BGE Python API

This changes how the BGE classes and Python work together, which hasnt changed since blender went opensource.
The main difference is PyObjectPlus - the base class for most game engine classes, no longer inherit from PyObject, and cannot be cast to a PyObject.

This has the advantage that the BGE does not have to keep 2 reference counts valid for C++ and Python.

Previously C++ classes would never be freed while python held a reference, however this reference could be problematic eg: a GameObject that isnt in a scene anymore should not be used by python, doing so could even crash blender in some cases.

Instead PyObjectPlus has a member "PyObject *m_proxy" which is lazily initialized when python needs it. m_proxy reference counts are managed by python, though it should never be freed while the C++ class exists since it holds a reference to avoid making and freeing it all the time.
When the C++ class is free'd it sets the m_proxy reference to NULL, If python accesses this variable it will raise a RuntimeError, (check the isValid attribute to see if its valid without raising an error).
- This replaces the m_zombie bool and IsZombie() tests added recently.

In python return values that used to be..
 return value->AddRef();
Are now
 return value->GetProxy();
or...
 return value->NewProxy(true); // true means python owns this C++ value which will be deleted when the PyObject is freed

7 files changed, 186 insertions, 120 deletions

diff --git a/source/gameengine/Expressions/InputParser.cpp b/source/gameengine/Expressions/InputParser.cpp
index 1698f1919d1..66075dd8d42 100644
--- a/source/gameengine/Expressions/InputParser.cpp
+++ b/source/gameengine/Expressions/InputParser.cpp
@@ -649,7 +649,7 @@ PyObject*	CParserPyMake(PyObject* ignored,PyObject* args)
 	CExpression* expr = parser.ProcessText(txt);
 	CValue* val = expr->Calculate();
 	expr->Release();
-	return val;
+	return val->GetProxy();
 }
 
 static PyMethodDef	CParserMethods[] = 
diff --git a/source/gameengine/Expressions/ListValue.cpp b/source/gameengine/Expressions/ListValue.cpp
index 37feba38f8b..eaed2b5c400 100644
--- a/source/gameengine/Expressions/ListValue.cpp
+++ b/source/gameengine/Expressions/ListValue.cpp
@@ -27,45 +27,61 @@
 #define Py_ssize_t int
 #endif
 
-Py_ssize_t listvalue_bufferlen(PyObject* list)
+Py_ssize_t listvalue_bufferlen(PyObject* self)
 {
-	return (Py_ssize_t)( ((CListValue*)list)->GetCount());
+	CListValue *list= static_cast<CListValue *>(BGE_PROXY_REF(self));
+	if (list==NULL)
+		return 0;
+	
+	return (Py_ssize_t)list->GetCount();
 }
 
-PyObject* listvalue_buffer_item(PyObject* list,Py_ssize_t index)
+PyObject* listvalue_buffer_item(PyObject* self, Py_ssize_t index)
 {
-	int count = ((CListValue*) list)->GetCount();
+	CListValue *list= static_cast<CListValue *>(BGE_PROXY_REF(self));
+	if (list==NULL) {
+		PyErr_SetString(PyExc_IndexError, BGE_PROXY_ERROR_MSG);
+		return NULL;
+	}
+	
+	int count = list->GetCount();
 	
 	if (index < 0)
 		index = count+index;
 	
 	if (index >= 0 && index < count)
 	{
-		PyObject* pyobj = ((CListValue*) list)->GetValue(index)->ConvertValueToPython();
+		PyObject* pyobj = list->GetValue(index)->ConvertValueToPython();
 		if (pyobj)
 			return pyobj;
 		else
-			return ((CListValue*) list)->GetValue(index)->AddRef();
+			return list->GetValue(index)->GetProxy();
 
 	}
 	PyErr_SetString(PyExc_IndexError, "Python ListIndex out of range");
 	return NULL;
 }
 
