    def check_add_foreign_key(*args)
      options = args.extract_options!
      from_table, to_table = args

      validate = options.fetch(:validate, true)
      if postgresql? && validate
        if StrongMigrations.safe_by_default
          safe_add_foreign_key(*args, **options)
          throw :safe
        end

        raise_error :add_foreign_key,
          add_foreign_key_code: command_str("add_foreign_key", [from_table, to_table, options.merge(validate: false)]),
          validate_foreign_key_code: command_str("validate_foreign_key", [from_table, to_table])
      elsif mysql? || mariadb?
        raise_error :add_foreign_key_mysql,
          add_foreign_key_code: command_str("add_foreign_key", [from_table, to_table, options]),
          # TODO exclude some options?
          remove_foreign_key_code: command_str("remove_foreign_key", [from_table, to_table, options])
      end
    end

    def check_add_index(*args)
      options = args.extract_options!
      table, columns = args

      if columns.is_a?(Array) && columns.size > 3 && !options[:unique]
        raise_error :add_index_columns, header: "Best practice"
      end

      # safe_by_default goes through this path as well
      if postgresql? && options[:algorithm] == :concurrently && adapter.index_corruption?
        raise_error :add_index_corruption
      end

      # safe to add non-concurrently to new tables (even after inserting data)
      # since the table won't be in use by the application
      if postgresql? && options[:algorithm] != :concurrently && !new_table?(table)
        if StrongMigrations.safe_by_default
          safe_add_index(*args, **options)
          throw :safe
        end

        raise_error :add_index, command: command_str("add_index", [table, columns, options.merge(algorithm: :concurrently)])
      end

      check_algorithm_option("add_index", *args, **options)

      check_lock_option("add_index", *args, **options)
    end

Échauffement