From b2862e2bd84d651c1f4fb2ced96ee6f40ea1f3e4 Mon Sep 17 00:00:00 2001

From: Andrei Golubev <andrei.golubev@qt.io>

Date: Fri, 20 Nov 2020 10:44:44 +0100

Subject: [PATCH 11/28] Fix QML property cache leaks of delegate items

The delegate items are destroyed through an event loop by a call to a

deleteLater(). This, however, doesn't work when the application is

in the process of exiting and the event loop is already closed (i.e.

we're in a stack unwinding part that starts after app.exec())

Combat this situation by setting a parent of the to-be-deleted object

to some QObject that will be destroyed e.g. QCoreApplication::instance()

before the program finishes. As QObjects clean their children on

destruction, this will make sure that we cleanup the previously leaking

thing regardless of the event loop

Added a test to check that delegates are destroyed (as a separate binary

due to differences in main() function)

Fixes: QTBUG-87228

Change-Id: I59066603b77497fe4fd8d051798c3e4b47c119f0

Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

(cherry picked from commit 3a5617dc45e281552b9c1f7a04f0561b8fa14d94)

---

 src/qmlmodels/qqmldelegatemodel.cpp           | 11 ++-

 .../qquickview_extra/data/qtbug_87228.qml     | 30 ++++++++

 .../qquickview_extra/qquickview_extra.pro     | 12 +++

 .../qquickview_extra/tst_qquickview_extra.cpp | 77 +++++++++++++++++++

 tests/auto/quick/quick.pro                    |  1 +

 5 files changed, 130 insertions(+), 1 deletion(-)

 create mode 100644 tests/auto/quick/qquickview_extra/data/qtbug_87228.qml

 create mode 100644 tests/auto/quick/qquickview_extra/qquickview_extra.pro

 create mode 100644 tests/auto/quick/qquickview_extra/tst_qquickview_extra.cpp

diff --git a/src/qmlmodels/qqmldelegatemodel.cpp b/src/qmlmodels/qqmldelegatemodel.cpp

index 725b9e8bc3..12c3d11937 100644

--- a/src/qmlmodels/qqmldelegatemodel.cpp

+++ b/src/qmlmodels/qqmldelegatemodel.cpp

@@ -1,6 +1,6 @@

 /****************************************************************************

 **

-** Copyright (C) 2016 The Qt Company Ltd.

+** Copyright (C) 2020 The Qt Company Ltd.

 ** Contact: https://www.qt.io/licensing/

 **

 ** This file is part of the QtQml module of the Qt Toolkit.

@@ -2379,6 +2379,15 @@ void QQmlDelegateModelItem::destroyObject()

         data->ownContext = nullptr;

         data->context = nullptr;

     }

+    /* QTBUG-87228: when destroying object at the application exit, the deferred

+     * parent by setting it to QCoreApplication instance if it's nullptr, so

+     * deletion won't work. Not to leak memory, make sure our object has a that

+     * the parent claims the object at the end of the lifetime. When not at the

+     * application exit, normal event loop will handle the deferred deletion

+     * earlier.

+     */

+    if (object->parent() == nullptr)

+        object->setParent(QCoreApplication::instance());

     object->deleteLater();

     if (attached) {

diff --git a/tests/auto/quick/qquickview_extra/data/qtbug_87228.qml b/tests/auto/quick/qquickview_extra/data/qtbug_87228.qml

new file mode 100644

index 0000000000..ff10eba23d

--- /dev/null

+++ b/tests/auto/quick/qquickview_extra/data/qtbug_87228.qml

@@ -0,0 +1,30 @@

+import QtQml 2.12

+import QtQml.Models 2.12

+import QtQuick 2.12

+

+Item {

+    height: 480

+    width: 320

+    Rectangle {

+        id: rootRect

+

+        function addItem(desc) {

+            myModel.append({"desc": desc});

+        }

+

+        Rectangle {

+            ListView {

+                objectName: "listView"

+                delegate: Text {

+                    required property string desc

+                    text: desc

+                }

+                model: ListModel { id: myModel }

+            }

+        }

+

+        Component.onCompleted: {

+            addItem("Test creation of a delegate with a property");

