active_record_scopes.md

How should ActiveRecord behave with merging conditions from various sources? See rails/rails#9813 for background.

• clobber: conflicting condition values are replaced with the rightmost value
• append: conflicting condition values are chained into an AND query

Direct find

class Person < ActiveRecord::Base
end

Example	3.2.12	3.2.14.rc2	Expected
Person.where(id: 1).find(2)	append	append
Person.where(id: [1, 3]).find(2)	append	append
Person.where("id = 1").find(2)	append	append
Person.where(name: "a").find_by_name("b")	append	append

Chained scopes

class Person < ActiveRecord::Base
  scope :sad, where(status: "sad")
  scope :confused, where(status: "confused")
  def self.frustrated
    where(status: "frustrated")
  end
end

Example	3.2.12	3.2.14.rc2	Expected
Person.where(status: "sad").where(status: "happy")	append	append
Person.confused.where(status: "happy")	append	append
Person.where(status: "happy").confused	clobber	clobber
Person.sad.confused	clobber	clobber
Person.sad.frustrated	append	append

Associations

class Manufacturer < ActiveRecord::Base
  has_many :products
end

class Product < ActiveRecord::Base
  belongs_to :manufacturer
end

Example	3.2.12	3.2.14.rc2	Expected
Manufacturer.find(1).products.where(manufacturer_id: 2)	append	append

Default Scopes

class Person < ActiveRecord::Base
  default_scope where(status: "meh")
  scope :confused, where(status: "confused")
  def self.frustrated
    where(status: "frustrated")
  end
end

Example	3.2.12	3.2.14.rc2	Expected
Person.confused	clobber	clobber
Person.frustrated	clobber	clobber