7 files changed, 294 insertions, 171 deletions
diff --git a/sources/pyside6/libpyside/CMakeLists.txt b/sources/pyside6/libpyside/CMakeLists.txt
index 6aa4d7580..7640d1cce 100644
--- a/sources/pyside6/libpyside/CMakeLists.txt
+++ b/sources/pyside6/libpyside/CMakeLists.txt
@@ -29,6 +29,7 @@ set(libpyside_HEADERS # installed below
     pyside_p.h
     pysideglobals_p.h
     pysideproperty.h
+    pysidepropertybase_p.h
     pysideproperty_p.h
     pysideqapp.h
     pysideqenum.h
diff --git a/sources/pyside6/libpyside/dynamicqmetaobject.cpp b/sources/pyside6/libpyside/dynamicqmetaobject.cpp
index db8e0c5ae..46bc3ace9 100644
--- a/sources/pyside6/libpyside/dynamicqmetaobject.cpp
+++ b/sources/pyside6/libpyside/dynamicqmetaobject.cpp
@@ -275,7 +275,7 @@ void MetaObjectBuilder::removeMethod(QMetaMethod::MethodType mtype, int index)
 int MetaObjectBuilderPrivate::getPropertyNotifyId(PySideProperty *property) const
 {
     int notifyId = -1;
-    if (property->d->notify) {
+    if (property->d->notify()) {
         if (const char *signalNotify = PySide::Property::getNotifyName(property))
             notifyId = indexOfMethod(QMetaMethod::Signal, signalNotify);
     }
@@ -316,13 +316,14 @@ QMetaPropertyBuilder
             }
         }
     }
-    const auto metaType = QMetaType::fromName(property->d->typeName);
+    const QByteArray &typeName = property->d->typeName();
+    const auto metaType = QMetaType::fromName(typeName);
     if (!metaType.isValid()) {
         const auto &msg = msgInvalidPropertyType(m_builder->className(), propertyName,
-                                                 property->d->typeName);
+                                                 typeName);
          PyErr_WarnEx(PyExc_RuntimeWarning, msg.constData(), 0);
     }
-    return builder->addProperty(propertyName, property->d->typeName, metaType, propertyNotifyId);
+    return builder->addProperty(propertyName, typeName, metaType, propertyNotifyId);
 }
 
 int MetaObjectBuilderPrivate::addProperty(const QByteArray &propertyName,
@@ -336,7 +337,7 @@ int MetaObjectBuilderPrivate::addProperty(const QByteArray &propertyName,
     auto newProperty = createProperty(property, propertyName);
 
     // Adding property attributes
-    const auto &flags = property->d->flags;
+    const auto flags = property->d->flags();
     newProperty.setReadable(flags.testFlag(PySide::Property::PropertyFlag::Readable));
     newProperty.setWritable(flags.testFlag(PySide::Property::PropertyFlag::Writable));
     newProperty.setResettable(flags.testFlag(PySide::Property::PropertyFlag::Resettable));
diff --git a/sources/pyside6/libpyside/pysideproperty.cpp b/sources/pyside6/libpyside/pysideproperty.cpp
index 3d1968045..0207a7320 100644
--- a/sources/pyside6/libpyside/pysideproperty.cpp
+++ b/sources/pyside6/libpyside/pysideproperty.cpp
@@ -16,6 +16,8 @@
 #include <sbktypefactory.h>
 #include <signature.h>
 
+#include <utility>
+
 using namespace Shiboken;
 
 using namespace Qt::StringLiterals;
@@ -101,9 +103,40 @@ PyTypeObject *PySideProperty_TypeF(void)
     return type;
 }
 
+PySidePropertyBase::PySidePropertyBase(Type t) : m_type(t)
+{
+}
+
+PySidePropertyBase::PySidePropertyBase(const PySidePropertyBase &rhs) = default;
+
+void PySidePropertyBase::tp_clearBase()
+{
+    Py_CLEAR(m_notify);
+    Py_CLEAR(m_pyTypeObject);
+}
+
+int PySidePropertyBase::tp_traverseBase(visitproc visit, void *arg)
+{
+    Py_VISIT(m_notify);
+    Py_VISIT(m_pyTypeObject);
+    return 0;
+}
+
+void PySidePropertyBase::increfBase()
+{
+    Py_XINCREF(m_notify);
+    Py_XINCREF(m_pyTypeObject);
+}
+
+PySidePropertyBase *PySidePropertyBase::clone() const
+{
+    Q_UNIMPLEMENTED();
+    return nullptr;
+}
+
 // Helper to check a callable function passed to a property instance.
-bool PySidePropertyPrivate::assignCheckCallable(PyObject *source, const char *name,
-                                                PyObject **target)
+bool PySidePropertyBase::assignCheckCallable(PyObject *source, const char *name,
+                                             PyObject **target)
 {
     if (source != nullptr && source != Py_None) {
         if (PyCallable_Check(source) == 0) {
@@ -117,8 +150,32 @@ bool PySidePropertyPrivate::assignCheckCallable(PyObject *source, const char *na
     return true;
 }
 
