ActiveRecord::Enum is an attribute where the values map to integers in the database and can be queried by name. Read more about enum here.

When we define an enum in ActiveRecord, it generates a set of methods to interact with these enum values. These methods allow us to easily query and manipulate the enum values associated with a particular model instance.

Before

For instance, let’s assume we have a User model with an enum field called role:

class User < ApplicationRecord
  enum :role, { admin: 0, moderator: 1, regular: 2 }
end

Currently, we expect to have methods like:

# Class methods / Scopes
User.roles
User.admins
User.moderators 
User.regulars
.
.
# Instance methods
user = User.first

user.admin?
user.moderator?
user.regular?
.
. 
user.admin!
user.moderator!
user.regular!
.
.

After

Rails 7.1 introduces an option to disable all auto generated methods of ActiveRecord.enum with instance_methods: false.

class User < ApplicationRecord
  enum :role, { admin: 0, moderator: 1, regular: 2 }, instance_methods: false
end

user = User.first

user.role # => admin

user.admin?
# => `method_missing': undefined method `admin?' for #<User id: 1

user.regular! 
# => `method_missing': undefined method `regular!' for #<User id: 1

Summary

To disable the default methods generated by ActiveRecord.enum due to conflicts or unnecessary requirements, use instance_methods: false. This option helps avoid the generation of conflicting or unnecessary enum methods.