8190411: NPE in SliderSkin:140 if Slider.Tooltip.autohide is true

Reviewed-by: arapte, angorya, kcr

Author: karthikpandelu

modules/javafx.controls/src/main/java/javafx/scene/control/skin/SliderSkin.java

@@ -35,6 +35,7 @@
 import javafx.scene.control.Control;
 import javafx.scene.control.SkinBase;
 import javafx.scene.control.Slider;
+import javafx.scene.control.Tooltip;
 import javafx.scene.layout.StackPane;
 import javafx.util.Duration;
 import javafx.util.StringConverter;
@@ -61,6 +62,9 @@ public class SliderSkin extends SkinBase<Slider> {
     private double trackToTickGap = 2;
 
     private boolean showTickMarks;
+
+    // Used to save and restore consumeAutoHidingEvents property of the tooltip to original value.
+    private boolean tooltipConsumeAutoHidingEvents;
     private double thumbWidth;
     private double thumbHeight;
 
@@ -389,6 +393,24 @@ public Object queryAccessibleAttribute(AccessibleAttribute attribute, Object...
                     cur.getX() - dragStart.getX() : -(cur.getY() - dragStart.getY());
             behavior.thumbDragged(me, preDragThumbPos + dragPos / trackLength);
         });
+
+        thumb.setOnMouseEntered(me -> {
+            Tooltip t = getSkinnable().getTooltip();
+            if (t != null && t.isAutoHide() && !t.consumeAutoHidingEventsProperty().isBound()) {
+                tooltipConsumeAutoHidingEvents = t.getConsumeAutoHidingEvents();
+                // Temporarily disable consuming auto hiding events from tooltip.
+                // This is done to receive mouse pressed event on thumb and
+                // inturn to detect start of drag.
+                t.setConsumeAutoHidingEvents(false);
+            }
+        });
+
+        thumb.setOnMouseExited(me -> {
+            Tooltip t = getSkinnable().getTooltip();
+            if (t != null && t.isAutoHide() && !t.consumeAutoHidingEventsProperty().isBound()) {
+                t.setConsumeAutoHidingEvents(tooltipConsumeAutoHidingEvents);
+            }
+        });
     }
 
     private void setShowTickMarks(boolean ticksVisible, boolean labelsVisible) {

tests/system/src/test/java/test/robot/javafx/scene/SliderTooltipNPETest.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package test.robot.javafx.scene;
+
+import java.util.concurrent.CountDownLatch;
+
+import javafx.application.Application;
+import javafx.scene.input.MouseButton;
+import javafx.application.Platform;
+import javafx.scene.robot.Robot;
+import javafx.scene.Scene;
+import javafx.scene.control.Slider;
+import javafx.stage.Stage;
+import javafx.stage.StageStyle;
+import javafx.scene.control.Tooltip;
+import javafx.stage.WindowEvent;
+
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import test.util.Util;
+
+/*
+ * Test for verifying Slider NPE error.
+ *
+ * There is 1 test in this file.
+ * Steps for testSliderTooltipNPE()
+ * 1. Create a slider and tooltip.
+ * 2. Make setAutoHide of tooltip as true and add tooltip to slider.
+ * 3. Hover over slider thumb and wait for tooltip. Drag the thumb.
+ * 4. Verify that NullPointerException is not thrown.
+ */
+
+public class SliderTooltipNPETest {
+    static CountDownLatch startupLatch = new CountDownLatch(1);
+    static CountDownLatch tooltipLatch = new CountDownLatch(1);
+    static Robot robot;
+    static Slider slider;
+
+    static volatile Throwable exception;
+    static volatile Stage stage;
+    static volatile Scene scene;
+
+    static final int SCENE_WIDTH = 250;
+    static final int SCENE_HEIGHT = SCENE_WIDTH;
+    static final int DRAG_DISTANCE = 10;
+
+    @Test
+    public void testSliderTooltipNPE() throws Throwable {
+        Assert.assertTrue(slider.getTooltip().getConsumeAutoHidingEvents());
+        dragSliderAfterTooltipDisplayed(DRAG_DISTANCE);
+        if (exception != null) {
+            exception.printStackTrace();
+            throw exception;
+        }
+        Assert.assertTrue(slider.getTooltip().getConsumeAutoHidingEvents());
+    }
+
+    private void dragSliderAfterTooltipDisplayed(int dragDistance) throws Exception {
+        Thread.sleep(1000); // Wait for slider to layout
+
+        Util.runAndWait(() -> {
+            robot.mouseMove((int)(scene.getWindow().getX() + scene.getX() +
+                                slider.getLayoutX() + slider.getLayoutBounds().getWidth()/2),
+                            (int)(scene.getWindow().getY() + scene.getY() +
+                                slider.getLayoutY() + slider.getLayoutBounds().getHeight()/2));
+        });
+
+        Util.waitForLatch(tooltipLatch, 5, "Timeout waiting for tooltip to display");
+        Thread.sleep(2000); // Wait for tooltip to display
+
+        Util.runAndWait(() -> {
+            robot.mousePress(MouseButton.PRIMARY);
+        });
+
+        for (int i = 0; i < dragDistance; i++) {
+            final int c = i;
+            Util.runAndWait(() -> {
+            robot.mouseMove((int)(scene.getWindow().getX() + scene.getX() +
+                                slider.getLayoutX() + slider.getLayoutBounds().getWidth()/2) + c,
+                            (int)(scene.getWindow().getY() + scene.getY() +
+                                slider.getLayoutY() + slider.getLayoutBounds().getHeight()/2));
+            });
+        }
+
+        Util.runAndWait(() -> {
+            robot.mouseRelease(MouseButton.PRIMARY);
+        });
+
+        // Move the cursor away from the slider
+        Util.runAndWait(() -> {
+            robot.mouseMove((int)(scene.getWindow().getX() + scene.getX()),
+                            (int)(scene.getWindow().getY() + scene.getY()));
+        });
+    }
+
+    public static class TestApp extends Application {
+
+        @Override
+        public void start(Stage primaryStage) {
+            robot = new Robot();
+            stage = primaryStage;
+
+            Tooltip tooltip = new Tooltip("Autohide tooltip");
+            tooltip.setAutoHide(true);
+            tooltip.setOnShown(event -> Platform.runLater(tooltipLatch::countDown));
+
+            slider = new Slider(0, 100, 50);
+            slider.setTooltip(tooltip);
+
+            scene = new Scene(slider, SCENE_WIDTH, SCENE_HEIGHT);
+            stage.setScene(scene);
+            stage.initStyle(StageStyle.UNDECORATED);
+            stage.setAlwaysOnTop(true);
+            stage.setOnShown(event -> Platform.runLater(startupLatch::countDown));
+            stage.show();
+
+            Thread.currentThread().setUncaughtExceptionHandler((t2, e) -> {
+                exception = e;
+            });
+        }
+    }
+
+    @BeforeClass
+    public static void initFX() {
+        Util.launch(startupLatch, TestApp.class);
+    }
+
+    @AfterClass
+    public static void exit() {
+        Util.shutdown(stage);
+    }
+}