-PySidePropertyPrivate::PySidePropertyPrivate() noexcept = default;
-PySidePropertyPrivate::~PySidePropertyPrivate() = default;
+void PySidePropertyPrivate::tp_clear()
+{
+    PySidePropertyBase::tp_clearBase();
+    Py_CLEAR(fget);
+    Py_CLEAR(fset);
+    Py_CLEAR(freset);
+    Py_CLEAR(fdel);
+}
+
+int PySidePropertyPrivate::tp_traverse(visitproc visit, void *arg)
+{
+    Py_VISIT(fget);
+    Py_VISIT(fset);
+    Py_VISIT(freset);
+    Py_VISIT(fdel);
+    return PySidePropertyBase::tp_traverseBase(visit, arg);
+}
+
+void PySidePropertyPrivate::incref()
+{
+    PySidePropertyBase::increfBase();
+    Py_XINCREF(fget);
+    Py_XINCREF(fset);
+    Py_XINCREF(freset);
+    Py_XINCREF(fdel);
+}
 
 PyObject *PySidePropertyPrivate::getValue(PyObject *source) const
 {
@@ -165,6 +222,13 @@ int PySidePropertyPrivate::reset(PyObject *source)
     return -1;
 }
 
+PySidePropertyPrivate *PySidePropertyPrivate::clone() const
+{
+    auto *result = new PySidePropertyPrivate(*this);
+    result->incref();
+    return result;
+}
+
 void PySidePropertyPrivate::metaCall(PyObject *source, QMetaObject::Call call, void **args)
 {
     switch (call) {
@@ -172,13 +236,13 @@ void PySidePropertyPrivate::metaCall(PyObject *source, QMetaObject::Call call, v
         AutoDecRef value(getValue(source));
         if (value.isNull())
             return;
-        if (typeName == "PyObject"_ba) {
+        if (typeName() == "PyObject"_ba) {
             // Manual conversion, see PyObjectWrapper converter registration
             auto *pw = reinterpret_cast<PySide::PyObjectWrapper *>(args[0]);
             pw->reset(value.object());
             return;
         }
-        if (Conversions::SpecificConverter converter(typeName); converter) {
+        if (Conversions::SpecificConverter converter(typeName()); converter) {
             converter.toCpp(value.object(), args[0]);
             return;
         }
@@ -188,7 +252,7 @@ void PySidePropertyPrivate::metaCall(PyObject *source, QMetaObject::Call call, v
         break;
 
     case QMetaObject::WriteProperty: {
-        Conversions::SpecificConverter converter(typeName);
+        Conversions::SpecificConverter converter(typeName());
         if (converter) {
             AutoDecRef value(converter.toPython(args[0]));
             setValue(source, value);
@@ -213,7 +277,7 @@ void PySidePropertyPrivate::metaCall(PyObject *source, QMetaObject::Call call, v
 static const char dataCapsuleName[] = "PropertyPrivate";
 static const char dataCapsuleKeyName[] = "_PropertyPrivate"; // key in keyword args
 
-static PySidePropertyPrivate *getDataFromKwArgs(PyObject *kwds)
+static PySidePropertyBase *getDataFromKwArgs(PyObject *kwds)
 {
     if (kwds != nullptr && PyDict_Check(kwds) != 0) {
         static PyObject *key = PyUnicode_InternFromString(dataCapsuleKeyName);
@@ -221,19 +285,27 @@ static PySidePropertyPrivate *getDataFromKwArgs(PyObject *kwds)
             Shiboken::AutoDecRef data(PyDict_GetItem(kwds, key));
             if (PyCapsule_CheckExact(data.object()) != 0) {
                 if (void *p = PyCapsule_GetPointer(data.object(), dataCapsuleName))
-                    return reinterpret_cast<PySidePropertyPrivate *>(p);
+                    return reinterpret_cast<PySidePropertyBase *>(p);
             }
         }
     }
     return nullptr;
 }
 
-static void addDataCapsuleToKwArgs(const AutoDecRef &kwds, PySidePropertyPrivate *data)
+static void addDataCapsuleToKwArgs(const AutoDecRef &kwds, PySidePropertyBase *data)
 {
     auto *capsule = PyCapsule_New(data, dataCapsuleName, nullptr);
     PyDict_SetItemString(kwds.object(), dataCapsuleKeyName, capsule);
 }
 
