id("elementId")
+                .isDisplayed());
         // check the forbidden url
         sendRequestAndValidateResponseStatusBadRequest(
                 "/VAADIN/build/%252E%252E");
@@ -47,7 +48,8 @@ public void staticResourceUriValidation_uriWithDirectoryChange_statusForbidden()
             throws Exception {
         // open a view and wait till the expected label is displayed
         open();
-        waitUntil(input -> $(LabelElement.class).id("elementId").isDisplayed());
+        waitUntil(input -> $(NativeLabelElement.class).id("elementId")
+                .isDisplayed());
         // check the forbidden url
         sendRequestAndValidateResponseStatusBadRequest(
                 "/VAADIN/build/%252E%252E/some-resource.css");