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Deprecate eager-evaluated scopes.

Don't use this:

    scope :red, where(color: 'red')
    default_scope where(color: 'red')

Use this:

    scope :red, -> { where(color: 'red') }
    default_scope { where(color: 'red') }

The former has numerous issues. It is a common newbie gotcha to do
the following:

    scope :recent, where(published_at: Time.now - 2.weeks)

Or a more subtle variant:

    scope :recent, -> { where(published_at: Time.now - 2.weeks) }
    scope :recent_red, recent.where(color: 'red')

Eager scopes are also very complex to implement within Active
Record, and there are still bugs. For example, the following does
not do what you expect:

    scope :remove_conditions, except(:where)
    where(...).remove_conditions # => still has conditions
  • Loading branch information...
commit 0a12a5f8169685915cbb7bf4d0a7bb482f7f2fd2 1 parent fd68bd2
@jonleighton jonleighton authored
View
31 activerecord/CHANGELOG.md
@@ -1,5 +1,36 @@
## Rails 4.0.0 (unreleased) ##
+* Deprecate eager-evaluated scopes.
+
+ Don't use this:
+
+ scope :red, where(color: 'red')
+ default_scope where(color: 'red')
+
+ Use this:
+
+ scope :red, -> { where(color: 'red') }
+ default_scope { where(color: 'red') }
+
+ The former has numerous issues. It is a common newbie gotcha to do
+ the following:
+
+ scope :recent, where(published_at: Time.now - 2.weeks)
+
+ Or a more subtle variant:
+
+ scope :recent, -> { where(published_at: Time.now - 2.weeks) }
+ scope :recent_red, recent.where(color: 'red')
+
+ Eager scopes are also very complex to implement within Active
+ Record, and there are still bugs. For example, the following does
+ not do what you expect:
+
+ scope :remove_conditions, except(:where)
+ where(...).remove_conditions # => still has conditions
+
+ *Jon Leighton*
+
* Remove IdentityMap
IdentityMap has never graduated to be an "enabled-by-default" feature, due
View
25 activerecord/lib/active_record/scoping/default.rb
@@ -1,4 +1,5 @@
require 'active_support/concern'
+require 'active_support/deprecation'
module ActiveRecord
module Scoping
@@ -51,7 +52,7 @@ def before_remove_const #:nodoc:
# the model.
#
# class Article < ActiveRecord::Base
- # default_scope where(:published => true)
+ # default_scope { where(:published => true) }
# end
#
# Article.all # => SELECT * FROM articles WHERE published = true
@@ -62,12 +63,6 @@ def before_remove_const #:nodoc:
# Article.new.published # => true
# Article.create.published # => true
#
- # You can also use <tt>default_scope</tt> with a block, in order to have it lazily evaluated:
- #
- # class Article < ActiveRecord::Base
- # default_scope { where(:published_at => Time.now - 1.week) }
- # end
- #
# (You can also pass any object which responds to <tt>call</tt> to the <tt>default_scope</tt>
# macro, and it will be called when building the default scope.)
#
@@ -75,8 +70,8 @@ def before_remove_const #:nodoc:
# be merged together:
#
# class Article < ActiveRecord::Base
- # default_scope where(:published => true)
- # default_scope where(:rating => 'G')
+ # default_scope { where(:published => true) }
+ # default_scope { where(:rating => 'G') }
# end
#
# Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
@@ -94,6 +89,16 @@ def before_remove_const #:nodoc:
# end
def default_scope(scope = {})
scope = Proc.new if block_given?
+
+ if scope.is_a?(Relation) || !scope.respond_to?(:call)
+ ActiveSupport::Deprecation.warn(
+ "Calling #default_scope without a block is deprecated. For example instead " \
+ "of `default_scope where(color: 'red')`, please use " \
+ "`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
+ "self.default_scope.)"
+ )
+ end
+
self.default_scopes = default_scopes + [scope]
end
@@ -106,7 +111,7 @@ def build_default_scope #:nodoc:
if scope.is_a?(Hash)
default_scope.apply_finder_options(scope)
elsif !scope.is_a?(Relation) && scope.respond_to?(:call)
- default_scope.merge(scope.call)
+ default_scope.merge(unscoped { scope.call })
else
default_scope.merge(scope)
end
View
18 activerecord/lib/active_record/scoping/named.rb
@@ -3,6 +3,7 @@
require 'active_support/core_ext/kernel/singleton_class'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/class/attribute'
