Fix crash on exit when using default property aliases with layouts

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.

This is a manual cherry-pick of
59c6c0e0b1b5b46747595a58e11311b7393d7e70.

Task-number: QTBUG-51927
Change-Id: I669f42beb8c3dd6b4b741cae0b16e017bb3409df
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>

4 files changed, 124 insertions, 0 deletions

diff --git a/src/imports/layouts/qquicklayout.cpp b/src/imports/layouts/qquicklayout.cpp
index abc8f97cec..99148265bb 100644
--- a/src/imports/layouts/qquicklayout.cpp
+++ b/src/imports/layouts/qquicklayout.cpp
@@ -698,6 +698,10 @@ QQuickLayout::QQuickLayout(QQuickLayoutPrivate &dd, QQuickItem *parent)
 QQuickLayout::~QQuickLayout()
 {
     d_func()->m_isReady = false;
+
+    const auto childItems = d_func()->childItems;
+    for (QQuickItem *child : childItems)
+        QQuickItemPrivate::get(child)->removeItemChangeListener(this, QQuickItemPrivate::SiblingOrder);
 }
 
 QQuickLayoutAttached *QQuickLayout::qmlAttachedProperties(QObject *object)
diff --git a/tests/auto/quick/qquicklayouts/data/rowlayout/Container.qml b/tests/auto/quick/qquicklayouts/data/rowlayout/Container.qml
new file mode 100644
index 0000000000..22205c18f0
--- /dev/null
+++ b/tests/auto/quick/qquicklayouts/data/rowlayout/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 2.7
+import QtQuick.Layouts 1.3
+
+Item {
+    objectName: "qtbug51927-window"
+    visible: true
+
+    default property alias _contents: customContent.data
+
+    RowLayout {
+        id: customContent
+        objectName: "qtbug51927-columnLayout"
+        anchors.fill: parent
+    }
+}
diff --git a/tests/auto/quick/qquicklayouts/data/rowlayout/ContainerUser.qml b/tests/auto/quick/qquicklayouts/data/rowlayout/ContainerUser.qml
new file mode 100644
index 0000000000..ff7ce6221b
--- /dev/null
+++ b/tests/auto/quick/qquicklayouts/data/rowlayout/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/quick/qquicklayouts/data/tst_rowlayout.qml b/tests/auto/quick/qquicklayouts/data/tst_rowlayout.qml
index 33b8fd0e4e..2d4e227a9e 100644
--- a/tests/auto/quick/qquicklayouts/data/tst_rowlayout.qml
+++ b/tests/auto/quick/qquicklayouts/data/tst_rowlayout.qml
@@ -926,5 +926,17 @@ Item {
             waitForRendering(layout)
             layout.destroy()
         }
+
+
+        function test_defaultPropertyAliasCrash() {
+            var containerUserComponent = Qt.createComponent("rowlayout/ContainerUser.qml");
+            compare(containerUserComponent.status, Component.Ready);
+
+            var containerUser = containerUserComponent.createObject(testCase);
+            verify(containerUser);
+
+            // Shouldn't crash.
+            containerUser.destroy();
+        }
     }
 }