AIKIDO-2026-569636

TL;DR

AshPostgres provides schema-based multitenancy where each tenant's data lives in its own PostgreSQL schema, and rename_tenant renames that schema. The function runs an ALTER SCHEMA ... RENAME TO ... statement with a non-raising query call, discards the result, and always returns :ok, so a rename that PostgreSQL rejects because the target schema already exists is still treated as successful. The manage_tenant update then commits the tenant record pointing at another existing tenant's schema, and subsequent reads and writes for that tenant run against the other tenant's data. The fix checks the query result and raises or rolls back the transaction when the rename fails.