QQmlListModel: emit dataChange signal when updating the translations

We can't really track the individual bindings. Updating all string
fields is a blunt thing to do, but it always works and it's not worse
than what we did before the translation binding optimization.

Pick-to: 6.2 6.4
Fixes: QTBUG-107208
Change-Id: I96b86c979b3168f052af4685874741f674e3337f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/qmlmodels/qqmllistmodel.cpp

@@ -2505,6 +2505,16 @@ void QQmlListModel::updateTranslations()
     if (m_dynamicRoles)
         return;
     Q_ASSERT(m_listModel);
+
+    QList<int> roles;
+    for (int i = 0, end = m_listModel->roleCount(); i != end; ++i) {
+        if (m_listModel->getExistingRole(i).type == ListLayout::Role::String)
+            roles.append(i);
+    }
+
+    if (!roles.isEmpty())
+        emitItemsChanged(0, rowCount(QModelIndex()), roles);
+
     m_listModel->updateTranslations();
 }
 

tests/auto/qml/qqmltranslation/CMakeLists.txt

@@ -21,6 +21,7 @@ qt_internal_add_test(tst_qqmltranslation
         Qt::Gui
         Qt::GuiPrivate
         Qt::QmlPrivate
+        Qt::QmlModelsPrivate
         Qt::Quick
         Qt::QuickTestUtilsPrivate
     TESTDATA ${test_data}

tests/auto/qml/qqmltranslation/data/translatedElements.qml

@@ -0,0 +1,15 @@
+import QtQml
+import QtQml.Models
+
+DelegateModel {
+    model: ListModel {
+        ListElement { dish: qsTr("soup"); price: 60 }
+        ListElement { dish: qsTr("fish"); price: 100 }
+        ListElement { dish: qsTr("meat"); price: 230 }
+        ListElement { dish: qsTr("bread"); price: 10 }
+    }
+
+    delegate: QtObject {
+        required property string dish
+    }
+}

tests/auto/qml/qqmltranslation/tst_qqmltranslation.cpp

@@ -9,6 +9,7 @@
 #include <QQuickItem>
 #include <private/qqmlengine_p.h>
 #include <private/qqmltypedata_p.h>
+#include <private/qqmldelegatemodel_p.h>
 #include <QtQuickTestUtils/private/qmlutils_p.h>
 
 class tst_qqmltranslation : public QQmlDataTest
@@ -23,6 +24,7 @@ private slots:
     void idTranslation();
     void translationChange();
     void preferJSContext();
+    void listModel();
 };
 
 void tst_qqmltranslation::translation_data()
@@ -170,6 +172,14 @@ class DummyTranslator : public QTranslator
             return QString::fromUtf8("Deutsch in mylibrary");
         if (!qstrcmp(sourceText, "English in translation") && !qstrcmp(context, "nested_js_translation"))
             return QString::fromUtf8("Deutsch in Setzung");
+        if (!qstrcmp(sourceText, "soup"))
+            return QString::fromUtf8("Suppe");
+        if (!qstrcmp(sourceText, "fish"))
+            return QString::fromUtf8("Fisch");
+        if (!qstrcmp(sourceText, "meat"))
+            return QString::fromUtf8("Fleisch");
+        if (!qstrcmp(sourceText, "bread"))
+            return QString::fromUtf8("Brot");
         return QString();
     }
 
@@ -231,6 +241,35 @@ void tst_qqmltranslation::preferJSContext()
     QCoreApplication::removeTranslator(&translator);
 }
 
+void tst_qqmltranslation::listModel()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("translatedElements.qml"));
+    QVERIFY2(component.isReady(), qPrintable(component.errorString()));
+    QScopedPointer<QObject> o(component.create());
+    QVERIFY(o);
+
+    QQmlDelegateModel *model = qobject_cast<QQmlDelegateModel *>(o.data());
+    QVERIFY(model);
+
+    QCOMPARE(model->count(), 4);
+
+    QCOMPARE(model->object(0)->property("dish").toString(), QStringLiteral("soup"));
+    QCOMPARE(model->object(1)->property("dish").toString(), QStringLiteral("fish"));
+    QCOMPARE(model->object(2)->property("dish").toString(), QStringLiteral("meat"));
+    QCOMPARE(model->object(3)->property("dish").toString(), QStringLiteral("bread"));
+
+    DummyTranslator translator;
+    QCoreApplication::installTranslator(&translator);
+    engine.setUiLanguage(QStringLiteral("xxx"));
+    engine.retranslate();
+
+    QCOMPARE(model->object(0)->property("dish").toString(), QStringLiteral("Suppe"));
+    QCOMPARE(model->object(1)->property("dish").toString(), QStringLiteral("Fisch"));
+    QCOMPARE(model->object(2)->property("dish").toString(), QStringLiteral("Fleisch"));
+    QCOMPARE(model->object(3)->property("dish").toString(), QStringLiteral("Brot"));
+}
+
 QTEST_MAIN(tst_qqmltranslation)
 
 #include "tst_qqmltranslation.moc"