When code inside a write_txn block raises an OperationalError that SQLite
has already auto-rolled-back (typical for disk I/O error,
database is locked, and database disk image is malformed), the
explicit ROLLBACK in write_txn.__exit__ itself raises
cannot rollback - no transaction is active and the secondary exception
replaces the original in the traceback. Operators see a misleading error
and lose the diagnostic information they need.
Swallow the rollback-time OperationalError so the caller always sees the
original cause.
Confirmed reproducer: tests/hermes_cli/test_kanban_db.py::
test_write_txn_preserves_original_exception_when_rollback_fails
e83252dc46