Added :include as an option for association declarations [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2898 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

9 files changed, 69 insertions, 13 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 75af4c8902..51a451e224 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,9 @@
 *SVN*
 
+* Added :include as an option for association declarations [DHH]. Example:
+
+    has_many :posts, :include => [ :author, :comments ]
+
 * Rename Base.constrain to Base.with_scope so it doesn't conflict with existing concept of database constraints.  Make scoping more robust: uniform method => parameters, validated method names and supported finder parameters, raise exception on nested scopes.  [Jeremy Kemper]  Example:
 
     Comment.with_scope(:find => { :conditions => 'active=true' }, :create => { :post_id => 5 }) do
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 45d23eac1d..ff6775e027 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -323,9 +323,11 @@ module ActiveRecord
       # * <tt>:counter_sql</tt>  - specify a complete SQL statement to fetch the size of the association. If +:finder_sql+ is
       #   specified but +:counter_sql+, +:counter_sql+ will be generated by replacing SELECT ... FROM with SELECT COUNT(*) FROM.
       # * <tt>:extend</tt>  - specify a named module for extending the proxy, see "Association extensions".
+      # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when the collection is loaded.
       #
       # Option examples:
       #   has_many :comments, :order => "posted_on"
+      #   has_many :comments, :include => :author
       #   has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
       #   has_many :tracks, :order => "position", :dependent => true
       #   has_many :subscribers, :class_name => "Person", :finder_sql =>
@@ -336,7 +338,7 @@ module ActiveRecord
       def has_many(association_id, options = {}, &extension)
         options.assert_valid_keys(
           :foreign_key, :class_name, :exclusively_dependent, :dependent, 
-          :conditions, :order, :finder_sql, :counter_sql, 
+          :conditions, :order, :include, :finder_sql, :counter_sql, 
           :before_add, :after_add, :before_remove, :after_remove, :extend
         )
 
@@ -417,13 +419,14 @@ module ActiveRecord
       # * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
       #   of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_one association will use "person_id"
       #   as the default foreign_key.
+      # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when this object is loaded.
       #
       # Option examples:
       #   has_one :credit_card, :dependent => true
       #   has_one :last_comment, :class_name => "Comment", :order => "posted_on"
       #   has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
       def has_one(association_id, options = {})
-        options.assert_valid_keys(:class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache, :extend)
+        options.assert_valid_keys(:class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend)
 
         association_name, association_class_name, association_class_primary_key_name =
             associate_identification(association_id, options[:class_name], options[:foreign_key], false)
@@ -496,6 +499,7 @@ module ActiveRecord
       #   and decrement_counter. The counter cache is incremented when an object of this class is created and decremented when it's
       #   destroyed. This requires that a column named "#{table_name}_count" (such as comments_count for a belonging Comment class)
       #   is used on the associate class (such as a Post class).
+      # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when this object is loaded.
       #
       # Option examples:
       #   belongs_to :firm, :foreign_key => "client_of"
@@ -503,7 +507,7 @@ module ActiveRecord
       #   belongs_to :valid_coupon, :class_name => "Coupon", :foreign_key => "coupon_id", 
       #              :conditions => 'discounts > #{payments_count}'
       def belongs_to(association_id, options = {})
-        options.assert_valid_keys(:class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache, :extend)
+        options.assert_valid_keys(:class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend)
 
         association_name, association_class_name, class_primary_key_name =
             associate_identification(association_id, options[:class_name], options[:foreign_key], false)
@@ -613,16 +617,18 @@ module ActiveRecord
       # * <tt>:insert_sql</tt> - overwrite the default generated SQL used to add links between the associated classes
       #   with a manual one
       # * <tt>:extend</tt>  - anonymous module for extending the proxy, see "Association extensions".
+      # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when the collection is loaded.
       #
       # Option examples:
       #   has_and_belongs_to_many :projects
+      #   has_and_belongs_to_many :projects, :include => [ :milestones, :manager ]
       #   has_and_belongs_to_many :nations, :class_name => "Country"
       #   has_and_belongs_to_many :categories, :join_table => "prods_cats"
       #   has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql => 
       #   'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}'
       def has_and_belongs_to_many(association_id, options = {}, &extension)
         options.assert_valid_keys(
-          :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions,
+          :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions, :include,
           :join_table, :finder_sql, :delete_sql, :insert_sql, :order, :uniq, :before_add, :after_add, 
           :before_remove, :after_remove, :extend
         )
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index 9dc0e26e10..528c42cea7 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -49,9 +49,13 @@ module ActiveRecord
       private
         def find_target
           if @options[:conditions]
-            @association_class.find_on_conditions(@owner[@association_class_primary_key_name], interpolate_sql(@options[:conditions]))
+            @association_class.find(
+              @owner[@association_class_primary_key_name], 
+              :conditions => interpolate_sql(@options[:conditions]),
+              :include    => @options[:include]
+            )
           else
-            @association_class.find(@owner[@association_class_primary_key_name])
+            @association_class.find(@owner[@association_class_primary_key_name], :include => @options[:include])
           end
         end
 
