Prevent errors when unloading Loader

Invalidate the context of the object so that destruction is signaled
and bindings no longer run.

Task-number: QTBUG-47321
Task-number: QTBUG-51995
Task-number: QTBUG-60344
Change-Id: I194a2fefe4e769a58c9ce022d39fe76cbe230de7
Reviewed-by: Michael Brasser <michael.brasser@live.com>

3 files changed, 185 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickloader/data/bindings.qml b/tests/auto/quick/qquickloader/data/bindings.qml
new file mode 100644
index 0000000000..e0eae2a3e5
--- /dev/null
+++ b/tests/auto/quick/qquickloader/data/bindings.qml
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the manual tests 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Item {
+    id: root
+
+    property alias game: theGame
+    property alias loader: theLoader
+
+    Item {
+        id: theGame
+
+        property bool isReady: false
+
+        onStateChanged: {
+            if (state == "invalid") {
+                // The Loader's active property is bound to isReady, so none of its bindings
+                // should be updated when isReady becomes false
+                isReady = false;
+
+                player.destroy();
+                player = null;
+            } else if (state == "running") {
+                player = Qt.createQmlObject("import QtQuick 2.0; Item { property color color: 'black' }", root);
+
+                isReady = true;
+            }
+        }
+
+        property Item player
+    }
+
+    Loader {
+        id: theLoader
+        active: theGame.isReady
+        sourceComponent: Rectangle {
+            width: 400
+            height: 400
+            color: game.player.color
+
+            property var game: theGame
+        }
+    }
+}
diff --git a/tests/auto/quick/qquickloader/data/parentErrors.qml b/tests/auto/quick/qquickloader/data/parentErrors.qml
new file mode 100644
index 0000000000..36607e7f05
--- /dev/null
+++ b/tests/auto/quick/qquickloader/data/parentErrors.qml
@@ -0,0 +1,47 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the manual tests 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Rectangle {
+    width: 360
+    height: 360
+
+    property alias loader: loader
+
+    Loader {
+        id: loader
+        anchors.fill: parent
+    }
+
+    property Component component: Rectangle {
+        width: parent.width
+        height: parent.height
+        color: "pink"
+    }
+}
diff --git a/tests/auto/quick/qquickloader/tst_qquickloader.cpp b/tests/auto/quick/qquickloader/tst_qquickloader.cpp
index c70b4c85e7..e557b592ee 100644
--- a/tests/auto/quick/qquickloader/tst_qquickloader.cpp
+++ b/tests/auto/quick/qquickloader/tst_qquickloader.cpp
@@ -114,11 +114,17 @@ private slots:
     void QTBUG_30183();
 
     void sourceComponentGarbageCollection();
+
+    void bindings();
+    void parentErrors();
 };
 
+Q_DECLARE_METATYPE(QList<QQmlError>)
+
 tst_QQuickLoader::tst_QQuickLoader()
 {
     qmlRegisterType<SlowComponent>("LoaderTest", 1, 0, "SlowComponent");
+    qRegisterMetaType<QList<QQmlError>>();
 }
 
 void tst_QQuickLoader::sourceOrComponent()
@@ -1174,6 +1180,67 @@ void tst_QQuickLoader::sourceComponentGarbageCollection()
     QCOMPARE(spy.count(), 1);
 }
 
+// QTBUG-51995
+void tst_QQuickLoader::bindings()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("bindings.qml"));
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(!object.isNull());
+
+    QQuickItem *game = object->property("game").value<QQuickItem*>();
+    QVERIFY(game);
+
+    QQuickLoader *loader = object->property("loader").value<QQuickLoader*>();
+    QVERIFY(loader);
+
+    QSignalSpy warningsSpy(&engine, SIGNAL(warnings(QList<QQmlError>)));
+
+    // Causes the Loader to become active
+    game->setState(QLatin1String("running"));
+    QTRY_VERIFY(loader->item());
+
+    // Causes the Loader to become inactive - should not cause binding errors
+    game->setState(QLatin1String("invalid"));
+    QTRY_VERIFY(!loader->item());
+
+    QString failureMessage;
+    if (!warningsSpy.isEmpty()) {
+        QDebug stream(&failureMessage);
+        stream << warningsSpy.first().first().value<QList<QQmlError>>();
+    }
+    QVERIFY2(warningsSpy.isEmpty(), qPrintable(failureMessage));
+}
+
+// QTBUG-47321
+void tst_QQuickLoader::parentErrors()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("parentErrors.qml"));
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(!object.isNull());
+
+    QQuickLoader *loader = object->property("loader").value<QQuickLoader*>();
+    QVERIFY(loader);
+
+    QSignalSpy warningsSpy(&engine, SIGNAL(warnings(QList<QQmlError>)));
+
+    // Give the loader a component
+    loader->setSourceComponent(object->property("component").value<QQmlComponent*>());
+    QTRY_VERIFY(loader->item());
+
+    // Clear the loader's component; should not cause binding errors
+    loader->setSourceComponent(nullptr);
+    QTRY_VERIFY(!loader->item());
+
+    QString failureMessage;
+    if (!warningsSpy.isEmpty()) {
+        QDebug stream(&failureMessage);
+        stream << warningsSpy.first().first().value<QList<QQmlError>>();
+    }
+    QVERIFY2(warningsSpy.isEmpty(), qPrintable(failureMessage));
+}
+
 QTEST_MAIN(tst_QQuickLoader)
 
 #include "tst_qquickloader.moc"