2 files changed, 26 insertions, 0 deletions
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
index ed7dde115a..515eb65d37 100644
--- a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -25,6 +25,8 @@ require "models/user"
 require "models/member"
 require "models/membership"
 require "models/sponsor"
+require "models/lesson"
+require "models/student"
 require "models/country"
 require "models/treaty"
 require "models/vertex"
@@ -780,6 +782,16 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal [projects(:active_record), projects(:action_controller)].map(&:id).sort, developer.project_ids.sort
   end
 
+  def test_singular_ids_are_reloaded_after_collection_concat
+    student = Student.create(name: "Alberto Almagro")
+    student.lesson_ids
+
+    lesson = Lesson.create(name: "DSI")
+    student.lessons << lesson
+
+    assert_includes student.lesson_ids, lesson.id
+  end
+
   def test_scoped_find_on_through_association_doesnt_return_read_only_records
     tag = Post.find(1).tags.find_by_name("General")
 
diff --git a/activerecord/test/cases/collection_cache_key_test.rb b/activerecord/test/cases/collection_cache_key_test.rb
index 844b2b2162..483383257b 100644
--- a/activerecord/test/cases/collection_cache_key_test.rb
+++ b/activerecord/test/cases/collection_cache_key_test.rb
@@ -42,6 +42,20 @@ module ActiveRecord
       assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
     end
 
+    test "cache_key for relation with custom select and limit" do
+      developers = Developer.where(salary: 100000).order(updated_at: :desc).limit(5)
+      developers_with_select = developers.select("developers.*")
+      last_developer_timestamp = developers.first.updated_at
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, developers_with_select.cache_key)
+
+      /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/ =~ developers_with_select.cache_key
+
+      assert_equal ActiveSupport::Digest.hexdigest(developers_with_select.to_sql), $1
+      assert_equal developers.count.to_s, $2
+      assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
+    end
+
     test "cache_key for loaded relation" do
       developers = Developer.where(salary: 100000).order(updated_at: :desc).limit(5).load
       last_developer_timestamp = developers.first.updated_at