In 8df61f6d99 we changed the requirements for creating materialized
views and MV-based indexes - instead of requiring the
rf_rack_valid_keyspaces flag to be set, we now require the keyspace to
be RF-rack-valid at the time of creation, and it is enforced to remain
RF-rack-valid while the MV exists. This validation is done in the cql
create view/index statements.
The same should be done also for alternator - when creating a table with
GSI or LSI, or when adding a GSI to an existing table, previously we
required the flag rf_rack_valid_keyspaces to be set. Now we change it to
instead check if the keyspace is RF-rack-valid, and if not the operation
fails with an appropriate error.
Fixes https://github.com/scylladb/scylladb/issues/28214
backport to 2025.4 to add RF-rack-valid enforcements in alternator
Closesscylladb/scylladb#28154
* github.com:scylladb/scylladb:
locator: document the exception type of assert_rf_rack_valid_keyspace
alternator: don't require rf_rack flag for indexes, validate instead
fe9237fdc9