From 2e4938b452af3db855fc2b371b68aaf90359b26a Mon Sep 17 00:00:00 2001
From: Mattias Pfeiffer <mattias@pfeiffer.dk>
Date: Thu, 19 Jan 2017 11:03:51 +0100
Subject: [PATCH] Add dirty tracking of paranoia attributes

---
 lib/paranoia.rb       | 12 ++++++++++--
 test/paranoia_test.rb | 31 +++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/lib/paranoia.rb b/lib/paranoia.rb
index 0c0e3657..37b7c829 100644
--- a/lib/paranoia.rb
+++ b/lib/paranoia.rb
@@ -94,7 +94,7 @@ def delete
       # if a transaction exists, add the record so that after_commit
       # callbacks can be run
       add_to_transaction
-      update_columns(paranoia_destroy_attributes)
+      paranoia_update_columns(paranoia_destroy_attributes)
     elsif !frozen?
       assign_attributes(paranoia_destroy_attributes)
     end
@@ -109,7 +109,7 @@ def restore!(opts = {})
         noop_if_frozen = ActiveRecord.version < Gem::Version.new("4.1")
         if (noop_if_frozen && !@attributes.frozen?) || !noop_if_frozen
           write_attribute paranoia_column, paranoia_sentinel_value
-          update_columns(paranoia_restore_attributes)
+          paranoia_update_columns(paranoia_restore_attributes)
           touch
         end
         restore_associated_records if opts[:recursive]
@@ -125,6 +125,14 @@ def paranoia_destroyed?
   end
   alias :deleted? :paranoia_destroyed?
 
+  def paranoia_update_columns(attributes)
+    attributes.keys.each do |key|
+      send("#{key}_will_change!")
+    end
+    update_columns(attributes)
+    changes_applied
+  end
+
   def really_destroy!
     transaction do
       run_callbacks(:real_destroy) do
diff --git a/test/paranoia_test.rb b/test/paranoia_test.rb
index a1bceeee..c422a159 100644
--- a/test/paranoia_test.rb
+++ b/test/paranoia_test.rb
@@ -175,6 +175,13 @@ def test_update_columns_on_paranoia_destroyed
     assert record.update_columns deleted_at: Time.now
   end
 
+  def test_dirty_tracking_on_paranoia_destroyed
+    record = ParentModel.create
+    record.destroy
+
+    assert_equal record.previous_changes.keys, ["deleted_at"]
+  end
+
   def test_scoping_behavior_for_paranoid_models
     parent1 = ParentModel.create
     parent2 = ParentModel.create
@@ -209,6 +216,13 @@ def test_destroy_behavior_for_custom_column_models
     assert_equal 1, model.class.deleted.count
   end
 
+  def test_dirty_tracking_for_custom_column_models
+    record = CustomColumnModel.create
+    record.destroy
+
+    assert_equal record.previous_changes.keys, ["destroyed_at"]
+  end
+
   def test_default_sentinel_value
     assert_equal nil, ParanoidModel.paranoia_sentinel_value
   end
@@ -240,6 +254,12 @@ def test_active_column_model
     assert_equal 1, model.class.deleted.count
   end
 
+  def test_dirty_tracking_for_active_column_model
+    record = ActiveColumnModel.create
+    record.destroy
+    assert_equal record.previous_changes.keys, ["deleted_at", "active"]
+  end
+
   def test_active_column_model_with_uniqueness_validation_only_checks_non_deleted_records
     a = ActiveColumnModelWithUniquenessValidation.create!(name: "A")
     a.destroy
@@ -426,6 +446,17 @@ def test_restore
     assert_equal false, model.paranoia_destroyed?
   end
 
+  def test_dirty_tracking_on_restore
+    model = ParanoidModel.new
+    model.save
+    id = model.id
+    model.destroy
+
+    model = ParanoidModel.only_deleted.find(id)
+    model.restore!
+    assert_equal model.previous_changes.keys, ['deleted_at']
+  end
+
   def test_restore_on_object_return_self
     model = ParanoidModel.create
     model.destroy