Use StrongMemoize and enable/disable cops properly

app/controllers/concerns/creates_commit.rb

 module CreatesCommit
   extend ActiveSupport::Concern
+  include Gitlab::Utils::StrongMemoize
 
   # rubocop:disable Cop/ModuleWithInstanceVariables
   def create_commit(service, success_path:, failure_path:, failure_view: nil, success_notice: nil)
@@ -94,15 +95,20 @@ module CreatesCommit
   # rubocop:enable Cop/ModuleWithInstanceVariables
 
   def existing_merge_request_path
-    project_merge_request_path(@project, @merge_request)
+    project_merge_request_path(@project, @merge_request) # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   # rubocop:disable Cop/ModuleWithInstanceVariables
   def merge_request_exists?
-    return @merge_request if defined?(@merge_request)
-
-    @merge_request = MergeRequestsFinder.new(current_user, project_id: @project.id).execute.opened
-      .find_by(source_project_id: @project_to_commit_into, source_branch: @branch_name, target_branch: @start_branch)
+    strong_memoize(:merge_request) do
+      MergeRequestsFinder.new(current_user, project_id: @project.id)
+        .execute
+        .opened
+        .find_by(
+          source_project_id: @project_to_commit_into,
+          source_branch: @branch_name,
+          target_branch: @start_branch)
+    end
   end
   # rubocop:enable Cop/ModuleWithInstanceVariables
 

app/controllers/concerns/group_tree.rb

 module GroupTree
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def render_group_tree(groups)
     @groups = if params[:filter].present?
                 Gitlab::GroupHierarchy.new(groups.search(params[:filter]))
@@ -20,5 +21,6 @@ module GroupTree
         render json: serializer.represent(@groups)
       end
     end
+    # rubocop:enable Cop/ModuleWithInstanceVariables
   end
 end

app/controllers/concerns/issuable_actions.rb

@@ -142,6 +142,7 @@ module IssuableActions
     @resource_name ||= controller_name.singularize
   end
 
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def render_entity_json
     if @issuable.valid?
       render json: serializer.represent(@issuable)
@@ -149,6 +150,7 @@ module IssuableActions
       render json: { errors: @issuable.errors.full_messages }, status: :unprocessable_entity
     end
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   def serializer
     raise NotImplementedError
@@ -159,6 +161,6 @@ module IssuableActions
   end
 
   def parent
-    @project || @group
+    @project || @group # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 end

app/controllers/concerns/issuable_collections.rb

@@ -2,6 +2,7 @@ module IssuableCollections
   extend ActiveSupport::Concern
   include SortingHelper
   include Gitlab::IssuableMetadata
+  include Gitlab::Utils::StrongMemoize
 
   included do
     helper_method :finder
@@ -43,7 +44,7 @@ module IssuableCollections
   def redirect_out_of_range(total_pages)
     return false if total_pages.zero?
 
-    out_of_range = @issuables.current_page > total_pages
+    out_of_range = @issuables.current_page > total_pages # rubocop:disable Cop/ModuleWithInstanceVariables
 
     if out_of_range
       redirect_to(url_for(params.merge(page: total_pages, only_path: true)))
@@ -53,7 +54,7 @@ module IssuableCollections
   end
 
   def issuable_page_count
-    page_count_for_relation(@issuables, finder.row_count)
+    page_count_for_relation(@issuables, finder.row_count) # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   def page_count_for_relation(relation, row_count)
@@ -133,9 +134,9 @@ module IssuableCollections
   end
 
   def finder
-    return @finder if defined?(@finder)
-
-    @finder = issuable_finder_for(@finder_type)
+    strong_memoize(:finder) do
+      issuable_finder_for(@finder_type) # rubocop:disable Cop/ModuleWithInstanceVariables
+    end
   end
 
   def collection_type

app/controllers/concerns/notes_actions.rb

-# rubocop:disable Cop/ModuleWithInstanceVariables
 module NotesActions
   include RendersNotes
+  include Gitlab::Utils::StrongMemoize
   extend ActiveSupport::Concern
 
   included do
@@ -31,6 +31,7 @@ module NotesActions
     render json: notes_json
   end
 
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def create
     create_params = note_params.merge(
       merge_request_diff_head_sha: params[:merge_request_diff_head_sha],
@@ -48,7 +49,9 @@ module NotesActions
       format.html { redirect_back_or_default }
     end
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def update
     @note = Notes::UpdateService.new(project, current_user, note_params).execute(note)
 