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index a90d89a69b..2a51efb94f 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -90,7 +90,7 @@ module ActiveRecord
           if @options[:finder_sql]
             records = @association_class.find_by_sql(@finder_sql)
           else
-            records = find(:all)
+            records = find(:all, :include => @options[:include])
           end
           
           @options[:uniq] ? uniq(records) : records
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index 9ee06ffbcb..3027e26ce0 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -23,12 +23,12 @@ module ActiveRecord
       # DEPRECATED.
       def find_all(runtime_conditions = nil, orderings = nil, limit = nil, joins = nil)
         if @options[:finder_sql]
-          records = @association_class.find_by_sql(@finder_sql)
+          @association_class.find_by_sql(@finder_sql)
         else
-          sql = @finder_sql
-          sql += " AND (#{sanitize_sql(runtime_conditions)})" if runtime_conditions
+          conditions = @finder_sql
+          conditions += " AND (#{sanitize_sql(runtime_conditions)})" if runtime_conditions
           orderings ||= @options[:order]
-          records = @association_class.find_all(sql, orderings, limit, joins)
+          @association_class.find_all(conditions, orderings, limit, joins)
         end
       end
 
@@ -105,7 +105,17 @@ module ActiveRecord
         end
             
         def find_target
-          find_all
+          if @options[:finder_sql]
+            @association_class.find_by_sql(@finder_sql)
+          else
+            @association_class.find(:all, 
+              :conditions => @finder_sql,
+              :order      => @options[:order], 
+              :limit      => @options[:limit],
+              :joins      => @options[:joins],
+              :include    => @options[:include]
+            )
+          end
         end
 
         def count_records
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index 18f84ee98f..edd9e53c19 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -57,7 +57,7 @@ module ActiveRecord
             
       private
         def find_target
-          @association_class.find(:first, :conditions => @finder_sql, :order => @options[:order])
+          @association_class.find(:first, :conditions => @finder_sql, :order => @options[:order], :include => @options[:include])
         end
 
         def target_obsolete?
diff --git a/activerecord/test/associations_go_eager_test.rb b/activerecord/test/associations_go_eager_test.rb
index c2e903fa2c..f05e5c6fe2 100644
--- a/activerecord/test/associations_go_eager_test.rb
+++ b/activerecord/test/associations_go_eager_test.rb
@@ -186,4 +186,29 @@ class EagerAssociationTest < Test::Unit::TestCase
     assert_nothing_raised { Post.find(:all, :include => 'comments') }
   end
 
+  def test_preconfigured_includes_with_belongs_to
+    author = posts(:welcome).author_with_posts
+    assert_equal 5, author.posts.size
+  end
+
+  def test_preconfigured_includes_with_has_one
+    comment = posts(:sti_comments).very_special_comment_with_post
+    assert_equal posts(:sti_comments), comment.post
+  end
+
+  def test_preconfigured_includes_with_has_many
+    posts = authors(:david).posts_with_comments
+    assert_equal 2, posts.first.comments.size
+  end
+
+  def test_preconfigured_includes_with_habtm
+    posts = authors(:david).posts_with_categories
+    assert_equal 2, posts.first.categories.size
+  end
+
+  def test_preconfigured_includes_with_has_many_and_habtm
+    posts = authors(:david).posts_with_comments_and_categories
+    assert_equal 2, posts.first.comments.size
+    assert_equal 2, posts.first.categories.size
+  end
 end
diff --git a/activerecord/test/fixtures/author.rb b/activerecord/test/fixtures/author.rb
index ea0094de39..c183940c2f 100644
--- a/activerecord/test/fixtures/author.rb
+++ b/activerecord/test/fixtures/author.rb
@@ -1,5 +1,9 @@
 class Author < ActiveRecord::Base
   has_many :posts
+  has_many :posts_with_comments, :include => :comments, :class_name => "Post"
+  has_many :posts_with_categories, :include => :categories, :class_name => "Post"
+  has_many :posts_with_comments_and_categories, :include => [ :comments, :categories ], :class_name => "Post"
+
   has_many :posts_with_callbacks, :class_name => "Post", :before_add => :log_before_adding,
   				 :after_add => :log_after_adding, :before_remove => :log_before_removing,
   				 :after_remove => :log_after_removing
diff --git a/activerecord/test/fixtures/post.rb b/activerecord/test/fixtures/post.rb
index 1697f0a599..bf44d8a0a5 100644
--- a/activerecord/test/fixtures/post.rb
+++ b/activerecord/test/fixtures/post.rb
@@ -5,6 +5,8 @@ class Post < ActiveRecord::Base
     end
   end
 
+  belongs_to :author_with_posts, :class_name => "Author", :include => :posts
+
   has_many   :comments, :order => "body" do
     def find_most_recent
       find(:first, :order => "id DESC")
@@ -12,6 +14,7 @@ class Post < ActiveRecord::Base
   end
 
   has_one  :very_special_comment
+  has_one  :very_special_comment_with_post, :class_name => "VerySpecialComment", :include => :post
   has_many :special_comments
 
   has_and_belongs_to_many :categories