Fix bug where size of through association is not correct after adding a has_many association (occurs only before main object has been reloaded).

[#5968 state:committed]

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

2 files changed, 7 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index 51770cff0f..0a5858f36e 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -69,7 +69,6 @@ module ActiveRecord
 
           through_association = @owner.send(@reflection.through_reflection.name)
           through_record = through_association.create!(construct_join_attributes(record))
-          through_association.proxy_target << through_record
         end
 
         # TODO - add dependent option support
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index 4b9f49f1ec..94e1eb8c89 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -449,4 +449,11 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     comment = post.comments.build
     assert author.comments.include?(comment)
   end
+
+  def test_size_of_through_association_should_increase_correctly_when_has_many_association_is_added
+    post = posts(:thinking)
+    readers = post.readers.size
+    post.people << people(:michael)
+    assert_equal readers + 1, post.readers.size
+  end
 end