@@ -61,6 +64,7 @@ module NotesActions
       format.html { redirect_back_or_default }
     end
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   def destroy
     if note.editable?
@@ -139,7 +143,7 @@ module NotesActions
         end
     else
       template = "discussions/_diff_discussion"
-      @fresh_discussion = true
+      @fresh_discussion = true # rubocop:disable Cop/ModuleWithInstanceVariables
 
       locals = { discussions: [discussion], on_image: on_image }
     end
@@ -192,7 +196,7 @@ module NotesActions
   end
 
   def noteable
-    @noteable ||= notes_finder.target || @note&.noteable
+    @noteable ||= notes_finder.target || @note&.noteable # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   def require_noteable!
@@ -212,20 +216,21 @@ module NotesActions
   end
 
   def note_project
-    return @note_project if defined?(@note_project)
-    return nil unless project
+    strong_memoize(:note_project) do
+      return nil unless project
 
-    note_project_id = params[:note_project_id]
+      note_project_id = params[:note_project_id]
 
-    @note_project =
-      if note_project_id.present?
-        Project.find(note_project_id)
-      else
-        project
-      end
+      the_project =
+        if note_project_id.present?
+          Project.find(note_project_id)
+        else
+          project
+        end
 
-    return access_denied! unless can?(current_user, :create_note, @note_project)
+      return access_denied! unless can?(current_user, :create_note, the_project)
 
-    @note_project
+      the_project
+    end
   end
 end

app/controllers/concerns/preview_markdown.rb

 module PreviewMarkdown
   extend ActiveSupport::Concern
 
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def preview_markdown
     result = PreviewMarkdownService.new(@project, current_user, params).execute
 
@@ -19,4 +20,5 @@ module PreviewMarkdown
       }
     }
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 end

app/controllers/concerns/renders_commits.rb

 module RendersCommits
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def prepare_commits_for_rendering(commits)
-    Banzai::CommitRenderer.render(commits, @project, current_user)
+    Banzai::CommitRenderer.render(commits, @project, current_user) # rubocop:disable Cop/ModuleWithInstanceVariables
 
     commits
   end

app/controllers/concerns/renders_notes.rb

@@ -8,6 +8,7 @@ module RendersNotes
 
     notes
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   private
 

app/controllers/concerns/service_params.rb

@@ -65,9 +65,8 @@ module ServiceParams
   # Parameters to ignore if no value is specified
   FILTER_BLANK_PARAMS = [:password].freeze
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def service_params
-    dynamic_params = @service.event_channel_names + @service.event_names
+    dynamic_params = @service.event_channel_names + @service.event_names # rubocop:disable Cop/ModuleWithInstanceVariables
     service_params = params.permit(:id, service: ALLOWED_PARAMS_CE + dynamic_params)
 
     if service_params[:service].is_a?(Hash)

app/controllers/concerns/snippets_actions.rb

@@ -15,6 +15,7 @@ module SnippetsActions
       filename: @snippet.sanitized_file_name
     )
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   private
 

app/controllers/concerns/spammable_actions.rb

@@ -2,6 +2,7 @@ module SpammableActions
   extend ActiveSupport::Concern
 
   include Recaptcha::Verify
+  include Gitlab::Utils::StrongMemoize
 
   included do
     before_action :authorize_submit_spammable!, only: :mark_as_spam
@@ -17,11 +18,10 @@ module SpammableActions
 
   private
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def ensure_spam_config_loaded!
-    return @spam_config_loaded if defined?(@spam_config_loaded)
-
-    @spam_config_loaded = Gitlab::Recaptcha.load_configurations!
+    strong_memoize(:spam_config_loaded) do
+      Gitlab::Recaptcha.load_configurations!
+    end
   end
 
   def recaptcha_check_with_fallback(&fallback)

app/controllers/concerns/toggle_subscription_action.rb

@@ -11,9 +11,8 @@ module ToggleSubscriptionAction
 
   private
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def subscribable_project
-    @project || raise(NotImplementedError)
+    @project ||= raise(NotImplementedError)
   end
 
   def subscribable_resource

app/models/concerns/mentionable.rb

@@ -43,15 +43,12 @@ module Mentionable
     self
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def all_references(current_user = nil, extractor: nil)
-    @extractors ||= {}
-
     # Use custom extractor if it's passed in the function parameters.
     if extractor
-      @extractors[current_user] = extractor
+      extractors[current_user] = extractor
     else
-      extractor = @extractors[current_user] ||= Gitlab::ReferenceExtractor.new(project, current_user)
+      extractor = extractors[current_user] ||= Gitlab::ReferenceExtractor.new(project, current_user)
 
       extractor.reset_memoized_values
     end
@@ -70,6 +67,10 @@ module Mentionable
     extractor
   end
 
