Merge pull request rails#51066 from airblade/bidirectional-has-one-through

Fix destroy of has_one with multiple belongs_to

Author: byroot

activerecord/lib/active_record/callbacks.rb

@@ -418,7 +418,7 @@ module ClassMethods
 
     def destroy # :nodoc:
       @_destroy_callback_already_called ||= false
-      return if @_destroy_callback_already_called
+      return true if @_destroy_callback_already_called
       @_destroy_callback_already_called = true
       _run_destroy_callbacks { super }
     rescue RecordNotDestroyed => e

activerecord/test/cases/associations/has_one_associations_test.rb

@@ -20,6 +20,8 @@
 require "models/membership"
 require "models/parrot"
 require "models/cpk"
+require "models/room"
+require "models/user"
 
 class HasOneAssociationsTest < ActiveRecord::TestCase
   self.use_transactional_tests = false unless supports_savepoints?
@@ -806,6 +808,28 @@ def test_has_one_with_touch_option_on_empty_update
     assert_no_queries { new_club.save }
   end
 
+  def test_has_one_double_belongs_to_destroys_both_from_either_end
+    landlord = User.create!
+    tenant = User.create!
+    room = Room.create!(landlord: landlord, tenant: tenant)
+
+    landlord.destroy!
+
+    assert_predicate(room, :destroyed?)
+    assert_predicate(landlord, :destroyed?)
+    assert_predicate(tenant, :destroyed?)
+
+    landlord = User.create!
+    tenant = User.create!
+    room = Room.create!(landlord: landlord, tenant: tenant)
+
+    tenant.destroy!
+
+    assert_predicate(room, :destroyed?)
+    assert_predicate(tenant, :destroyed?)
+    assert_predicate(landlord, :destroyed?)
+  end
+
   class SpecialBook < ActiveRecord::Base
     self.table_name = "books"
     belongs_to :author, class_name: "SpecialAuthor"

activerecord/test/cases/token_for_test.rb

@@ -4,6 +4,7 @@
 require "models/matey"
 require "models/user"
 require "models/cpk"
+require "models/room"
 require "active_support/message_verifier"
 
 class TokenForTest < ActiveRecord::TestCase

activerecord/test/models/room.rb

@@ -3,4 +3,7 @@
 class Room < ActiveRecord::Base
   belongs_to :user
   belongs_to :owner, class_name: "User"
+
+  belongs_to :landlord, class_name: "User", dependent: :destroy, inverse_of: :let_room
+  belongs_to :tenant, class_name: "User", dependent: :destroy, inverse_of: :rented_room
 end

activerecord/test/models/user.rb

@@ -18,6 +18,9 @@ class User < ActiveRecord::Base
   has_one :family_tree, -> { where(token: nil) }, foreign_key: "member_id"
   has_one :family, through: :family_tree
   has_many :family_members, through: :family, source: :members
+
+  has_one :let_room, class_name: "Room", foreign_key: "landlord_id", dependent: :destroy
+  has_one :rented_room, class_name: "Room", foreign_key: "tenant_id", dependent: :destroy
 end
 
 class UserWithNotification < User

activerecord/test/schema/schema.rb

@@ -1070,6 +1070,8 @@
   create_table :rooms, force: true do |t|
     t.references :user
     t.references :owner
+    t.references :landlord
+    t.references :tenant
   end
 
   disable_referential_integrity do