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  1. Qt
  2. QTBUG-106093

No specific warning when trying to expose a C++ type to QML which has no default constructor

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    Description

      I had a type which I had copied from elsewhere and had forgotten to remove its constructor:

          class ComponentCreator : public QObject
    {
        Q_OBJECT
        QML_ELEMENT
        QML_SINGLETON
        Q_MOC_INCLUDE(<QtQml/qqmlcomponent.h>)

    public:
        ComponentCreator(QQmlEngine *engine);

        Q_INVOKABLE QQmlComponent *createComponent(const QByteArray &data);
    };

      Attemping to use this in QML resulted in a vague warning:

      QWARN  : tst_controls::Basic::StackView::test_componentCreatedFromCpp() file:///home/mitch/dev/qt-dev/qtdeclarative/tests/auto/quickcontrols2/controls/data/tst_stackview.qml:1555: TypeError: Cannot call method 'createComponent' of undefined

      It would be easier for users to understand what was going wrong if there was a specific error message. For example:

      "ComponentCreator cannot be exposed to QML because it has no default constructor."

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          duplicates

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-104899 QML(_NAMED)_ELEMENT should generate a clear error if the type in not default constructible

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-87834 Provide a more detailed error message when a C++ type that's exposed to QML cannot be created

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
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              qtqmlteam Qt Qml Team User
              mitch_curtis Mitch Curtis
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                Created:
                Updated:
                Resolved:

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