ROM::Struct mapping question

Hello ROM Community,

I’m currently exploring ROM for database interactions and have encountered an issue with mapping database results to my custom entity, specifically regarding a custom enum type.

Repository Setup: I have a Users::Repository set up as follows:

# frozen_string_literal: true

require 'rom-repository'

module Users
  class Repository < ROM::Repository[:users]
    commands :create, update: :by_pk, delete: :by_pk

    struct_namespace Users::Entities
    auto_struct true

I understood that struct_namespace Users::Entities would automatically map the database results to objects within the specified namespace.

Entity Definition: Here’s the definition of my User entity:

# frozen_string_literal: true

module Users
  module Entities
    class User < Users::Entity
      attribute :name, Types::String
      attribute :password, Types::String
      attribute :email, Types::String
      attribute :role, Types::Role

Custom Type Definition: The Types::Role is a custom enum type defined as:

module Types
    MEMBER = 'member'
    ADMIN = 'admin'

    Role = Types::String.default(MEMBER).enum(MEMBER => 0, ADMIN => 1).freeze

Issue: When fetching a user from the repository with user_repo.users.by_pk(6).one, the role attribute doesn’t map to its string representation (‘member’ or ‘admin’) but remains as an integer:

#<Users::Entities::User name="Name" password="hashed_pwd" email="" role=0 id=6>

However, when explicitly mapping to Users::Entities::User using user_repo.users.by_pk(6).map_to(Users::Entities::User).one, the mapping works correctly:

#<Users::Entities::User name="Name" password="hashed_pwd" email="" role='member' id=6>

Question: Why doesn’t the automatic mapping via struct_namespace correctly apply my custom enum type? Is there a configuration step I’m missing, or is this an expected behavior requiring explicit mapping?

Any insights or suggestions on how to resolve this would be greatly appreciated.

Thank you!