Fix Instantiator-created MenuItems disappearing

When d5cb26bc fixed a bug in Menu, it also broke the use case
of having an Instantiator create menu items. Using an Instantiator
like this allows users to create a "Recent Files" menu, for example.
The issue was that we would indiscriminately recreate items, even
those owned by an Instantiator.

This patch avoids recreating items owned by Instantiators.
It also adds a logging category for Menu, to aid debugging.

Fixes: QTBUG-71066
Change-Id: Ie0e46de1cbfaee81b43d63f3143435f2514371d5
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

4 files changed, 279 insertions, 4 deletions

diff --git a/src/quicktemplates2/qquickmenu.cpp b/src/quicktemplates2/qquickmenu.cpp
index 7086db91..42059e7f 100644
--- a/src/quicktemplates2/qquickmenu.cpp
+++ b/src/quicktemplates2/qquickmenu.cpp
@@ -43,6 +43,7 @@
 #include "qquickpopuppositioner_p_p.h"
 #include "qquickaction_p.h"
 
+#include <QtCore/qloggingcategory.h>
 #include <QtGui/qevent.h>
 #include <QtGui/qcursor.h>
 #include <QtGui/qpa/qplatformintegration.h>
@@ -54,6 +55,8 @@
 #include <QtQml/private/qv4variantobject_p.h>
 #include <QtQml/private/qv4qobjectwrapper_p.h>
 #include <QtQml/private/qqmlobjectmodel_p.h>
+#include <QtQml/private/qqmlinstantiator_p.h>
+#include <QtQml/private/qqmlinstantiator_p_p.h>
 #include <QtQuick/private/qquickitem_p.h>
 #include <QtQuick/private/qquickitemchangelistener_p.h>
 #include <QtQuick/private/qquickitemview_p.h>
@@ -65,6 +68,8 @@ QT_BEGIN_NAMESPACE
 // copied from qfusionstyle.cpp
 static const int SUBMENU_DELAY = 225;
 
+Q_LOGGING_CATEGORY(qlcQQuickMenu, "qt.quick.controls.menu")
+
 /*!
     \qmltype Menu
     \inherits Popup
@@ -279,11 +284,37 @@ void QQuickMenuPrivate::recreateItems()
     // removeItem() will remove stuff from contentData, so we have to make a copy of it.
     const auto originalContentData = contentData;
 
-    while (contentModel->count() > 0)
-        removeItem(0, itemAt(0));
+    qCDebug(qlcQQuickMenu) << "removing items so that we can recreate them:";
+    QSet<QObject*> instantiatedObjects;
+    for (int i = 0; i < contentModel->count(); ) {
+        QQuickItem *item = itemAt(i);
+        QQmlInstantiator *instantiator = qobject_cast<QQmlInstantiator*>(item->parent());
+        if (instantiator) {
+            // Don't try to recreate items owned by an instantiator.
+            qCDebug(qlcQQuickMenu) << "- item" << item << "at index" << i << "with parent"
+                << item->parent() << "was instantiated by Instantiator; ignoring";
+            instantiatedObjects.insert(item);
+            ++i;
+        } else {
+            qCDebug(qlcQQuickMenu) << "- removing item" << item << "at index" << i << "with parent" << item->parent();
+            removeItem(0, item);
+        }
+    }
 
-    for (QObject *object : originalContentData)
-        createAndAppendItem(object);
+    qCDebug(qlcQQuickMenu) << "recreating items:";
+    for (QObject *object : originalContentData) {
+        QQmlInstantiator *instantiator = qobject_cast<QQmlInstantiator*>(object);
+        // Instantiators are part of our contentData. If this particular object is an Instantiator,
+        // let it recreate its own items, otherwise strange things happen (the items are culled).
+        if (instantiator) {
+            qCDebug(qlcQQuickMenu) << "- contentData object" << object << "is an Instantiator;"
+                << "asking them to regenerate their own items";
+            QQmlInstantiatorPrivate::get(instantiator)->regenerate();
+        } else if (!instantiatedObjects.contains(object)) {
+            qCDebug(qlcQQuickMenu) << "- creating MenuItem for contentData object" << object;
+            createAndAppendItem(object);
+        }
+    }
 }
 
