Drop RequestStore in favour of ActiveSupport::CurrentAttributes

Author: joshuay03

lib/paper_trail/frameworks/rails/railtie.rb

@@ -26,5 +26,12 @@ class Railtie < ::Rails::Railtie
         require "paper_trail/frameworks/active_record"
       end
     end
+
+    # ActiveSupport::CurrentAttributes resets all attributes before and after each request.
+    # Resetting after a request breaks backwards compatibility with the previous RequestStore
+    # implementation. This initializer ensures this reset is skipped.
+    initializer "active_support.reset_all_current_attributes_instances" do |app|
+      app.executor.to_run { PaperTrail::Request::CurrentAttributes.skip_reset = true }
+    end
   end
 end

lib/paper_trail/request.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "request_store"
+require "paper_trail/request/current_attributes"
 
 module PaperTrail
   # Manages variables that affect the current HTTP request, such as `whodunnit`.
@@ -20,9 +20,7 @@ class << self
       #   PaperTrail.request.controller_info # => { ip: '127.0.0.1' }
       #
       # @api public
-      def controller_info=(value)
-        store[:controller_info] = value
-      end
+      delegate :controller_info=, to: :current_attributes
 
       # Returns the data from the controller that you want PaperTrail to store.
       # See also `PaperTrail::Rails::Controller#info_for_paper_trail`.
@@ -31,9 +29,7 @@ def controller_info=(value)
       #   PaperTrail.request.controller_info # => { ip: '127.0.0.1' }
       #
       # @api public
-      def controller_info
-        store[:controller_info]
-      end
+      delegate :controller_info, to: :current_attributes
 
       # Switches PaperTrail off for the given model.
       # @api public
@@ -49,30 +45,29 @@ def enable_model(model_class)
 
       # Sets whether PaperTrail is enabled or disabled for the current request.
       # @api public
-      def enabled=(value)
-        store[:enabled] = value
-      end
+      delegate :enabled=, to: :current_attributes
 
       # Returns `true` if PaperTrail is enabled for the request, `false` otherwise.
       # See `PaperTrail::Rails::Controller#paper_trail_enabled_for_controller`.
       # @api public
       def enabled?
-        !!store[:enabled]
+        !!current_attributes.enabled
       end
 
       # Sets whether PaperTrail is enabled or disabled for this model in the
       # current request.
       # @api public
       def enabled_for_model(model, value)
-        store[:"enabled_for_#{model}"] = value
+        current_attributes.enabled_for[model] = value
       end
 
       # Returns `true` if PaperTrail is enabled for this model in the current
       # request, `false` otherwise.
       # @api public
       def enabled_for_model?(model)
         model.include?(::PaperTrail::Model::InstanceMethods) &&
-          !!store.fetch(:"enabled_for_#{model}", true)
+          !!(current_attributes.enabled_for[model] ||
+            current_attributes.enabled_for[model].nil?)
       end
 
       # Temporarily set `options` and execute a block.
@@ -97,15 +92,13 @@ def with(options)
       # inserting a `Version` record.
       #
       # @api public
-      def whodunnit=(value)
-        store[:whodunnit] = value
-      end
+      delegate :whodunnit=, to: :current_attributes
 
-      # Returns who is reponsible for any changes that occur during request.
+      # Returns who is responsible for any changes that occur during request.
       #
       # @api public
       def whodunnit
-        who = store[:whodunnit]
+        who = current_attributes.whodunnit
         who.respond_to?(:call) ? who.call : who
       end
 
@@ -114,31 +107,36 @@ def whodunnit
       # @api private
       def merge(options)
         options.to_h.each do |k, v|
-          store[k] = v
+          if k.start_with?("enabled_for_")
+            model_klass = k.to_s.sub("enabled_for_", "").constantize
+            current_attributes.enabled_for[model_klass] = v
+          else
+            current_attributes.public_send("#{k}=", v)
+          end
         end
       end
 
       # @api private
       def set(options)
-        store.clear
+        current_attributes.reset
         merge(options)
       end
 
-      # Returns a Hash, initializing with default values if necessary.
+      # Returns the current request attributes with default values initialized if necessary.
       # @api private
-      def store
-        RequestStore.store[:paper_trail] ||= {
-          enabled: true
-        }
+      def current_attributes
+        CurrentAttributes.tap do |attrs|
+          attrs.enabled = true if attrs.enabled.nil?
+        end
       end
 
-      # Returns a deep copy of the internal hash from our RequestStore. Keys are
+      # Returns a deep copy of the current attributes. Keys are
       # all symbols. Values are mostly primitives, but whodunnit can be a Proc.
       # We cannot use Marshal.dump here because it doesn't support Proc. It is
       # unclear exactly how `deep_dup` handles a Proc, but it doesn't complain.
       # @api private
       def to_h
-        store.deep_dup
+        current_attributes.attributes.deep_dup
       end
 
       # Provide a helpful error message if someone has a typo in one of their

lib/paper_trail/request/current_attributes.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module PaperTrail
+  module Request
+    # Thread-isolated attributes for managing the current request.
+    class CurrentAttributes < ActiveSupport::CurrentAttributes
+      attribute :enabled
+      attribute :enabled_for
+      attribute :controller_info
+      attribute :whodunnit
+      attribute :skip_reset
+
+      def enabled_for
+        super || self.enabled_for = {}
+      end
+
+      # Overrides ActiveSupport::CurrentAttributes#reset to support skipping.
+      def reset
+        return if skip_reset
+        super
+      end
+    end
+  end
+end

paper_trail.gemspec

@@ -49,9 +49,6 @@ has been destroyed.
   # See discussion in paper_trail/compatibility.rb
   s.add_dependency "activerecord", ::PaperTrail::Compatibility::ACTIVERECORD_GTE
 
-  # PT supports request_store versions for 3 years.
-  s.add_dependency "request_store", "~> 1.4"
-
   s.add_development_dependency "appraisal", "~> 2.4.1"
   s.add_development_dependency "byebug", "~> 11.1"
   s.add_development_dependency "ffaker", "~> 2.20"

spec/controllers/widgets_controller_spec.rb

@@ -5,8 +5,6 @@
 RSpec.describe WidgetsController, type: :controller, versioning: true do
   before { request.env["REMOTE_ADDR"] = "127.0.0.1" }
 
-  after { RequestStore.store[:paper_trail] = nil }
-
   describe "#create" do
     context "with PT enabled" do
       it "stores information like IP address in version" do