mongodb/mongoid · error · AttributeError

Field #{name} is not an aliased field

Error message

Field #{name} is not an aliased field

What it means

Error "Field #{name} is not an aliased field" thrown in mongodb/mongoid.

Source

Thrown at lib/mongoid/attributes.rb:335

        aliased_fields[name.to_s] = original.to_s

        alias_method name, original
        alias_method "#{name}=", "#{original}="
        alias_method "#{name}?", "#{original}?"
        alias_method "#{name}_change", "#{original}_change"
        alias_method "#{name}_changed?", "#{original}_changed?"
        alias_method "reset_#{name}!", "reset_#{original}!"
        alias_method "reset_#{name}_to_default!", "reset_#{original}_to_default!"
        alias_method "#{name}_was", "#{original}_was"
        alias_method "#{name}_will_change!", "#{original}_will_change!"
        alias_method "#{name}_before_type_cast", "#{original}_before_type_cast"
      end

      # Removes a field alias.
      #
      # @param [ Symbol ] name The aliased field name to remove.
      def unalias_attribute(name)
        raise AttributeError, "Field #{name} is not an aliased field" unless aliased_fields.delete(name.to_s)

        remove_method name
        remove_method "#{name}="
        remove_method "#{name}?"
        remove_method "#{name}_change"
        remove_method "#{name}_changed?"
        remove_method "reset_#{name}!"
        remove_method "reset_#{name}_to_default!"
        remove_method "#{name}_was"
        remove_method "#{name}_will_change!"
        remove_method "#{name}_before_type_cast"
      end
    end

    def lookup_attribute_presence(name, value)
      value = localized_fields[name].send(:lookup, value) if localized_fields.has_key?(name) && value
      value.present?
    end

View on GitHub (pinned to 0da0e23d71)

When it happens

Trigger: Thrown at lib/mongoid/attributes.rb:335 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mongodb/mongoid@0da0e23d71 (2026-08-23). Data as JSON: /api/errors/9eae0c7acf61e751. Report an issue: GitHub.