This is another article in the chapter Justice from the classical manual on Sharia called Reliance of the Traveller. The articles are posted one by one in the order they are given in the book.
019.0 EXAMPLES OF BREAKING AND NOT BREAKING OATHS
019.1 If one swears, “I will not eat this wheat,” but then makes it into flour or bread (A: and eats it), one has not broken one’s oath.
If one swears, “I will not drink from this river,” but then drinks its water from a jug, one has broken one’s oath.
If one swears, “I will not eat meat,” but then eats fat, kidneys, tripe, liver, heart, spleen, fish, or locusts, one has not broken one’s oath.
019.3 If one swears, “I will not enter the house,” but then does so absentmindedly, in ignorance of its being the house, under compulsion, or by being carried in, then one’s oath is not broken and is still in effect.
019.5 When a person swearing an oath about something (0: in the future, affirming or denying that it will occur) includes the expression in sha’ Allah (“if Allah wills”) before finishing the oath, then the oath is not broken in any event if he thereby intends to provide for exceptions. But if he merely says it out of habit, not intending to make an exception to his oath, or if he says it after having finished swearing the oath, then the exception is not valid (0: because when an oath has been completed, its efficacy is established and not eradicable by a statement of exception).