Don?t modify tuples that others may already have references to.

Fixes egg room private chat channels and entering Teledahn buckets with Python 2.7. These and other uses of ptSDL.setIndex() only worked by chance with Python 2.3 because the tuples happened to have reference counts of 1.

MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/FeatureLib/pfPython/plPythonSDLModifier.cpp

@@ -208,6 +208,22 @@ void plPythonSDLModifier::SetItemIdx(const char* key, int idx, PyObject* value,
 		return;
 	}
 
+	if (pyTuple && pyTuple->ob_refcnt != 1)
+	{
+		// others already have references to the tuple and expect it to be immutable, must make a copy
+		int n = PyTuple_Size(pyTuple);
+		PyObject* newTuple = PyTuple_New(n);
+		for (int j = 0; j < n; j++)
+		{
+			PyObject* item = PyTuple_GetItem(pyTuple, j);
+			Py_INCREF(item);
+			PyTuple_SetItem(newTuple, j, item);
+		}
+		Py_DECREF(pyTuple);
+		pyTuple = newTuple;
+		it->second.obj = newTuple;
+	}
+
 	if (pyTuple)
 	{
 		if (PyTuple_Size(pyTuple) <= idx)