Looks like Rihanna has a stalker situation on her hands!!!!

Rihanna had her lawyers run to court after a crazed fan was captured walking on the roof of her house ... and she fears he's up to no good.

A judge has ordered Robert Melanson to stay 100 yards clear of Rihanna, her house and her place of business.  Melanson was skulking on the singer's roof with detailed property maps in hand on June 17.  He was placed on a psychiatric hold and released 2 days later.

Rihanna claimed in her legal docs she fears for her safety because Melanson is unstable and has a criminal history.

It's scary, because unstable people often throw restraining orders in the trash can.  Nonetheless, Rihanna will try and make the restraining order permanent on July 10.