Associations: speedup duplicate record check. Closes #10011.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8051 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Associations: speedup duplicate record check.  #10011 [lifofifo]
+
 * Make sure that << works on has_many associations on unsaved records.  Closes #9989 [hasmanyjosh]
 
 * Allow association redefinition in subclasses.  #9346 [wildchild]

activerecord/lib/active_record/associations.rb

@@ -1402,9 +1402,36 @@ def instantiate(rows)
               end
               construct(@base_records_hash[primary_id], @associations, join_associations.dup, row)
             end
+            remove_duplicate_results!(join_base.active_record, @base_records_in_order, @associations)
             return @base_records_in_order
           end
 
+          def remove_duplicate_results!(base, records, associations)
+            case associations
+              when Symbol, String
+                reflection = base.reflections[associations]
+                if reflection && [:has_many, :has_and_belongs_to_many].include?(reflection.macro)
+                  records.each { |record| record.send(reflection.name).target.uniq! }
+                end
+              when Array
+                associations.each do |association|
+                  remove_duplicate_results!(base, records, association)
+                end
+              when Hash
+                associations.keys.each do |name|
+                  reflection = base.reflections[name]
+                  is_collection = [:has_many, :has_and_belongs_to_many].include?(reflection.macro)
+
+                  parent_records = records.map do |record|
+                    next unless record.send(reflection.name)
+                    is_collection ? record.send(reflection.name).target.uniq! : record.send(reflection.name)
+                  end.flatten.compact
+
+                  remove_duplicate_results!(reflection.class_name.constantize, parent_records, associations[name]) unless parent_records.empty?
+                end
+            end
+          end
+
           def aliased_table_names_for(table_name)
             joins.select{|join| join.table_name == table_name }.collect{|join| join.aliased_table_name}
           end
@@ -1461,7 +1488,7 @@ def construct_association(record, join, row)
 
                   return nil if record.id.to_s != join.parent.record_id(row).to_s or row[join.aliased_primary_key].nil?
                   association = join.instantiate(row)
-                  collection.target.push(association) unless collection.target.include?(association)
+                  collection.target.push(association)
                 when :has_one
                   return if record.id.to_s != join.parent.record_id(row).to_s
                   association = join.instantiate(row) unless row[join.aliased_primary_key].nil?