Who are those whose passing in front of a worshiper invalidates his prayer, and what should the worshiper do in this case, and what is the ruling if he doubts whether his prayer has been invalidated?

Scholars have differed regarding the nullification of prayer by the passing of a woman, a donkey, and a black dog. Ahmad ibn Hanbal was of the opinion that the black dog nullifies it, and he hesitated concerning the woman and the donkey. Meanwhile, Malik, Abu Hanifa, Al-Shafi'i, and the majority of scholars held that prayer is not invalidated by the passing of any of these or other things. They interpreted the hadith to mean that what is intended by "nullification" is the imperfection of the prayer due to the heart being preoccupied with these things, not its complete invalidation. Aisha denied this and mentioned that she used to lie down in front of the Prophet, peace and blessings be upon him, while he was praying. Accordingly, if one of these things passes in front of a person, their prayer is not nullified. Prayer is not invalidated by doubt unless a certain nullifier occurs or if continuing it would lead to the destruction of a respected life.