+require 'active_support/deprecation'
module ActiveRecord
# = Active Record Named \Scopes
@@ -171,11 +172,24 @@ def scope_attributes? # :nodoc:
# Article.published.featured.latest_article
# Article.featured.titles
- def scope(name, scope_options = {}, &block)
+ def scope(name, body = {}, &block)
extension = Module.new(&block) if block
+ # Check body.is_a?(Relation) to prevent the relation actually being
+ # loaded by respond_to?
+ if body.is_a?(Relation) || !body.respond_to?(:call)
+ ActiveSupport::Deprecation.warn(
+ "Using #scope without passing a callable object is deprecated. For " \
+ "example `scope :red, where(color: 'red')` should be changed to " \
+ "`scope :red, -> { where(color: 'red') }`. There are numerous gotchas " \
+ "in the former usage and it makes the implementation more complicated " \
+ "and buggy. (If you prefer, you can just define a class method named " \
+ "`self.red`.)"
+ )
+ end
+
singleton_class.send(:define_method, name) do |*args|
- options = scope_options.respond_to?(:call) ? unscoped { scope_options.call(*args) } : scope_options
+ options = body.respond_to?(:call) ? unscoped { body.call(*args) } : body
options = scoped.apply_finder_options(options) if options.is_a?(Hash)
relation = scoped.merge(options)
View
45 activerecord/test/cases/named_scope_test.rb
@@ -123,16 +123,6 @@ def test_scope_with_object
assert objects.all?(&:approved?), 'all objects should be approved'
end
- def test_extensions
- assert_equal 1, Topic.anonymous_extension.one
- assert_equal 2, Topic.named_extension.two
- end
-
- def test_multiple_extensions
- assert_equal 2, Topic.multiple_extensions.extension_two
- assert_equal 1, Topic.multiple_extensions.extension_one
- end
-
def test_has_many_associations_have_access_to_scopes
assert_not_equal Post.containing_the_letter_a, authors(:david).posts
assert !Post.containing_the_letter_a.empty?
@@ -464,6 +454,41 @@ def test_scoped_are_lazy_loaded_if_table_still_does_not_exist
require "models/without_table"
end
end
+
+ def test_eager_scopes_are_deprecated
+ klass = Class.new(ActiveRecord::Base)
+ klass.table_name = 'posts'
+
+ assert_deprecated do
+ klass.scope :welcome, { :conditions => { :id => posts(:welcome).id } }
+ end
+ assert_equal [posts(:welcome).title], klass.welcome.map(&:title)
+
+ assert_deprecated do
+ klass.scope :welcome_2, klass.where(:id => posts(:welcome).id)
+ end
+ assert_equal [posts(:welcome).title], klass.welcome_2.map(&:title)
+ end
+
+ def test_eager_default_scope_hashes_are_deprecated
+ klass = Class.new(ActiveRecord::Base)
+ klass.table_name = 'posts'
+
+ assert_deprecated do
+ klass.send(:default_scope, :conditions => { :id => posts(:welcome).id })
+ end
+ assert_equal [posts(:welcome).title], klass.all.map(&:title)
+ end
+
+ def test_eager_default_scope_relations_are_deprecated
+ klass = Class.new(ActiveRecord::Base)
+ klass.table_name = 'posts'
+
+ assert_deprecated do
+ klass.send(:default_scope, klass.where(:id => posts(:welcome).id))
+ end
+ assert_equal [posts(:welcome).title], klass.all.map(&:title)
+ end
end
class DynamicScopeMatchTest < ActiveRecord::TestCase
View
4 activerecord/test/models/author.rb
@@ -140,8 +140,8 @@ def testing_proxy_target
has_many :posts_with_default_include, :class_name => 'PostWithDefaultInclude'
has_many :comments_on_posts_with_default_include, :through => :posts_with_default_include, :source => :comments
- scope :relation_include_posts, includes(:posts)
- scope :relation_include_tags, includes(:tags)
+ scope :relation_include_posts, -> { includes(:posts) }
+ scope :relation_include_tags, -> { includes(:tags) }
attr_accessor :post_log
after_initialize :set_post_log
View
2  activerecord/test/models/bulb.rb
@@ -1,5 +1,5 @@
class Bulb < ActiveRecord::Base
- default_scope where(:name => 'defaulty')
+ default_scope { where(:name => 'defaulty') }
belongs_to :car
attr_protected :car_id, :frickinawesome
View
12 activerecord/test/models/car.rb
@@ -11,18 +11,18 @@ class Car < ActiveRecord::Base
has_many :engines, :dependent => :destroy
has_many :wheels, :as => :wheelable, :dependent => :destroy
- scope :incl_tyres, includes(:tyres)
- scope :incl_engines, includes(:engines)
+ scope :incl_tyres, -> { includes(:tyres) }
+ scope :incl_engines, -> { includes(:engines) }
