This series makes result metadata handling for auth LIST statements consistent and adds coverage for the driver-visible behavior.
The first patch makes the result-column metadata construction shared across the affected statements, so the metadata shape used for PREPARE and EXECUTE stays uniform and easier to reason about.
The second patch adds regression coverage for both sides of the metadata-id flow:
- a Python auth-cluster test verifies that prepared LIST ROLES OF returns a non-empty result metadata id and that a later EXECUTE reuses it without METADATA_CHANGED
- a Boost transport test covers the recovery path where the client sends an empty request metadata id and the server responds with METADATA_CHANGED and the full metadata
Together these patches tighten the implementation and protect the prepared-metadata-id behavior exposed to drivers.
Fixes: https://scylladb.atlassian.net/browse/SCYLLADB-1218
backport: this change should be backported to all active branches to help the driver operation
Closesscylladb/scylladb#29347
de19714763