-PyObject* listvalue_mapping_subscript(PyObject* list,PyObject* pyindex)
+PyObject* listvalue_mapping_subscript(PyObject* self, PyObject* pyindex)
 {
+	CListValue *list= static_cast<CListValue *>(BGE_PROXY_REF(self));
+	if (list==NULL) {
+		PyErr_SetString(PyExc_IndexError, BGE_PROXY_ERROR_MSG);
+		return NULL;
+	}
+	
 	if (PyString_Check(pyindex))
 	{
 		STR_String  index(PyString_AsString(pyindex));
 		CValue *item = ((CListValue*) list)->FindValue(index);
 		if (item)
-			return (PyObject*) item;
+			return item->GetProxy();
 			
 	}
 	if (PyInt_Check(pyindex))
 	{
 		int index = PyInt_AsLong(pyindex);
-		return listvalue_buffer_item(list, index);
+		return listvalue_buffer_item(self, index);
 	}
 	
 	PyObject *pyindex_str = PyObject_Repr(pyindex); /* new ref */
@@ -76,10 +92,16 @@ PyObject* listvalue_mapping_subscript(PyObject* list,PyObject* pyindex)
 
 
 /* just slice it into a python list... */
-PyObject* listvalue_buffer_slice(PyObject* list,Py_ssize_t ilow, Py_ssize_t ihigh)
+PyObject* listvalue_buffer_slice(PyObject* self,Py_ssize_t ilow, Py_ssize_t ihigh)
 {
+	CListValue *list= static_cast<CListValue *>(BGE_PROXY_REF(self));
+	if (list==NULL) {
+		PyErr_SetString(PyExc_IndexError, BGE_PROXY_ERROR_MSG);
+		return NULL;
+	}
+	
 	int i, j;
-	PyListObject *newlist;
+	PyObject *newlist;
 
 	if (ilow < 0) ilow = 0;
 
@@ -90,18 +112,18 @@ PyObject* listvalue_buffer_slice(PyObject* list,Py_ssize_t ilow, Py_ssize_t ihig
     if (ihigh < ilow)
         ihigh = ilow;
 
-	newlist = (PyListObject *) PyList_New(ihigh - ilow);
+	newlist = PyList_New(ihigh - ilow);
 	if (!newlist)
 		return NULL;
 
 	for (i = ilow, j = 0; i < ihigh; i++, j++)
 	{
-		PyObject* pyobj = ((CListValue*) list)->GetValue(i)->ConvertValueToPython();
+		PyObject* pyobj = list->GetValue(i)->ConvertValueToPython();
 		if (!pyobj)
-			pyobj = ((CListValue*) list)->GetValue(i)->AddRef();
-		newlist->ob_item[j] = pyobj;
+			pyobj = list->GetValue(i)->GetProxy();
+		PyList_SET_ITEM(newlist, i, pyobj);
 	}	
-	return (PyObject *) newlist;
+	return newlist;
 }
 
 
@@ -109,11 +131,16 @@ PyObject* listvalue_buffer_slice(PyObject* list,Py_ssize_t ilow, Py_ssize_t ihig
 static PyObject *
 listvalue_buffer_concat(PyObject * self, PyObject * other)
 {
+	CListValue *listval= static_cast<CListValue *>(BGE_PROXY_REF(self));
+	if (listval==NULL) {
+		PyErr_SetString(PyExc_IndexError, BGE_PROXY_ERROR_MSG);
+		return NULL;
+	}
+	
 	// for now, we support CListValue concatenated with items
 	// and CListValue concatenated to Python Lists
 	// and CListValue concatenated with another CListValue
-
-	CListValue* listval = (CListValue*) self;
+	
 	listval->AddRef();
 	if (other->ob_type == &PyList_Type)
 	{
@@ -519,8 +546,8 @@ PyObject* CListValue::Pyfrom_id(PyObject* self, PyObject* value)
 	int numelem = GetCount();
 	for (int i=0;i<numelem;i++)
 	{
-		if (reinterpret_cast<BGE_ID_TYPE>(static_cast<PyObject*>(m_pValueArray[i])) == id)
-			return GetValue(i);
+		if (reinterpret_cast<BGE_ID_TYPE>(m_pValueArray[i]->m_proxy) == id)
+			return GetValue(i)->GetProxy();
 	
