fix: unwrap Savepoint objects when passing them in as parameters.

[karenc-bq]

Summary

fix: unwrap Savepoint objects when passing them in as parameters.

Description

Fixes #328

SavepointWrappper objects are passed to ConnectionWrapper#*rollback(final Savepoint savepoint) as parameters, which are then passed to the target driver's rollback methods.

PGJDBC internally explicitly casts the Savepoint parameter to an internal object: https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/PgConnection.java#L1836

PSQLSavepoint pgSavepoint = (PSQLSavepoint) savepoint;

Since the driver passed in a SavepointWrappper object, this line in pgjdbc will throw a ClassCastException.

The only solution is to unwrap the Savepoint object before passing it in.

Additional Reviewers

@joyc-bq
@aaronchung-bitquill

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[davecramer]

are there any others ?

[karenc-bq]

are there any others ?

Haven't found any others yet.