Fix crash on exit when using default property aliases with layoutsv5.6.25.6.2

The layout was being destroyed before the text, which meant that the
removeItemChangeListener() call never got hit. To ensure that the
listener is always removed, loop through each child in QQuickLayout's
destructor.

Task-number: QTBUG-51927
Change-Id: I4235579501bd1790e9483a8741915e55f1b1b803
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>

4 files changed, 122 insertions, 0 deletions

diff --git a/src/layouts/qquicklayout.cpp b/src/layouts/qquicklayout.cpp
index f28a7d07..a7e63195 100644
--- a/src/layouts/qquicklayout.cpp
+++ b/src/layouts/qquicklayout.cpp
@@ -695,6 +695,9 @@ QQuickLayout::QQuickLayout(QQuickLayoutPrivate &dd, QQuickItem *parent)
 QQuickLayout::~QQuickLayout()
 {
     d_func()->m_isReady = false;
+
+    foreach (QQuickItem *child, d_func()->childItems)
+        QQuickItemPrivate::get(child)->removeItemChangeListener(this, QQuickItemPrivate::SiblingOrder);
 }
 
 QQuickLayoutAttached *QQuickLayout::qmlAttachedProperties(QObject *object)
diff --git a/tests/auto/controls/data/layout/Container.qml b/tests/auto/controls/data/layout/Container.qml
new file mode 100644
index 00000000..db3d68c4
--- /dev/null
+++ b/tests/auto/controls/data/layout/Container.qml
@@ -0,0 +1,55 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 QtQuick 2.5
+import QtQuick.Layouts 1.2
+
+Item {
+    objectName: "qtbug51927-window"
+    visible: true
+
+    default property alias _contents: customContent.data
+
+    ColumnLayout {
+        id: customContent
+        objectName: "qtbug51927-columnLayout"
+        anchors.fill: parent
+    }
+}
diff --git a/tests/auto/controls/data/layout/ContainerUser.qml b/tests/auto/controls/data/layout/ContainerUser.qml
new file mode 100644
index 00000000..ff7ce622
--- /dev/null
+++ b/tests/auto/controls/data/layout/ContainerUser.qml
@@ -0,0 +1,53 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 QtQuick 2.6
+import QtQuick.Window 2.2
+
+Container {
+    visible: true
+
+    Text {
+        objectName: "qtbug51927-text"
+        text: qsTr("Hello World")
+        anchors.centerIn: parent
+        renderType: Text.QtRendering
+    }
+}
diff --git a/tests/auto/controls/data/tst_layout.qml b/tests/auto/controls/data/tst_layout.qml
index fc62b8a4..da0b1dd9 100644
--- a/tests/auto/controls/data/tst_layout.qml
+++ b/tests/auto/controls/data/tst_layout.qml
@@ -53,5 +53,16 @@ TestCase {
         var object = Qt.createQmlObject('import QtQuick 2.2; import QtQuick.Layouts 1.0; QtObject { Layout.fillWidth: true }', testCase, '');
         object.destroy()
     }
+
+    function test_defaultPropertyAliasCrash() {
+        var containerUserComponent = Qt.createComponent("layout/ContainerUser.qml");
+        compare(containerUserComponent.status, Component.Ready);
+
+        var containerUser = containerUserComponent.createObject(testCase);
+        verify(containerUser);
+
+        // Shouldn't crash.
+        containerUser.destroy();
+    }
 }