Handle composite foreign keys in positioning scope changes

Gemfile

@@ -18,12 +18,7 @@ end
 
 case ENV["DB"]
 when "sqlite"
-  if ENV["RAILS_VERSION"] &&
-      Gem::Version.new(ENV["RAILS_VERSION"]) >= Gem::Version.new("7.2")
-    gem "sqlite3", "~> 2.9.0"
-  else
-    gem "sqlite3", "~> 1.7.3"
-  end
+  gem "sqlite3", "~> 2.9.0"
 when "postgresql"
   gem "pg", "~> 1.6.3"
 else

lib/positioning.rb

@@ -35,7 +35,7 @@ def positioned(on: [], column: :position)
             reflection = reflections[scope_component]
 
             if reflection&.belongs_to?
-              positioning_columns[column][:scope_columns] << reflection.foreign_key
+              positioning_columns[column][:scope_columns].concat Array(reflection.foreign_key)
               positioning_columns[column][:scope_columns] << reflection.foreign_type if reflection.polymorphic?
               positioning_columns[column][:scope_associations] << reflection.name
             else

lib/positioning/mechanisms.rb

@@ -222,7 +222,7 @@ def positioning_scope_changed?
 
     def destroyed_via_positioning_scope?
       @positioned.destroyed_by_association && scope_columns.any? do |scope_column|
-        @positioned.destroyed_by_association.foreign_key == scope_column
+        Array(@positioned.destroyed_by_association.foreign_key).include?(scope_column)
       end
     end
   end

test/models/composite_foreign_key_item.rb

@@ -0,0 +1,5 @@
+class CompositeForeignKeyItem < ActiveRecord::Base
+  belongs_to :list, class_name: "CompositePrimaryKeyItem", foreign_key: [:cpki_item_id, :cpki_account_id]
+
+  positioned on: :list
+end

test/models/composite_primary_key_item.rb

@@ -3,5 +3,7 @@ class CompositePrimaryKeyItem < ActiveRecord::Base
 
   belongs_to :list
 
+  has_many :composite_foreign_key_items, -> { order(:position) }, foreign_key: [:cpki_item_id, :cpki_account_id], dependent: :destroy
+
   positioned on: :list
 end

test/support/active_record.rb

@@ -55,6 +55,15 @@
 
     add_index :composite_primary_key_items, [:list_id, :position], unique: true
 
+    create_table :composite_foreign_key_items, force: true do |t|
+      t.string :name
+      t.integer :position, null: false
+      t.integer :cpki_item_id, null: false
+      t.integer :cpki_account_id, null: false
+    end
+
+    add_index :composite_foreign_key_items, [:cpki_item_id, :cpki_account_id, :position], unique: true, name: "index_cfki_on_scope_and_position"
+
     create_table :categories, force: true do |t|
       t.string :name
       t.integer :position, null: false

test/test_helper.rb

@@ -11,6 +11,7 @@
 require_relative "models/new_item"
 require_relative "models/default_scope_item"
 require_relative "models/composite_primary_key_item"
+require_relative "models/composite_foreign_key_item"
 require_relative "models/product"
 require_relative "models/category"
 require_relative "models/categorised_item"

test/test_positioning.rb

@@ -566,6 +566,23 @@ def test_destroyed_via_positioning_scope?
     list.destroy
     assert mechanisms.send(:destroyed_via_positioning_scope?)
   end
+
+  def test_destroyed_via_positioning_scope_with_composite_foreign_key
+    list = List.create(name: "List")
+    parent = CompositePrimaryKeyItem.create(item_id: 1, account_id: 1, list: list, name: "Parent")
+    child1 = parent.composite_foreign_key_items.create(name: "Child 1")
+    child2 = parent.composite_foreign_key_items.create(name: "Child 2")
+
+    mechanisms = Positioning::Mechanisms.new(child1, :position)
+    refute mechanisms.send(:destroyed_via_positioning_scope?)
+
+    mechanisms = Positioning::Mechanisms.new(child2, :position)
+    child2.destroy
+    refute mechanisms.send(:destroyed_via_positioning_scope?)
+
+    parent.destroy
+    assert mechanisms.send(:destroyed_via_positioning_scope?)
+  end
 end
 
 class TestPositioningScopes < Minitest::Test
@@ -606,6 +623,13 @@ def test_that_position_columns_will_cope_with_polymorphic_belong_to
     assert_equal({position: {scope_columns: ["includable_id", "includable_type"], scope_associations: [:includable]}}, Entity.positioning_columns)
   end
 
+  def test_that_position_columns_will_cope_with_composite_foreign_key
+    assert_equal(
+      {position: {scope_columns: ["cpki_item_id", "cpki_account_id"], scope_associations: [:list]}},
+      CompositeForeignKeyItem.positioning_columns
+    )
+  end
+
   def test_that_position_columns_must_have_unique_keys
     assert_raises(Positioning::Error) do
       Item.send :positioned, on: :list
@@ -1135,8 +1159,6 @@ def test_destroying_multiple_items
 
 class TestCompositePrimaryKeyPositioning < TestPositioning
   def configure
-    skip if ActiveRecord.version < Gem::Version.new("7.1.0")
-
     @association = :composite_primary_key_items
     @id = Enumerator.new do |yielder|
       number = 1
@@ -1149,6 +1171,38 @@ def configure
   end
 end
 
+class TestCompositeForeignKeyPositioning < TestPositioning
+  def configure
+    @association = :composite_foreign_key_items
+    @id = Enumerator.new do |yielder|
+      loop do
+        yielder.yield(nil)
+      end
+    end
+  end
+
+  def setup
+    configure
+
+    list = List.create name: "List"
+    @first_list = CompositePrimaryKeyItem.create(item_id: 1, account_id: 1, list: list, name: "First List")
+    @second_list = CompositePrimaryKeyItem.create(item_id: 2, account_id: 2, list: list, name: "Second List")
+    @first_item = @first_list.send(@association).create id: @id.next, name: "First Item"
+    @second_item = @first_list.send(@association).create id: @id.next, name: "Second Item"
+    @third_item = @first_list.send(@association).create id: @id.next, name: "Third Item"
+    @fourth_item = @second_list.send(@association).create id: @id.next, name: "Fourth Item"
+    @fifth_item = @second_list.send(@association).create id: @id.next, name: "Fifth Item"
+    @sixth_item = @second_list.send(@association).create id: @id.next, name: "Sixth Item"
+
+    @models = [
+      @first_list, @second_list, @first_item, @second_item,
+      @third_item, @fourth_item, @fifth_item, @sixth_item
+    ]
+
+    reload_models
+  end
+end
+
 class TestNoScopePositioning < Minitest::Test
   include Minitest::Hooks