Rails Active Record 8.1

Apply the Ruby on Rails 8.1 prompt first, including its Ruby 4.0 baseline. Active Record is released in lockstep with the other Rails gems, so upgrade it together with the rest of the framework rather than on its own.

Queries and scope integrity

• Prefer typed hash predicates such as where(id: id) or fixed SQL templates with separate values such as where("amount >= ?", amount). Review find_by_sql, exec_query, and fragments in select, pluck, order, group, having, joins, and from; map exposed query choices to fixed expressions and bind values through each API's parameter interface.
• Treat Arel.sql as permission to use SQL syntax. Supply only a trusted template and separate binds; wrapping an interpolated string does not sanitize it, and placeholder tokens without bind arguments remain literal SQL.
• Do not pass untrusted SQL strings to sanitize_sql_for_conditions or sanitize_sql_for_assignment: they return plain strings unchanged. Their array forms quote values without column-aware type casting. For literal LIKE searches, apply sanitize_sql_like to the search text before supplying the resulting pattern as a query value.
• Make authorization scopes return none or raise when identity or policy input is absent. A named scope returning nil or false falls back to the current relation, and where(nil) or where({}) leaves it unrestricted by that call.
• Review unscoped, unscope, rewhere, invert_where, and merge for removed, replaced, or inverted tenant predicates; scope both branches of or. An association's unscoped can