Support polymorphic has many

lib/generators/paper_trail_association_tracking/templates/create_version_associations.rb.erb

@@ -6,10 +6,11 @@ class CreateVersionAssociations < ActiveRecord::Migration<%= migration_version %
       t.integer  :version_id
       t.string   :foreign_key_name, null: false
       t.integer  :foreign_key_id
+      t.string   :foreign_type, null: false
     end
     add_index :version_associations, [:version_id]
     add_index :version_associations,
-      %i(foreign_key_name foreign_key_id),
+      %i(foreign_key_name foreign_key_id foreign_type),
       name: "index_version_associations_on_foreign_key"
   end
 

lib/paper_trail_association_tracking/record_trail.rb

@@ -136,7 +136,8 @@ def save_habtm_associations(version)
           ::PaperTrail::VersionAssociation.create(
             version_id: version.transaction_id,
             foreign_key_name: a.name,
-            foreign_key_id: id
+            foreign_key_id: id,
+            foreign_type: a.klass
           )
         end
       end
@@ -168,12 +169,14 @@ def save_bt_association(assoc, version)
       }
 
       if assoc.options[:polymorphic]
-        associated_record = @record.send(assoc.name) if @record.send(assoc.foreign_type)
-        if associated_record && ::PaperTrail.request.enabled_for_model?(associated_record.class)
-          assoc_version_args[:foreign_key_id] = associated_record.id
+        foreign_type = @record.send(assoc.foreign_type)
+        if foreign_type && ::PaperTrail.request.enabled_for_model?(foreign_type.constantize)
+          assoc_version_args[:foreign_key_id] = @record.send(assoc.foreign_key)
+          assoc_version_args[:foreign_type] = foreign_type
         end
       elsif ::PaperTrail.request.enabled_for_model?(assoc.klass)
         assoc_version_args[:foreign_key_id] = @record.send(assoc.foreign_key)
+        assoc_version_args[:foreign_type] = assoc.klass
       end
 
       if assoc_version_args.key?(:foreign_key_id)

lib/paper_trail_association_tracking/reifiers/has_many.rb

@@ -100,6 +100,7 @@ def load_versions_for_hm_association(assoc, model, version_table, tx_id, version
             select("MIN(version_id)").
             where("foreign_key_name = ?", assoc.foreign_key).
             where("foreign_key_id = ?", model.id).
+            where("foreign_type = ?", model.class.name).
             where("#{version_table}.item_type = ?", assoc.klass.base_class.name).
             where("created_at >= ? OR transaction_id = ?", version_at, tx_id).
             group("item_id").

spec/dummy_app/app/models/book.rb

@@ -7,5 +7,7 @@ class Book < ActiveRecord::Base
   has_many :editorships, dependent: :destroy
   has_many :editors, through: :editorships
 
+  has_many :notes, as: :object
+
   has_paper_trail
 end

spec/dummy_app/app/models/note.rb

@@ -0,0 +1,4 @@
+class Note < ActiveRecord::Base
+  belongs_to :object, polymorphic: true
+  has_paper_trail
+end

spec/dummy_app/app/models/person.rb

@@ -15,6 +15,8 @@ class Person < ActiveRecord::Base
   has_one :thing
   has_one :thing_2, class_name: "Thing"
 
+  has_many :notes, as: :object
+
   if ActiveRecord.gem_version >= Gem::Version.new("5.0")
     belongs_to :mentor, class_name: "Person", foreign_key: :mentor_id, optional: true
   else

spec/dummy_app/db/migrate/20110208155312_set_up_test_tables.rb

@@ -78,10 +78,11 @@ def up
       t.integer  :version_id
       t.string   :foreign_key_name, null: false
       t.integer  :foreign_key_id
+      t.string   :foreign_type, null: false
     end
     add_index :version_associations, [:version_id]
     add_index :version_associations,
-      %i[foreign_key_name foreign_key_id],
+      %i[foreign_key_name foreign_key_id foreign_type],
       name: "index_version_associations_on_foreign_key"
 
     create_table :wotsits, force: true do |t|
@@ -214,6 +215,12 @@ def up
       t.integer :parent_id
       t.integer :partner_id
     end
+
+    create_table :notes, force: true do |t|
+      t.string :body
+      t.string :object_type
+      t.integer :object_id
+    end
   end
 
   def down

spec/models/note_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Note, type: :model, versioning: true do
+  it "baseline test setup" do
+    expect(Note.new).to be_versioned
+  end
+
+  describe "#object" do
+    it "can be reified" do
+      person = Person.create!(name: "Marielle")
+      note = Note.create!(body: "Note on Marielle", object: person)
+
+      note.update_attributes!(body: "Modified note")
+      person.update_attributes!(name: "Modified")
+
+      reified_note = note.versions.last.reify(belongs_to: true)
+      expect(reified_note.body).to eq("Note on Marielle")
+      expect(reified_note.object.name).to eq("Marielle")
+    end
+  end
+end

spec/models/person_spec.rb

@@ -35,4 +35,21 @@
       )
     end
   end
+
+  describe "#notes" do
+    it "can be reified" do
+      person = Person.create!(id: 1, name: "Jessica")
+      book = Book.create!(id: 1, title: "La Chute")
+      person_note = Note.create!(body: "Some note on person", object: person)
+      book_note = Note.create!(body: "Some note on book", object: book)
+
+      person.update_attributes!(name: "Jennyfer")
+      book_note.update_attributes!(body: "Modified note on book")
+      person_note.update_attributes!(body: "Modified note on person")
+
+      reified_person = person.versions.last.reify(has_many: true)
+      expect(reified_person.notes.length).to eq(1)
+      expect(reified_person.notes.first.body).to eq("Some note on person")
+    end
+  end
 end