I would like to check if a cycles material has been updated since the last check.
The easiest way to do that would probably be to store the nodetree somewhere and check against the current node tree. But that creates additional data in my files I would like to avoid.
I believe it might be easier to check for a user operation on a node tree and change a custom property, indicating a change has been made. After the check, the property could be reset.
To do that, I need to detect an update on a node tree.
I know that in the Animation Nodes addon there is a functionality used for Auto-Execution of the AN-Nodetree, but just by looking at the AN code, I can't figure out, how to do that.
I also noticed that a node tree has an "Is updated" property, but the documantation on that is minimal. As is the documentaion on the update() mentioned in this question.
So... how can I check for the update of a node tree?
(Also, if just saving all material node trees is more efficient thats fine by me as well)