qmltc: stop using QQmlListReference to append

Instead of using a QQmlListReference to append into lists, use directly
the underlying QList<T*> for types compiled with qmltc and
QQmlListProperty<T> for types not compiled with qmltc (e.g. types
defined in c++).
Add a test that tests the private c++ backed "data" property of
QQuickItem and different kind of lists (QtObjects and HelloWorlds).
Also, append multiple objects to QLists in one go.

Fixes: QTBUG-104664
Change-Id: Id5ce6307a241c4c8a167feca677ba5e9b492bc07
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

tests/auto/qml/qmltc/QmltcTests/CMakeLists.txt

@@ -98,6 +98,7 @@ set(qml_sources
     translations.qml
     translationsById.qml
     generalizedGroupedProperty.qml
+    appendToQQmlListProperty.qml
 
     # support types:
     DefaultPropertySingleChild.qml

tests/auto/qml/qmltc/QmltcTests/appendToQQmlListProperty.qml

@@ -0,0 +1,70 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+import QtQuick
+import QmltcTests
+
+Item {
+
+    property var myComponentList
+    property list<int> myValueTypeList
+    property list<QtObject> myQtObjectList
+    property list<HelloWorld> myHelloWorldList
+
+    property Item myItem: Item {
+        // test qquickitems default data list (appending to private property of qquickitem)
+        HelloWorld {
+            hello: "hello1"
+        }
+        HelloWorld {
+            hello: "hello2"
+        }
+        Rectangle {
+            property string hello: "I am a Rectangle."
+        }
+    }
+
+    myComponentList: [
+        "Hello",
+        42,
+        4.0,
+    ]
+
+    myValueTypeList: [
+        12489,
+        10,
+        42
+    ]
+
+    myQtObjectList: [
+        HelloWorld {
+            hello: "Guten Morgen!"
+        },
+        Rectangle {
+            property string hello: "I am a Rectangle."
+        },
+        HelloWorld {
+            hello: "Moin!"
+        }
+    ]
+
+    myHelloWorldList: [
+        HelloWorld{
+            hello: "Good morning1"
+        },
+        HelloWorld {
+            hello: "Good morning2"
+        },
+        HelloWorld {
+            hello: "Good morning3"
+        }
+    ]
+
+    property var extended: TypeWithExtension {
+        myList: [
+            HelloWorld {},
+            Rectangle {},
+            QtObject {}
+        ]
+    }
+}

tests/auto/qml/qmltc/QmltcTests/cpptypes/extensiontypes.cpp

@@ -100,3 +100,8 @@ QBindable<int> TypeWithExtensionNamespace::bindableCount()
 {
     return QBindable<int>(&m_count);
 }
+
+QQmlListProperty<QObject> Extension::getMyList()
+{
+    return QQmlListProperty<QObject>(this, &m_myList);
+}

tests/auto/qml/qmltc/QmltcTests/cpptypes/extensiontypes.h

@@ -14,9 +14,11 @@ class Extension : public QObject
     QML_ANONYMOUS
     Q_PROPERTY(int count READ getCount WRITE setCount BINDABLE bindableCount)
     Q_PROPERTY(double foo READ getFoo WRITE setFoo BINDABLE bindableFoo)
+    Q_PROPERTY(QQmlListProperty<QObject> myList READ getMyList)
 
     QProperty<int> m_extCount { 0 };
     QProperty<double> m_foo { 0 };
+    QList<QObject *> m_myList;
 
 public:
     Extension(QObject *parent = nullptr);
@@ -27,6 +29,8 @@ public:
     double getFoo() const;
     void setFoo(double v);
     QBindable<double> bindableFoo();
+
+    QQmlListProperty<QObject> getMyList();
 };
 
 class IndirectExtension : public Extension

tests/auto/qml/qmltc/tst_qmltc.cpp

@@ -73,6 +73,7 @@
 #include "translationsbyid.h"
 #include "defaultalias.h"
 #include "generalizedgroupedproperty.h"
+#include "appendtoqqmllistproperty.h"
 