 	}
 	PyErr_SetString(PyExc_IndexError, "from_id(#), id not found in CValueList");
diff --git a/source/gameengine/Expressions/ListValue.h b/source/gameengine/Expressions/ListValue.h
index cf2976c2bbb..2af5a330c43 100644
--- a/source/gameengine/Expressions/ListValue.h
+++ b/source/gameengine/Expressions/ListValue.h
@@ -61,9 +61,11 @@ public:
 
 	virtual PyObject* py_getattro(PyObject* attr);
 	virtual PyObject* py_repr(void) {
-		PyObject *py_list= PySequence_List((PyObject *)this);
+		PyObject *py_proxy= this->GetProxy();
+		PyObject *py_list= PySequence_List(py_proxy);
 		PyObject *py_string= PyObject_Repr(py_list);
 		Py_DECREF(py_list);
+		Py_DECREF(py_proxy);
 		return py_string;
 	}
 
diff --git a/source/gameengine/Expressions/PyObjectPlus.cpp b/source/gameengine/Expressions/PyObjectPlus.cpp
index 0db2e8991fc..2c5ba3f39fc 100644
--- a/source/gameengine/Expressions/PyObjectPlus.cpp
+++ b/source/gameengine/Expressions/PyObjectPlus.cpp
@@ -54,6 +54,7 @@
  * PyObjectPlus Type		-- Every class, even the abstract one should have a Type
 ------------------------------*/
 
+
 PyTypeObject PyObjectPlus::Type = {
 	PyObject_HEAD_INIT(NULL)
 	0,				/*ob_size*/
@@ -74,21 +75,33 @@ PyTypeObject PyObjectPlus::Type = {
 	Methods
 };
 
+
 PyObjectPlus::~PyObjectPlus()
 {
-	if (ob_refcnt)
-	{
-		_Py_ForgetReference(this);
+	if(m_proxy) {
+		Py_DECREF(m_proxy);			/* Remove own reference, python may still have 1 */
+		BGE_PROXY_REF(m_proxy)= NULL;
 	}
 //	assert(ob_refcnt==0);
 }
 
+void PyObjectPlus::PyDestructor(PyObject *self)				// python wrapper
+{
+	PyObjectPlus *self_plus= BGE_PROXY_REF(self);
+	if(self_plus) {
+		if(BGE_PROXY_PYOWNS(self)) { /* Does python own this?, then delete it  */
+			delete self_plus;
+		}
+		
+		BGE_PROXY_REF(self)= NULL; // not really needed
+	}
+	PyObject_DEL( self );
+};
+
 PyObjectPlus::PyObjectPlus(PyTypeObject *T) 				// constructor
 {
 	MT_assert(T != NULL);
-	this->ob_type = T; 
-	_Py_NewReference(this);
-	SetZombie(false);
+	m_proxy= NULL;
 };
   
 /*------------------------------
@@ -131,7 +144,7 @@ PyObject *PyObjectPlus::py_getattro(PyObject* attr)
 		if (PyCObject_Check(descr)) {
 			return py_get_attrdef((void *)this, (const PyAttributeDef*)PyCObject_AsVoidPtr(descr));
 		} else if (descr->ob_type->tp_descr_get) {
-			return PyCFunction_New(((PyMethodDescrObject *)descr)->d_method, (PyObject *)this);
+			return PyCFunction_New(((PyMethodDescrObject *)descr)->d_method, this->m_proxy);
 		} else {
 			fprintf(stderr, "Unknown attribute type (PyObjectPlus::py_getattro)");
 			return descr;
@@ -794,5 +807,47 @@ PyObject *py_getattr_dict(PyObject *pydict, PyObject *tp_dict)
 	return pydict;
 }
 
