QQuickDeliverAgent: don't propagate hover to siblings

From testing Qt 6.1, hover events should not propagate
between siblings. As soon as a leaf item is found that
receives a hover events, the event should only propagate
up the parent chain starting from the leaf item.

Change-Id: I7448f5322f529addb2260b0ee2b02d2cfadb55e1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 499828b855d125ac236917f6ed01d8f1e7d88505)
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

5 files changed, 109 insertions, 12 deletions

diff --git a/src/quick/util/qquickdeliveryagent.cpp b/src/quick/util/qquickdeliveryagent.cpp
index 36f1128a39..20faa23a09 100644
--- a/src/quick/util/qquickdeliveryagent.cpp
+++ b/src/quick/util/qquickdeliveryagent.cpp
@@ -990,6 +990,7 @@ bool QQuickDeliveryAgentPrivate::deliverHoverEvent(
     // list at the end of this function and look for items with an old hoverId,
     // remove them from the list, and update their state accordingly.
     currentHoverId++;
+    hoveredLeafItemFound = false;
 
     const bool itemsWasHovered = !hoverItems.isEmpty();
     deliverHoverEventRecursive(rootItem, scenePos, lastScenePos, modifiers, timestamp);
@@ -1037,6 +1038,11 @@ bool QQuickDeliveryAgentPrivate::deliverHoverEvent(
     end up as the only one hovered. Any other HoverHandler that may be a child
     of an item that is stacked underneath, will not. Note that since siblings
     can overlap, there can be more than one leaf item under the mouse.
+
+    For legacy reasons (Qt 6.1), as soon as we find a leaf item that has hover
+    enabled, and therefore receives the event, we stop recursing into the remaining
+    siblings (even if the event was ignored). This means that we only allow hover
+    events to propagate up the direct parent-child hierarchy, and not to siblings.
 */
 bool QQuickDeliveryAgentPrivate::deliverHoverEventRecursive(
         QQuickItem *item, const QPointF &scenePos, const QPointF &lastScenePos,
@@ -1066,6 +1072,10 @@ bool QQuickDeliveryAgentPrivate::deliverHoverEventRecursive(
             // Stop propagation / recursion
             return true;
         }
+        if (hoveredLeafItemFound) {
+            // Don't propagate to siblings, only to ancestors
+            break;
+        }
     }
 
     // All decendants have been visited.
@@ -1098,6 +1108,9 @@ bool QQuickDeliveryAgentPrivate::deliverHoverEventToItem(
     qCDebug(lcHoverTrace) << "item:" << item << "scene pos:" << scenePos << "localPos:" << localPos
                           << "wasHovering:" << wasHovering << "isHovering:" << isHovering;
 
+    if (isHovering)
+        hoveredLeafItemFound = true;
+
     // Send enter/move/leave event to the item
     bool accepted = false;
     if (isHovering && !clearHover) {
diff --git a/src/quick/util/qquickdeliveryagent_p_p.h b/src/quick/util/qquickdeliveryagent_p_p.h
index 3e551beb27..b962864103 100644
--- a/src/quick/util/qquickdeliveryagent_p_p.h
+++ b/src/quick/util/qquickdeliveryagent_p_p.h
@@ -120,6 +120,7 @@ public:
     bool allowChildEventFiltering = true;
     bool allowDoubleClick = true;
     bool frameSynchronousHoverEnabled = true;
+    bool hoveredLeafItemFound = false;
 
     bool isSubsceneAgent = false;
     static bool subsceneAgentsExist;
diff --git a/tests/auto/quick/pointerhandlers/qquickhoverhandler/BLACKLIST b/tests/auto/quick/pointerhandlers/qquickhoverhandler/BLACKLIST
index 62a6c67407..c815c0baf9 100644
--- a/tests/auto/quick/pointerhandlers/qquickhoverhandler/BLACKLIST
+++ b/tests/auto/quick/pointerhandlers/qquickhoverhandler/BLACKLIST
@@ -1,10 +1,2 @@
 [movingItemWithHoverHandler]
 macos  # Can't move cursor (QTBUG-76312)
-
-# QTBUG-98492
-[mouseAreaAndUnderlyingHoverHandler]
-macos
-
-# QTBUG-98492
-[hoverHandlerAndUnderlyingMouseArea]
-macos
diff --git a/tests/auto/quick/pointerhandlers/qquickhoverhandler/tst_qquickhoverhandler.cpp b/tests/auto/quick/pointerhandlers/qquickhoverhandler/tst_qquickhoverhandler.cpp
index b26a055e60..d4ce666c4d 100644
--- a/tests/auto/quick/pointerhandlers/qquickhoverhandler/tst_qquickhoverhandler.cpp
+++ b/tests/auto/quick/pointerhandlers/qquickhoverhandler/tst_qquickhoverhandler.cpp
@@ -272,8 +272,8 @@ void tst_HoverHandler::hoverHandlerAndUnderlyingMouseArea()
 #endif
 
     QTest::mouseMove(window, buttonCenter);
-    QCOMPARE(bottomSidebarMA->hovered(), true);
-    QCOMPARE(sidebarHoveredSpy.count(), 1);
+    QCOMPARE(bottomSidebarMA->hovered(), false);
+    QCOMPARE(sidebarHoveredSpy.count(), 2);
     QCOMPARE(buttonHH->isHovered(), true);
     QCOMPARE(buttonHoveredSpy.count(), 1);
 #if QT_CONFIG(cursor)
@@ -282,7 +282,7 @@ void tst_HoverHandler::hoverHandlerAndUnderlyingMouseArea()
 