 #include "testprivateproperty.h"
 
@@ -183,6 +184,7 @@ void tst_qmltc::initTestCase()
         QUrl("qrc:/qt/qml/QmltcTests/privatePropertySubclass.qml"),
         QUrl("qrc:/qt/qml/QmltcTests/calqlatrBits.qml"),
         QUrl("qrc:/qt/qml/QmltcTests/valueTypeListProperty.qml"),
+        QUrl("qrc:/qt/qml/QmltcTests/appendToQQmlListProperty.qml"),
     };
 
     QQmlEngine e;
@@ -2506,4 +2508,76 @@ void tst_qmltc::generalizedGroupedProperty()
     }
 }
 
+void tst_qmltc::appendToQQmlListProperty()
+{
+    QQmlEngine e;
+    PREPEND_NAMESPACE(appendToQQmlListProperty) fromQmltc(&e);
+    QQmlComponent component(&e, "qrc:/qt/qml/QmltcTests/appendToQQmlListProperty.qml");
+    QVERIFY2(component.isReady(), qPrintable(component.errorString()));
+    QScopedPointer<QObject> fromEngine(component.create());
+
+    auto itemFromEngine = fromEngine->property("myItem").value<QQuickItem *>();
+    auto itemFromQmltc = fromQmltc.myItem();
+
+    QCOMPARE(itemFromEngine->children().size(), 3);
+    QCOMPARE(itemFromQmltc->children().size(), 3);
+
+    QCOMPARE(itemFromEngine->children().at(0)->property("hello"), u"hello1"_s);
+    QCOMPARE(itemFromEngine->children().at(1)->property("hello"), u"hello2"_s);
+    QCOMPARE(itemFromEngine->children().at(2)->property("hello"), u"I am a Rectangle."_s);
+
+    QCOMPARE(itemFromQmltc->children().at(0)->property("hello"), u"hello1"_s);
+    QCOMPARE(itemFromQmltc->children().at(1)->property("hello"), u"hello2"_s);
+    QCOMPARE(itemFromQmltc->children().at(2)->property("hello"), u"I am a Rectangle."_s);
+
+    QVariantList referenceComponentList = { QVariant(u"Hello"_s), QVariant(42), QVariant(4.0) };
+    QCOMPARE(fromQmltc.myComponentList().toList(), referenceComponentList);
+    QCOMPARE(fromEngine->property("myComponentList").toList(), referenceComponentList);
+
+    QList<int> referenceValueTypeList = { 12489, 10, 42 };
+    QVariantList referenceValueTypeList2 = { 12489, 10, 42 };
+    QCOMPARE(fromQmltc.myValueTypeList().toList(), referenceValueTypeList);
+    QCOMPARE(fromEngine->property("myValueTypeList").toList(), referenceValueTypeList2);
+
+    QQmlListReference qtObjectsFromQmltc(&fromQmltc, "myQtObjectList");
+    QVERIFY(qtObjectsFromQmltc.isValid());
+    QQmlListReference qtObjectsFromEngine(fromEngine.data(), "myQtObjectList");
+    QVERIFY(qtObjectsFromEngine.isValid());
+
+    QCOMPARE(qtObjectsFromQmltc.size(), 3);
+    QCOMPARE(qtObjectsFromEngine.size(), 3);
+
+    QCOMPARE(qtObjectsFromQmltc.at(0)->property("hello"), u"Guten Morgen!"_s);
+    QCOMPARE(qtObjectsFromQmltc.at(1)->property("hello"), u"I am a Rectangle."_s);
+    QCOMPARE(qtObjectsFromQmltc.at(2)->property("hello"), u"Moin!"_s);
+
+    QCOMPARE(qtObjectsFromEngine.at(0)->property("hello"), u"Guten Morgen!"_s);
+    QCOMPARE(qtObjectsFromEngine.at(1)->property("hello"), u"I am a Rectangle."_s);
+    QCOMPARE(qtObjectsFromEngine.at(2)->property("hello"), u"Moin!"_s);
+
+    QQmlListReference qtHWFromQmltc(&fromQmltc, "myHelloWorldList");
+    QQmlListReference qtHWFromEngine(fromEngine.data(), "myHelloWorldList");
+
+    QCOMPARE(qtHWFromQmltc.size(), 3);
+    QCOMPARE(qtHWFromEngine.size(), 3);
+
+    QCOMPARE(qtHWFromQmltc.at(0)->property("hello"), u"Good morning1"_s);
+    QCOMPARE(qtHWFromQmltc.at(1)->property("hello"), u"Good morning2"_s);
+    QCOMPARE(qtHWFromQmltc.at(2)->property("hello"), u"Good morning3"_s);
+
+    QCOMPARE(qtHWFromEngine.at(0)->property("hello"), u"Good morning1"_s);
+    QCOMPARE(qtHWFromEngine.at(1)->property("hello"), u"Good morning2"_s);
+    QCOMPARE(qtHWFromEngine.at(2)->property("hello"), u"Good morning3"_s);
+
+    // make sure that extensions are handled correctly, as they require a slightly different code
+    // path to be generated
+    QQmlListReference extendedFromQmltc(fromQmltc.extended().value<QObject *>(), "myList");
+    QVERIFY(extendedFromQmltc.isValid());
+    QQmlListReference extendedFromEngine(fromEngine->property("extended").value<QObject *>(),
+                                         "myList");
+    QVERIFY(extendedFromEngine.isValid());
+    QCOMPARE(extendedFromQmltc.size(), 3);
+    QCOMPARE(extendedFromEngine.size(), 3);
+}
+
 QTEST_MAIN(tst_qmltc)

