Best way to Rollback if a COMMIT fails

Thanks Mark. Hey what about this :

EXCEPTION WHEN OTHERS THEN
ROLLBACK;
RAISE;

You are correct, the "WHEN OTHERS THEN" words are also required.  (I was distracted when I posted that response yesterday.)

But, I still think it is very rare for an Oracle procedure to fail on a "commit".  Failures usually happen on other statements in the procedure.

a commit never fails. (unless you can halt the database at that split second)
it's getting to the commit which can fail

an error is returned upon executing a statement
not when committing

technically, you don't commit inside the procedure
this should be done by the calling program

if this procedure is only part of something, you would commit at the complete end
not in the middle