+  def extractors
+    @extractors ||= {}
+  end
+
   def mentioned_users(current_user = nil)
     all_references(current_user).users
   end

app/models/concerns/milestoneish.rb

@@ -102,11 +102,12 @@ module Milestoneish
     end
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def memoize_per_user(user, method_name)
-    @memoized ||= {}
-    @memoized[method_name] ||= {}
-    @memoized[method_name][user&.id] ||= yield
+    memoized_users[method_name][user&.id] ||= yield
+  end
+
+  def memoized_users
+    @memoized_users ||= Hash.new { |h, k| h[k] = {} }
   end
 
   # override in a class that includes this module to get a faster query

app/models/concerns/noteable.rb

@@ -55,6 +55,7 @@ module Noteable
         discussion_notes.resolvable.discussions(self)
       end
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   def discussions_resolvable?
     resolvable_discussions.any?(&:resolvable?)

app/models/concerns/relative_positioning.rb

@@ -44,7 +44,6 @@ module RelativePositioning
     next_pos
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def move_between(before, after)
     return move_after(before) unless after
     return move_before(after) unless before
@@ -53,13 +52,12 @@ module RelativePositioning
     # to its predecessor. This process will recursively move all the predecessors until we have a place
     if (after.relative_position - before.relative_position) < 2
       before.move_before
-      @positionable_neighbours = [before]
+      @positionable_neighbours = [before] # rubocop:disable Cop/ModuleWithInstanceVariables
     end
 
     self.relative_position = position_between(before.relative_position, after.relative_position)
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def move_after(before = self)
     pos_before = before.relative_position
     pos_after = before.next_relative_position
@@ -67,7 +65,7 @@ module RelativePositioning
     if before.shift_after?
       issue_to_move = self.class.in_projects(project_ids).find_by!(relative_position: pos_after)
       issue_to_move.move_after
-      @positionable_neighbours = [issue_to_move]
+      @positionable_neighbours = [issue_to_move] # rubocop:disable Cop/ModuleWithInstanceVariables
 
       pos_after = issue_to_move.relative_position
     end
@@ -75,7 +73,6 @@ module RelativePositioning
     self.relative_position = position_between(pos_before, pos_after)
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def move_before(after = self)
     pos_after = after.relative_position
     pos_before = after.prev_relative_position
@@ -83,7 +80,7 @@ module RelativePositioning
     if after.shift_before?
       issue_to_move = self.class.in_projects(project_ids).find_by!(relative_position: pos_before)
       issue_to_move.move_before
-      @positionable_neighbours = [issue_to_move]
+      @positionable_neighbours = [issue_to_move] # rubocop:disable Cop/ModuleWithInstanceVariables
 
       pos_before = issue_to_move.relative_position
     end
@@ -144,4 +141,5 @@ module RelativePositioning
 
     status
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 end

app/models/concerns/resolvable_discussion.rb

@@ -84,7 +84,6 @@ module ResolvableDiscussion
 
   private
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def update
     # Do not select `Note.resolvable`, so that system notes remain in the collection
     notes_relation = Note.where(id: notes.map(&:id))

app/models/concerns/routable.rb

@@ -86,10 +86,9 @@ module Routable
     end
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def full_name
     if route && route.name.present?
-      @full_name ||= route.name
+      @full_name ||= route.name # rubocop:disable Cop/ModuleWithInstanceVariables
     else
       update_route if persisted?
 
@@ -113,7 +112,7 @@ module Routable
 
   def expires_full_path_cache
     RequestStore.delete(full_path_key) if RequestStore.active?
-    @full_path = nil
+    @full_path = nil # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   def build_full_path
@@ -126,10 +125,9 @@ module Routable
 
   private
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def uncached_full_path
     if route && route.path.present?
-      @full_path ||= route.path
+      @full_path ||= route.path # rubocop:disable Cop/ModuleWithInstanceVariables
     else
       update_route if persisted?
 
