fix: restore has_one with scope

lib/paranoia.rb

@@ -210,6 +210,16 @@ def timestamp_attributes_with_current_time
     timestamp_attributes_for_update_in_model.each_with_object({}) { |attr,hash| hash[attr] = current_time_from_proper_timezone }
   end
 
+  def paranoia_find_has_one_target(association)
+    association_foreign_key = association.options[:through].present? ? association.klass.primary_key : association.foreign_key
+    association_find_conditions = { association_foreign_key => self.id }
+    association_find_conditions[association.type] = self.class.name if association.type
+
+    scope = association.klass.only_deleted.where(association_find_conditions)
+    scope = scope.merge(association.scope) if association.scope
+    scope.first
+  end
+
   # restore associated records that have been soft deleted when
   # we called #destroy
   def restore_associated_records(recovery_window_range = nil)
@@ -233,13 +243,8 @@ def restore_associated_records(recovery_window_range = nil)
       end
 
       if association_data.nil? && association.macro.to_s == "has_one"
-        association_class = association.klass
-        if association_class.paranoid?
-          association_foreign_key = association.options[:through].present? ? association.klass.primary_key : association.foreign_key
-          association_find_conditions = { association_foreign_key => self.id }
-          association_find_conditions[association.type] = self.class.name if association.type
-
-          association_class.only_deleted.where(association_find_conditions).first
+        if association.klass.paranoid?
+          paranoia_find_has_one_target(association)
             .try!(:restore, recursive: true, :recovery_window_range => recovery_window_range)
         end
       end

test/paranoia_test.rb

@@ -54,6 +54,7 @@ def setup!
     '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',
+    'paranoid_has_one_with_scopes' => 'deleted_at DATETIME, kind STRING, paranoid_has_one_with_scope_id INTEGER',
   }.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
@@ -1223,6 +1224,37 @@ def test_counter_cache_column_on_restore
     end
   end
 
+  def test_has_one_with_scope_missed
+    parent = ParanoidHasOneWithScope.create
+    gamma = ParanoidHasOneWithScope.create(kind: :gamma, paranoid_has_one_with_scope: parent) # this has to be first
+    alpha = ParanoidHasOneWithScope.create(kind: :alpha, paranoid_has_one_with_scope: parent)
+    beta = ParanoidHasOneWithScope.create(kind: :beta, paranoid_has_one_with_scope: parent)
+
+    parent.destroy
+    assert !gamma.reload.destroyed?
+    gamma.destroy
+    assert_equal 0, ParanoidHasOneWithScope.count # all destroyed
+    parent.reload # we unload associations
+    parent.restore(recursive: true)
+
+    assert_equal "alpha", parent.alpha&.kind, "record was not restored"
+    assert_equal "beta", parent.beta&.kind, "record was not restored"
+    assert_nil parent.gamma, "record was incorrectly restored"
+  end
+
+  def test_has_one_with_scope_not_restored
+    parent = ParanoidHasOneWithScope.create
+    gamma = ParanoidHasOneWithScope.create(kind: :gamma, paranoid_has_one_with_scope: parent)
+    parent.destroy
+    assert_equal 1, ParanoidHasOneWithScope.count # gamma not deleted
+    gamma.destroy
+    parent.reload # we unload associations
+    parent.restore(recursive: true)
+
+    assert gamma.reload.deleted?, "the record was incorrectly restored"
+    assert_equal 1, ParanoidHasOneWithScope.count # gamma deleted
+  end
+
   private
   def get_featureful_model
     FeaturefulModel.new(:name => "not empty")
@@ -1627,3 +1659,11 @@ class ParanoidHasManyThrough < ActiveRecord::Base
   belongs_to :paranoid_has_through_restore_parent
   belongs_to :empty_paranoid_model, dependent: :destroy
 end
+
+class ParanoidHasOneWithScope < ActiveRecord::Base
+  acts_as_paranoid
+  has_one :alpha, -> () { where(kind: :alpha) }, class_name: "ParanoidHasOneWithScope", dependent: :destroy
+  has_one :beta, -> () { where(kind: :beta) }, class_name: "ParanoidHasOneWithScope", dependent: :destroy
+  has_one :gamma, -> () { where(kind: :gamma) }, class_name: "ParanoidHasOneWithScope"
+  belongs_to :paranoid_has_one_with_scope
+end