Thread safety for #without_versioning

lib/paper_trail.rb

@@ -32,6 +32,16 @@ def self.enabled_for_controller?
     !!paper_trail_store[:request_enabled_for_controller]
   end
 
+  # Sets whether PaperTrail is enabled or disabled for this model in the current request.
+  def self.enabled_for_model(model, value)
+    paper_trail_store[:"request_enabled_for_#{model}"] = value
+  end
+
+  # Returns `true` if PaperTrail is enabled for this model in the current request, `false` otherwise.
+  def self.enabled_for_model?(model)
+    !!(paper_trail_store.fetch(:"request_enabled_for_#{model}", model.paper_trail_enabled_for_model))
+  end
+
   # Set the field which records when a version was created.
   def self.timestamp_field=(field_name)
     PaperTrail.config.timestamp_field = field_name

lib/paper_trail/has_paper_trail.rb

@@ -81,12 +81,16 @@ def has_paper_trail(options = {})
 
       # Switches PaperTrail off for this class.
       def paper_trail_off
-        self.paper_trail_enabled_for_model = false
+        PaperTrail.enabled_for_model(self, false)
       end
 
       # Switches PaperTrail on for this class.
       def paper_trail_on
-        self.paper_trail_enabled_for_model = true
+        PaperTrail.enabled_for_model(self, true)
+      end
+
+      def paper_trail_enabled_for_model?
+        PaperTrail.enabled_for_model?(self)
       end
 
       def paper_trail_version_class
@@ -194,11 +198,11 @@ def next_version
 
       # Executes the given method or block without creating a new version.
       def without_versioning(method = nil)
-        paper_trail_was_enabled = self.paper_trail_enabled_for_model
-        self.class.paper_trail_off
+        paper_trail_was_enabled = PaperTrail.enabled_for_model?(self.class)
+        PaperTrail.enabled_for_model(self.class, false)
         method ? method.to_proc.call(self) : yield
       ensure
-        self.class.paper_trail_on if paper_trail_was_enabled
+        PaperTrail.enabled_for_model(self.class, paper_trail_was_enabled)
       end
 
       private
@@ -323,7 +327,7 @@ def changed_and_not_ignored
       end
 
       def paper_trail_switched_on?
-        PaperTrail.enabled? && PaperTrail.enabled_for_controller? && self.paper_trail_enabled_for_model
+        PaperTrail.enabled? && PaperTrail.enabled_for_controller? && PaperTrail.enabled_for_model?(self.class)
       end
 
       def save_version?

test/dummy/app/controllers/test_controller.rb

@@ -1,5 +1,5 @@
 class TestController < ActionController::Base
-  def user_for_paper_trail
-    Thread.current.object_id
+  def current_user
+    @current_user ||= OpenStruct.new(:id => Thread.current.object_id)
   end
 end

test/functional/thread_safety_test.rb

@@ -1,7 +1,7 @@
 require 'test_helper'
 
 class ThreadSafetyTest < ActionController::TestCase
-  test "be thread safe" do
+  test "be thread safe when using #set_paper_trail_whodunnit" do
     blocked = true
 
     slow_thread = Thread.new do
@@ -23,4 +23,28 @@ class ThreadSafetyTest < ActionController::TestCase
 
     assert_not_equal slow_thread.value, fast_thread.value
   end
+
+  test "be thread safe when using #without_versioning" do
+    enabled = nil
+
+    slow_thread = Thread.new do
+      Widget.new.without_versioning do
+        sleep(0.01)
+        enabled = PaperTrail.enabled_for_model?(Widget)
+        sleep(0.01)
+      end
+
+      enabled
+    end
+
+    fast_thread = Thread.new do
+      sleep(0.005)
+      enabled = PaperTrail.enabled_for_model?(Widget)
+      enabled
+    end
+
+    assert_not_equal slow_thread.value, fast_thread.value
+    assert Widget.paper_trail_enabled_for_model
+    assert PaperTrail.enabled_for_model?(Widget)
+  end
 end

test/unit/model_test.rb

@@ -495,7 +495,7 @@ def without(&block)
       context 'when destroyed "without versioning"' do
         should 'leave paper trail off after call' do
           @widget.without_versioning :destroy
-          assert !Widget.paper_trail_enabled_for_model
+          assert !PaperTrail.enabled_for_model?(Widget)
         end
       end