The loader is writing to pending replica even when write selector is set
to previous. If migration is reverted, then the writes won't be rolled
back as it assumes pending replicas weren't written to yet. That can
cause data resurrection if tablet is later migrated back into the same
replica.
NOTE: write selector is handled correctly when set to next, because
get_natural_endpoints() will return the next replica set, and none
of the replicas will be considered leaving. And of course, selector
set to both is also handled correctly.
Fixes#17892.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#17902