 QQuickItem *QQuickMenuPrivate::beginCreateItem()
@@ -358,6 +389,7 @@ void QQuickMenuPrivate::resizeItems()
 void QQuickMenuPrivate::itemChildAdded(QQuickItem *, QQuickItem *child)
 {
     // add dynamically reparented items (eg. by a Repeater)
+    qCDebug(qlcQQuickMenu) << "item child added" << child;
     if (!QQuickItemPrivate::get(child)->isTransparentForPositioner() && !contentData.contains(child))
         insertItem(contentModel->count(), child);
 }
@@ -365,6 +397,7 @@ void QQuickMenuPrivate::itemChildAdded(QQuickItem *, QQuickItem *child)
 void QQuickMenuPrivate::itemParentChanged(QQuickItem *item, QQuickItem *parent)
 {
     // remove dynamically unparented items (eg. by a Repeater)
+    qCDebug(qlcQQuickMenu) << "parent of item" << item << "changed to" << parent;
     if (!parent)
         removeItem(contentModel->indexOf(item, nullptr), item);
 }
@@ -375,6 +408,8 @@ void QQuickMenuPrivate::itemSiblingOrderChanged(QQuickItem *)
     Q_Q(QQuickMenu);
     QList<QQuickItem *> siblings = contentItem->childItems();
 
+    qCDebug(qlcQQuickMenu) << "item sibling order changed";
+
     int to = 0;
     for (int i = 0; i < siblings.count(); ++i) {
         QQuickItem* sibling = siblings.at(i);
@@ -387,6 +422,7 @@ void QQuickMenuPrivate::itemSiblingOrderChanged(QQuickItem *)
 
 void QQuickMenuPrivate::itemDestroyed(QQuickItem *item)
 {
+    qCDebug(qlcQQuickMenu) << "item child destroyed" << item;
     QQuickPopupPrivate::itemDestroyed(item);
     int index = contentModel->indexOf(item, nullptr);
     if (index != -1)
@@ -662,12 +698,16 @@ void QQuickMenuPrivate::contentData_append(QQmlListProperty<QObject> *prop, QObj
     QQuickMenuPrivate *p = QQuickMenuPrivate::get(q);
 
     if (!p->complete) {
+        qCDebug(qlcQQuickMenu) << "appending object" << obj
+            << "to contentData, but delaying MenuItem creation (if necessary) until we're completed";
         // Don't add items until we're complete, as the delegate could change in the meantime.
         // We'll add it to contentData and create it when we're complete.
         p->contentData.append(obj);
         return;
     }
 
+    qCDebug(qlcQQuickMenu) << "appending object" << obj
+        << "to contentData and creating MenuItem for it if necessary";
     p->createAndAppendItem(obj);
 }
 
diff --git a/tests/auto/qquickmenu/data/instantiator.qml b/tests/auto/qquickmenu/data/instantiator.qml
new file mode 100644
index 00000000..270266c3
--- /dev/null
+++ b/tests/auto/qquickmenu/data/instantiator.qml
@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQml 2.11
+import QtQuick 2.11
+import QtQuick.Controls 2.4
+
+ApplicationWindow {
+    width: 200
+    height: 200
+
+    property alias menu: menu
+
+    Menu {
+        id: menu
+
+        Instantiator {
+            model: ["A", "B"]
+
+            MenuItem {
+                objectName: text
+                text: modelData
+            }
+
+            onObjectAdded: menu.insertItem(index, object)
+            onObjectRemoved: menu.removeItem(object)
+        }
+    }
+}
diff --git a/tests/auto/qquickmenu/data/instantiatorWithItemsBeforeAndAfter.qml b/tests/auto/qquickmenu/data/instantiatorWithItemsBeforeAndAfter.qml
new file mode 100644
index 00000000..9f3ef430
--- /dev/null
+++ b/tests/auto/qquickmenu/data/instantiatorWithItemsBeforeAndAfter.qml
@@ -0,0 +1,88 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQml 2.11
+import QtQuick 2.11
+import QtQuick.Controls 2.4
+
+ApplicationWindow {
+    width: 200
+    height: 200
+
+    property alias menu: menu
+
+    Menu {
+        id: menu
+
+        MenuItem {
+            objectName: text
+            text: "Before"
+        }
+
+        Instantiator {
+            model: ["Instantiated #1", "Instantiated #2"]
+
+            MenuItem {
+                objectName: text
+                text: modelData
+            }
+
+            // We want our items to be added after the "Before" MenuItem,
+            // so we have to insert items at the index after it.
+            onObjectAdded: menu.insertItem(1 + index, object)
+            onObjectRemoved: menu.removeItem(object)
+        }
+
+        MenuItem {
+            objectName: text
+            text: "After"
+        }
+    }
+}
diff --git a/tests/auto/qquickmenu/tst_qquickmenu.cpp b/tests/auto/qquickmenu/tst_qquickmenu.cpp
index 27cd8aaa..2ba9363b 100644
--- a/tests/auto/qquickmenu/tst_qquickmenu.cpp
+++ b/tests/auto/qquickmenu/tst_qquickmenu.cpp
@@ -89,6 +89,8 @@ private slots:
     void scrollable_data();
     void scrollable();
     void delegateFromSeparateComponent();
+    void instantiator();
+    void instantiatorWithItemsBeforeAndAfter();
 };
 
