Especially when rollup is configured with multiple outputs, I find this particular onwarn to be helpful in reducing warning clutter. It just displays each circular reference once and doesn't repeat the warning for each output:

I think my personal preference would be to see them all at once. Or maybe limit it to up to 10 messages and then list the count of how many more messages were not displayed. Pick your reaction

Another thing we could do to limit output would be to only every show the first circular dependency warning. I think we already do this for other types of warnings. Then you would need to tackle the warnings one-by-one, though.