@@ -164,12 +162,11 @@ module Routable
     route.save
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def prepare_route
     route || build_route(source: self)
     route.path = build_full_path
     route.name = build_full_name
-    @full_path = nil
-    @full_name = nil
+    @full_path = nil # rubocop:disable Cop/ModuleWithInstanceVariables
+    @full_name = nil # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 end

app/models/concerns/taskable.rb

@@ -36,11 +36,10 @@ module Taskable
   end
 
   # Called by `TaskList::Summary`
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def task_list_items
     return [] if description.blank?
 
-    @task_list_items ||= Taskable.get_tasks(description)
+    @task_list_items ||= Taskable.get_tasks(description) # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   def tasks

app/models/concerns/time_trackable.rb

@@ -36,6 +36,7 @@ module TimeTrackable
     end
   end
   alias_method :spend_time=, :spend_time
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   def total_time_spent
     timelogs.sum(:time_spent)
@@ -51,11 +52,11 @@ module TimeTrackable
 
   private
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def reset_spent_time
-    timelogs.new(time_spent: total_time_spent * -1, user: @time_spent_user)
+    timelogs.new(time_spent: total_time_spent * -1, user: @time_spent_user) # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
+  # rubocop:disable Cop/ModuleWithInstanceVariables
   def add_or_subtract_spent_time
     timelogs.new(
       time_spent: time_spent,
@@ -63,17 +64,19 @@ module TimeTrackable
       spent_at: @spent_at
     )
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def check_negative_time_spent
     return if time_spent.nil? || time_spent == :reset
 
-    # we need to cache the total time spent so multiple calls to #valid?
-    # doesn't give a false error
-    @original_total_time_spent ||= total_time_spent
-
-    if time_spent < 0 && (time_spent.abs > @original_total_time_spent)
+    if time_spent < 0 && (time_spent.abs > original_total_time_spent)
       errors.add(:time_spent, 'Time to subtract exceeds the total time spent')
     end
   end
+
+  # we need to cache the total time spent so multiple calls to #valid?
+  # doesn't give a false error
+  def original_total_time_spent
+    @original_total_time_spent ||= total_time_spent
+  end
 end

app/serializers/concerns/with_pagination.rb

@@ -14,7 +14,7 @@ module WithPagination
   # we shouldn't try to paginate single resources
   def represent(resource, opts = {})
     if paginated? && resource.respond_to?(:page)
-      super(@paginator.paginate(resource), opts)
+      super(paginator.paginate(resource), opts)
     else
       super(resource, opts)
     end

app/services/concerns/issues/resolve_discussions.rb

 module Issues
   module ResolveDiscussions
+    include Gitlab::Utils::StrongMemoize
+
     attr_reader :merge_request_to_resolve_discussions_of_iid, :discussion_to_resolve_id
 
     # rubocop:disable Cop/ModuleWithInstanceVariables
@@ -7,21 +9,20 @@ module Issues
       @merge_request_to_resolve_discussions_of_iid ||= params.delete(:merge_request_to_resolve_discussions_of)
       @discussion_to_resolve_id ||= params.delete(:discussion_to_resolve)
     end
+    # rubocop:enable Cop/ModuleWithInstanceVariables
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def merge_request_to_resolve_discussions_of
-      return @merge_request_to_resolve_discussions_of if defined?(@merge_request_to_resolve_discussions_of)
-
-      @merge_request_to_resolve_discussions_of = MergeRequestsFinder.new(current_user, project_id: project.id)
-                                                     .execute
-                                                     .find_by(iid: merge_request_to_resolve_discussions_of_iid)
+      strong_memoize(:merge_request_to_resolve_discussions_of) do
+        MergeRequestsFinder.new(current_user, project_id: project.id)
+          .execute
+          .find_by(iid: merge_request_to_resolve_discussions_of_iid)
+      end
     end
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def discussions_to_resolve
       return [] unless merge_request_to_resolve_discussions_of
 