- scope :order_using_new_style, order('name asc')
- scope :order_using_old_style, :order => 'name asc'
+ scope :order_using_new_style, -> { order('name asc') }
+ scope :order_using_old_style, -> { { :order => 'name asc' } }
end
class CoolCar < Car
- default_scope :order => 'name desc'
+ default_scope { order('name desc') }
end
class FastCar < Car
- default_scope :order => 'name desc'
+ default_scope { order('name desc') }
end
View
2  activerecord/test/models/categorization.rb
@@ -12,7 +12,7 @@ class Categorization < ActiveRecord::Base
class SpecialCategorization < ActiveRecord::Base
self.table_name = 'categorizations'
- default_scope where(:special => true)
+ default_scope { where(:special => true) }
belongs_to :author
belongs_to :category
View
2  activerecord/test/models/category.rb
@@ -27,7 +27,7 @@ def self.what_are_you
has_many :authors, :through => :categorizations
has_many :authors_with_select, :through => :categorizations, :source => :author, :select => 'authors.*, categorizations.post_id'
- scope :general, :conditions => { :name => 'General' }
+ scope :general, -> { where(:name => 'General') }
end
class SpecialCategory < Category
View
14 activerecord/test/models/comment.rb
@@ -1,12 +1,10 @@
class Comment < ActiveRecord::Base
scope :limit_by, lambda {|l| limit(l) }
- scope :containing_the_letter_e, :conditions => "comments.body LIKE '%e%'"
- scope :not_again, where("comments.body NOT LIKE '%again%'")
- scope :for_first_post, :conditions => { :post_id => 1 }
- scope :for_first_author,
- :joins => :post,
- :conditions => { "posts.author_id" => 1 }
- scope :created
+ scope :containing_the_letter_e, -> { where("comments.body LIKE '%e%'") }
+ scope :not_again, -> { where("comments.body NOT LIKE '%again%'") }
+ scope :for_first_post, -> { where(:post_id => 1) }
+ scope :for_first_author, -> { joins(:post).where("posts.author_id" => 1) }
+ scope :created, -> { scoped }
belongs_to :post, :counter_cache => true
has_many :ratings
@@ -25,7 +23,7 @@ def self.search_by_type(q)
def self.all_as_method
all
end
- scope :all_as_scope, {}
+ scope :all_as_scope, -> { scoped }
end
class SpecialComment < Comment
View
32 activerecord/test/models/developer.rb
@@ -45,7 +45,7 @@ def find_least_recent
has_many :audit_logs
- scope :jamises, :conditions => {:name => 'Jamis'}
+ scope :jamises, -> { where(:name => 'Jamis') }
validates_inclusion_of :salary, :in => 50000..200000
validates_length_of :name, :within => 3..20
@@ -88,20 +88,20 @@ def raise_if_projects_empty!
class DeveloperWithSelect < ActiveRecord::Base
self.table_name = 'developers'
- default_scope select('name')
+ default_scope { select('name') }
end
class DeveloperWithIncludes < ActiveRecord::Base
self.table_name = 'developers'
has_many :audit_logs, :foreign_key => :developer_id
- default_scope includes(:audit_logs)
+ default_scope { includes(:audit_logs) }
end
class DeveloperOrderedBySalary < ActiveRecord::Base
self.table_name = 'developers'
- default_scope :order => 'salary DESC'
+ default_scope { order('salary DESC') }
- scope :by_name, order('name DESC')
+ scope :by_name, -> { order('name DESC') }
def self.all_ordered_by_name
with_scope(:find => { :order => 'name DESC' }) do
@@ -112,7 +112,7 @@ def self.all_ordered_by_name
class DeveloperCalledDavid < ActiveRecord::Base
self.table_name = 'developers'
- default_scope where("name = 'David'")
+ default_scope { where("name = 'David'") }
end
class LazyLambdaDeveloperCalledDavid < ActiveRecord::Base
@@ -140,7 +140,7 @@ def self.default_scope
class ClassMethodReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
self.table_name = 'developers'
- scope :david, where(:name => 'David')
+ scope :david, -> { where(:name => 'David') }
def self.default_scope
david
@@ -149,40 +149,40 @@ def self.default_scope
class LazyBlockReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
self.table_name = 'developers'
- scope :david, where(:name => 'David')
+ scope :david, -> { where(:name => 'David') }
default_scope { david }
end
class DeveloperCalledJamis < ActiveRecord::Base
self.table_name = 'developers'
- default_scope where(:name => 'Jamis')
- scope :poor, where('salary < 150000')
+ default_scope { where(:name => 'Jamis') }
+ scope :poor, -> { where('salary < 150000') }
