Added support for has_and_belongs_to_many association tracking.

.rubocop_todo.yml

@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2018-01-16 15:37:33 -0500 using RuboCop version 0.48.1.
+# on 2018-01-17 21:47:30 -0500 using RuboCop version 0.48.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -31,9 +31,9 @@ Lint/ParenthesesAsGroupedExpression:
   Exclude:
     - 'spec/integration/integration_spec.rb'
 
-# Offense count: 21
+# Offense count: 22
 Metrics/AbcSize:
-  Max: 45
+  Max: 62
 
 # Offense count: 114
 # Configuration parameters: CountComments, ExcludedMethods.
@@ -43,29 +43,29 @@ Metrics/BlockLength:
 # Offense count: 1
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 114
+  Max: 123
 
-# Offense count: 5
+# Offense count: 6
 Metrics/CyclomaticComplexity:
   Max: 10
 
-# Offense count: 457
+# Offense count: 461
 # Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
 # URISchemes: http, https
 Metrics/LineLength:
   Max: 688
 
-# Offense count: 15
+# Offense count: 16
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
-  Max: 23
+  Max: 25
 
 # Offense count: 2
 # Configuration parameters: CountComments.
 Metrics/ModuleLength:
-  Max: 180
+  Max: 200
 
-# Offense count: 5
+# Offense count: 6
 Metrics/PerceivedComplexity:
   Max: 12
 
@@ -107,3 +107,21 @@ Style/IfInsideElse:
 Style/MultilineBlockChain:
   Exclude:
     - 'lib/mongoid/history/tracker.rb'
+
+# Offense count: 1
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: symmetrical, new_line, same_line
+Style/MultilineMethodCallBraceLayout:
+  Exclude:
+    - 'spec/unit/options_spec.rb'
+
+# Offense count: 2
+# Configuration parameters: NamePrefix, NamePrefixBlacklist, NameWhitelist.
+# NamePrefix: is_, has_, have_
+# NamePrefixBlacklist: is_, has_, have_
+# NameWhitelist: is_a?
+Style/PredicateName:
+  Exclude:
+    - 'spec/**/*'
+    - 'lib/mongoid/history/trackable.rb'

README.md

@@ -168,11 +168,11 @@ class Post
   field           :body
   field           :rating
 
-  track_history   :on => [:fields] # all fields will be tracked
+  track_history   :on => [ :fields ] # only fields will be tracked
 end
 ```
 
-You can also track changes on all embedded relations.
+You can also track changes on all embedded (`embeds_one` and `embeds_many`) or referenced (`has_and_belongs_to_many`) relations.
 
 ```ruby
 class Post
@@ -182,7 +182,10 @@ class Post
   embeds_many :comments
   embeds_one  :content
 