+static inline PySidePropertyPrivate *propertyPrivate(PyObject *self)
+{
+    auto *data = reinterpret_cast<PySideProperty *>(self);
+    Q_ASSERT(data->d != nullptr);
+    Q_ASSERT(data->d->type() == PySidePropertyBase::Type::Property);
+    return static_cast<PySidePropertyPrivate *>(data->d);
+}
+
 static PyObject *qpropertyTpNew(PyTypeObject *subtype, PyObject * /* args */, PyObject *kwds)
 {
     auto *me = PepExt_TypeCallAlloc<PySideProperty>(subtype, 0);
@@ -245,8 +317,10 @@ static PyObject *qpropertyTpNew(PyTypeObject *subtype, PyObject * /* args */, Py
 
 static int qpropertyTpInit(PyObject *self, PyObject *args, PyObject *kwds)
 {
-    auto *data = reinterpret_cast<PySideProperty *>(self);
-    PySidePropertyPrivate *pData = data->d;
+    auto *pData = propertyPrivate(self);
+
+    if (!pData->typeName().isEmpty()) // Cloned copy, already initialized
+        return 0;
 
     static const char *kwlist[] = {"type", "fget", "fset", "freset", "fdel", "doc", "notify",
                                    "designable", "scriptable", "stored",
@@ -274,27 +348,24 @@ static int qpropertyTpInit(PyObject *self, PyObject *args, PyObject *kwds)
         || !PySidePropertyPrivate::assignCheckCallable(fset, "fset", &pData->fset)
         || !PySidePropertyPrivate::assignCheckCallable(freset, "freset", &pData->freset)
         || !PySidePropertyPrivate::assignCheckCallable(fdel, "fdel", &pData->fdel)) {
-        pData->fget = pData->fset = pData->freset = pData->fdel = pData->notify = nullptr;
+        pData->fget = pData->fset = pData->freset = pData->fdel = nullptr;
+        pData->setNotify(nullptr);
         return -1;
     }
 
     if (notify != nullptr && notify != Py_None)
-        pData->notify = notify;
+        pData->setNotify(notify);
 
     // PYSIDE-1019: Fetching the default `__doc__` from fget would fail for inherited functions
     // because we don't initialize the mro with signatures (and we will not!).
     // But it is efficient and in-time to do that on demand in qPropertyDocGet.
     pData->getter_doc = false;
-    if (doc)
-        pData->doc = doc;
-    else
-        pData->doc.clear();
+    pData->setDoc(doc != nullptr ? QByteArray(doc) : QByteArray{});
 
-    pData->pyTypeObject = type;
-    Py_XINCREF(pData->pyTypeObject);
-    pData->typeName = PySide::Signal::getTypeName(type);
+    pData->setPyTypeObject(type);
+    pData->setTypeName(PySide::Signal::getTypeName(type));
 
-    auto &flags = pData->flags;
+    PySide::Property::PropertyFlags flags;
     flags.setFlag(PySide::Property::PropertyFlag::Readable, pData->fget != nullptr);
     flags.setFlag(PySide::Property::PropertyFlag::Writable, pData->fset != nullptr);
     flags.setFlag(PySide::Property::PropertyFlag::Resettable, pData->freset != nullptr);
@@ -304,24 +375,22 @@ static int qpropertyTpInit(PyObject *self, PyObject *args, PyObject *kwds)
     flags.setFlag(PySide::Property::PropertyFlag::User, user);
     flags.setFlag(PySide::Property::PropertyFlag::Constant, constant);
     flags.setFlag(PySide::Property::PropertyFlag::Final, finalProp);
+    pData->setFlags(flags);
 
-    if (type == Py_None || pData->typeName.isEmpty())
+    if (type == Py_None || pData->typeName().isEmpty())
         PyErr_SetString(PyExc_TypeError, "Invalid property type or type name.");
     else if (constant && pData->fset != nullptr)
         PyErr_SetString(PyExc_TypeError, "A constant property cannot have a WRITE method.");
-    else if (constant && pData->notify != nullptr)
+    else if (constant && pData->notify() != nullptr)
         PyErr_SetString(PyExc_TypeError, "A constant property cannot have a NOTIFY signal.");
 
     if (PyErr_Occurred() != nullptr) {
-        pData->fget = pData->fset = pData->freset = pData->fdel = pData->notify = nullptr;
+        pData->fget = pData->fset = pData->freset = pData->fdel = nullptr;
+        pData->setNotify(nullptr);
         return -1;
     }
 
