Fix masked MouseArea hovered state on visibility change

This fixes the issue where given two hoverable MouseAreas A & B where B
masks A, the `containsMouse` property of A will be incorrectly set to
true if the cursor is positioned above both A and B and the visibility
of A is toggled from true to false back to true.

This patch fixes the above issue by checking if the QQuickMouseArea is
marked as a hovered item in its windows QQuickDeliveryAgentPrivate(QDAP)
instance. If the QQuickMouseArea is masked by another QQuickMouseArea
then it will not be a in the QDAPs hovered items list and we skip
setting the hovered property on QQuickMouseArea, fixing the issue.

This patch also adds a test case to prevent future regressions.

Fixes: QTBUG-109567
Change-Id: I5f024a097b56ef5e0836ca9f8ae547983a089b44
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
(cherry picked from commit 000df08653be46420298acae8e16f831056a85b7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 109 insertions, 6 deletions

diff --git a/src/quick/items/qquickmousearea.cpp b/src/quick/items/qquickmousearea.cpp
index 4e361d833f..a99976473f 100644
--- a/src/quick/items/qquickmousearea.cpp
+++ b/src/quick/items/qquickmousearea.cpp
@@ -1039,13 +1039,43 @@ void QQuickMouseArea::itemChange(ItemChange change, const ItemChangeData &value)
     Q_D(QQuickMouseArea);
     switch (change) {
     case ItemVisibleHasChanged:
-        if (d->effectiveEnable && d->enabled && hoverEnabled() && d->hovered != (isVisible() && isUnderMouse())) {
-            if (!d->hovered) {
-                QPointF cursorPos = QGuiApplicationPrivate::lastCursorPosition;
-                d->lastScenePos = d->window->mapFromGlobal(cursorPos.toPoint());
-                d->lastPos = mapFromScene(d->lastScenePos);
+        if (d->effectiveEnable && d->enabled && hoverEnabled()
+            && d->hovered != (isVisible() && isUnderMouse())) {
+            if (d->hovered) {
+                // If hovered but no longer under the mouse then un-hover.
+                setHovered(false);
+            } else {
+                // If under the mouse but not hovered then hover the QQuickMouseArea if it is
+                // marked as a hovered item under the windows QQuickDeliveryAgentPrivate instance.
+                // This is required as this QQuickMouseArea may be masked by another hoverable
+                // QQuickMouseArea higher up in the scenes z-index ordering.
+                QPointF globalPos{ QGuiApplicationPrivate::lastCursorPosition.toPoint() };
+                QPointF scenePos{ d->window->mapFromGlobal(globalPos) };
+
+                QQuickWindowPrivate *wd = QQuickWindowPrivate::get(d->window);
+                QQuickDeliveryAgentPrivate *dap = wd->deliveryAgentPrivate();
+
+                // If the QQuickDeliveryAgentPrivate has not already found a hovered leaf
+                // item then attempt to find one.
+                if (!dap->hoveredLeafItemFound) {
+                    dap->deliverHoverEvent(scenePos, scenePos, Qt::NoModifier,
+                                           QDateTime::currentSecsSinceEpoch());
+                }
+
+                // Now if the QQuickDeliveryAgentPrivate has found a hovered leaf item check
+                // that this QQuickMouseArea item was one of the hovered items.
+                if (dap->hoveredLeafItemFound) {
+                    for (auto hoverItem : dap->hoverItems) {
+                        if (hoverItem.first == this) {
+                            // Found a match so update the hover state.
+                            d->lastScenePos = scenePos;
+                            d->lastPos = mapFromScene(d->lastScenePos);
+                            setHovered(true);
+                            break;
+                        }
+                    }
+                }
             }
-            setHovered(!d->hovered);
         }
         if (d->pressed && (!isVisible())) {
             // This happens when the mouse area sets itself disabled or hidden
diff --git a/tests/auto/quick/qquickmousearea/data/containsMouseMasked.qml b/tests/auto/quick/qquickmousearea/data/containsMouseMasked.qml
new file mode 100644
index 0000000000..35cfd4b7ef
--- /dev/null
+++ b/tests/auto/quick/qquickmousearea/data/containsMouseMasked.qml
@@ -0,0 +1,24 @@
+import QtQuick
+
+Rectangle {
+    width: 200
+    height: 200
+    visible: true
+    MouseArea {
+        id: mouseArea1
+        objectName: "mouseArea1"
+        anchors.fill: parent
+        hoverEnabled: true
+        visible: true
+    }
+
+    MouseArea {
+        id: mouseArea2
+        objectName: "mouseArea2"
+        anchors.centerIn: mouseArea1
+        width: 50
+        height: 50
+        hoverEnabled: true
+        visible: true
+    }
+}
diff --git a/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp b/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
index 755dad6312..345b42487e 100644
--- a/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
+++ b/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
@@ -136,6 +136,7 @@ private slots:
     void settingHiddenInPressUngrabs();
     void negativeZStackingOrder();
     void containsMouseAndVisibility();
+    void containsMouseAndVisibilityMasked();
     void doubleClickToHide();
     void releaseFirstTouchAfterSecond();
 #if QT_CONFIG(tabletevent)
@@ -2404,6 +2405,54 @@ void tst_QQuickMouseArea::containsMouseAndVisibility()
     QVERIFY(!mouseArea->hovered());
 }
 