 void tst_QQuickMenu::defaults()
@@ -1434,6 +1436,75 @@ void tst_QQuickMenu::delegateFromSeparateComponent()
     QCOMPARE(actionItem2Bg->property("color").value<QColor>(), green);
 }
 
+void tst_QQuickMenu::instantiator()
+{
+    if (QGuiApplication::styleHints()->tabFocusBehavior() != Qt::TabFocusAllControls)
+        QSKIP("This platform only allows tab focus for text controls");
+
+    QQuickApplicationHelper helper(this, QLatin1String("instantiator.qml"));
+
+    QQuickApplicationWindow *window = helper.appWindow;
+    window->show();
+    window->requestActivate();
+    QVERIFY(QTest::qWaitForWindowActive(window));
+    QVERIFY(QGuiApplication::focusWindow() == window);
+    centerOnScreen(window);
+    moveMouseAway(window);
+
+    QQuickMenu *menu = window->property("menu").value<QQuickMenu*>();
+    menu->open();
+    QVERIFY(menu->isVisible());
+    waitForMenuListViewPolish(menu);
+    menu->setFocus(true);
+
+    // Highlight the first item.
+    QQuickMenuItem *firstItem = qobject_cast<QQuickMenuItem *>(menu->itemAt(0));
+    QVERIFY(firstItem);
+    QTest::keyClick(window, Qt::Key_Tab);
+    QVERIFY(firstItem->hasActiveFocus());
+    QVERIFY(firstItem->hasVisualFocus());
+    QVERIFY(firstItem->isHighlighted());
+    QTRY_VERIFY(!QQuickItemPrivate::get(firstItem)->culled);
+
+    // Highlight the second item.
+    QQuickMenuItem *secondItem = qobject_cast<QQuickMenuItem *>(menu->itemAt(1));
+    QVERIFY(secondItem);
+    QTest::keyClick(window, Qt::Key_Down);
+    QVERIFY(secondItem->hasActiveFocus());
+    QVERIFY(secondItem->hasVisualFocus());
+    QVERIFY(secondItem->isHighlighted());
+    QVERIFY(!QQuickItemPrivate::get(secondItem)->culled);
+}
+
+void tst_QQuickMenu::instantiatorWithItemsBeforeAndAfter()
+{
+    QQuickApplicationHelper helper(this, QLatin1String("instantiatorWithItemsBeforeAndAfter.qml"));
+
+    QQuickApplicationWindow *window = helper.appWindow;
+    window->show();
+    window->requestActivate();
+    QVERIFY(QTest::qWaitForWindowActive(window));
+    QVERIFY(QGuiApplication::focusWindow() == window);
+    centerOnScreen(window);
+    moveMouseAway(window);
+
+    QQuickMenu *menu = window->property("menu").value<QQuickMenu*>();
+    menu->open();
+    QVERIFY(menu->isVisible());
+    waitForMenuListViewPolish(menu);
+
+    QStringList expectedItemTexts;
+    expectedItemTexts << QLatin1String("Before") << QLatin1String("Instantiated #1")
+        << QLatin1String("Instantiated #2") << QLatin1String("After");
+
+    for (int i = 0; i < expectedItemTexts.size(); ++i) {
+        const QString expectedText = expectedItemTexts.at(i);
+        QQuickMenuItem *menuItem = qobject_cast<QQuickMenuItem*>(menu->itemAt(i));
+        QVERIFY(menuItem);
+        QCOMPARE(menuItem->text(), expectedText);
+    }
+}
+
 QTEST_MAIN(tst_QQuickMenu)
 
 #include "tst_qquickmenu.moc"