-    Py_XINCREF(pData->fget);
-    Py_XINCREF(pData->fset);
-    Py_XINCREF(pData->freset);
-    Py_XINCREF(pData->fdel);
-    Py_XINCREF(pData->notify);
+    pData->incref();
     return 0;
 }
 
@@ -336,88 +405,80 @@ static void qpropertyDeAlloc(PyObject *self)
 }
 
 // Create a copy of the property to prevent the @property.setter from modifying
-// the property in place and avoid strange side effects in derived classes
-// (cf https://bugs.python.org/issue1620).
-static PyObject *
-_property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *reset, PyObject *del)
+// the property in place and avoid strange side effects when modifying the
+// property in derived classes (cf https://bugs.python.org/issue1620,
+// pysidetest/property_python_test.py).
+static PyObject *copyProperty(PyObject *old)
 {
-    auto *pold = reinterpret_cast<PySideProperty *>(old);
-    PySidePropertyPrivate *pData = pold->d;
-
     AutoDecRef type(PyObject_Type(old));
-    QByteArray doc{};
-    if (type.isNull())
-        return nullptr;
-
-    if (get == nullptr || get == Py_None) {
-        Py_XDECREF(get);
-        get = pData->fget ? pData->fget : Py_None;
-    }
-    if (set == nullptr || set == Py_None) {
-        Py_XDECREF(set);
-        set = pData->fset ? pData->fset : Py_None;
-    }
-    if (reset == nullptr || reset == Py_None) {
-        Py_XDECREF(reset);
-        reset = pData->freset ? pData->freset : Py_None;
-    }
-    if (del == nullptr || del == Py_None) {
-        Py_XDECREF(del);
-        del = pData->fdel ? pData->fdel : Py_None;
-    }
-    // make _init use __doc__ from getter
-    if ((pData->getter_doc && get != Py_None) || pData->doc.isEmpty())
-        doc.clear();
-    else
-        doc = pData->doc;
-
-    auto *notify = pData->notify ? pData->notify : Py_None;
-
-    const auto &flags = pData->flags;
-    PyObject *obNew =
-        PyObject_CallFunction(type, "OOOOOsO" "bbb" "bbb",
-                              pData->pyTypeObject, get, set, reset, del, doc.data(), notify,
-                              flags.testFlag(PySide::Property::PropertyFlag::Designable),
-                              flags.testFlag(PySide::Property::PropertyFlag::Scriptable),
-                              flags.testFlag(PySide::Property::PropertyFlag::Stored),
-                              flags.testFlag(PySide::Property::PropertyFlag::User),
-                              flags.testFlag(PySide::Property::PropertyFlag::Constant),
-                              flags.testFlag(PySide::Property::PropertyFlag::Final));
-
-    return obNew;
+    Shiboken::AutoDecRef kwds(PyDict_New());
+    addDataCapsuleToKwArgs(kwds, propertyPrivate(old)->clone());
+    Shiboken::AutoDecRef args(PyTuple_New(0));
+    return PyObject_Call(type.object(), args.object(), kwds.object());
 }
 
 static PyObject *qPropertyGetter(PyObject *self, PyObject *getter)
 {
-    return _property_copy(self, getter, nullptr, nullptr, nullptr);
+    PyObject *result = copyProperty(self);
+    if (result != nullptr) {
+        auto *data = propertyPrivate(result);
+        auto *old = std::exchange(data->fget, getter);
+        Py_XINCREF(data->fget);
+        Py_XDECREF(old);
+        data->setFlag(PySide::Property::PropertyFlag::Readable);
+    }
+    return result;
 }
 
 static PyObject *qPropertySetter(PyObject *self, PyObject *setter)
 {
-    return _property_copy(self, nullptr, setter, nullptr, nullptr);
+    PyObject *result = copyProperty(self);
+    if (result != nullptr) {
+        auto *data = propertyPrivate(result);
+        auto *old = std::exchange(data->fset, setter);
+        Py_XINCREF(data->fset);
+        Py_XDECREF(old);
+        data->setFlag(PySide::Property::PropertyFlag::Writable);
+    }
+    return result;
 }
 
 static PyObject *qPropertyResetter(PyObject *self, PyObject *resetter)
 {
-    return _property_copy(self, nullptr, nullptr, resetter, nullptr);
+    PyObject *result = copyProperty(self);
+    if (result != nullptr) {
+        auto *data = propertyPrivate(result);
+        auto *old = std::exchange(data->freset, resetter);
+        Py_XINCREF(data->freset);
+        Py_XDECREF(old);
+        data->setFlag(PySide::Property::PropertyFlag::Resettable);
+    }
+    return result;
 }
 
