Historical Rules · 1 October 2010
Rule 701.15d
Official source text from the 1 October 2010 Rules release
If an effect would cause a player to shuffle a set of objects into a library, that library is shuffled even if there are no objects in that set. Example: Loaming Shaman says "When Loaming Shaman enters the battlefield, target player shuffles any number of target cards from his or her graveyard into his or her library." It enters the battlefield, its ability triggers, and no cards are targeted. When the ability resolves, the targeted player will still have to shuffle his or her library.