+
+
+PyObject *PyObjectPlus::GetProxy_Ext(PyObjectPlus *self, PyTypeObject *tp)
+{
+	if (self->m_proxy==NULL)
+	{
+		self->m_proxy = reinterpret_cast<PyObject *>PyObject_NEW( PyObjectPlus_Proxy, tp);
+		BGE_PROXY_PYOWNS(self->m_proxy) = false;
+	}
+	//PyObject_Print(self->m_proxy, stdout, 0);
+	//printf("ref %d\n", self->m_proxy->ob_refcnt);
+	
+	BGE_PROXY_REF(self->m_proxy) = self; /* Its possible this was set to NULL, so set it back here */
+	Py_INCREF(self->m_proxy); /* we own one, thos ones fore the return */
+	return self->m_proxy;
+}
+
+PyObject *PyObjectPlus::NewProxy_Ext(PyObjectPlus *self, PyTypeObject *tp, bool py_owns)
+{
+	if (self->m_proxy)
+	{
+		if(py_owns)
+		{	/* Free */
+			BGE_PROXY_REF(self->m_proxy) = NULL;
+			Py_DECREF(self->m_proxy);
+			self->m_proxy= NULL;
+		}
+		else {
+			Py_INCREF(self->m_proxy);
+			return self->m_proxy;
+		}
+		
+	}
+	
+	GetProxy_Ext(self, tp);
+	if(py_owns) {
+		BGE_PROXY_PYOWNS(self->m_proxy) = py_owns;
+		Py_DECREF(self->m_proxy); /* could avoid thrashing here but for now its ok */
+	}
+	return self->m_proxy;
+}
+
 #endif //NO_EXP_PYTHON_EMBEDDING
 
diff --git a/source/gameengine/Expressions/PyObjectPlus.h b/source/gameengine/Expressions/PyObjectPlus.h
index 58a74e4ca74..3be9a2f2bcb 100644
--- a/source/gameengine/Expressions/PyObjectPlus.h
+++ b/source/gameengine/Expressions/PyObjectPlus.h
@@ -81,6 +81,20 @@ static inline void Py_Fatal(const char *M) {
 	exit(-1);
 };
 
+typedef struct {
+	PyObject_HEAD		/* required python macro   */
+	class PyObjectPlus *ref;
+	bool py_owns;
+} PyObjectPlus_Proxy;
+
+#define BGE_PROXY_ERROR_MSG "Blender Game Engine data has been freed, cannot use this python variable"
+#define BGE_PROXY_REF(_self) (((PyObjectPlus_Proxy *)_self)->ref)
+#define BGE_PROXY_PYOWNS(_self) (((PyObjectPlus_Proxy *)_self)->py_owns)
+
+/* Note, sometimes we dont care what BGE type this is as long as its a proxy */
+#define BGE_PROXY_CHECK_TYPE(_self) ((_self)->ob_type->tp_dealloc == PyDestructor)
+
+
 								// This must be the first line of each 
 								// PyC++ class
 #define Py_Header \
@@ -90,7 +104,10 @@ static inline void Py_Fatal(const char *M) {
   static PyAttributeDef Attributes[]; \
   static PyParentObject Parents[]; \
   virtual PyTypeObject *GetType(void) {return &Type;}; \
-  virtual PyParentObject *GetParents(void) {return Parents;}
+  virtual PyParentObject *GetParents(void) {return Parents;} \
+  virtual PyObject *GetProxy() {return GetProxy_Ext(this, &Type);}; \
+  virtual PyObject *NewProxy(bool py_owns) {return NewProxy_Ext(this, &Type, py_owns);}; \
+
 
 
 
@@ -106,7 +123,7 @@ static inline void Py_Fatal(const char *M) {
 		if (PyCObject_Check(descr)) { \
 			return py_get_attrdef((void *)this, (const PyAttributeDef*)PyCObject_AsVoidPtr(descr)); \
 		} else if (descr->ob_type->tp_descr_get) { \
-			return PyCFunction_New(((PyMethodDescrObject *)descr)->d_method, (PyObject *)this); \
+			return PyCFunction_New(((PyMethodDescrObject *)descr)->d_method, this->m_proxy); \
 		} else { \
 			fprintf(stderr, "unknown attribute type"); \
 			return descr; \
@@ -165,52 +182,60 @@ static inline void Py_Fatal(const char *M) {
 #define KX_PYMETHOD(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* args, PyObject* kwds); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* args, PyObject* kwds) { \
-		return ((class_name*) self)->Py##method_name(self, args, kwds);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self, args, kwds);		\
 	}; \
 
