QMetaProperty::write behavior changed with Qt 5.6

[prophecy]

I've written an ORM for Qt. With Qt5.6 I've run into a very special problem. The behavior of QMetaProperty::write has changed. It did work for me from Qt5 to Qt5.5, with 5.6 it is no longer working as intended.

// working with Qt < 5.6, failing with Qt 5.6
 void EntityHelper::setListProperty(const QSharedPointer<Entity> &entity,
                                QList<QSharedPointer<Entity>> &list,
                                const QMetaProperty &property)  {
 QVariant var;
 var.setValue<QList<QSharedPointer<Entity>>>(list);
 property.write(entity.data(), var); //returns false and property attribute is not being changed - but it should be...
 }

Since Qt 5.6 this doesn't work anymore for QList<QSharedPointer<Entity>>.
The problem seems to be related to such a list, as the following code (for single properties) still works:

// single Entities are still being written - even with Qt 5.6
void EntityHelper::setProperty(const QSharedPointer<Entity> &entity,
                           QSharedPointer<Entity> value,
                           const QMetaProperty &property) {
if (value && value->getProperty(value->getPrimaryKey()).toLongLong()
        > -1) {
    QVariant var;
    var.setValue<QSharedPointer<Entity>>(value);
    property.write(entity.data(), var); //returns true, property is being changed
}
}

A few explanations for a general understanding of where the code belongs to and what it should do:
Every entity class inherits from my main "Entity" class. Entity inherits from QObject and uses the Q_OBJECT macro.
Each Entity Object is wrapped by a QSharedPointer (to be on the safe side, memory-wise).
Properties in the child classes are defined with the Q_PROPERTY macro.
For example:

// defining a property:
Q_PROPERTY(QSharedPointer<Person> mainTeacher READ getMainTeacher WRITE
           setMainTeacher)
// defining a list property:
Q_PROPERTY(QList<QSharedPointer<Person>> persons READ
           getPersons WRITE setPersons)

(You can find the code here: https://github.com/Professi/cuteentitymanager/blob/master/src/entityhelper.cpp)

I've seen that some changes have been made to QMetaProperty::write since Qt5.5 https://github.com/qtproject/qtbase/blob/5.6/src/corelib/kernel/qmetaobject.cpp (Line 3038 ff.)

I can't find a way to fix this problem. Is it a bug or a feature? Does anybody have an idea for a workaround?

[A Former User]

Hi, and welcome to the Qt forum!

Looks like a bug to me. I think you should talk to the developers on the interest mailing list.

Cheers!