Add support for dynamic properties for QObjects in JavaScript

In QtScript you could add properties to a JS object that wraps a QObject.
Depending on the wrap option the property was either stored on the JavaScript
side or as dynamic QObject property.

In QJSEngine/QJSValue, neither was supported - properties could not be added.
For QObjects wrapped in JavaScript that weren't created by QML, we can restore
the behavior of storing dynamically added properties as JavaScript properties.

This makes porting from QtScript to QJS* much easier.

Task-number: QTBUG-37408
Change-Id: I5ef1f379c08c3d84de9bdcac9b6a9397238064de
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index f611be2965..de556dc9ed 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -682,9 +682,16 @@ void QObjectWrapper::put(Managed *m, const StringRef name, const ValueRef value)
 
     QQmlContextData *qmlContext = QV4::QmlContextWrapper::callingContext(v4);
     if (!setQmlProperty(v4->currentContext(), qmlContext, that->m_object, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, value)) {
-        QString error = QLatin1String("Cannot assign to non-existent property \"") +
-                        name->toQString() + QLatin1Char('\"');
-        v4->currentContext()->throwError(error);
+        QQmlData *ddata = QQmlData::get(that->m_object);
+        // Types created by QML are not extensible at run-time, but for other QObjects we can store them
+        // as regular JavaScript properties, like on JavaScript objects.
+        if (ddata && ddata->compiledData) {
+            QString error = QLatin1String("Cannot assign to non-existent property \"") +
+                            name->toQString() + QLatin1Char('\"');
+            v4->currentContext()->throwError(error);
+        } else {
+            QV4::Object::put(m, name, value);
+        }
     }
 }