end
class PoorDeveloperCalledJamis < ActiveRecord::Base
self.table_name = 'developers'
- default_scope where(:name => 'Jamis', :salary => 50000)
+ default_scope -> { where(:name => 'Jamis', :salary => 50000) }
end
class InheritedPoorDeveloperCalledJamis < DeveloperCalledJamis
self.table_name = 'developers'
- default_scope where(:salary => 50000)
+ default_scope -> { where(:salary => 50000) }
end
class MultiplePoorDeveloperCalledJamis < ActiveRecord::Base
self.table_name = 'developers'
- default_scope where(:name => 'Jamis')
- default_scope where(:salary => 50000)
+ default_scope -> { where(:name => 'Jamis') }
+ default_scope -> { where(:salary => 50000) }
end
module SalaryDefaultScope
extend ActiveSupport::Concern
- included { default_scope where(:salary => 50000) }
+ included { default_scope { where(:salary => 50000) } }
end
class ModuleIncludedPoorDeveloperCalledJamis < DeveloperCalledJamis
@@ -195,7 +195,7 @@ class EagerDeveloperWithDefaultScope < ActiveRecord::Base
self.table_name = 'developers'
has_and_belongs_to_many :projects, :foreign_key => 'developer_id', :join_table => 'developers_projects', :order => 'projects.id'
- default_scope includes(:projects)
+ default_scope { includes(:projects) }
end
class EagerDeveloperWithClassMethodDefaultScope < ActiveRecord::Base
View
2  activerecord/test/models/organization.rb
@@ -8,5 +8,5 @@ class Organization < ActiveRecord::Base
has_one :author, :primary_key => :name
has_one :author_owned_essay_category, :through => :author, :source => :owned_essay_category
- scope :clubs, { :from => 'clubs' }
+ scope :clubs, -> { from('clubs') }
end
View
4 activerecord/test/models/person.rb
@@ -27,8 +27,8 @@ class Person < ActiveRecord::Base
has_many :agents_posts, :through => :agents, :source => :posts
has_many :agents_posts_authors, :through => :agents_posts, :source => :author
- scope :males, :conditions => { :gender => 'M' }
- scope :females, :conditions => { :gender => 'F' }
+ scope :males, -> { where(:gender => 'M') }
+ scope :females, -> { where(:gender => 'F') }
end
class PersonWithDependentDestroyJobs < ActiveRecord::Base
View
16 activerecord/test/models/post.rb
@@ -5,8 +5,8 @@ def author
end
end
- scope :containing_the_letter_a, where("body LIKE '%a%'")
- scope :ranked_by_comments, order("comments_count DESC")
+ scope :containing_the_letter_a, -> { where("body LIKE '%a%'") }
+ scope :ranked_by_comments, -> { order("comments_count DESC") }
scope :limit_by, lambda {|l| limit(l) }
scope :with_authors_at_address, lambda { |address| {
@@ -30,8 +30,8 @@ def first_comment
has_one :first_comment, :class_name => 'Comment', :order => 'id ASC'
has_one :last_comment, :class_name => 'Comment', :order => 'id desc'
- scope :with_special_comments, :joins => :comments, :conditions => {:comments => {:type => 'SpecialComment'} }
- scope :with_very_special_comments, joins(:comments).where(:comments => {:type => 'VerySpecialComment'})
+ scope :with_special_comments, -> { joins(:comments).where(:comments => {:type => 'SpecialComment'}) }
+ scope :with_very_special_comments, -> { joins(:comments).where(:comments => {:type => 'VerySpecialComment'}) }
scope :with_post, lambda {|post_id|
{ :joins => :comments, :conditions => {:comments => {:post_id => post_id} } }
}
@@ -171,7 +171,7 @@ class PostForAuthor < ActiveRecord::Base
class FirstPost < ActiveRecord::Base
self.table_name = 'posts'
- default_scope where(:id => 1)
+ default_scope { where(:id => 1) }
has_many :comments, :foreign_key => :post_id
has_one :comment, :foreign_key => :post_id
@@ -179,16 +179,16 @@ class FirstPost < ActiveRecord::Base
class PostWithDefaultInclude < ActiveRecord::Base
self.table_name = 'posts'
- default_scope includes(:comments)
+ default_scope { includes(:comments) }
has_many :comments, :foreign_key => :post_id
end
class PostWithDefaultScope < ActiveRecord::Base
self.table_name = 'posts'
- default_scope :order => :title
+ default_scope { order(:title) }
end
class SpecialPostWithDefaultScope < ActiveRecord::Base
self.table_name = 'posts'
- default_scope where(:id => [1, 5,6])
+ default_scope { where(:id => [1, 5,6]) }
end
View
2  activerecord/test/models/project.rb
@@ -32,7 +32,7 @@ def set_developers_log
def self.all_as_method
all
end
