Merge branch 'master' into adequaterecord

* master: (70 commits)
  [ci skip] Added link to ruby-lang.org installation.
  Use the index on hidden field
  `collection_check_boxes` respects `:index` option for the hidden filed name.
  docs, double meaning of `serialize` argument. Closes #14284.
  Just call read_attribute, no need to use `send`.
  - Fix lingering reference to `:text` instead of the newer `:plain` - Section references `form_tag` instead of the `form_for` used in the example
  again, read_attribute is public, so just call it
  read_attribute is public, so we should just call it
  Disable assest cache store in docs [ci skip]
  Make counter cache decrementation on destroy idempotent
  Write the failing test case for concurrent counter cache
  [ci skip] Use plain underscore instead of "\_".
  Update documentation to use Rails.application instead
  Add a changelog entry for #14546 [ci skip]
  Move tests for deep_dup and duplicable to object directory
  Missing 'are' in note - [ci skip]
  CollectionHelpers now accepts a readonly option
  Fix a few typos [ci skip]
  Bundle tzinfo-data on :x64_mingw (64-bit Ruby on Windows).
  don't bother with an offset if the offset is zero
  ...

1 files changed, 13 insertions, 1 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 026a7fe635..6675e19dd9 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -1102,7 +1102,19 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal [posts(:thinking)], person.reload.first_posts
   end
 
-  def test_has_many_through_with_includes_in_through_association_scope
+  test "has many through with includes in through association scope" do
     assert_not_empty posts(:welcome).author_address_extra_with_address
   end
+
+  test "insert records via has_many_through association with scope" do
+    club = Club.create!
+    member = Member.create!
+    Membership.create!(club: club, member: member)
+
+    club.favourites << member
+    assert_equal [member], club.favourites
+
+    club.reload
+    assert_equal [member], club.favourites
+  end
 end