     QTest::mouseMove(window, rightOfButton);
     QCOMPARE(bottomSidebarMA->hovered(), true);
-    QCOMPARE(sidebarHoveredSpy.count(), 1);
+    QCOMPARE(sidebarHoveredSpy.count(), 3);
     QCOMPARE(buttonHH->isHovered(), false);
     QCOMPARE(buttonHoveredSpy.count(), 2);
 #if QT_CONFIG(cursor)
@@ -291,7 +291,7 @@ void tst_HoverHandler::hoverHandlerAndUnderlyingMouseArea()
 
     QTest::mouseMove(window, outOfSidebar);
     QCOMPARE(bottomSidebarMA->hovered(), false);
-    QCOMPARE(sidebarHoveredSpy.count(), 2);
+    QCOMPARE(sidebarHoveredSpy.count(), 4);
     QCOMPARE(buttonHH->isHovered(), false);
     QCOMPARE(buttonHoveredSpy.count(), 2);
 #if QT_CONFIG(cursor)
diff --git a/tests/auto/quick/qquickdeliveryagent/tst_qquickdeliveryagent.cpp b/tests/auto/quick/qquickdeliveryagent/tst_qquickdeliveryagent.cpp
index 2de8f403d1..ac00cfede7 100644
--- a/tests/auto/quick/qquickdeliveryagent/tst_qquickdeliveryagent.cpp
+++ b/tests/auto/quick/qquickdeliveryagent/tst_qquickdeliveryagent.cpp
@@ -62,6 +62,26 @@ struct ViewportTransformHelper : public QQuickDeliveryAgent::Transform
     }
 };
 
+struct HoverItem : public QQuickItem
+{
+    HoverItem(QQuickItem *parent) : QQuickItem(parent){}
+    void hoverEnterEvent(QHoverEvent *e) override
+    {
+        hoverEnter = true;
+        e->setAccepted(block);
+    }
+
+    void hoverLeaveEvent(QHoverEvent *e) override
+    {
+        hoverLeave = true;
+        e->setAccepted(block);
+    }
+
+    bool hoverEnter = false;
+    bool hoverLeave = false;
+    bool block = false;
+};
+
 // A QQuick3DViewport simulator
 class SubsceneRootItem : public QQuickShaderEffectSource
 {
@@ -135,6 +155,9 @@ private slots:
     void passiveGrabberOrder();
     void tapHandlerDoesntOverrideSubsceneGrabber();
     void touchCompression();
+    void hoverPropagation_nested_data();
+    void hoverPropagation_nested();
+    void hoverPropagation_siblings();
 
 private:
     QScopedPointer<QPointingDevice> touchDevice = QScopedPointer<QPointingDevice>(QTest::createTouchDevice());
@@ -278,6 +301,74 @@ void tst_qquickdeliveryagent::touchCompression()
     QCOMPARE(agentPriv->compressedTouchCount, 0);
 }
 
+void tst_qquickdeliveryagent::hoverPropagation_nested_data()
+{
+    QTest::addColumn<bool>("block");
+    QTest::newRow("block=false") << false;
+    QTest::newRow("block=true") << true;
+}
+
+void tst_qquickdeliveryagent::hoverPropagation_nested()
+{
+    QFETCH(bool, block);
+
+    QQuickWindow window;
+    window.resize(200, 200);
+    window.show();
+    QVERIFY(QTest::qWaitForWindowActive(&window));
+
+    HoverItem child(window.contentItem());
+    child.setAcceptHoverEvents(true);
+    child.setWidth(100);
+    child.setHeight(100);
+
+    HoverItem grandChild(&child);
+    grandChild.setAcceptHoverEvents(true);
+    grandChild.block = block;
+    grandChild.setWidth(100);
+    grandChild.setHeight(100);
+
+    // Start by moving the mouse to the window
+    QTest::mouseMove(&window, QPoint(150, 150));
+    QCOMPARE(child.hoverEnter, false);
+    QCOMPARE(grandChild.hoverEnter, false);
+
+    // Move the mouse inside the items. If block is true, only
+    // the grandchild should be hovered. Otherwise both.
+    QTest::mouseMove(&window, QPoint(50, 50));
+    QCOMPARE(child.hoverEnter, !block);
+    QCOMPARE(grandChild.hoverEnter, true);
+}
+
+void tst_qquickdeliveryagent::hoverPropagation_siblings()
+{
+    QQuickWindow window;
+    window.resize(200, 200);
+    window.show();
+    QVERIFY(QTest::qWaitForWindowActive(&window));
+
+    HoverItem sibling1(window.contentItem());
+    sibling1.setAcceptHoverEvents(true);
+    sibling1.setWidth(100);
+    sibling1.setHeight(100);
+
+    HoverItem sibling2(window.contentItem());
+    sibling2.setAcceptHoverEvents(true);
+    sibling2.setWidth(100);
+    sibling2.setHeight(100);
+
+    // Start by moving the mouse to the window
+    QTest::mouseMove(&window, QPoint(150, 150));
+    QCOMPARE(sibling1.hoverEnter, false);
+    QCOMPARE(sibling2.hoverEnter, false);
+
+    // Move the mouse inside the items. Only the
+    // sibling on the top should receive hover
+    QTest::mouseMove(&window, QPoint(50, 50));
+    QCOMPARE(sibling1.hoverEnter, false);
+    QCOMPARE(sibling2.hoverEnter, true);
+}
+
 QTEST_MAIN(tst_qquickdeliveryagent)
 
 #include "tst_qquickdeliveryagent.moc"