Add missing source_type if provided on hmt which belongs to an sti record

Fixes #23209

3 files changed, 10 insertions, 0 deletions

diff --git a/activerecord/test/models/chef.rb b/activerecord/test/models/chef.rb
index 698a52e045..9d3dd01016 100644
--- a/activerecord/test/models/chef.rb
+++ b/activerecord/test/models/chef.rb
@@ -2,3 +2,7 @@ class Chef < ActiveRecord::Base
   belongs_to :employable, polymorphic: true
   has_many :recipes
 end
+
+class ChefList < Chef
+  belongs_to :employable_list, polymorphic: true
+end
diff --git a/activerecord/test/models/hotel.rb b/activerecord/test/models/hotel.rb
index 491f8dfde3..9c90ffcff4 100644
--- a/activerecord/test/models/hotel.rb
+++ b/activerecord/test/models/hotel.rb
@@ -3,5 +3,9 @@ class Hotel < ActiveRecord::Base
   has_many :chefs, through: :departments
   has_many :cake_designers, source_type: 'CakeDesigner', source: :employable, through: :chefs
   has_many :drink_designers, source_type: 'DrinkDesigner', source: :employable, through: :chefs
+
+  has_many :chef_lists, as: :employable_list
+  has_many :mocktail_designers, through: :chef_lists, source: :employable, :source_type => "MocktailDesigner"
+
   has_many :recipes, through: :chefs
 end
diff --git a/activerecord/test/models/mocktail_designer.rb b/activerecord/test/models/mocktail_designer.rb
new file mode 100644
index 0000000000..77b44651a3
--- /dev/null
+++ b/activerecord/test/models/mocktail_designer.rb
@@ -0,0 +1,2 @@
+class MocktailDesigner < DrinkDesigner
+end