Jackson Odell Had History of Heroin Use, But Last Drug Test Came Back Clean

Jackson Odell -- the former teen actor and songwriter who died on Friday -- had a history of heroin use, but he was clean when he last underwent a drug test ... TMZ has learned.

Law enforcement sources tell TMZ ... Jackson had been at a sober living home for about 3 weeks when he was found unresponsive. We have also learned there were no drugs or drug paraphernalia found when his body was discovered.

TMZ broke the story ... Jackson -- best known for his role as Ari Caldwell on "The Goldbergs" -- died in the San Fernando Valley. As we reported ... no foul play was suspected. An autopsy and toxicology testing is underway to determine the cause of death.

Jackson was 20.

RIP