-      @discussions_to_resolve ||=
+      @discussions_to_resolve ||= # rubocop:disable Cop/ModuleWithInstanceVariables
         if discussion_to_resolve_id
           discussion_or_nil = merge_request_to_resolve_discussions_of
                                 .find_discussion(discussion_to_resolve_id)

app/services/spam_check_service.rb

@@ -14,6 +14,7 @@ module SpamCheckService
     @recaptcha_verified = params.delete(:recaptcha_verified)
     @spam_log_id        = params.delete(:spam_log_id)
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
   # In order to be proceed to the spam check process, @spammable has to be
   # a dirty instance, which means it should be already assigned with the new
@@ -26,4 +27,5 @@ module SpamCheckService
       user.spam_logs.find_by(id: @spam_log_id)&.update!(recaptcha_verified: true)
     end
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 end

app/workers/concerns/new_issuable.rb

@@ -8,18 +8,16 @@ module NewIssuable
     user && issuable
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def set_user(user_id)
-    @user = User.find_by(id: user_id)
+    @user = User.find_by(id: user_id) # rubocop:disable Cop/ModuleWithInstanceVariables
 
-    log_error(User, user_id) unless @user
+    log_error(User, user_id) unless @user # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def set_issuable(issuable_id)
-    @issuable = issuable_class.find_by(id: issuable_id)
+    @issuable = issuable_class.find_by(id: issuable_id) # rubocop:disable Cop/ModuleWithInstanceVariables
 
-    log_error(issuable_class, issuable_id) unless @issuable
+    log_error(issuable_class, issuable_id) unless @issuable # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   def log_error(record_class, record_id)

config/initializers/fix_local_cache_middleware.rb

@@ -4,10 +4,9 @@ module LocalCacheRegistryCleanupWithEnsure
   LocalStore =
     ActiveSupport::Cache::Strategy::LocalCache::LocalStore
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def call(env)
     LocalCacheRegistry.set_cache_for(local_cache_key, LocalStore.new)
-    response = @app.call(env)
+    response = @app.call(env) # rubocop:disable Cop/ModuleWithInstanceVariables
     response[2] = ::Rack::BodyProxy.new(response[2]) do
       LocalCacheRegistry.set_cache_for(local_cache_key, nil)
     end

config/initializers/rspec_profiling.rb

@@ -16,14 +16,13 @@ module RspecProfilingExt
   end
 
   module Run
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def example_finished(*args)
       super
     rescue => err
-      return if @already_logged_example_finished_error
+      return if @already_logged_example_finished_error # rubocop:disable Cop/ModuleWithInstanceVariables
 
       $stderr.puts "rspec_profiling couldn't collect an example: #{err}. Further warnings suppressed."
-      @already_logged_example_finished_error = true
+      @already_logged_example_finished_error = true # rubocop:disable Cop/ModuleWithInstanceVariables
     end
 
     alias_method :example_passed, :example_finished

config/initializers/rugged_use_gitlab_git_attributes.rb

@@ -14,10 +14,12 @@
 module Rugged
   class Repository
     module UseGitlabGitAttributes
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def fetch_attributes(name, *)
+        attributes.attributes(name)
+      end
+
+      def attributes
         @attributes ||= Gitlab::Git::Attributes.new(path)
-        @attributes.attributes(name)
       end
     end
 

lib/api/helpers.rb

@@ -33,6 +33,10 @@ module API
     end
 
     # rubocop:disable Cop/ModuleWithInstanceVariables
+    # We can't rewrite this with StrongMemoize because `sudo!` would
+    # actually write to `@current_user`, and `sudo?` would immediately
+    # call `current_user` again which reads from `@current_user`.
+    # We should rewrite this in a way that using StrongMemoize is possible
     def current_user
       return @current_user if defined?(@current_user)
 
@@ -46,6 +50,7 @@ module API
 
       @current_user
     end
+    # rubocop:enable Cop/ModuleWithInstanceVariables
 
     def sudo?
       initial_current_user != current_user
@@ -394,6 +399,7 @@ module API
 
     private
 
+    # rubocop:disable Cop/ModuleWithInstanceVariables
     def initial_current_user
       return @initial_current_user if defined?(@initial_current_user)
 
@@ -403,8 +409,8 @@ module API
         unauthorized!
       end
     end
+    # rubocop:enable Cop/ModuleWithInstanceVariables
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def sudo!
       return unless sudo_identifier
 
@@ -423,7 +429,7 @@ module API
       sudoed_user = find_user(sudo_identifier)
       not_found!("User with ID or username '#{sudo_identifier}'") unless sudoed_user
 
