Recently I was working on getting a rather complex data structure to serialize. Something in the data structure wasn't serializable and I was having trouble determining exactly how that something was being referenced. I had a sniff [^] for existing tools to help with this kind of thing but nothing was forthcoming. Therefore, I wrote my own. This tool, which I have christened Sertool, walks an object hierarchy and outputs the details of all items that will be serialized. It also highlights any serialization errors it finds. Once an error is detected, you can use the IDs of the objects (shown in magenta) to determine what is referencing those items.