Fix inline habtm fixtures for tables with composite primary keys

activerecord/lib/active_record/fixture_set/table_row.rb

@@ -193,8 +193,25 @@ def add_join_records(association)
 
             targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
             joins   = targets.map do |target|
-              join = { lhs_key => @row[model_metadata.primary_key_name],
-                       rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
+              join = {}
+
+              if rhs_key.is_a?(Array)
+                composite_key = ActiveRecord::FixtureSet.composite_identify(target, rhs_key)
+                composite_key.each do |column, value|
+                  join[column] = value
+                end
+              else
+                join[rhs_key] = ActiveRecord::FixtureSet.identify(target, column_type)
+              end
+
+              if lhs_key.is_a?(Array)
+                lhs_key.zip(model_metadata.primary_key_name).each do |fkey, pkey|
+                  join[fkey] = @row[pkey]
+                end
+              else
+                join[lhs_key] = @row[model_metadata.primary_key_name]
+              end
+
               association.timestamp_column_names.each do |col|
                 join[col] = @now
               end

activerecord/test/cases/fixtures_test.rb

@@ -1737,7 +1737,15 @@ def readonly_config
   end
 
   class CompositePkFixturesTest < ActiveRecord::TestCase
-    fixtures :cpk_orders, :cpk_books, :cpk_authors, :cpk_reviews, :cpk_order_agreements
+    fixtures :cpk_orders, :cpk_books, :cpk_posts, :cpk_tags, :cpk_authors, :cpk_reviews, :cpk_order_agreements
+
+    def test_supports_inline_habtm
+      assert(cpk_posts(:welcome).tags.include?(cpk_tags(:cpk_tag_ruby_on_rails)))
+      assert(cpk_posts(:welcome).tags.include?(cpk_tags(:cpk_tag_digital_product)))
+      assert_not(cpk_posts(:welcome).tags.include?(cpk_tags(:cpk_tag_loyal_customer)))
+
+      assert_equal(cpk_posts(:thinking).tags, [cpk_tags(:cpk_tag_digital_product)])
+    end
 
     def test_generates_composite_primary_key_for_partially_filled_fixtures
       alice = cpk_authors(:cpk_great_author)

activerecord/test/fixtures/cpk_posts.yml

@@ -0,0 +1,12 @@
+_fixture:
+  model_class: Cpk::Post
+
+welcome:
+  title: Welcome to the weblog
+  author: David
+  tags: cpk_tag_ruby_on_rails, cpk_tag_digital_product
+
+thinking:
+  title: So I was thinking
+  author: Bob
+  tags: cpk_tag_digital_product

activerecord/test/models/cpk.rb

@@ -9,6 +9,7 @@
 require_relative "cpk/tag"
 require_relative "cpk/chapter"
 require_relative "cpk/post"
+require_relative "cpk/posts_tag"
 require_relative "cpk/comment"
 require_relative "cpk/car"
 require_relative "cpk/car_review"

activerecord/test/models/cpk/post.rb

@@ -4,5 +4,7 @@ module Cpk
   class Post < ActiveRecord::Base
     self.table_name = :cpk_posts
     has_many :comments, class_name: "Cpk::Comment", query_constraints: %i[commentable_title commentable_author], as: :commentable
+    has_many :posts_tags, class_name: "Cpk::PostsTag", query_constraints: %i[post_title post_author]
+    has_many :tags, through: :posts_tags, class_name: "Cpk::Tag"
   end
 end

activerecord/test/models/cpk/posts_tag.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module Cpk
+  class PostsTag < ActiveRecord::Base
+    self.table_name = :cpk_posts_tags
+
+    belongs_to :post, class_name: "Cpk:Post", query_constraints: %i[post_title post_author]
+    belongs_to :tag, class_name: "Cpk::Tag"
+  end
+end

activerecord/test/schema/schema.rb

@@ -267,6 +267,12 @@
     t.string :author
   end
 
+  create_table :cpk_posts_tags, force: true do |t|
+    t.string :post_title
+    t.string :post_author
+    t.integer :tag_id
+  end
+
   create_table :cpk_comments, force: true do |t|
     t.string :commentable_title
     t.string :commentable_author