v-kolesnikov/emilito

This cop looks for has_many or has_one associations that don't specify a :dependent option. It doesn't register an offense if :through option was specified.

Example:

# bad
class User < ActiveRecord::Base
  has_many :comments
  has_one :avatar
end
 
# good
class User < ActiveRecord::Base
  has_many :comments, dependent: :restrict_with_exception
  has_one :avatar, dependent: :destroy
  has_many :patients, through: :appointments
end

This cop looks for has_many or has_one associations that don't specify a :dependent option. It doesn't register an offense if :through option was specified.

Example:

# bad
class User < ActiveRecord::Base
  has_many :comments
  has_one :avatar
end
 
# good
class User < ActiveRecord::Base
  has_many :comments, dependent: :restrict_with_exception
  has_one :avatar, dependent: :destroy
  has_many :patients, through: :appointments
end

This cop looks for has_many or has_one associations that don't specify a :dependent option. It doesn't register an offense if :through option was specified.

Example:

# bad
class User < ActiveRecord::Base
  has_many :comments
  has_one :avatar
end
 
# good
class User < ActiveRecord::Base
  has_many :comments, dependent: :restrict_with_exception
  has_one :avatar, dependent: :destroy
  has_many :patients, through: :appointments
end

This cop looks for has(one|many) and belongsto associations where ActiveRecord can't automatically determine the inverse association because of a scope or the options used. This can result in unnecessary queries in some circumstances. :inverse_of must be manually specified for associations to work in both ways, or set to false to opt-out.

Example:

# good
class Blog < ApplicationRecord
  has_many :posts
end
 
class Post < ApplicationRecord
  belongs_to :blog
end

Example:

# bad
class Blog < ApplicationRecord
  has_many :posts, -> { order(published_at: :desc) }
end
 
class Post < ApplicationRecord
  belongs_to :blog
end
 
# good
class Blog < ApplicationRecord
  has_many(:posts,
    -> { order(published_at: :desc) },
    inverse_of: :blog
  )
end
 
class Post < ApplicationRecord
  belongs_to :blog
end
 
# good
class Blog < ApplicationRecord
  with_options inverse_of: :blog do
    has_many :posts, -> { order(published_at: :desc) }
  end
end
 
class Post < ApplicationRecord
  belongs_to :blog
end

Example:

# bad
class Picture < ApplicationRecord
  belongs_to :imageable, polymorphic: true
end
 
class Employee < ApplicationRecord
  has_many :pictures, as: :imageable
end
 
class Product < ApplicationRecord
  has_many :pictures, as: :imageable
end
 
# good
class Picture < ApplicationRecord
  belongs_to :imageable, polymorphic: true
end
 
class Employee < ApplicationRecord
  has_many :pictures, as: :imageable, inverse_of: :imageable
end
 
class Product < ApplicationRecord
  has_many :pictures, as: :imageable, inverse_of: :imageable
end

Example:

# bad
# However, RuboCop can not detect this pattern...
class Physician < ApplicationRecord
  has_many :appointments
  has_many :patients, through: :appointments
end
 
class Appointment < ApplicationRecord
  belongs_to :physician
  belongs_to :patient
end
 
class Patient < ApplicationRecord
  has_many :appointments
  has_many :physicians, through: :appointments
end
 
# good
class Physician < ApplicationRecord
  has_many :appointments
  has_many :patients, through: :appointments
end
 
class Appointment < ApplicationRecord
  belongs_to :physician, inverse_of: :appointments
  belongs_to :patient, inverse_of: :appointments
end
 
class Patient < ApplicationRecord
  has_many :appointments
  has_many :physicians, through: :appointments
end

@see http://guides.rubyonrails.org/association_basics.html#bi-directional-associations @see http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#module-ActiveRecord::Associations::ClassMethods-label-Setting+Inverses