-  track_history   :on => [:embedded_relations] # all embedded relations will be tracked
+  track_history   :on => [
+    :embedded_relations,
+    :rereferenced_relations
+  ] # only embedded and references relations will be tracked
 end
 ```
 

lib/mongoid/history/options.rb

@@ -82,17 +82,25 @@ def parse_tracked_fields_and_relations
 
         if options[:on].include?(:fields)
           @options[:on] = options[:on].reject { |opt| opt == :fields }
-          @options[:on] = options[:on] | trackable.fields.keys.map(&:to_sym) - reserved_fields.map(&:to_sym)
+          @options[:on] = options[:on] |
+                          trackable.fields.keys.map(&:to_sym) -
+                          reserved_fields.map(&:to_sym)
         end
 
         if options[:on].include?(:embedded_relations)
           @options[:on] = options[:on].reject { |opt| opt == :embedded_relations }
+          p trackable.embedded_relations.keys
           @options[:on] = options[:on] | trackable.embedded_relations.keys
         end
 
+        if options[:on].include?(:referenced_relations)
+          @options[:on] = options[:on].reject { |opt| opt == :referenced_relations }
+          @options[:on] = options[:on] | trackable.referenced_relations.keys
+        end
+
         @options[:fields] = []
         @options[:dynamic] = []
-        @options[:relations] = { embeds_one: {}, embeds_many: {} }
+        @options[:relations] = { embeds_one: {}, embeds_many: {}, has_and_belongs_to_many: {} }
 
         options[:on].each do |option|
           field = get_database_field_name(option)
@@ -146,6 +154,8 @@ def categorize_tracked_option(field, field_options = nil)
           track_relation(field, :embeds_one, field_options)
         elsif trackable.embeds_many?(field)
           track_relation(field, :embeds_many, field_options)
+        elsif trackable.has_and_belongs_to_many?(field)
+          track_relation(field, :has_and_belongs_to_many, field_options)
         elsif trackable.fields.keys.include?(field)
           @options[:fields] << field
         else

lib/mongoid/history/trackable.rb

@@ -4,6 +4,13 @@ module Trackable
       extend ActiveSupport::Concern
 
       module ClassMethods
+        def has_and_belongs_to_many(field, opts = {})
+          super field, {
+            before_add: :track_references,
+            before_remove: :track_references
+          }.merge(opts)
+        end
+
         def track_history(options = {})
           extend RelationMethods
 
@@ -19,7 +26,6 @@ def track_history(options = {})
           end
 
           include MyInstanceMethods
-          include HasAndBelongsToManyMethods
           extend SingletonMethods
 
           delegate :history_trackable_options, to: 'self.class'
@@ -249,6 +255,34 @@ def track_destroy(&block)
           track_history_for_action(:destroy, &block) unless destroyed?
         end
 
+        def track_references(related)
+          # skip for new records (track_create will capture assignment) and when track updates disabled
+          return true if new_record? || !track_history? || !history_trackable_options[:track_update]
+          metadata = reflect_on_all_associations(:has_and_belongs_to_many).find { |m| m.class_name == related.class.name }
+
+          related_id = related.id
+          original_ids = send(metadata.key.to_sym)
+          modified_ids = if original_ids.include?(related_id)
+                           original_ids.reject { |id| id == related_id }
+                         else
+                           original_ids + [related_id]
+                         end
+
+          modified = { metadata.key => modified_ids }
+          original = { metadata.key => original_ids }
+          action = :update
+          current_version = increment_current_version
+          self.class.tracker_class.create!(
+            history_tracker_attributes(action.to_sym).merge(
+              version: current_version,
+              action: action.to_s,
+              original: original,
+              modified: modified,
+              trackable: self
+            )
+          )
+        end
+
         def clear_trackable_memoization
           @history_tracker_attributes = nil
           @modified_attributes_for_create = nil
@@ -300,44 +334,6 @@ def track_history_for_action(action)
         end
       end
 
-      module HasAndBelongsToManyMethods
-        def track_has_and_belongs_to_many(related)
-          metadata = reflect_on_all_associations(:has_and_belongs_to_many).find { |m| m.class_name == related.class.name }
-
-          related_id = related.id
-          original_ids = send(metadata.key.to_sym)
-          modified_ids = if original_ids.include?(related_id)
-                           original_ids.reject { |id| id == related_id }
-                         else
-                           original_ids + [related_id]
-                         end
-
-          modified = { metadata.key => modified_ids }
-          original = { metadata.key => original_ids }