 static PyObject *qPropertyDeleter(PyObject *self, PyObject *deleter)
 {
-    return _property_copy(self, nullptr, nullptr, nullptr, deleter);
+    PyObject *result = copyProperty(self);
+    if (result != nullptr) {
+        auto *data = propertyPrivate(result);
+        auto *old = std::exchange(data->fdel, deleter);
+        Py_XINCREF(data->fdel);
+        Py_XDECREF(old);
+    }
+    return result;
 }
 
 static PyObject *qPropertyCall(PyObject *self, PyObject *args, PyObject * /* kw */)
 {
     PyObject *getter = PyTuple_GetItem(args, 0);
-    return _property_copy(self, getter, nullptr, nullptr, nullptr);
+    return qPropertyGetter(self, getter);
 }
 
 // PYSIDE-1019: Provide the same getters as Pythons `PyProperty`.
 
 static PyObject *qProperty_fget(PyObject *self, void *)
 {
-    auto *func = reinterpret_cast<PySideProperty *>(self)->d->fget;
+    auto *func = propertyPrivate(self)->fget;
     if (func == nullptr)
         Py_RETURN_NONE;
     Py_INCREF(func);
@@ -426,7 +487,7 @@ static PyObject *qProperty_fget(PyObject *self, void *)
 
 static PyObject *qProperty_fset(PyObject *self, void *)
 {
-    auto *func = reinterpret_cast<PySideProperty *>(self)->d->fset;
+    auto *func = propertyPrivate(self)->fset;
     if (func == nullptr)
         Py_RETURN_NONE;
     Py_INCREF(func);
@@ -435,7 +496,7 @@ static PyObject *qProperty_fset(PyObject *self, void *)
 
 static PyObject *qProperty_freset(PyObject *self, void *)
 {
-    auto *func = reinterpret_cast<PySideProperty *>(self)->d->freset;
+    auto *func = propertyPrivate(self)->freset;
     if (func == nullptr)
         Py_RETURN_NONE;
     Py_INCREF(func);
@@ -444,7 +505,7 @@ static PyObject *qProperty_freset(PyObject *self, void *)
 
 static PyObject *qProperty_fdel(PyObject *self, void *)
 {
-    auto *func = reinterpret_cast<PySideProperty *>(self)->d->fdel;
+    auto *func = propertyPrivate(self)->fdel;
     if (func == nullptr)
         Py_RETURN_NONE;
     Py_INCREF(func);
@@ -454,16 +515,15 @@ static PyObject *qProperty_fdel(PyObject *self, void *)
 static PyObject *qPropertyDocGet(PyObject *self, void *)
 {
     auto *data = reinterpret_cast<PySideProperty *>(self);
-    PySidePropertyPrivate *pData = data->d;
+    if (!data->d->doc().isEmpty() || data->d->type() != PySidePropertyBase::Type::Property)
+        return PyUnicode_FromString(data->d->doc());
 
-    QByteArray doc(pData->doc);
-    if (!doc.isEmpty())
-        return PyUnicode_FromString(doc);
+    auto *pData = static_cast<PySidePropertyPrivate *>(data->d);
     if (pData->fget != nullptr) {
         // PYSIDE-1019: Fetch the default `__doc__` from fget. We do it late.
         AutoDecRef get_doc(PyObject_GetAttr(pData->fget, PyMagicName::doc()));
         if (!get_doc.isNull() && get_doc.object() != Py_None) {
-            pData->doc = String::toCString(get_doc);
+            pData->setDoc(String::toCString(get_doc));
             pData->getter_doc = true;
             if (Py_TYPE(self) == PySideProperty_TypeF())
                 return qPropertyDocGet(self, nullptr);
@@ -486,10 +546,8 @@ static PyObject *qPropertyDocGet(PyObject *self, void *)
 static int qPropertyDocSet(PyObject *self, PyObject *value, void *)
 {
     auto *data = reinterpret_cast<PySideProperty *>(self);
-    PySidePropertyPrivate *pData = data->d;
-
     if (String::check(value)) {
-        pData->doc = String::toCString(value);
+        data->d->setDoc(String::toCString(value));
         return 0;
     }
     PyErr_SetString(PyExc_TypeError, "String argument expected.");
@@ -498,34 +556,20 @@ static int qPropertyDocSet(PyObject *self, PyObject *value, void *)
 
