Bukhari

Hadith Commentary:
(1)
Imam Bukhari rahimahullah, before these ahadith, narrated the hadith of Rafi‘ bin Khadij through Hasan al-Basri, stating that both the one who performs cupping and the one who gets cupped have broken their fast.
(Jami‘ at-Tirmidhi, al-Sawm, Hadith: 774)
After this, he mentioned the narrations of Ibn ‘Abbas and Anas radi Allahu anhuma, from which it is understood that there is no harm in getting cupped while fasting.
There appears to be a contradiction between these two narrations.
From Imam Bukhari rahimahullah’s approach, it is understood that the narrations regarding the fast being broken by cupping are abrogated, because at the time of the conquest of Makkah, a person was getting cupped while fasting, so the Messenger of Allah sallallahu alayhi wa sallam said:
“Both of their fasts are gone.”
And the hadith of Ibn ‘Abbas radi Allahu anhu was stated on the occasion of the Farewell Pilgrimage (Hajjat al-Wada‘), and this event took place in the tenth year of Hijrah, whereas Makkah was conquered in the eighth year of Hijrah.
This is a principle: the later hadith abrogates the earlier one. Furthermore, in the hadith of Ibn ‘Abbas it is mentioned that the Messenger of Allah sallallahu alayhi wa sallam had cupping done while in the state of ihram, which also indicates that this was during the Farewell Pilgrimage.
(Fath al-Bari: 4/226)
(2)
Some scholars have explained that both the one who performs cupping and the one who gets cupped expose themselves to breaking the fast, because the one who performs cupping, when he sucks the blood, there remains a risk that blood may enter his stomach, and the one who gets cupped may be compelled to break his fast due to weakness.
In the hadith of Anas radi Allahu anhu, there is an indication that cupping does not invalidate the fast, but rather it causes weakness.
(Fath al-Bari: 4/227)
In any case, getting cupped does not break the fast.
This is further supported by the narration of Abu Sa‘id al-Khudri radi Allahu anhu, that the Messenger of Allah sallallahu alayhi wa sallam permitted cupping.
(Musannaf Ibn Abi Shaybah: 3/53)
Concession always comes after strictness.
Hafiz Ibn Hazm rahimahullah has also adopted this position.
(Fath al-Bari: 4/227)