Recursive restore with has_many/one through assocs

The query to find deleted has_many or has_one through associations
was being generated incorrectly because of specifying the wrong
foreign key for the table. This change uses the has_one/has_many
model's primary key as the foreign key.

lib/paranoia.rb

@@ -217,7 +217,12 @@ def restore_associated_records(recovery_window_range = nil)
 
       if association_data.nil? && association.macro.to_s == "has_one"
         association_class_name = association.klass.name
-        association_foreign_key = association.foreign_key
+
+        association_foreign_key = if association.options[:through].present?
+          association.klass.primary_key
+        else
+          association.foreign_key
+        end
 
         if association.type
           association_polymorphic_type = association.type
@@ -226,7 +231,7 @@ def restore_associated_records(recovery_window_range = nil)
           association_find_conditions = { association_foreign_key => self.id }
         end
 
-        association_class = association_class_name.constantize
+        association_class = association.klass
         if association_class.paranoid?
           association_class.only_deleted.where(association_find_conditions).first
             .try!(:restore, recursive: true, :recovery_window_range => recovery_window_range)

test/paranoia_test.rb

@@ -49,7 +49,11 @@ def setup!
     'active_column_model_with_uniqueness_validations' => 'name VARCHAR(32), deleted_at DATETIME, active BOOLEAN',
     'paranoid_model_with_belongs_to_active_column_model_with_has_many_relationships' => 'name VARCHAR(32), deleted_at DATETIME, active BOOLEAN, active_column_model_with_has_many_relationship_id INTEGER',
     'active_column_model_with_has_many_relationships' => 'name VARCHAR(32), deleted_at DATETIME, active BOOLEAN',
-    'without_default_scope_models' => 'deleted_at DATETIME'
+    'without_default_scope_models' => 'deleted_at DATETIME',
+    'paranoid_has_through_restore_parents' => 'deleted_at DATETIME',
+    'empty_paranoid_models' => 'deleted_at DATETIME',
+    'paranoid_has_one_throughs' => 'paranoid_has_through_restore_parent_id INTEGER NOT NULL, empty_paranoid_model_id INTEGER NOT NULL, deleted_at DATETIME',
+    'paranoid_has_many_throughs' => 'paranoid_has_through_restore_parent_id INTEGER NOT NULL, empty_paranoid_model_id INTEGER NOT NULL, deleted_at DATETIME',
   }.each do |table_name, columns_as_sql_string|
     ActiveRecord::Base.connection.execute "CREATE TABLE #{table_name} (id INTEGER NOT NULL PRIMARY KEY, #{columns_as_sql_string})"
   end
@@ -1055,6 +1059,40 @@ def test_restore_recursive_on_polymorphic_has_one_association
     assert_equal 1, polymorphic.class.count
   end
 
+  def test_recursive_restore_with_has_through_associations
+    parent = ParanoidHasThroughRestoreParent.create
+    one = EmptyParanoidModel.create
+    ParanoidHasOneThrough.create(
+      :paranoid_has_through_restore_parent => parent,
+      :empty_paranoid_model => one,
+    )
+    many = Array.new(3) do
+      many = EmptyParanoidModel.create
+      ParanoidHasManyThrough.create(
+        :paranoid_has_through_restore_parent => parent,
+        :empty_paranoid_model => many,
+      )
+
+      many
+    end
+
+    assert_equal true, parent.empty_paranoid_model.present?
+    assert_equal 3, parent.empty_paranoid_models.count
+
+    parent.destroy
+
+    assert_equal true, parent.empty_paranoid_model.reload.deleted?
+    assert_equal 0, parent.empty_paranoid_models.count
+
+    parent = ParanoidHasThroughRestoreParent.with_deleted.first
+    parent.restore(recursive: true)
+
+    assert_equal false, parent.empty_paranoid_model.deleted?
+    assert_equal one, parent.empty_paranoid_model
+    assert_equal 3, parent.empty_paranoid_models.count
+    assert_equal many, parent.empty_paranoid_models
+  end
+
   # Ensure that we're checking parent_type when restoring
   def test_missing_restore_recursive_on_polymorphic_has_one_association
     parent = ParentModel.create
@@ -1555,3 +1593,29 @@ class ParanoidBelongsTo < ActiveRecord::Base
     belongs_to :paranoid_has_one
   end
 end
+
+class ParanoidHasThroughRestoreParent < ActiveRecord::Base
+  acts_as_paranoid
+
+  has_one :paranoid_has_one_through, dependent: :destroy
+  has_one :empty_paranoid_model, through: :paranoid_has_one_through, dependent: :destroy
+
+  has_many :paranoid_has_many_throughs, dependent: :destroy
+  has_many :empty_paranoid_models, through: :paranoid_has_many_throughs, dependent: :destroy
+end
+
+class EmptyParanoidModel < ActiveRecord::Base
+  acts_as_paranoid
+end
+
+class ParanoidHasOneThrough < ActiveRecord::Base
+  acts_as_paranoid
+  belongs_to :paranoid_has_through_restore_parent
+  belongs_to :empty_paranoid_model, dependent: :destroy
+end
+
+class ParanoidHasManyThrough < ActiveRecord::Base
+  acts_as_paranoid
+  belongs_to :paranoid_has_through_restore_parent
+  belongs_to :empty_paranoid_model, dependent: :destroy
+end