-      @current_user = sudoed_user
+      @current_user = sudoed_user # rubocop:disable Cop/ModuleWithInstanceVariables
     end
 
     def sudo_identifier

lib/api/helpers/internal_helpers.rb

@@ -8,16 +8,14 @@ module API
 
       attr_reader :redirected_path
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def wiki?
-        set_project unless defined?(@wiki)
-        @wiki
+        set_project unless defined?(@wiki) # rubocop:disable Cop/ModuleWithInstanceVariables
+        @wiki # rubocop:disable Cop/ModuleWithInstanceVariables
       end
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def project
-        set_project unless defined?(@project)
-        @project
+        set_project unless defined?(@project) # rubocop:disable Cop/ModuleWithInstanceVariables
+        @project # rubocop:disable Cop/ModuleWithInstanceVariables
       end
 
       def ssh_authentication_abilities
@@ -78,6 +76,7 @@ module API
           @project, @wiki, @redirected_path = Gitlab::RepoPath.parse(params[:project])
         end
       end
+      # rubocop:enable Cop/ModuleWithInstanceVariables
 
       # Project id to pass between components that don't share/don't have
       # access to the same filesystem mounts

lib/extracts_path.rb

@@ -37,11 +37,10 @@ module ExtractsPath
   #
   # Returns an Array where the first value is the tree-ish and the second is the
   # path
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def extract_ref(id)
     pair = ['', '']
 
-    return pair unless @project
+    return pair unless @project # rubocop:disable Cop/ModuleWithInstanceVariables
 
     if id =~ /^(\h{40})(.+)/
       # If the ref appears to be a SHA, we're done, just split the string
@@ -133,10 +132,10 @@ module ExtractsPath
   rescue RuntimeError, NoMethodError, InvalidPathError
     render_404
   end
+  # rubocop:enable Cop/ModuleWithInstanceVariables
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def tree
-    @tree ||= @repo.tree(@commit.id, @path)
+    @tree ||= @repo.tree(@commit.id, @path) # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 
   private
@@ -148,10 +147,9 @@ module ExtractsPath
     id
   end
 
-  # rubocop:disable Cop/ModuleWithInstanceVariables
   def ref_names
-    return [] unless @project
+    return [] unless @project # rubocop:disable Cop/ModuleWithInstanceVariables
 
-    @ref_names ||= @project.repository.ref_names
+    @ref_names ||= @project.repository.ref_names # rubocop:disable Cop/ModuleWithInstanceVariables
   end
 end

lib/gitlab/cache/request_cache.rb

@@ -45,12 +45,13 @@ module Gitlab
         klass.prepend(extension)
       end
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
+      attr_accessor :request_cache_key_block
+
       def request_cache_key(&block)
         if block_given?
-          @request_cache_key = block
+          self.request_cache_key_block = block
         else
-          @request_cache_key
+          request_cache_key_block
         end
       end
 

lib/gitlab/ci/charts.rb

@@ -2,12 +2,11 @@ module Gitlab
   module Ci
     module Charts
       module DailyInterval
-        # rubocop:disable Cop/ModuleWithInstanceVariables
         def grouped_count(query)
           query
             .group("DATE(#{::Ci::Pipeline.table_name}.created_at)")
             .count(:created_at)
-            .transform_keys { |date| date.strftime(@format) }
+            .transform_keys { |date| date.strftime(@format) } # rubocop:disable Cop/ModuleWithInstanceVariables
         end
 
         def interval_step

lib/gitlab/ci/config/entry/configurable.rb

@@ -24,21 +24,20 @@ module Gitlab
             end
           end
 
-          # rubocop:disable Cop/ModuleWithInstanceVariables
           def compose!(deps = nil)
             return unless valid?
 
             self.class.nodes.each do |key, factory|
               factory
-                .value(@config[key])
+                .value(config[key])
                 .with(key: key, parent: self)
 
-              @entries[key] = factory.create!
+              entries[key] = factory.create!
             end
 
             yield if block_given?
 