+// QTBUG-109567
+void tst_QQuickMouseArea::containsMouseAndVisibilityMasked()
+{
+    QQuickView window;
+    QVERIFY(QQuickTest::showView(window, testFileUrl("containsMouseMasked.qml")));
+
+    QQuickMouseArea *mouseArea1 = window.rootObject()->findChild<QQuickMouseArea *>("mouseArea1");
+    QVERIFY(mouseArea1 != nullptr);
+    QVERIFY(mouseArea1->isVisible());
+
+    QQuickMouseArea *mouseArea2 = window.rootObject()->findChild<QQuickMouseArea *>("mouseArea2");
+    QVERIFY(mouseArea2 != nullptr);
+    QVERIFY(mouseArea2->isVisible());
+
+    QTest::mouseMove(&window, QPoint(window.width() / 2, window.height() / 2));
+
+    // Check that mouseArea" (i.e. the masking MouseArea) is the only hovered MouseArea.
+    QTRY_VERIFY(!mouseArea1->hovered());
+    QTRY_VERIFY(mouseArea2->hovered());
+
+    // Toggle the visibility of the masked MouseArea (mouseArea1).
+    mouseArea1->setVisible(false);
+    QVERIFY(!mouseArea1->isVisible());
+
+    mouseArea1->setVisible(true);
+    QVERIFY(mouseArea1->isVisible());
+
+    // Check that the masked MouseArea is not now hovered depite being under the mouse after
+    // changing the visibility to visible. mouseArea2 should be the only hovered MouseArea still.
+    QTRY_VERIFY(!mouseArea1->hovered());
+    QTRY_VERIFY(mouseArea2->hovered());
+
+    QTest::mouseMove(&window, QPoint(10, 10));
+
+    QTRY_VERIFY(mouseArea1->hovered());
+    QTRY_VERIFY(!mouseArea2->hovered());
+
+    // Toggle the visibility of the masked MouseArea (mouseArea1).
+    mouseArea1->setVisible(false);
+    QVERIFY(!mouseArea1->isVisible());
+
+    mouseArea1->setVisible(true);
+    QVERIFY(mouseArea1->isVisible());
+
+    QTRY_VERIFY(mouseArea1->hovered());
+    QTRY_VERIFY(!mouseArea2->hovered());
+}
+
 // QTBUG-35995 and QTBUG-102158
 void tst_QQuickMouseArea::doubleClickToHide()
 {