QML: Allow conversion from QV4::Sequence to different iterable

Pick-to: 6.5
Fixes: QTBUG-112291
Change-Id: Idd47ea8daf9c54759af6c1feba68bd52d1163615
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/qml/jsruntime/qv4engine.cpp

@@ -2444,6 +2444,23 @@ void ExecutionEngine::setExtensionData(int index, Deletable *data)
     m_extensionData[index] = data;
 }
 
+template<typename Source>
+bool convertToIterable(QMetaType metaType, void *data, Source *sequence)
+{
+    QSequentialIterable iterable;
+    if (!QMetaType::view(metaType, data, QMetaType::fromType<QSequentialIterable>(), &iterable))
+        return false;
+
+    const QMetaType elementMetaType = iterable.valueMetaType();
+    QVariant element(elementMetaType);
+    for (qsizetype i = 0, end = sequence->getLength(); i < end; ++i) {
+        if (!ExecutionEngine::metaTypeFromJS(sequence->get(i), elementMetaType, element.data()))
+            element = QVariant(elementMetaType);
+        iterable.addValue(element, QSequentialIterable::AtEnd);
+    }
+    return true;
+}
+
 // Converts a JS value to a meta-type.
 // data must point to a place that can store a value of the given type.
 // Returns true if conversion succeeded, false otherwise.
@@ -2711,22 +2728,15 @@ bool ExecutionEngine::metaTypeFromJS(const Value &value, QMetaType metaType, voi
             metaType.construct(data, result.constData());
             return true;
         }
+
+        if (convertToIterable(metaType, data, sequence))
+            return true;
     }
 
     if (const QV4::ArrayObject *array = value.as<ArrayObject>()) {
-        QSequentialIterable iterable;
+        if (convertToIterable(metaType, data, array))
-        if (QMetaType::view(
-                    metaType, data, QMetaType::fromType<QSequentialIterable>(), &iterable)) {
-            const QMetaType elementMetaType = iterable.valueMetaType();
-            QVariant element(elementMetaType);
-            for (qsizetype i = 0, end = array->getLength(); i < end; ++i) {
-                if (!metaTypeFromJS(array->get(i), elementMetaType, element.data()))
-                    element = QVariant(elementMetaType);
-                iterable.addValue(element, QSequentialIterable::AtEnd);
-            }
             return true;
     }
-    }
 
     return false;
 }

tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt

@@ -15,6 +15,7 @@ set(cpp_sources
     multiforeign.h
     objectwithmethod.h
     person.cpp person.h
+    sequenceToIterable.h
     sequencetypeexample.cpp sequencetypeexample.h
     state.h
     theme.cpp theme.h
@@ -184,6 +185,7 @@ set(qml_files
     scopeVsObject.qml
     script.js
     script.mjs
+    sequenceToIterable.qml
     shadowedMethod.qml
     shared/Slider.qml
     shifts.qml

tests/auto/qml/qmlcppcodegen/data/sequenceToIterable.h

@@ -0,0 +1,56 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#ifndef SEQUENCETOITERABLE_H
+#define SEQUENCETOITERABLE_H
+
+#include <QtCore/qobject.h>
+#include <QtQml/qqml.h>
+
+class Entry : public QObject {
+    Q_OBJECT
+
+public:
+    explicit Entry(const QString &name, QObject *parent = nullptr)
+        : QObject(parent), m_name(name)
+    {
+        setObjectName(name);
+    }
+
+private:
+    QString m_name;
+};
+
+class EntryWrapper {
+    Q_GADGET
+    QML_FOREIGN(Entry)
+    QML_NAMED_ELEMENT(Entry)
+    QML_UNCREATABLE("These are my Entry objects")
+};
+
+class EntryListRegistration
+{
+    Q_GADGET
+    QML_FOREIGN(QList<Entry*>)
+    QML_ANONYMOUS
+    QML_SEQUENTIAL_CONTAINER(Entry*)
+};
+
+class EntrySource : public QObject {
+    Q_OBJECT
+    QML_ELEMENT
+    QML_SINGLETON
+
+public:
+    explicit EntrySource(QObject* parent = nullptr) : QObject(parent) {
+        for (int i = 0; i < 10; i++) {
+            m_entries.push_back(new Entry(QString("Item %1").arg(i), this));
+        }
+    }
+    Q_INVOKABLE QList<Entry*> getEntries() const { return m_entries; }
+
+private:
+    QList<Entry*> m_entries;
+};
+
+#endif // SEQUENCETOITERABLE_H

tests/auto/qml/qmlcppcodegen/data/sequenceToIterable.qml

@@ -0,0 +1,19 @@
+pragma Strict
+import QtQuick
+import TestTypes
+
+Item {
+    Component.onCompleted: () => {
+        repeater.model = EntrySource.getEntries()
+    }
+
+    Repeater {
+        id: repeater
+        Item {
+            required property int index
+            required property QtObject modelData
+        }
+    }
+
+    property int c: children.length
+}

tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp

@@ -154,6 +154,7 @@ private slots:
     void revisions();
     void scopeObjectDestruction();
     void scopeVsObject();
+    void sequenceToIterable();
     void shadowedMethod();
     void shifts();
     void signalHandler();
@@ -3255,6 +3256,16 @@ void tst_QmlCppCodegen::scopeVsObject()
     QCOMPARE(object->property("objectName").toString(), u"foobar"_s);
 }
 
+void tst_QmlCppCodegen::sequenceToIterable()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, QUrl(u"qrc:/qt/qml/TestTypes/sequenceToIterable.qml"_s));
+    QVERIFY2(!component.isError(), component.errorString().toUtf8());
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(!object.isNull());
+    QCOMPARE(object->property("c").toInt(), 11);
+}
+
 void tst_QmlCppCodegen::shadowedMethod()
 {
     QQmlEngine e;