4 files changed, 75 insertions, 8 deletions
diff --git a/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.cpp b/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.cpp
index d2b9b689e..873ec53ce 100644
--- a/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.cpp
+++ b/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.cpp
@@ -180,15 +180,10 @@ int PySide::qmlRegisterSingletonType(PyObject *pyObj, const char *uri, int versi
     const QMetaObject *metaObject = nullptr;
 
     if (isQObject) {
-        static PyTypeObject *qobjectType = Conversions::getPythonTypeObject("QObject*");
-        assert(qobjectType);
-
         PyTypeObject *pyObjType = reinterpret_cast<PyTypeObject *>(pyObj);
-        if (!PySequence_Contains(pyObjType->tp_mro, reinterpret_cast<PyObject *>(qobjectType))) {
-            PyErr_Format(PyExc_TypeError, "A type inherited from %s expected, got %s.",
-                         qobjectType->tp_name, pyObjType->tp_name);
+
+        if (!isQObjectDerived(pyObjType, true))
             return -1;
-        }
 
         // If we don't have a callback we'll need the pyObj to stay allocated indefinitely
         if (!hasCallback)
@@ -273,6 +268,55 @@ int PySide::qmlRegisterSingletonType(PyObject *pyObj, const char *uri, int versi
     return QQmlPrivate::qmlregister(QQmlPrivate::SingletonRegistration, &type);
 }
 
+int PySide::qmlRegisterSingletonInstance(PyObject *pyObj, const char *uri, int versionMajor,
+                                         int versionMinor, const char *qmlName,
+                                         PyObject *instanceObject)
+{
+    using namespace Shiboken;
+
+    static PyTypeObject *qobjectType = Conversions::getPythonTypeObject("QObject*");
+    assert(qobjectType);
+
+    // Check if the Python Type inherit from QObject
+    PyTypeObject *pyObjType = reinterpret_cast<PyTypeObject *>(pyObj);
+
+    if (!isQObjectDerived(pyObjType, true))
+        return -1;
+
+    // Check if the instance object derives from QObject
+    PyTypeObject *typeInstanceObject = instanceObject->ob_type;
+
+    if (!isQObjectDerived(typeInstanceObject, true))
+        return -1;
+
+    // Convert the instanceObject (PyObject) into a QObject
+    QObject *instanceQObject = reinterpret_cast<QObject*>(
+            Object::cppPointer(reinterpret_cast<SbkObject*>(instanceObject), qobjectType));
+
+    // Create Singleton Functor to pass the QObject to the Type registration step
+    // similarly to the case when we have a callback
+    QQmlPrivate::SingletonFunctor registrationFunctor;
+    registrationFunctor.m_object = instanceQObject;
+
+    const QMetaObject *metaObject = PySide::retrieveMetaObject(pyObjType);
+    Q_ASSERT(metaObject);
+
+    QQmlPrivate::RegisterSingletonType type;
+    type.structVersion = 0;
+
+    type.uri = uri;
+    type.version = QTypeRevision::fromVersion(versionMajor, versionMinor);
+    type.typeName = qmlName;
+    type.instanceMetaObject = metaObject;
+
+    // FIXME: Fix this to assign new type ids each time.
+    type.typeId = QMetaType(QMetaType::QObjectStar);
+    type.qObjectApi = registrationFunctor;
+
+
+    return QQmlPrivate::qmlregister(QQmlPrivate::SingletonRegistration, &type);
+}
+
 extern "C"
 {
 
diff --git a/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.h b/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.h
index 9cc7379e9..2a90a07e0 100644
--- a/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.h
+++ b/sources/pyside6/PySide6/QtQml/pysideqmlregistertype.h
@@ -71,7 +71,7 @@ int qmlRegisterType(PyObject *pyObj, const char *uri, int versionMajor, int vers
                     const char *qmlName, const char *noCreationReason = nullptr, bool creatable = true);
 
 /**
- * PySide implementation of qmlRegisterType<T> function.
+ * PySide implementation of qmlRegisterSingletonType<T> function.
  *
  * \param pyObj Python type to be registered.
  * \param uri QML element uri.
@@ -84,6 +84,20 @@ int qmlRegisterType(PyObject *pyObj, const char *uri, int versionMajor, int vers
 int qmlRegisterSingletonType(PyObject *pyObj,const char *uri, int versionMajor, int versionMinor, const char *qmlName,
                              PyObject *callback, bool isQObject, bool hasCallback);
 
+/**
+ * PySide implementation of qmlRegisterSingletonInstance<T> function.
+ *
+ * \param pyObj Python type to be registered.
+ * \param uri QML element uri.
+ * \param versionMajor QML component major version.
+ * \param versionMinor QML component minor version.
+ * \param qmlName QML element name
+ * \param instanceObject singleton object to be registered.
+ * \return the metatype id of the registered type.
+ */
+int qmlRegisterSingletonInstance(PyObject *pyObj, const char *uri, int versionMajor,
+                                 int versionMinor, const char *qmlName, PyObject *instanceObject);
+
 
 /**
  * PySide implementation of the QML_ELEMENT macro
diff --git a/sources/pyside6/PySide6/QtQml/typesystem_qml.xml b/sources/pyside6/PySide6/QtQml/typesystem_qml.xml
index 1b855a073..ad883f09d 100644
--- a/sources/pyside6/PySide6/QtQml/typesystem_qml.xml
+++ b/sources/pyside6/PySide6/QtQml/typesystem_qml.xml
@@ -92,6 +92,10 @@
       <inject-code class="target" file="../glue/qtqml.cpp" snippet="qmlregistersingletontype_qjsvalue"/>
     </add-function>
 
+    <add-function signature="qmlRegisterSingletonInstance(PyTypeObject,const char*,int,int,const char*,PyObject*)" return-type="int">
+      <inject-code class="target" file="../glue/qtqml.cpp" snippet="qmlregistersingletoninstance"/>
+    </add-function>
+
     <add-function signature="qmlRegisterUncreatableType(PyTypeObject,const char*,int,int,const char*,const char*)" return-type="int">
         <inject-code class="target" file="../glue/qtqml.cpp" snippet="qmlregisteruncreatabletype"/>
     </add-function>
diff --git a/sources/pyside6/PySide6/glue/qtqml.cpp b/sources/pyside6/PySide6/glue/qtqml.cpp
index eab6eab95..99a1c441a 100644
--- a/sources/pyside6/PySide6/glue/qtqml.cpp
+++ b/sources/pyside6/PySide6/glue/qtqml.cpp
@@ -57,6 +57,11 @@ int %0 = PySide::qmlRegisterSingletonType(nullptr, %ARGUMENT_NAMES, false, true)
 %PYARG_0 = %CONVERTTOPYTHON[int](%0);
 // @snippet qmlregistersingletontype_qjsvalue
 
+// @snippet qmlregistersingletoninstance
+int %0 = PySide::qmlRegisterSingletonInstance(%ARGUMENT_NAMES);
+%PYARG_0 = %CONVERTTOPYTHON[int](%0);
+// @snippet qmlregistersingletoninstance
+
 // @snippet qmlregisteruncreatabletype
 int %0 = PySide::qmlRegisterType(%ARGUMENT_NAMES, false);
 %PYARG_0 = %CONVERTTOPYTHON[int](%0);