Is expiation (kaffarah) obligatory for someone who swore not to memorize a part of the lesson, but then memorized it unintentionally?

If the one who swore an oath intended to memorize (the Qur'an) deliberately by her oath, and the memorization occurred unintentionally during revision, then no expiation is due upon her. Oaths are governed by the intention of the one who swears them; so, if one intends by their oath something that it can bear, their oath turns to that. The intention of the swearer particularizes their general utterance and restricts their absolute utterance.