Rails 7.2.0中Enum已绑定数据库列仍报错的问题求助

在Rails 7.2.0环境下运行Tournament模型测试时，#status和#billing_status枚举属性抛出错误：

RuntimeError: Undeclared attribute type for enum 'status' in Tournament. Enums must be backed by a database column or declared with an explicit type via `attribute`.

但这两个字段已绑定PostgreSQL原生枚举列，db/schema.rb定义如下：

create_enum "tournament_billing_status", ["pending", "paid", "canceled", "rejected", "failed"]
create_enum "tournament_status", ["started", "created", "linked", "registering", "in_progress", "completed"]

create_table "tournaments", force: :cascade do |t|
  t.bigint "account_id"
  t.string "first_name"
  t.string "last_name"
  t.string "email"
  t.date "start_date"
  t.enum "status", default: "started", enum_type: "tournament_status"
  t.enum "billing_status", default: "pending", enum_type: "tournament_billing_status"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
  t.index ["account_id"], name: "index_tournaments_on_account_id"
end

模型使用Rails 7+的新Enum语法声明：

class Tournament < ApplicationRecord
  broadcasts_refreshes

  belongs_to :account

  validates :first_name, :last_name, :email, presence: true

  enum :status, {
    started: "started",
    created: "created",
    linked: "linked",
    registering: "registering",
    in_progress: "in_progress",
    completed: "completed"
  }

  enum :billing_status, {
    pending: "pending",
    paid: "paid",
    canceled: "canceled",
    rejected: "rejected",
    failed: "failed"
  }
end

手动添加attribute :status, :string和attribute :billing_status, :string后测试可正常通过，但理论上无需手动声明属性类型，特此求助问题原因及解决办法。

Rails 7.2.0强化了枚举的类型检查逻辑：当使用PostgreSQL原生枚举时，测试环境下Rails的属性加载机制可能无法正确识别枚举列的类型映射——原生枚举在Rails内部被标记为enum类型，但新的检查逻辑默认只认string类型列绑定枚举；再加上测试环境的schema缓存可能未完整加载枚举类型信息，最终触发该错误。

方案1：枚举声明时显式指定类型（最推荐） #

无需手动添加attribute，直接在枚举声明中通过type: :string指定类型（原生枚举本质是带约束的字符串类型）：

enum :status, {
  started: "started",
  created: "created",
  linked: "linked",
  registering: "registering",
  in_progress: "in_progress",
  completed: "completed"
}, type: :string

enum :billing_status, {
  pending: "pending",
  paid: "paid",
  canceled: "canceled",
  rejected: "rejected",
  failed: "failed"
}, type: :string

方案2：强制测试环境刷新schema缓存 #

在test_helper.rb中添加配置，每次测试前清空并重新加载schema缓存，确保Rails获取正确的枚举类型信息：

class ActiveSupport::TestCase
  setup do
    ActiveRecord::Base.connection.clear_cache!
    ActiveRecord::Base.schema_cache.clear!
    ActiveRecord::Base.connection.schema_cache.load!
  end
end

方案3：临时回退到7.1默认配置（不推荐长期使用） #

若项目从旧版Rails升级到7.2.0，可暂时修改config/application.rb中的默认加载版本，避开7.2的新检查逻辑，但建议尽快适配新特性：

config.load_defaults 7.1

Rails 7.2.0的类型检查是为了避免隐式类型错误，原生枚举本质是带约束的字符串类型，因此显式指定type: :string符合Rails设计逻辑，是最稳妥的解决方案。

内容的提问来源于stack exchange，提问作者Yardboy