 static int qpropertyTraverse(PyObject *self, visitproc visit, void *arg)
 {
-    PySidePropertyPrivate *data = reinterpret_cast<PySideProperty *>(self)->d;
-    if (!data)
-        return 0;
-
-    Py_VISIT(data->fget);
-    Py_VISIT(data->fset);
-    Py_VISIT(data->freset);
-    Py_VISIT(data->fdel);
-    Py_VISIT(data->notify);
-    Py_VISIT(data->pyTypeObject);
-    return 0;
+    auto *pData = propertyPrivate(self);
+    return pData != nullptr ? pData->tp_traverse(visit, arg) : 0;
 }
 
 static int qpropertyClear(PyObject *self)
 {
-    PySidePropertyPrivate *data = reinterpret_cast<PySideProperty *>(self)->d;
-    if (!data)
+    auto *data = reinterpret_cast<PySideProperty *>(self);
+    if (data->d == nullptr)
         return 0;
 
-    Py_CLEAR(data->fget);
-    Py_CLEAR(data->fset);
-    Py_CLEAR(data->freset);
-    Py_CLEAR(data->fdel);
-    Py_CLEAR(data->notify);
-    Py_CLEAR(data->pyTypeObject);
-
-    delete data;
-    reinterpret_cast<PySideProperty *>(self)->d = nullptr;
+    auto *baseData = std::exchange(data->d, nullptr);
+    Q_ASSERT(baseData->type() == PySidePropertyBase::Type::Property);
+    static_cast<PySidePropertyPrivate *>(baseData)->tp_clear();
+    delete baseData;
     return 0;
 }
 
@@ -588,22 +632,22 @@ bool checkType(PyObject *pyObj)
 
 PyObject *getValue(PySideProperty *self, PyObject *source)
 {
-    return self->d->getValue(source);
+    return static_cast<PySidePropertyPrivate *>(self->d)->getValue(source);
 }
 
 int setValue(PySideProperty *self, PyObject *source, PyObject *value)
 {
-    return self->d->setValue(source, value);
+    return static_cast<PySidePropertyPrivate *>(self->d)->setValue(source, value);
 }
 
 int reset(PySideProperty *self, PyObject *source)
 {
-    return self->d->reset(source);
+    return static_cast<PySidePropertyPrivate *>(self->d)->reset(source);
 }
 
 const char *getTypeName(const PySideProperty *self)
 {
-    return self->d->typeName;
+    return self->d->typeName().constData();
 }
 
 PySideProperty *getObject(PyObject *source, PyObject *name)
@@ -624,28 +668,28 @@ PySideProperty *getObject(PyObject *source, PyObject *name)
 
 const char *getNotifyName(PySideProperty *self)
 {
-    if (self->d->notifySignature.isEmpty()) {
-        AutoDecRef str(PyObject_Str(self->d->notify));
-        self->d->notifySignature = Shiboken::String::toCString(str);
+    if (self->d->notifySignature().isEmpty()) {
+        AutoDecRef str(PyObject_Str(self->d->notify()));
+        self->d->setNotifySignature(Shiboken::String::toCString(str));
     }
 
-    return self->d->notifySignature.isEmpty()
-        ? nullptr : self->d->notifySignature.constData();
+    return self->d->notifySignature().isEmpty()
+        ? nullptr : self->d->notifySignature().constData();
 }
 
 void setTypeName(PySideProperty *self, const char *typeName)
 {
-    self->d->typeName = typeName;
+    self->d->setTypeName(typeName);
 }
 
 PyObject *getTypeObject(const PySideProperty *self)
 {
-    return self->d->pyTypeObject;
+    return self->d->pyTypeObject();
 }
 
 PyObject *create(const char *typeName, PyObject *getter,
                  PyObject *setter, PyObject *notifySignature,
-                 PySidePropertyPrivate *data)
+                 PySidePropertyBase *data)
 {
     Shiboken::AutoDecRef kwds(PyDict_New());
     PyDict_SetItemString(kwds.object(), "type", PyUnicode_FromString(typeName));
@@ -669,7 +713,7 @@ PyObject *create(const char *typeName, PyObject *getter,
 
 PyObject *create(const char *typeName, PyObject *getter,
                  PyObject *setter, const char *notifySignature,
-                 PySidePropertyPrivate *data)
+                 PySidePropertyBase *data)
 {
 
     PyObject *obNotifySignature = notifySignature != nullptr
diff --git a/sources/pyside6/libpyside/pysideproperty.h b/sources/pyside6/libpyside/pysideproperty.h
index 90c40e174..c2ce006a9 100644
--- a/sources/pyside6/libpyside/pysideproperty.h
+++ b/sources/pyside6/libpyside/pysideproperty.h
@@ -10,7 +10,7 @@
 