 #define KX_PYMETHOD_VARARGS(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* args); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* args) { \
-		return ((class_name*) self)->Py##method_name(self, args);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self, args);		\
 	}; \
 
 #define KX_PYMETHOD_NOARGS(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self); \
 	static PyObject* sPy##method_name( PyObject* self) { \
-		return ((class_name*) self)->Py##method_name(self);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self);		\
 	}; \
 	
 #define KX_PYMETHOD_O(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* value); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* value) { \
-		return ((class_name*) self)->Py##method_name(self, value);		\
+		PyObjectPlus *self_plus= ((PyObjectPlus_Proxy *)self)->ref; \
+		return ((class_name*) self_plus)->Py##method_name(self, value);		\
 	}; \
 
 #define KX_PYMETHOD_DOC(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* args, PyObject* kwds); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* args, PyObject* kwds) { \
-		return ((class_name*) self)->Py##method_name(self, args, kwds);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self, args, kwds);		\
 	}; \
     static const char method_name##_doc[]; \
 
 #define KX_PYMETHOD_DOC_VARARGS(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* args); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* args) { \
-		return ((class_name*) self)->Py##method_name(self, args);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self, args);		\
 	}; \
     static const char method_name##_doc[]; \
 
 #define KX_PYMETHOD_DOC_O(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self, PyObject* value); \
 	static PyObject* sPy##method_name( PyObject* self, PyObject* value) { \
-		return ((class_name*) self)->Py##method_name(self, value);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self, value);		\
 	}; \
     static const char method_name##_doc[]; \
 
 #define KX_PYMETHOD_DOC_NOARGS(class_name, method_name)			\
 	PyObject* Py##method_name(PyObject* self); \
 	static PyObject* sPy##method_name( PyObject* self) { \
-		return ((class_name*) self)->Py##method_name(self);		\
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self); \
+		return ((class_name*)self_plus)->Py##method_name(self);		\
 	}; \
     static const char method_name##_doc[]; \
 
@@ -233,19 +258,19 @@ static inline void Py_Fatal(const char *M) {
  */
 #define KX_PYMETHODDEF_DOC(class_name, method_name, doc_string) \
 const char class_name::method_name##_doc[] = doc_string; \
-PyObject* class_name::Py##method_name(PyObject*, PyObject* args, PyObject*)
+PyObject* class_name::Py##method_name(PyObject* self, PyObject* args, PyObject*)
 
 #define KX_PYMETHODDEF_DOC_VARARGS(class_name, method_name, doc_string) \
 const char class_name::method_name##_doc[] = doc_string; \
-PyObject* class_name::Py##method_name(PyObject*, PyObject* args)
+PyObject* class_name::Py##method_name(PyObject* self, PyObject* args)
 
 #define KX_PYMETHODDEF_DOC_O(class_name, method_name, doc_string) \
 const char class_name::method_name##_doc[] = doc_string; \
-PyObject* class_name::Py##method_name(PyObject*, PyObject* value)
+PyObject* class_name::Py##method_name(PyObject* self, PyObject* value)
 
 #define KX_PYMETHODDEF_DOC_NOARGS(class_name, method_name, doc_string) \
 const char class_name::method_name##_doc[] = doc_string; \
-PyObject* class_name::Py##method_name(PyObject*)
+PyObject* class_name::Py##method_name(PyObject* self)
 
 /**
  * Attribute management
@@ -394,19 +419,17 @@ typedef struct KX_PYATTRIBUTE_DEF {
 ------------------------------*/
 typedef PyTypeObject * PyParentObject;				// Define the PyParent Object
 
