You can use the auto-generate guids flag on heat (-ag
), which essentially sets it to '*'. This is then expanded at compile time based on the keypath in the component (in your case, the file). If the file never changes, the compiler generates the exact same GUID every time.
I don't know a way of setting the permanent flag through heat off the top of my head, but you could certainly do it with an XSL transform which you could pass in to Heat.