[myrroddin]

After reading the above, I thought perhaps I didn't write with clarity. The API page for callbacks suggests code for ResExpired and ResCastCancelled to be something like this:

function MyAddon:LibResInfo_ResExpired(targetUnit, targetGUID)
    -- do something
end
 
function MyAddon:LibResInfo_ResCastCancelled(casterUnit, casterGUID, targetUnit, targetGUID)
    -- do something
end

But according to LRI's code, the callbacks are actually

function MyAddon:LibResInfo_ResExpired(targetGUID, targetUnit)
  -- oops, better make sure we have the right info!
end
 
function MyAddon:LibResInfo_ResCastCancelled(casterGUID, casterUnit, targetGUID, targetUnit)
    -- backwards?
end

All other callbacks follow the API page.