Must one fast without having formed the intention due to not having woken up from sleep?

If the fast is supererogatory (nafilah), then it is permissible to fast with an intention made during the day before zawal (midday), based on what was narrated from Aisha (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said to her: "Indeed, I am fasting," after he asked her if they had anything and they found nothing. As for an obligatory fast, such as making up for Ramadan, the intention must be made during the night. The intention is not valid if accompanied by hesitation or conditionality; rather, it must be definitive.