Change reify_has_many_through to consider :source

Also modified test (changed authorship.person to authorship.author so that source is not the same as the class name) to verify this case.

[Fixes #777]

CHANGELOG.md

@@ -31,6 +31,8 @@
 
 ### Fixed
 
+- [#777](https://github.com/airblade/paper_trail/issues/777) -
+  Support HMT associations with `:source` option.
 - [#731](https://github.com/airblade/paper_trail/pull/731) -
   Map enums to database values before storing in `object_changes` column.
 - [#715](https://github.com/airblade/paper_trail/issues/715) -

lib/paper_trail/reifier.rb

@@ -255,7 +255,7 @@ module PaperTrail
             }
           else
             collection_keys = through_collection.map { |through_model|
-              through_model.send(assoc.association_foreign_key)
+              through_model.send(assoc.source_reflection.foreign_key)
             }
 
             version_id_subquery = assoc.klass.paper_trail_version_class.

test/dummy/app/models/authorship.rb

@@ -1,5 +1,5 @@
 class Authorship < ActiveRecord::Base
   belongs_to :book
-  belongs_to :person
+  belongs_to :author, class_name: "Person"
   has_paper_trail
 end

test/dummy/app/models/book.rb

@@ -1,6 +1,6 @@
 class Book < ActiveRecord::Base
   has_many :authorships, dependent: :destroy
-  has_many :authors, through: :authorships, source: :person
+  has_many :authors, through: :authorships
 
   has_many :editorships, dependent: :destroy
   has_many :editors, through: :editorships

test/dummy/app/models/person.rb

@@ -1,5 +1,5 @@
 class Person < ActiveRecord::Base
-  has_many :authorships, dependent: :destroy
+  has_many :authorships, foreign_key: :author_id, dependent: :destroy
   has_many :books, through: :authorships
   has_paper_trail
 

test/dummy/db/migrate/20110208155312_set_up_test_tables.rb

@@ -138,7 +138,7 @@ class SetUpTestTables < ActiveRecord::Migration
 
     create_table :authorships, force: true do |t|
       t.integer :book_id
-      t.integer :person_id
+      t.integer :author_id
     end
 
     create_table :people, force: true do |t|

test/dummy/db/schema.rb

@@ -27,7 +27,7 @@ ActiveRecord::Schema.define(version: 20110208155312) do
 
   create_table "authorships", force: :cascade do |t|
     t.integer "book_id"
-    t.integer "person_id"
+    t.integer "author_id"
   end
 
   create_table "banana_versions", force: :cascade do |t|

test/unit/associations_test.rb

@@ -523,7 +523,7 @@ class AssociationsTest < ActiveSupport::TestCase
             should "mark the newly associated-through for destruction" do
               assert @book_0.
                 authorships.
-                detect { |as| as.person.name == "author_1" }.
+                detect { |as| as.author.name == "author_1" }.
                 marked_for_destruction?
             end
           end
@@ -564,7 +564,7 @@ class AssociationsTest < ActiveSupport::TestCase
             should "mark the newly associated-through for destruction" do
               assert @book_0.
                 authorships.
-                detect { |as| as.person.name == "person_existing" }.
+                detect { |as| as.author.name == "person_existing" }.
                 marked_for_destruction?
             end
           end

test/unit/model_test.rb

@@ -1025,7 +1025,7 @@ class HasPaperTrailModelTest < ActiveSupport::TestCase
       @book.authorships.reload.last.destroy
       assert_equal 1, PaperTrail::Version.count - count
       assert_equal @book, PaperTrail::Version.last.reify.book
-      assert_equal @dostoyevsky, PaperTrail::Version.last.reify.person
+      assert_equal @dostoyevsky, PaperTrail::Version.last.reify.author
     end
 
     should "store version on join clear" do
@@ -1034,7 +1034,7 @@ class HasPaperTrailModelTest < ActiveSupport::TestCase
       @book.authorships.reload.destroy_all
       assert_equal 1, PaperTrail::Version.count - count
       assert_equal @book, PaperTrail::Version.last.reify.book
-      assert_equal @dostoyevsky, PaperTrail::Version.last.reify.person
+      assert_equal @dostoyevsky, PaperTrail::Version.last.reify.author
     end
   end