Support required properties in model delegates

If a delegates declares a required property of a given name, and that
name exists as a role in the model, we set the property accordingly.
The same holds true for the special properties that come from the
QQmlDelegateModel like "index" and "model".

All roles are still injected into scope and thus accessible;
changing this in Qt5 would be tedious or even impossible while still
maintaining backwardscompatibility with delegates that do not use
required properties.

Change-Id: I4f388ba549c42f1ff9822bdb3b8357c4d45e4b66
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

3 files changed, 186 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicktableview/data/delegateWithRequired.qml b/tests/auto/quick/qquicktableview/data/delegateWithRequired.qml
new file mode 100644
index 0000000000..bebfd86931
--- /dev/null
+++ b/tests/auto/quick/qquicktableview/data/delegateWithRequired.qml
@@ -0,0 +1,70 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** 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-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+import QtQuick.Window 2.3
+
+Item {
+    width: 640
+    height: 450
+
+    property alias tableView: tableView
+
+    TableView {
+        id: tableView
+        width: 600
+        height: 400
+        delegate: tableViewDelegate
+    }
+
+    Component {
+        id: tableViewDelegate
+        Rectangle {
+            id: rect
+            required property string position
+            required property bool hasModelChildren
+            required property QtObject model
+            Text {text: rect.position}
+            implicitWidth: 100
+            implicitHeight: 100
+            Component.onCompleted: () => {if (rect.position === "R1:C1" && rect.model.hasModelChildren == rect.hasModelChildren)  console.info("success")}
+        }
+    }
+
+}
diff --git a/tests/auto/quick/qquicktableview/data/delegatewithRequiredUnset.qml b/tests/auto/quick/qquicktableview/data/delegatewithRequiredUnset.qml
new file mode 100644
index 0000000000..0c685cd49e
--- /dev/null
+++ b/tests/auto/quick/qquicktableview/data/delegatewithRequiredUnset.qml
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** 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-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+import QtQuick.Window 2.3
+
+Item {
+    width: 640
+    height: 450
+
+    property alias tableView: tableView
+
+    TableView {
+        id: tableView
+        width: 600
+        height: 400
+        delegate: tableViewDelegate
+    }
+
+    Component {
+        id: tableViewDelegate
+        Rectangle {
+            id: rect
+            required property string position
+            required property bool unset
+            required property bool hasModelChildren
+            required property QtObject model
+            Text {text: rect.position}
+            implicitWidth: 100
+            implicitHeight: 100
+            Component.onCompleted: () => {if (rect.position === "R1:C1" && rect.model.hasModelChildren == rect.hasModelChildren)  console.info("success")}
+        }
+    }
+
+}
diff --git a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
index 19967efcd9..e3f79995d2 100644
--- a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
+++ b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
@@ -172,6 +172,7 @@ private slots:
     void checkSyncView_differentSizedModels();
     void checkSyncView_connect_late_data();
     void checkSyncView_connect_late();
+    void delegateWithRequiredProperties();
 };
 
 tst_QQuickTableView::tst_QQuickTableView()
@@ -2592,6 +2593,50 @@ void tst_QQuickTableView::checkSyncView_connect_late()
 
 }
 
+void tst_QQuickTableView::delegateWithRequiredProperties()
+{
+    constexpr static int PositionRole = Qt::UserRole+1;
+    struct MyTable : QAbstractTableModel {
+
+
+        using QAbstractTableModel::QAbstractTableModel;
+
+        int rowCount(const QModelIndex& = QModelIndex()) const override {
+            return 3;
+        }
+
+        int columnCount(const QModelIndex& = QModelIndex()) const override {
+            return 3;
+        }
+
+        QVariant data(const QModelIndex &index, int = Qt::DisplayRole) const override {
+            return QVariant::fromValue(QString::asprintf("R%d:C%d", index.row(), index.column()));
+        }
+
+        QHash<int, QByteArray> roleNames() const override {
+            return QHash<int, QByteArray> { {PositionRole, "position"} };
+        }
+    };
+
+    auto model =  QVariant::fromValue(QSharedPointer<MyTable>(new MyTable));
+    {
+        QTest::ignoreMessage(QtMsgType::QtInfoMsg, "success");
+        LOAD_TABLEVIEW("delegateWithRequired.qml")
+        QVERIFY(tableView);
+        tableView->setModel(model);
+        WAIT_UNTIL_POLISHED;
+        QVERIFY(view->errors().empty());
+    }
+    {
+        QTest::ignoreMessage(QtMsgType::QtWarningMsg, QRegularExpression(R"|(TableView: failed loading index: \d)|"));
+        LOAD_TABLEVIEW("delegatewithRequiredUnset.qml")
+        QVERIFY(tableView);
+        tableView->setModel(model);
+        WAIT_UNTIL_POLISHED;
+        QTRY_VERIFY(view->errors().empty());
+    }
+}
+
 QTEST_MAIN(tst_QQuickTableView)
 
 #include "tst_qquicktableview.moc"