We just learned that A$AP Rocky shot a guy (perhaps A$AP Relli) on a Hollywood street after an argument last November.

It could be Rocky's baby mama-to-be Rihanna just learned that, too.

Rocky was arrested yesterday morning for assault with a deadly weapon after getting off a private jet with Rihanna at LAX airport.  

The cops cuffed the rapper and took him in as they simultaneously searched his LA home for evidence.

The LAPD chose not to warn Rocky about the arrest -- which they had been working on for a week -- and sources say Rihanna was "shocked" and "surprised" but what went down on the airstrip.

Rocky has since made bail.  

The week before Rocky was arrested he was involved in a cheating scandal involving a woman who works for Rihanna.  Rocky and the woman both denied that they had hooked up and the blogger who reported the rumor has retracted it.