Slugs should always find their sluggable, even when they are soft deleted by acts_as_paranoid

[padi]

Probably fixes #822, as the test case is likely what he has encountered. His report most probably required 2 things to be true:

1. He used friendly_id ... :dependent => false
2. friendly_id is used in a Rails 5.0 app

Previously, when a sluggable is soft deleted and a slug persists
(i.e. :dependent => false), slug can't find its corresponding
sluggable.

Additionally, in Rails 5.0, belongs_to_required_by_default has been
introduced to be true by default (unless changed back to false), therefore making Friendly::Slug
invalid with the error message 'Sluggable must exist'.

[padi]

2 failing builds remaining. Haven't investigated why. https://travis-ci.org/norman/friendly_id/builds/283262267?utm_source=github_status&utm_medium=notification

[parndt]

Hey, thanks for this! I'm uncomfortable adding the development dependency on acts_as_paranoid, but I think that we can get a working test by just reproducing how it works:

• Set a default scope on the model which filters by deleted_at: nil
• Update the record to set deleted_at to not nil

What do you think of these changes below?

diff --git a/friendly_id.gemspec b/friendly_id.gemspec
index 52aac43..883e20b 100644
--- a/friendly_id.gemspec
+++ b/friendly_id.gemspec
@@ -26,7 +26,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'i18n'
   s.add_development_dependency 'ffaker'
   s.add_development_dependency 'simplecov'
-  s.add_development_dependency 'acts_as_paranoid'

   s.description = <<-EOM
 FriendlyId is the "Swiss Army bulldozer" of slugging and permalink plugins for
diff --git a/lib/friendly_id/slug.rb b/lib/friendly_id/slug.rb
index 8f549f8..9a6694c 100644
--- a/lib/friendly_id/slug.rb
+++ b/lib/friendly_id/slug.rb
@@ -3,7 +3,7 @@ module FriendlyId
   #
   # @see FriendlyId::History
   class Slug < ActiveRecord::Base
-    belongs_to :sluggable, :polymorphic => true, required: true
+    belongs_to :sluggable, :polymorphic => true

     def sluggable
       sluggable_type.constantize.unscoped { super }
diff --git a/test/history_test.rb b/test/history_test.rb
index 6d00915..3c95158 100644
--- a/test/history_test.rb
+++ b/test/history_test.rb
@@ -212,27 +212,25 @@ class DependentDestroyTest < HistoryTest
 end

 if ActiveRecord::VERSION::STRING >= '5.0'
-  class HistoryTestWithActsAsParanoid < HistoryTest
-    require 'acts_as_paranoid'
+  class HistoryTestWithParanoidDeletes < HistoryTest
     class ParanoidRecord < ActiveRecord::Base
-      acts_as_paranoid
       extend FriendlyId
       friendly_id :name, :use => :history, :dependent => false
+
+      default_scope { where(deleted_at: nil) }
     end

     def model_class
       ParanoidRecord
     end

-    test 'slug should have a sluggable even when soft deleted via acts_as_paranoid' do
+    test 'slug should have a sluggable even when soft deleted by a library' do
       transaction do
-        assert FriendlyId::Slug.belongs_to_required_by_default
-
         assert FriendlyId::Slug.find_by_slug('paranoid').nil?
         record = model_class.create(name: 'paranoid')
         assert FriendlyId::Slug.find_by_slug('paranoid').present?

-        record.destroy
+        record.update_attribute(:deleted_at, Time.now)

         orphan_slug = FriendlyId::Slug.find_by_slug('paranoid')
         assert orphan_slug.present?, 'Orphaned slug should exist'

Thanks!

[padi]

@parndt took your suggestions in the next commit I just pushed. Thanks for the feedback, that is indeed a better way of implementing the soft deletion.