From 699a3725ad0a9a3f82c48fb7311cd4a72fa85fb8 Mon Sep 17 00:00:00 2001
From: Gannon McGibbon <gannon.mcgibbon@gmail.com>
Date: Wed, 21 Jun 2023 17:01:44 -0500
Subject: [PATCH] Add support for unpersisted CPK has_one/has_many through
 associations

Fixes loading of has_one and has_many associations with composite
primary key though associations that have unpersisted owner records.
---
 .../associations/has_many_through_association.rb         | 2 +-
 .../active_record/associations/through_association.rb    | 4 +++-
 .../associations/has_many_through_associations_test.rb   | 8 ++++++++
 .../associations/has_one_through_associations_test.rb    | 9 +++++++++
 activerecord/test/models/cpk/book.rb                     | 5 +++++
 5 files changed, 26 insertions(+), 2 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 e09d23f0b14fe..845e5e564266a 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -113,7 +113,7 @@ def remove_records(existing_records, records, method)
         end
 
         def target_reflection_has_associated_record?
-          !(through_reflection.belongs_to? && owner[through_reflection.foreign_key].blank?)
+          !(through_reflection.belongs_to? && Array(through_reflection.foreign_key).all? { |foreign_key_column| owner[foreign_key_column].blank? })
         end
 
         def update_through_counter?(method)
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index 707d0bc1677f5..ac0911a25f007 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -86,7 +86,9 @@ def stale_state
         end
 
         def foreign_key_present?
-          through_reflection.belongs_to? && !owner[through_reflection.foreign_key].nil?
+          through_reflection.belongs_to? && Array(through_reflection.foreign_key).all? do |foreign_key_column|
+            !owner[foreign_key_column].nil?
+          end
         end
 
         def ensure_mutable
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 1c155394c693b..07e9f312f5129 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -1631,6 +1631,14 @@ def test_tags_has_manu_posts_through_association_with_composite_query_constraint
     assert_equal(expected_blog_post_ids.sort, blog_post_ids.sort)
   end
 
+  def test_loading_cpk_association_with_unpersisted_owner
+    order = Cpk::Order.create!(shop_id: 1)
+    book = Cpk::BookWithOrderAgreements.new(number: 2, author_id: 1, order: order)
+    order_agreement = Cpk::OrderAgreement.create!(order: order)
+
+    assert_equal([order_agreement], book.order_agreements.to_a)
+  end
+
   private
     def make_model(name)
       Class.new(ActiveRecord::Base) { define_singleton_method(:name) { name } }
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 afe1ec81fd6a2..e4e344a8635e2 100644
--- a/activerecord/test/cases/associations/has_one_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_through_associations_test.rb
@@ -22,6 +22,7 @@
 require "models/carrier"
 require "models/shop_account"
 require "models/customer_carrier"
+require "models/cpk"
 
 class HasOneThroughAssociationsTest < ActiveRecord::TestCase
   fixtures :member_types, :members, :clubs, :memberships, :sponsors, :organizations, :minivans,
@@ -445,4 +446,12 @@ def test_has_one_through_do_not_cache_association_reader_if_the_though_method_ha
   ensure
     CustomerCarrier.current_customer = nil
   end
+
+  def test_loading_cpk_association_with_unpersisted_owner
+    order = Cpk::Order.create!(shop_id: 1)
+    book = Cpk::BookWithOrderAgreements.new(number: 2, author_id: 1, order: order)
+    order_agreement = Cpk::OrderAgreement.create!(order: order)
+
+    assert_equal(order_agreement, book.order_agreement)
+  end
 end
diff --git a/activerecord/test/models/cpk/book.rb b/activerecord/test/models/cpk/book.rb
index 28aced1221403..077977e57f04d 100644
--- a/activerecord/test/models/cpk/book.rb
+++ b/activerecord/test/models/cpk/book.rb
@@ -20,4 +20,9 @@ class BrokenBook < Book
   class NullifiedBook < Book
     has_one :chapter, query_constraints: [:author_id, :book_number], dependent: :nullify
   end
+
+  class BookWithOrderAgreements < Book
+    has_many :order_agreements, through: :order
+    has_one :order_agreement, through: :order, source: :order_agreements
+  end
 end