-class PyObjectPlus : public PyObject 
+class PyObjectPlus 
 {				// The PyObjectPlus abstract class
 	Py_Header;							// Always start with Py_Header
 	
 public:
 	PyObjectPlus(PyTypeObject *T);
-	bool m_zombie;
+
+	PyObject *m_proxy; /* actually a PyObjectPlus_Proxy */
 	
 	virtual ~PyObjectPlus();					// destructor
-	static void PyDestructor(PyObject *P)				// python wrapper
-	{
-		delete ((PyObjectPlus *) P);  
-	};
+	static void PyDestructor(PyObject *self);				// python wrapper
 	
 //	void INCREF(void) {
 //		  Py_INCREF(this);
@@ -418,15 +441,15 @@ public:
 	virtual PyObject *py_getattro(PyObject *attr);			// py_getattro method
 	static  PyObject *py_base_getattro(PyObject * self, PyObject *attr) 	// This should be the entry in Type. 
 	{
-		if (((PyObjectPlus*)self)->IsZombie()) {
-			if (!strcmp(PyString_AsString(attr), "isValid")) {
-				Py_RETURN_FALSE;
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self);
+		if(self_plus==NULL) {
+			if(!strcmp("isValid", PyString_AsString(attr))) {
+				Py_RETURN_TRUE;
 			}
-			((PyObjectPlus*)self)->IsZombiePyErr(); /* raise an error */
+			PyErr_SetString(PyExc_RuntimeError, "data has been removed");
 			return NULL;
 		}
-		
-		return ((PyObjectPlus*) self)->py_getattro(attr); 
+		return self_plus->py_getattro(attr); 
 	}
 	
 	static PyObject*	py_get_attrdef(void *self, const PyAttributeDef *attrdef);
@@ -441,22 +464,29 @@ public:
 	virtual int py_setattro(PyObject *attr, PyObject *value);		// py_setattro method
 	static  int py_base_setattro(PyObject *self, PyObject *attr, PyObject *value) // the PyType should reference this
 	{
-		if (((PyObjectPlus*)self)->IsZombie()) {
-			/* you cant set isValid anyway */
-			((PyObjectPlus*)self)->IsZombiePyErr();
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self);
+		if(self_plus==NULL) {
+			PyErr_SetString(PyExc_RuntimeError, "data has been removed");
 			return -1;
 		}
 		
 		if (value==NULL)
-			return ((PyObjectPlus*)self)->py_delattro(attr);
+			return self_plus->py_delattro(attr);
 		
-		return ((PyObjectPlus*)self)->py_setattro(attr, value); 
+		return self_plus->py_setattro(attr, value); 
 	}
 	
 	virtual PyObject *py_repr(void);				// py_repr method
-	static  PyObject *py_base_repr(PyObject *PyObj)			// This should be the entry in Type.
+	static  PyObject *py_base_repr(PyObject *self)			// This should be the entry in Type.
 	{
-		return ((PyObjectPlus*) PyObj)->py_repr();  
+		
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self);
+		if(self_plus==NULL) {
+			PyErr_SetString(PyExc_RuntimeError, "data has been removed");
+			return NULL;
+		}
+		
+		return self_plus->py_repr();  
 	}
 	
 									// isA methods
@@ -465,43 +495,20 @@ public:
 	PyObject *Py_isA(PyObject *value);
 	static PyObject *sPy_isA(PyObject *self, PyObject *value)
 	{
-		return ((PyObjectPlus*)self)->Py_isA(value);
-	}
-	
-	/* Kindof dumb, always returns True, the false case is checked for, before this function gets accessed */
-	static PyObject*	pyattr_get_is_valid(void *self_v, const KX_PYATTRIBUTE_DEF *attrdef);
-	
-	bool IsZombie()
-	{
-		return m_zombie;
-	}
-	
-	bool IsZombiePyErr()
-	{
-		if(m_zombie) {
-			/*
-			PyObject *this_pystr = PyObject_Repr(this);
-			
-			PyErr_Format(
-					PyExc_RuntimeError,
-					"\"%s\" of type \"%s\" has been freed by the blender game engine, "
-					"scripts cannot access this anymore, check for this case with the \"isValid\" attribute",
-					PyString_AsString(this_pystr), ob_type->tp_name );
-			
-			Py_DECREF(this_pystr);
-			*/
-			
-			PyErr_SetString(PyExc_RuntimeError, "This value has been freed by the blender game engine but python is still holding a reference, this value cant be used.");
+		PyObjectPlus *self_plus= BGE_PROXY_REF(self);
+		if(self_plus==NULL) {
+			PyErr_SetString(PyExc_RuntimeError, "data has been removed");
+			return NULL;
 		}
 		