-            @entries.each_value do |entry|
+            entries.each_value do |entry|
               entry.compose!(deps)
             end
           end

lib/gitlab/ci/config/entry/node.rb

@@ -90,6 +90,12 @@ module Gitlab
           def self.aspects
             @aspects ||= []
           end
+
+          private
+
+          def entries
+            @entries
+          end
         end
       end
     end

lib/gitlab/ci/config/entry/validatable.rb

@@ -12,9 +12,8 @@ module Gitlab
             end
           end
 
-          # rubocop:disable Cop/ModuleWithInstanceVariables
           def errors
-            @validator.messages + descendants.flat_map(&:errors)
+            @validator.messages + descendants.flat_map(&:errors) # rubocop:disable Cop/ModuleWithInstanceVariables
           end
 
           class_methods do

lib/gitlab/ci/pipeline/chain/helpers.rb

@@ -3,21 +3,19 @@ module Gitlab
     module Pipeline
       module Chain
         module Helpers
-          # rubocop:disable Cop/ModuleWithInstanceVariables
-          def branch_exists?
-            return @is_branch if defined?(@is_branch)
+          include Gitlab::Utils::StrongMemoize
 
-            @is_branch = project.repository.branch_exists?(pipeline.ref)
+          def branch_exists?
+            strong_memoize(:is_branch) do
+              project.repository.branch_exists?(pipeline.ref)
+            end
           end
-          # rubocop:enable Cop/ModuleWithInstanceVariables
 
-          # rubocop:disable Cop/ModuleWithInstanceVariables
           def tag_exists?
-            return @is_tag if defined?(@is_tag)
-
-            @is_tag = project.repository.tag_exists?(pipeline.ref)
+            strong_memoize(:is_tag) do
+              project.repository.tag_exists?(pipeline.ref)
+            end
           end
-          # rubocop:enable Cop/ModuleWithInstanceVariables
 
           def error(message)
             pipeline.errors.add(:base, message)

lib/gitlab/current_settings.rb

@@ -52,9 +52,8 @@ module Gitlab
       ::ApplicationSetting.create_from_defaults || in_memory_application_settings
     end
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def in_memory_application_settings
-      @in_memory_application_settings ||= ::ApplicationSetting.new(::ApplicationSetting.defaults)
+      @in_memory_application_settings ||= ::ApplicationSetting.new(::ApplicationSetting.defaults) # rubocop:disable Cop/ModuleWithInstanceVariables
     rescue ActiveRecord::StatementInvalid, ActiveRecord::UnknownAttributeError
       # In case migrations the application_settings table is not created yet,
       # we fallback to a simple OpenStruct

lib/gitlab/cycle_analytics/base_query.rb

@@ -11,13 +11,12 @@ module Gitlab
         @base_query ||= stage_query
       end
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def stage_query
         query = mr_closing_issues_table.join(issue_table).on(issue_table[:id].eq(mr_closing_issues_table[:issue_id]))
           .join(issue_metrics_table).on(issue_table[:id].eq(issue_metrics_table[:issue_id]))
-          .where(issue_table[:project_id].eq(@project.id))
+          .where(issue_table[:project_id].eq(@project.id)) # rubocop:disable Cop/ModuleWithInstanceVariables
           .where(issue_table[:deleted_at].eq(nil))
-          .where(issue_table[:created_at].gteq(@options[:from]))
+          .where(issue_table[:created_at].gteq(@options[:from])) # rubocop:disable Cop/ModuleWithInstanceVariables
 
         # Load merge_requests
         query = query.join(mr_table, Arel::Nodes::OuterJoin)

lib/gitlab/cycle_analytics/production_helper.rb

 module Gitlab
   module CycleAnalytics
     module ProductionHelper
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def stage_query
-        super.where(mr_metrics_table[:first_deployed_to_production_at].gteq(@options[:from]))
+        super
+          .where(mr_metrics_table[:first_deployed_to_production_at]
+          .gteq(@options[:from])) # rubocop:disable Cop/ModuleWithInstanceVariables
       end
     end
   end

lib/gitlab/database/rename_reserved_paths_migration/v1/migration_classes.rb

@@ -3,11 +3,10 @@ module Gitlab
     module RenameReservedPathsMigration
       module V1
         module MigrationClasses
-          # rubocop:disable Cop/ModuleWithInstanceVariables
           module Routable
             def full_path
               if route && route.path.present?
-                @full_path ||= route.path
+                @full_path ||= route.path # rubocop:disable Cop/ModuleWithInstanceVariables
               else
                 update_route if persisted?
 
