No, Shaedon Sharpe has never been a member of the Golden State Warriors. Hopefully, he stays with the Portland Trail Blazers for a long time. However, the Blazers aren't making it any easier on themselves to make that a reality by low-balling him in extension talks.
We just saw how messy restricted free agency can get with Jonathan Kuminga in Golden State. If the Blazers don't increase their offer to Sharpe before the start of the season, it's very possible that the NBA's next RFA saga will take place in Portland.
Blazers must learn from Warriors' messy Jonathan Kuminga saga
NBA insider Jake Fischer reported on The Stein Line (subscription required) that Portland offered Sharpe a rookie-scale extension offer in the range of four years, $90 million.