Through associations should set both parent ids on join models

member = Member.new(club: Club.new)
member.save!

Before:

member.current_membership.club_id # => nil

After:

member.current_membership.club_id # => club's id

2 files changed, 27 insertions, 0 deletions

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 2e62189e7a..8641584c0c 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -330,6 +330,19 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert post.single_people.include?(person)
   end
 
+  def test_both_parent_ids_set_when_saving_new
+    post = Post.new(title: 'Hello', body: 'world')
+    person = Person.new(first_name: 'Sean')
+
+    post.people = [person]
+    post.save
+
+    assert post.id
+    assert person.id
+    assert_equal post.id, post.readers.first.post_id
+    assert_equal person.id, post.readers.first.person_id
+  end
+
   def test_delete_association
     assert_queries(2){posts(:welcome);people(:michael); }
 
diff --git a/activerecord/test/cases/associations/has_one_through_associations_test.rb b/activerecord/test/cases/associations/has_one_through_associations_test.rb
index a2725441b3..089cb0a3a2 100644
--- a/activerecord/test/cases/associations/has_one_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_through_associations_test.rb
@@ -45,6 +45,20 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal clubs(:moustache_club), new_member.club
   end
 
+  def test_creating_association_sets_both_parent_ids_for_new
+    member = Member.new(name: 'Sean Griffin')
+    club = Club.new(name: 'Da Club')
+
+    member.club = club
+
+    member.save!
+
+    assert member.id
+    assert club.id
+    assert_equal member.id, member.current_membership.member_id
+    assert_equal club.id, member.current_membership.club_id
+  end
+
   def test_replace_target_record
     new_club = Club.create(:name => "Marx Bros")
     @member.club = new_club