output.txt

# Rails 4.0

-- create_table(:posts)
   -> 0.0217s
-- create_table(:comments)
   -> 0.0005s
4.0.1
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?  ORDER BY comments.id desc
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?  ORDER BY comments.id desc
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?  ORDER BY comments.id desc

# Rails edge

-- create_table(:posts)
   -> 0.0056s
-- create_table(:comments)
   -> 0.0005s
4.1.0.beta
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?  ORDER BY comments.id desc
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?
SELECT "comments".* FROM "comments"  WHERE "comments"."post_id" = ?

unscope.rb

gem "rails", "~> 4.0.0"

require "active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")

ActiveRecord::Schema.define do
  create_table :posts

  create_table :comments do |t|
    t.integer :post_id
  end
end

class Comment < ActiveRecord::Base
  default_scope { order "comments.id desc" }
end

class Post < ActiveRecord::Base
  has_many :comments
end

puts ActiveRecord::VERSION::STRING

post = Post.create

puts post.comments.to_sql
puts post.comments.except(:order).to_sql
puts post.comments.unscope(:order).to_sql