clear rolled back versions from associated model

lib/paper_trail/has_paper_trail.rb

@@ -78,6 +78,7 @@ def has_paper_trail(options = {})
           after_update  :clear_version_instance!
         end
         after_destroy :record_destroy, :if => :save_version? if options_on.empty? || options_on.include?(:destroy)
+        after_rollback :clear_rolled_back_versions
       end
 
       # Switches PaperTrail off for this class.
@@ -180,6 +181,12 @@ def originator
         (source_version || send(self.class.versions_association_name).last).try(:whodunnit)
       end
 
+      # Invoked after rollbacks to ensure versions records are not created
+      # for changes that never actually took place
+      def clear_rolled_back_versions
+        send(self.class.versions_association_name).reload
+      end
+
       # Returns the object (not a Version) as it was at the given timestamp.
       def version_at(timestamp, reify_options={})
         # Because a version stores how its object looked *before* the change,

paper_trail.gemspec

@@ -32,6 +32,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec-rails', '~> 3.1.0'
   s.add_development_dependency 'generator_spec'
   s.add_development_dependency 'database_cleaner', '~> 1.2'
+  s.add_development_dependency 'test_after_commit', '~> 0.4'
 
   # JRuby support for the test ENV
   unless defined?(JRUBY_VERSION)

spec/models/widget_spec.rb

@@ -85,6 +85,28 @@
         expect(widget.version).to eq(widget.versions.last)
       end
     end
+
+    describe :after_rollback do
+      let(:rolled_back_name) { 'Big Moo' }
+
+      before do
+        begin
+          widget.transaction do
+            widget.update_attributes!(name: rolled_back_name)
+            widget.update_attributes!(name: described_class::EXCLUDED_NAME)
+          end
+        rescue ActiveRecord::RecordInvalid
+          widget.name = nil
+          widget.save
+        end
+      end
+
+      it 'does not create an event for changes that did not happen' do
+        widget.versions.map(&:changeset).each do |changeset|
+          expect(changeset.fetch('name', [])).to_not include(rolled_back_name)
+        end
+      end
+    end
   end
 
   describe "Association", :versioning => true do

test/dummy/app/models/widget.rb

@@ -2,6 +2,10 @@ class Widget < ActiveRecord::Base
   has_paper_trail
   has_one :wotsit
 
+  EXCLUDED_NAME = 'Biglet'
+
+  validates :name, exclusion: { in: [EXCLUDED_NAME] }
+
   if ::ActiveRecord::VERSION::MAJOR >= 4 # `has_many` syntax for specifying order uses a lambda in Rails 4
     has_many :fluxors, lambda { order(:name) }
   else