Is breaking an oath not to fast considered fulfilled if one is already fasting and completes the day?

Primary text

If a person swears not to fast, and he is already fasting, completing that day does not break the oath, according to the opinion of Al-Qadi. However, another possibility exists where the oath is considered broken because fasting, like sleeping, is an action that occurs through continuation, indicated by phrases such as 'He fasted a day.'