 #include <QtCore/qmetaobject.h>
 
-class PySidePropertyPrivate;
+class PySidePropertyBase;
 
 extern "C"
 {
@@ -19,7 +19,7 @@ extern "C"
     struct PYSIDE_API PySideProperty
     {
         PyObject_HEAD
-        PySidePropertyPrivate* d;
+        PySidePropertyBase* d;
     };
 };
 
@@ -71,12 +71,12 @@ PYSIDE_API void setTypeName(PySideProperty *self, const char *typeName);
 /// Create a property from type, getter, setter and notification signature.
 PYSIDE_API PyObject *create(const char *typeName, PyObject *getter,
                             PyObject *setter, PyObject *notifySignature,
-                            PySidePropertyPrivate *data = nullptr);
+                            PySidePropertyBase *data = nullptr);
 /// Create a property from type, getter, optional setter and notification signature.
 PYSIDE_API PyObject *create(const char *typeName, PyObject *getter,
                             PyObject *setter = nullptr,
                             const char *notifySignature = nullptr,
-                            PySidePropertyPrivate *data = nullptr);
+                            PySidePropertyBase *data = nullptr);
 
 } //namespace PySide::Property
 
diff --git a/sources/pyside6/libpyside/pysideproperty_p.h b/sources/pyside6/libpyside/pysideproperty_p.h
index bd223d0be..baf0df178 100644
--- a/sources/pyside6/libpyside/pysideproperty_p.h
+++ b/sources/pyside6/libpyside/pysideproperty_p.h
@@ -7,6 +7,7 @@
 #include <sbkpython.h>
 
 #include "pysideproperty.h"
+#include "pysidepropertybase_p.h"
 #include <pysidemacros.h>
 
 #include <QtCore/qbytearray.h>
@@ -16,53 +17,34 @@
 
 struct PySideProperty;
 
-namespace PySide::Property {
-
-enum class PropertyFlag {
-    Readable    = 0x001,
-    Writable    = 0x002,
-    Resettable  = 0x004,
-    Designable  = 0x008,
-    Scriptable  = 0x010,
-    Stored      = 0x020,
-    User        = 0x040,
-    Constant    = 0x080,
-    Final       = 0x100
-};
-Q_DECLARE_FLAGS(PropertyFlags, PropertyFlag)
-
-} // namespace PySide::Property
-
-class PYSIDE_API PySidePropertyPrivate
+class PYSIDE_API PySidePropertyPrivate : public PySidePropertyBase
 {
 public:
+    PySidePropertyPrivate(const PySidePropertyPrivate &) = default;
+    PySidePropertyPrivate &operator=(const PySidePropertyPrivate &) = delete;
+    PySidePropertyPrivate(PySidePropertyPrivate &&) = delete;
+    PySidePropertyPrivate &operator=(PySidePropertyPrivate &&) = delete;
 
-    Q_DISABLE_COPY_MOVE(PySidePropertyPrivate)
+    PySidePropertyPrivate() : PySidePropertyBase(Type::Property) {}
+    ~PySidePropertyPrivate() override = default;
 
-    PySidePropertyPrivate() noexcept;
-    virtual ~PySidePropertyPrivate();
+    [[nodiscard]] PySidePropertyPrivate *clone() const override;
 
-    virtual void metaCall(PyObject *source, QMetaObject::Call call, void **args);
+    void metaCall(PyObject *source, QMetaObject::Call call, void **args) override;
+
+    void tp_clear();
+    int tp_traverse(visitproc visit, void *arg);
+    void incref();
 
     PyObject *getValue(PyObject *source) const;
     int setValue(PyObject *source, PyObject *value);
     int reset(PyObject *source);
 
-    static bool assignCheckCallable(PyObject *source, const char *name, PyObject **target);
-
-    QByteArray typeName;
-    // Type object: A real PyTypeObject ("@Property(int)") or a string
-    // "@Property('QVariant')".
-    PyObject *pyTypeObject = nullptr;
     PyObject *fget = nullptr;
     PyObject *fset = nullptr;
     PyObject *freset = nullptr;
     PyObject *fdel = nullptr;
-    PyObject *notify = nullptr;
     bool getter_doc = false;
-    QByteArray notifySignature;
-    QByteArray doc;
-    PySide::Property::PropertyFlags flags;
 };
 
