There's a flaw in table::query() -- calling querier_opt->close() can dereferences a disengaged std::optional. The fix pretty simple. Once fixed, there are two if-s checking for querier_opt being engaged or not that are worth being merged.
The problem doesn't really shows itself becase table::query() is not called with null saved_querier, so the de-facto if is always correct. However, better to be on safe-side.
The problem doesn't show itself for real, not worth backporting
Closesscylladb/scylladb#29142
* github.com:scylladb/scylladb:
table: merge adjacent querier_opt checks in query()
table: don't close a disengaged querier in query()
56c375b1f3