- scope :all_as_scope, {}
+ scope :all_as_scope, -> { scoped }
end
class SpecialProject < Project
View
2  activerecord/test/models/reference.rb
@@ -19,5 +19,5 @@ def make_comments
class BadReference < ActiveRecord::Base
self.table_name = 'references'
- default_scope where(:favourite => false)
+ default_scope { where(:favourite => false) }
end
View
2  activerecord/test/models/reply.rb
@@ -1,7 +1,7 @@
require 'models/topic'
class Reply < Topic
- scope :base
+ scope :base, -> { scoped }
belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true
belongs_to :topic_with_primary_key, :class_name => "Topic", :primary_key => "title", :foreign_key => "parent_title", :counter_cache => "replies_count"
View
23 activerecord/test/models/topic.rb
@@ -1,21 +1,24 @@
class Topic < ActiveRecord::Base
- scope :base
+ scope :base, -> { scoped }
scope :written_before, lambda { |time|
if time
{ :conditions => ['written_on < ?', time] }
end
}
- scope :approved, :conditions => {:approved => true}
- scope :rejected, :conditions => {:approved => false}
+ scope :approved, -> { where(:approved => true) }
+ scope :rejected, -> { where(:approved => false) }
scope :scope_with_lambda, lambda { scoped }
- scope :by_lifo, :conditions => {:author_name => 'lifo'}
+ scope :by_lifo, -> { where(:author_name => 'lifo') }
- scope :approved_as_hash_condition, :conditions => {:topics => {:approved => true}}
- scope 'approved_as_string', :conditions => {:approved => true}
- scope :replied, :conditions => ['replies_count > 0']
- scope :anonymous_extension do
+ ActiveSupport::Deprecation.silence do
+ scope :approved_as_hash_condition, :conditions => {:topics => {:approved => true}}
+ scope :replied, :conditions => ['replies_count > 0']
+ end
+
+ scope 'approved_as_string', -> { where(:approved => true) }
+ scope :anonymous_extension, -> { scoped } do
def one
1
end
@@ -42,8 +45,8 @@ def extension_two
2
end
end
- scope :named_extension, :extend => NamedExtension
- scope :multiple_extensions, :extend => [MultipleExtensionTwo, MultipleExtensionOne]
+ scope :named_extension, -> { { :extend => NamedExtension } }
+ scope :multiple_extensions, -> { { :extend => [MultipleExtensionTwo, MultipleExtensionOne] } }
has_many :replies, :dependent => :destroy, :foreign_key => "parent_id"
has_many :replies_with_primary_key, :class_name => "Reply", :dependent => :destroy, :primary_key => "title", :foreign_key => "parent_title"
View
2  activerecord/test/models/toy.rb
@@ -2,5 +2,5 @@ class Toy < ActiveRecord::Base
self.primary_key = :toy_id
belongs_to :pet
- scope :with_pet, joins(:pet)
+ scope :with_pet, -> { joins(:pet) }
end
View
2  activerecord/test/models/without_table.rb
@@ -1,3 +1,3 @@
class WithoutTable < ActiveRecord::Base
- default_scope where(:published => true)
+ default_scope -> { where(:published => true) }
end

7 comments on commit 0a12a5f

@drewblas

I agree with the concept of the change that scopes should be encapsulated in a proc/block in order to prevent errors from execution However, why is the method signature of 'scope' and 'default_scope' so different? They should both either take a block or a lambda (or both). But instead, scope takes a block and does something totally different with it. Either they should both do the same thing with the block or not take a block at all. Otherwise it becomes very confusing to track which method accepts which format.

@jonleighton
Collaborator

At the moment scope takes a proxy extension as its block argument. I plan to deprecate that too, after which we can make it use the block as its definition as an alternative.

Note that that requires parens around the args so it's a matter of style:

scope :foo, -> { ... }
scope(:foo) { ... }
@exviva

how about taking a hash:

scope foo: -> { ... }
@drewblas

Awesome, +1 for deprecating the proxy extension.

@fxn
Owner

@jonleighton could you please update the finders guide? There's a section about scopes. Documentation needs to reflect the current ways to do things. There is no need to add content about the deprecated idioms, guides rarely mention deprecated APIs, modernizing the current coverage is enough.

@jonleighton
Collaborator
@fxn
Owner

@jonleighton awesome

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