EXCLUSIVE

Gun-toting thugs invaded Post Malone's home -- or so they thought -- attacking one person while shouting for the rapper, but the problem is ... Post doesn't live there anymore.

Law enforcement sources tell us ... 3 male suspects smashed a front window a little after midnight on September 1 and entered the San Fernando Valley house. We're told a resident living there was pistol whipped.

We're told one of the 3 men yelled, "Where's Post Malone?!" ... before stealing a bunch of cash, jewelry and cell phones ... about $20k worth. The barking out of Post's name makes it clear they were targeting him, but it's been months since he lived there.

We're told the people living there now have no connection to Post.