Index: src/org/python/core/PyGetSetDescr.java
===================================================================
--- src/org/python/core/PyGetSetDescr.java	(revision 3001)
+++ src/org/python/core/PyGetSetDescr.java	(working copy)
@@ -10,6 +10,8 @@
 
     private Method set_meth;
 
+    private Method del_meth;
+
     private Class getset_type;
 
     public PyGetSetDescr(PyType dtype,
@@ -17,6 +19,18 @@
                          Class c,
                          String get,
                          String set) {
+        this(dtype, name, c, get, set, null);
+    }
+    public PyGetSetDescr(String name, Class c, String get, String set) {
+        this(PyType.fromClass(c), name, c, get, set, null);
+    }
+
+    public PyGetSetDescr(PyType dtype,
+                         String name,
+                         Class c,
+                         String get,
+                         String set,
+                         String del) {
         this.name = name;
         this.dtype = dtype;
         try {
@@ -36,10 +50,19 @@
             if(Modifier.isStatic(set_meth.getModifiers()))
                 throw Py.SystemError("static getset not supported");
         }
-    }
+        if(del != null) {
+            try {
+                del_meth = c.getMethod(del, new Class[] {});
+            } catch(NoSuchMethodException e) {
+                throw Py.SystemError("bogus getset spec");
+            }
+            if(Modifier.isStatic(del_meth.getModifiers()))
+                throw Py.SystemError("static getset not supported");
+        }
+     }
 
-    public PyGetSetDescr(String name, Class c, String get, String set) {
-        this(PyType.fromClass(c), name, c, get, set);
+    public PyGetSetDescr(String name, Class c, String get, String set, String del) {
+        this(PyType.fromClass(c), name, c, get, set, del);
     }
 
     public String toString() {
@@ -97,6 +120,23 @@
         }
     }
 
+    public void __delete__(PyObject obj) {
+        try {
+            if(obj != null) {
+                PyType objtype = obj.getType();
+                if(objtype != dtype && !objtype.isSubType(dtype))
+                    throw get_wrongtype(objtype);
+                del_meth.invoke(obj, new Object[0]);
+            }
+        } catch(IllegalArgumentException e) {
+            throw Py.JavaError(e);
+        } catch(IllegalAccessException e) {
+            throw Py.JavaError(e); // unexpected
+        } catch(InvocationTargetException e) {
+            throw Py.JavaError(e);
+        }
+    }
+
     /**
      * @see org.python.core.PyObject#implementsDescrSet()
      */
@@ -104,10 +144,15 @@
         return set_meth != null;
     }
 
+    public boolean implementsDescrDelete() {
+        return del_meth != null;
+    }
+
     /**
      * @see org.python.core.PyObject#isDataDescr()
      */
     public boolean isDataDescr() {
         return true;
     }
+
 }
Index: src/org/python/core/PyObject.java
===================================================================
--- src/org/python/core/PyObject.java	(revision 3001)
+++ src/org/python/core/PyObject.java	(working copy)
@@ -2791,7 +2791,16 @@
         return null;
     }
 
+    public void setDict(PyObject newDict) {
+    	// fallback if setDict not implemented in subclass
+    	throw Py.TypeError("can't set attribute '__dict__' of instance of " + getType().safeRepr());
+    }
 
+    public void delDict() {
+        // fallback to error
+        throw Py.TypeError("can't delete attribute '__dict__' of instance of '" + getType().safeRepr()+ "'");
+    }
+
     public boolean implementsDescrSet() {
         return objtype.has_set;
     }
Index: src/org/python/core/PyType.java
===================================================================
--- src/org/python/core/PyType.java	(revision 3001)
+++ src/org/python/core/PyType.java	(working copy)
@@ -21,7 +21,7 @@
     public static final String exposed_name="type";
 
     public static void typeSetup(PyObject dict,PyType.Newstyle marker) {
-        dict.__setitem__("__dict__",new PyGetSetDescr("__dict__",PyType.class,"getDict",null));
+        dict.__setitem__("__dict__",new PyGetSetDescr("__dict__",PyType.class,"getDict","setDict","delDict"));
         dict.__setitem__("__name__",new PyGetSetDescr("__name__",PyType.class,"fastGetName",null));
         dict.__setitem__("__base__",new PyGetSetDescr("__base__",PyType.class,"getBase",null));
         dict.__setitem__("__bases__",new PyGetSetDescr("__bases__",PyType.class,"getBases",null));
@@ -732,7 +732,7 @@
         
         // __dict__ descriptor
         if (newtype.needs_userdict && newtype.lookup("__dict__")==null) {
-            dict.__setitem__("__dict__",new PyGetSetDescr(newtype,"__dict__",PyObject.class,"getDict",null));
+            dict.__setitem__("__dict__",new PyGetSetDescr(newtype,"__dict__",PyObject.class,"getDict","setDict","delDict"));
         }
 
         newtype.has_set = newtype.lookup("__set__") != null;
@@ -1296,7 +1296,15 @@
     public PyObject getDict() { // xxx return dict-proxy
         return dict;
     }
+    
+    public void setDict(PyObject newDict) {
+    	throw Py.TypeError("can't set attribute '__dict__' of type '" + name + "'");
+    }
 
+    public void delDict() {
+    	throw Py.TypeError("can't delete attribute '__dict__' of type '" + name + "'");
+    }
+
     public Object __tojava__(Class c) {
         if (underlying_class!= null &&(
             c == Object.class || c == Class.class || c == Serializable.class)) {
Index: src/templates/gderived-defs
===================================================================
--- src/templates/gderived-defs	(revision 3000)
+++ src/templates/gderived-defs	(working copy)
@@ -70,6 +70,19 @@
     return dict;
   }
 
+  public void setDict(PyObject newDict) {
+    if (newDict instanceof PyStringMap || newDict instanceof PyDictionary ) {
+      dict = newDict;
+    }
+    else {
+      throw Py.TypeError("__dict__ must be set to a Dictionary " + newDict.getClass().getName());
+    }
+  }
+
+  public void delDict() {
+    dict = new PyStringMap();  
+  }
+
 define: (ClassBodyDeclarations)ctr
   public `concat`(`base,Derived)(PyType subtype,`extraargs) {
     super(subtype,`extra);