Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
495 views
in Technique[技术] by (71.8m points)

activerecord - With Rails 4, Model.scoped is deprecated but Model.all can't replace it

Starting Rails 4, Model.scoped is now deprecated.

DEPRECATION WARNING: Model.scoped is deprecated. Please use Model.all instead.

But, there's a difference inModel.scoped and Model.all, that is, scoped.scoped returns a scope, while all.all runs the query.

On Rails 3:

> Model.scoped.scoped.is_a?(ActiveRecord::Relation)
=> true

On Rails 4:

> Model.all.all.is_a?(ActiveRecord::Relation)
DEPRECATION WARNING: Relation#all is deprecated. If you want to eager-load a relation, you can call #load (e.g. `Post.where(published: true).load`). If you want to get an array of records from a relation, you can call #to_a (e.g. `Post.where(published: true).to_a`).
=> false

There are use cases in libraries / concerns that returns scoped when there's a conditional to do something or nothing, like so:

module AmongConcern
  extend ActiveSupport::Concern

  module ClassMethods
    def among(ids)
      return scoped if ids.blank?

      where(id: ids)
    end
  end
end

If you'd change this scoped to all, you'd face random problems depending where the among was used in the scope chain. For instance, Model.where(some: value).among(ids) would run the query instead of returning a scope.

What I want is an idempotent method on ActiveRecord::Relation that simply returns a scope.

What should I do here?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

It seems that where(nil) is a real replacement of scoped, which works both on Rails 3 and 4. :(


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...