Historical Rules · 8 September 2022
Rule 701.20d
Official source text from the 8 September 2022 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 their graveyard into their 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 their library.