-          action = :update
-          self.class.tracker_class.create!(
-            history_tracker_attributes(action.to_sym)
-            .merge(version: increment_and_set_version,
-                   action: action.to_s,
-                   original: original,
-                   modified: modified,
-                   trackable: self)
-          )
-        end
-
-        private
-
-        def increment_and_set_version
-          if Mongoid::Compatibility::Version.mongoid3?
-            inc(:version, 1)
-          else
-            current_version = (version || 0) + 1
-            set(version: current_version)
-            current_version
-          end
-        end
-      end
-
       module RelationMethods
         # Returns a relation class for the given field.
         #
@@ -367,6 +363,15 @@ def embeds_many?(field)
           relation_of(field) == Mongoid::Relations::Embedded::Many
         end
 
+        # Indicates whether there is an Referenced::ManyToMany relation for the given embedded field.
+        #
+        # @param [ String | Symbol ] field The name of the referenced field.
+        #
+        # @return [ Boolean ] true if there is an Referenced::ManyToMany relation for the given referenced field.
+        def has_and_belongs_to_many?(field)
+          relation_of(field) == Mongoid::Relations::Referenced::ManyToMany
+        end
+
         # Retrieves the database representation of an embedded field name, in case the :store_as option is used.
         #
         # @param [ String | Symbol ] embed The name or alias of the embedded field.
@@ -477,6 +482,12 @@ def reserved_tracked_fields
                                        end
         end
 
+        def referenced_relations
+          relations.select do |_, r|
+            r.relation == Mongoid::Relations::Referenced::ManyToMany
+          end
+        end
+
         def field_formats
           @field_formats ||= history_trackable_options[:format]
         end

spec/integration/has_and_belongs_to_many_spec.rb

@@ -2,17 +2,6 @@
 
 describe Mongoid::History do
   before :all do
-    class Post
-      include Mongoid::Document
-      include Mongoid::Timestamps
-      include Mongoid::History::Trackable
-
-      field :title
-      field :body
-      has_and_belongs_to_many :tags, before_add: :track_has_and_belongs_to_many, before_remove: :track_has_and_belongs_to_many
-      track_history on: %i[all], track_create: false, track_update: false
-    end
-
     class Tag
       include Mongoid::Document
 
@@ -22,6 +11,19 @@ class Tag
   end
 
   describe 'track' do
+    before :all do
+      class Post
+        include Mongoid::Document
+        include Mongoid::Timestamps
+        include Mongoid::History::Trackable
+
+        field :title
+        field :body
+        has_and_belongs_to_many :tags
+        track_history on: %i[fields]
+      end
+    end
+
     let(:tag) { Tag.create! }
 
     describe 'on creation' do
@@ -35,8 +37,8 @@ class Tag
         expect(post.history_tracks.first.modified).to include('tag_ids' => [tag.id])
       end
 
-      it 'should assign empty tag_ids on original' do
-        expect(post.history_tracks.first.original).to include('tag_ids' => [])
+      it 'should be empty on original' do
+        expect(post.history_tracks.first.original).to eq({})
       end
     end
 
@@ -110,10 +112,67 @@ class Tag
         expect(post.history_tracks.last.original).to include('tag_ids' => [])
       end
     end
+
+    after :all do
+      Object.send(:remove_const, :Post)
+    end
+  end
+
+  describe 'not track' do
+    let!(:post) { Post.create! }
+
+    context 'track_update: false' do
+      before :all do
+        class Post
+          include Mongoid::Document
+          include Mongoid::Timestamps
+          include Mongoid::History::Trackable
+
+          field :title
+          field :body
+          has_and_belongs_to_many :tags
+          track_history on: %i[fields], track_update: false
+        end
+      end
+
+      it 'should not create track' do
+        expect { post.tags = [Tag.create!] }.not_to change(Tracker, :count)
+      end
+
+      after :all do
+        Object.send(:remove_const, :Post)
+      end
+    end
+
+    context '#disable_tracking' do
+      before :all do
+        class Post
+          include Mongoid::Document
+          include Mongoid::Timestamps
+          include Mongoid::History::Trackable
+
+          field :title
+          field :body
+          has_and_belongs_to_many :tags
+          track_history on: %i[fields]
+        end
+      end
+
+      it 'should not create track' do
+        expect do
+          Post.disable_tracking do
+            post.tags = [Tag.create!]
+          end
+        end.not_to change(Tracker, :count)
+      end
+
+      after :all do
+        Object.send(:remove_const, :Post)
+      end
+    end
   end
 
   after :all do
-    Object.send(:remove_const, :Post)
     Object.send(:remove_const, :Tag)
   end
 end