+        }

+    }

+}

diff --git a/tests/auto/quick/qquickview_extra/qquickview_extra.pro b/tests/auto/quick/qquickview_extra/qquickview_extra.pro

new file mode 100644

index 0000000000..b40af0ce19

--- /dev/null

+++ b/tests/auto/quick/qquickview_extra/qquickview_extra.pro

@@ -0,0 +1,12 @@

+CONFIG += testcase

+TARGET = tst_qquickview_extra

+macx:CONFIG -= app_bundle

+

+SOURCES += tst_qquickview_extra.cpp

+

+include (../../shared/util.pri)

+include (../shared/util.pri)

+

+TESTDATA = data/*

+

+QT += core-private gui-private qml-private quick-private testlib

diff --git a/tests/auto/quick/qquickview_extra/tst_qquickview_extra.cpp b/tests/auto/quick/qquickview_extra/tst_qquickview_extra.cpp

new file mode 100644

index 0000000000..f697a438bd

--- /dev/null

+++ b/tests/auto/quick/qquickview_extra/tst_qquickview_extra.cpp

@@ -0,0 +1,77 @@

+/****************************************************************************

+**

+** Copyright (C) 2020 The Qt Company Ltd.

+** Contact: https://www.qt.io/licensing/

+**

+** This file is part of the test suite of the Qt Toolkit.

+**

+** $QT_BEGIN_LICENSE:GPL-EXCEPT$

+** 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.

+**

+** GNU General Public License Usage

+** Alternatively, this file may be used under the terms of the GNU

+** General Public License version 3 as published by the Free Software

+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT

+** included in the packaging of this file. Please review the following

+** information to ensure the GNU General Public License requirements will

+** be met: https://www.gnu.org/licenses/gpl-3.0.html.

+**

+** $QT_END_LICENSE$

+**

+****************************************************************************/

+#include <qtest.h>

+#include <QtTest/QSignalSpy>

+#include <QtQuick/qquickview.h>

+#include <QtQuick/qquickitem.h>

+#include <QtQml/qqmlengine.h>

+#include "../../shared/util.h"

+#include <QtCore/QDebug>

+#include <QtCore/QTimer>

+

+// Extra app-less tests

+class tst_QQuickViewExtra : public QQmlDataTest

+{

+    Q_OBJECT

+public:

+    tst_QQuickViewExtra();

+

+private slots:

+    void qtbug_87228();

+};

+

+tst_QQuickViewExtra::tst_QQuickViewExtra() { }

+

+void tst_QQuickViewExtra::qtbug_87228()

+{

+    QScopedPointer<QSignalSpy> deletionSpy;

+    {

+        int argc = 0;

+        QGuiApplication app(argc, nullptr);

+        QQuickView view;

+

+        view.setSource(testFileUrl("qtbug_87228.qml"));

+        view.show();

+        QTimer::singleShot(500, &app, QCoreApplication::quit);

+        app.exec();

+

+        QObject *listView = view.findChild<QObject *>("listView");

+        QVERIFY(listView);

+        QQuickItem *contentItem = listView->property("contentItem").value<QQuickItem *>();

+        QVERIFY(contentItem);

+        auto children = contentItem->childItems();

+        QVERIFY(children.size() > 0);

+        // for the sake of this test, any child would be suitable, so pick first

+        deletionSpy.reset(new QSignalSpy(children[0], SIGNAL(destroyed(QObject *))));

+    }

+    QCOMPARE(deletionSpy->count(), 1);

+}

+

+QTEST_APPLESS_MAIN(tst_QQuickViewExtra)

+

+#include "tst_qquickview_extra.moc"

diff --git a/tests/auto/quick/quick.pro b/tests/auto/quick/quick.pro

index 541bfdd527..45bcf8a9ce 100644

--- a/tests/auto/quick/quick.pro

+++ b/tests/auto/quick/quick.pro

@@ -85,6 +85,7 @@ QUICKTESTS += \

     qquicktextinput \

     qquickvisualdatamodel \

     qquickview \

+    qquickview_extra \

     qquickcanvasitem \

     qquickdesignersupport \

     qquickscreen \

-- 

2.31.1