halacha - When do Sefardim start mourning in a year that Tisha B'av is postponed until Sunday?

As mentioned here, Sefardim observe the mourning period known to Ashkenazim as "The Nine Days" only during the week that Tisha B'av occurs.

Tisha B'av falls out on Shabbat this year (5772), and the fast is postponed until Sunday.

Do Sefardim observe the mourning period during the week the 9th day of Av occurs, or the week that the fast occurs?

In other words, do they end up having no days of mourning this year, or does the mourning period start from sunday, the 3rd of Av?

Answer

The Shulchan Aruch (551:4) rules regarding both the case of Tisha b'Av on Saturday and Tisha b'Av on Sunday that there is no mourning period and some say (Yesh Omrim) that there is mourning the entire preceding week. Generally when the Shulchan Aruch quotes two opinions and only the latter is prefaced by 'some say', the halacha follows the former opinion (Yad Malachai Klalei HaShulchan Aruch 17).

The Kaf haChaim (sk 78) rules as such, but notes that it is proper to be stringent only regarding haircuts for either the entire preceding week or at least just the Friday before in order to not enter Tisha b'Av looking too nice.