/// This is here to force the test to be done whenever parent_buffer
/// is accessed.
Buffer const * parent() const {
+ // if parent_buffer is not loaded, then it has been unloaded,
+ // which means that parent_buffer is an invalid pointer. So we
+ // set it to null in that case.
if (!theBufferList().isLoaded(parent_buffer))
parent_buffer = 0;
return parent_buffer;