Assert in QPluginLoader

/*!
    Returns a the meta data for the plugin as a QJsonObject.

    \sa Q_PLUGIN_METADATA()
*/
QJsonObject QStaticPlugin::metaData() const
{
    auto ptr = static_cast<const char *>(rawMetaData);

    QString errMsg;
    QJsonDocument doc = qJsonFromRawLibraryMetaData(ptr, rawMetaDataSize, &errMsg);
    Q_ASSERT(doc.isObject()); // <--- this line
    Q_ASSERT(errMsg.isEmpty()); // <--- the error is not empty either
    return doc.object();
}