Imam Qushairy (Allah have mercy on him) said,

“It is essential (wajib) for the murid to conceal his private affairs with utmost vigilance.  He should not disclose them to his closest friend.

However, this concealment should not be done when dealing with the Shaykh.

If an individuals hides even a single breath from his Shaykh then indeed he has committed a great breach of trust in the rights of the Shaykh.”

Nasihah-lil-mustarshadin translation of last chapter of ‘Risala Qushairia: al-wasiay lil-murideen‘, via Ma’arif e Sufiya, page 310