 namespace PySide::Property {
diff --git a/sources/pyside6/libpyside/pysidepropertybase_p.h b/sources/pyside6/libpyside/pysidepropertybase_p.h
new file mode 100644
index 000000000..c8ef778ca
--- /dev/null
+++ b/sources/pyside6/libpyside/pysidepropertybase_p.h
@@ -0,0 +1,95 @@
+// Copyright (C) 2025 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef PYSIDE_PROPERTYBASE_P_H
+#define PYSIDE_PROPERTYBASE_P_H
+
+#include <sbkpython.h>
+
+#include <pysidemacros.h>
+
+#include <QtCore/qbytearray.h>
+#include <QtCore/qtclasshelpermacros.h>
+#include <QtCore/qflags.h>
+#include <QtCore/qmetaobject.h>
+
+struct PySideProperty;
+
+namespace PySide::Property {
+
+enum class PropertyFlag {
+    Readable    = 0x001,
+    Writable    = 0x002,
+    Resettable  = 0x004,
+    Designable  = 0x008,
+    Scriptable  = 0x010,
+    Stored      = 0x020,
+    User        = 0x040,
+    Constant    = 0x080,
+    Final       = 0x100
+};
+Q_DECLARE_FLAGS(PropertyFlags, PropertyFlag)
+
+} // namespace PySide::Property
+
+// Base class for meta-callable properties (Normal properties, QmlListProperty)
+class PYSIDE_API PySidePropertyBase
+{
+public:
+    PySidePropertyBase &operator=(const PySidePropertyBase &) = delete;
+    PySidePropertyBase(PySidePropertyBase &&) = delete;
+    PySidePropertyBase &operator=(PySidePropertyBase &&) = delete;
+
+    enum class Type : unsigned char { Property, ListProperty };
+
+    virtual ~PySidePropertyBase() = default;
+
+    // For handling decorator like "@property.getter"
+    [[nodiscard]] virtual PySidePropertyBase *clone() const;
+
+    virtual void metaCall(PyObject *source, QMetaObject::Call call, void **args) = 0;
+
+    [[nodiscard]] Type type() const { return m_type; }
+
+    [[nodiscard]] const QByteArray &typeName() const { return m_typeName; }
+    void setTypeName(const QByteArray &newTypeName) { m_typeName = newTypeName; }
+
+    [[nodiscard]] PyObject *pyTypeObject() const { return m_pyTypeObject; }
+    void setPyTypeObject(PyObject *pt)  { m_pyTypeObject = pt; }
+
+    [[nodiscard]] PyObject *notify() const { return m_notify; }
+    void setNotify(PyObject *n) { m_notify = n; }
+
+    [[nodiscard]] const QByteArray &notifySignature() const { return m_notifySignature; }
+    void setNotifySignature(const QByteArray &s) { m_notifySignature = s; }
+
+    [[nodiscard]] const QByteArray &doc() const { return m_doc; }
+    void setDoc(const QByteArray &doc) { m_doc = doc; }
+
+    [[nodiscard]] PySide::Property::PropertyFlags flags() const { return m_flags; }
+    void setFlags(PySide::Property::PropertyFlags f) { m_flags = f; }
+    void setFlag(PySide::Property::PropertyFlag f) { m_flags.setFlag(f); }
+
+    static bool assignCheckCallable(PyObject *source, const char *name, PyObject **target);
+
+protected:
+    explicit PySidePropertyBase(Type t);
+    PySidePropertyBase(const PySidePropertyBase &rhs);
+
+    void tp_clearBase();
+    int tp_traverseBase(visitproc visit, void *arg);
+    void increfBase();
+
+private:
+    QByteArray m_typeName;
+    // Type object: A real PyTypeObject ("@Property(int)") or a string
+    // "@Property('QVariant')".
+    PyObject *m_pyTypeObject = nullptr;
+    PyObject *m_notify = nullptr;
+    QByteArray m_notifySignature;
+    QByteArray m_doc;
+    PySide::Property::PropertyFlags m_flags;
+    Type m_type;
+};
+
+#endif // PYSIDE_PROPERTYBASE_P_H
diff --git a/sources/pyside6/libpyside/signalmanager.cpp b/sources/pyside6/libpyside/signalmanager.cpp
index 211588eea..01b08e283 100644
--- a/sources/pyside6/libpyside/signalmanager.cpp
+++ b/sources/pyside6/libpyside/signalmanager.cpp
@@ -404,7 +404,7 @@ int SignalManagerPrivate::qtPropertyMetacall(QObject *object,
             PyErr_WarnFormat(PyExc_RuntimeWarning, 0,
                 ign ? "Unknown property type '%s' of QObject '%s' used in fset"
                     : "Unknown property type '%s' of QObject '%s' used in fget with %R",
-                pp->d->typeName.constData(), metaObject->className(), errorStash.getException());
+                pp->d->typeName().constData(), metaObject->className(), errorStash.getException());
             if (PyErr_Occurred())
                 Shiboken::Errors::storeErrorOrPrint();
             errorStash.release();