Fixed bug where using update_attribute after pushing a record to a habtm association of the object caused duplicate rows in the join table. #2888

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3167 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 17 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index c5116d6d9e..40c0fd25ed 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Fixed bug where using update_attribute after pushing a record to a habtm association of the object caused duplicate rows in the join table. #2888 [Florian Weber]
+
 * MySQL, PostgreSQL: reconnect! also reconfigures the connection.  Otherwise, the connection 'loses' its settings if it times out and is reconnected.  #2978 [Shugo Maeda]
 
 * has_and_belongs_to_many: use JOIN instead of LEFT JOIN.  [Jeremy Kemper]
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index d4b7f88907..70bc4a4d65 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -800,6 +800,7 @@ module ActiveRecord
 
           after_callback = <<-end_eval
             association = instance_variable_get("@#{association_name}")
+            
             if association.respond_to?(:loaded?)
               if @new_record_before_save
                 records_to_save = association
@@ -809,8 +810,11 @@ module ActiveRecord
               records_to_save.each { |record| association.send(:insert_record, record) }
               association.send(:construct_sql)   # reconstruct the SQL queries now that we know the owner's id
             end
+            
+            @new_record_before_save = false
+            true
           end_eval
-
+                
           # Doesn't use after_save as that would save associations added in after_create/after_update twice
           after_create(after_callback)
           after_update(after_callback)
diff --git a/activerecord/test/associations_test.rb b/activerecord/test/associations_test.rb
index ef2872e13c..df53118040 100755
--- a/activerecord/test/associations_test.rb
+++ b/activerecord/test/associations_test.rb
@@ -1397,5 +1397,14 @@ class HasAndBelongsToManyAssociationsTest < Test::Unit::TestCase
     assert developer.special_projects.include?(special_project)
     assert !developer.special_projects.include?(other_project)
   end
-
+  
+  def test_update_attributes_after_push_without_duplicate_join_table_rows
+    developer = Developer.new("name" => "Kano")
+    project = SpecialProject.create("name" => "Special Project")
+    assert developer.save
+    developer.projects << project
+    developer.update_attribute("name", "Bruza")
+    assert_equal "1", developer.connection.select_one("SELECT count(*) FROM developers_projects WHERE 
+      project_id = #{project.id} AND developer_id = #{developer.id}")["count(*)"]
+  end
 end