tests/auto/qml/qmltc/tst_qmltc.h

@@ -85,4 +85,5 @@ private slots:
     void valueTypeListProperty();
     void translations();
     void generalizedGroupedProperty();
+    void appendToQQmlListProperty();
 };

tools/qmltc/qmltccompilerpieces.cpp

@@ -92,17 +92,21 @@ void QmltcCodeGenerator::generate_assignToListProperty(
     const bool populateLocalListProperty = qmlListVarName.isEmpty();
 
     if (populateLocalListProperty) {
-        qmlListVarName = u"listref_%1"_s.arg(p.propertyName());
-        *block << u"QQmlListReference %1(%2, %3);"_s.arg(
-                qmlListVarName, accessor,
-                QQmlJSUtils::toLiteral(p.propertyName(), u"QByteArrayLiteral"));
-        *block << QStringLiteral("Q_ASSERT(%1.canAppend());").arg(qmlListVarName);
+        auto [extensionPrologue, extensionAccessor, extensionEpilogue] =
+                QmltcCodeGenerator::wrap_extensionType(
+                        type, p, QmltcCodeGenerator::wrap_privateClass(accessor, p));
+
+        qmlListVarName = u"listprop_%1"_s.arg(p.propertyName());
+        *block << u"QQmlListProperty<%1> %2;"_s.arg(p.type()->internalName(), qmlListVarName);
+        *block << extensionPrologue;
+        *block << u"%1 = %2->%3();"_s.arg(qmlListVarName, extensionAccessor, p.read());
+        *block << extensionEpilogue;
     }
     for (const QString &value : values) {
         auto [prologue, wrappedValue, epilogue] =
                 QmltcCodeGenerator::wrap_mismatchingTypeConversion(p, value);
         *block << prologue;
-        *block << u"%1.append(%2);"_s.arg(qmlListVarName, wrappedValue);
+        *block << u"%1.append(std::addressof(%1), %2);"_s.arg(qmlListVarName, wrappedValue);
         *block << epilogue;
     }
 }