CollectionProxy < Relation

This helps bring the interfaces of CollectionProxy and Relation closer
together, and reduces the delegation backflips we need to perform.

For example, first_or_create is defined thus:

class ActiveRecord::Relation
  def first_or_create(...)
    first || create(...)
  end
end

If CollectionProxy < Relation, then post.comments.first_or_create will
hit the association's #create method which will actually add the new record
to the association, just as post.comments.create would.

With the previous delegation, post.comments.first_or_create expands to
post.comments.scoped.first_or_create, where post.comments.scoped has no
knowledge of the association.

1 files changed, 9 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
index f6d178db7a..80d087a9ea 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -5,7 +5,12 @@ require 'active_record/relation/merger'
 
 module ActiveRecord
   module SpawnMethods
-    
+
+    # This is overridden by Associations::CollectionProxy
+    def spawn #:nodoc:
+      clone
+    end
+
     # Merges in the conditions from <tt>other</tt>, if <tt>other</tt> is an <tt>ActiveRecord::Relation</tt>.
     # Returns an array representing the intersection of the resulting records with <tt>other</tt>, if <tt>other</tt> is an array.
     #
@@ -23,7 +28,7 @@ module ActiveRecord
       if other.is_a?(Array)
         to_a & other
       elsif other
-        clone.merge!(other)
+        spawn.merge!(other)
       else
         self
       end
@@ -42,7 +47,7 @@ module ActiveRecord
     #   Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order
     #
     def except(*skips)
-      result = self.class.new(@klass, table, values.except(*skips))
+      result = Relation.new(klass, table, values.except(*skips))
       result.default_scoped = default_scoped
       result.extend(*extending_values) if extending_values.any?
       result
@@ -56,7 +61,7 @@ module ActiveRecord
     #   Post.order('id asc').only(:where, :order) # uses the specified order
     #
     def only(*onlies)
-      result = self.class.new(@klass, table, values.slice(*onlies))
+      result = Relation.new(klass, table, values.slice(*onlies))
       result.default_scoped = default_scoped
       result.extend(*extending_values) if extending_values.any?
       result