-		return m_zombie;
+		return self_plus->Py_isA(value);
 	}
 	
-	void SetZombie(bool is_zombie)
-	{
-		m_zombie= is_zombie;
-	}
+	/* Kindof dumb, always returns True, the false case is checked for, before this function gets accessed */
+	static PyObject*	pyattr_get_is_valid(void *self_v, const KX_PYATTRIBUTE_DEF *attrdef);
 	
+	static PyObject *GetProxy_Ext(PyObjectPlus *self, PyTypeObject *tp);
+	static PyObject *NewProxy_Ext(PyObjectPlus *self, PyTypeObject *tp, bool py_owns);
 };
 
 PyObject *py_getattr_dict(PyObject *pydict, PyObject *tp_dict);
diff --git a/source/gameengine/Expressions/Value.cpp b/source/gameengine/Expressions/Value.cpp
index 63776c39d70..7958c16ca81 100644
--- a/source/gameengine/Expressions/Value.cpp
+++ b/source/gameengine/Expressions/Value.cpp
@@ -501,12 +501,6 @@ int	CValue::Release()
 	// Decrease local reference count, if it reaches 0 the object should be freed
 	if (--m_refcount > 0)
 	{
-		// Benoit suggest this as a way to automatically set the zombie flag, but I couldnt get it working - Campbell
-		/*
-		if (m_refcount == 1 && ob_refcnt > 1)
-			SetZombie(true); // the remaining refcount is held by Python!!
-		*/	
-		
 		// Reference count normal, return new reference count
 		return m_refcount;
 	}
@@ -544,9 +538,6 @@ void CValue::AddDataToReplica(CValue *replica)
 {
 	replica->m_refcount = 1;
 
-	//register with Python
-	_Py_NewReference(replica);
-
 #ifdef _DEBUG
 	//gRefCountValue++;
 #endif
@@ -616,7 +607,7 @@ PyObject*	CValue::py_getattro(PyObject *attr)
 		if (pyconvert)
 			return pyconvert;
 		else
-			return resultattr; // also check if it's already in pythoninterpreter!
+			return resultattr->GetProxy();
 	}
 	py_getattro_up(PyObjectPlus);
 }
diff --git a/source/gameengine/Expressions/Value.h b/source/gameengine/Expressions/Value.h
index bcee355cda2..a687e1a493c 100644
--- a/source/gameengine/Expressions/Value.h
+++ b/source/gameengine/Expressions/Value.h
@@ -225,21 +225,6 @@ public:
 
 
 	virtual PyObject*			py_getattro(PyObject *attr);
-
-	void	SpecialRelease()
-	{
-		if (ob_refcnt == 0) /* make sure python always holds a reference */
-		{
-			_Py_NewReference(this);
-			
-		}
-		Release();
-	}
-	static void PyDestructor(PyObject *P)				// python wrapper
-	{
-	  ((CValue*)P)->SpecialRelease();
-	};
-
 	virtual PyObject*	ConvertValueToPython() {
 		return NULL;
 	}
@@ -352,7 +337,6 @@ private:
 	std::map<STR_String,CValue*>*		m_pNamedPropertyArray;									// Properties for user/game etc
 	ValueFlags			m_ValFlags;												// Frequently used flags in a bitfield (low memoryusage)
 	int					m_refcount;												// Reference Counter	
-	bool				m_zombie;												// Object is invalid put its still being referenced (by python)
 	static	double m_sZeroVec[3];	
 	static bool			m_ignore_deprecation_warnings;