Bukkit/CraftBukkit — pull request #529 by wizjany (2011-11-05 19:43:24+00:00)
Title: Send RIGHT_CLICK_AIR interact events even if the item in hand is null

Completely safe afaik because the event factory will construct a CraftItemStack which will set the values to 0 if the ItemStack passed is null.

This allows plugins to catch player right clicks on air even if the player has nothing in their hand.