@@ -31,7 +30,7 @@ module Gitlab
             def prepare_route
               route || build_route(source: self)
               route.path = build_full_path
-              @full_path = nil
+              @full_path = nil # rubocop:disable Cop/ModuleWithInstanceVariables
             end
           end
 

lib/gitlab/import_export/command_line_util.rb

@@ -30,10 +30,9 @@ module Gitlab
         execute(%W(tar -#{options} #{archive} -C #{dir}))
       end
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def execute(cmd)
         output, status = Gitlab::Popen.popen(cmd)
-        @shared.error(Gitlab::ImportExport::Error.new(output.to_s)) unless status.zero?
+        @shared.error(Gitlab::ImportExport::Error.new(output.to_s)) unless status.zero? # rubocop:disable Cop/ModuleWithInstanceVariables
         status.zero?
       end
 

lib/gitlab/metrics/influx_db.rb

@@ -171,6 +171,7 @@ module Gitlab
           @pool
         end
       end
+      # rubocop:enable Cop/ModuleWithInstanceVariables
     end
   end
 end

lib/gitlab/metrics/prometheus.rb

@@ -4,6 +4,7 @@ module Gitlab
   module Metrics
     module Prometheus
       include Gitlab::CurrentSettings
+      include Gitlab::Utils::StrongMemoize
 
       REGISTRY_MUTEX = Mutex.new
       PROVIDER_MUTEX = Mutex.new
@@ -16,18 +17,19 @@ module Gitlab
           ::File.writable?(multiprocess_files_dir)
       end
 
-      # rubocop:disable Cop/ModuleWithInstanceVariables
       def prometheus_metrics_enabled?
-        return @prometheus_metrics_enabled if defined?(@prometheus_metrics_enabled)
-
-        @prometheus_metrics_enabled = prometheus_metrics_enabled_unmemoized
+        strong_memoize(:prometheus_metrics_enabled) do
+          prometheus_metrics_enabled_unmemoized
+        end
       end
 
       def registry
-        return @registry if @registry
-
-        REGISTRY_MUTEX.synchronize do
-          @registry ||= ::Prometheus::Client.registry
+        strong_memoize(:registry) do
+          REGISTRY_MUTEX.synchronize do
+            strong_memoize(:registry) do
+              ::Prometheus::Client.registry
+            end
+          end
         end
       end
 

lib/gitlab/path_regex.rb

-# rubocop:disable Cop/ModuleWithInstanceVariables
 module Gitlab
   module PathRegex
     extend self

lib/gitlab/slash_commands/presenters/issue_base.rb

@@ -10,36 +10,37 @@ module Gitlab
           issuable.open? ? 'Open' : 'Closed'
         end
 
-        # rubocop:disable Cop/ModuleWithInstanceVariables
         def project
-          @resource.project
+          resource.project
         end
 
-        # rubocop:disable Cop/ModuleWithInstanceVariables
         def author
-          @resource.author
+          resource.author
         end
 
-        # rubocop:disable Cop/ModuleWithInstanceVariables
         def fields
           [
             {
               title: "Assignee",
-              value: @resource.assignees.any? ? @resource.assignees.first.name : "_None_",
+              value: resource.assignees.any? ? resource.assignees.first.name : "_None_",
               short: true
             },
             {
               title: "Milestone",
-              value: @resource.milestone ? @resource.milestone.title : "_None_",
+              value: resource.milestone ? resource.milestone.title : "_None_",
               short: true
             },
             {
               title: "Labels",
-              value: @resource.labels.any? ? @resource.label_names.join(', ') : "_None_",
+              value: resource.labels.any? ? resource.label_names.join(', ') : "_None_",
               short: true
             }
           ]
         end
+
+        private
+
+        attr_reader :resource
       end
     end
   end

lib/tasks/gettext.rake

@@ -23,6 +23,7 @@ namespace :gettext do
   desc 'Lint all po files in `locale/'
   task lint: :environment do
     require 'simple_po_parser'
+    require 'gitlab/utils'
 
     FastGettext.silence_errors
     files = Dir.glob(Rails.root.join('locale/*/gitlab.po'))

lib/tasks/gitlab/task_helpers.rb

 require 'rainbow/ext/string'
+require 'gitlab/utils/strong_memoize'
 
 module Gitlab
   TaskFailedError = Class.new(StandardError)
   TaskAbortedByUserError = Class.new(StandardError)
 
   module TaskHelpers
+    include Gitlab::Utils::StrongMemoize
+
     extend self
 
     # Ask if the user wants to continue
@@ -104,19 +107,17 @@ module Gitlab
       Gitlab.config.gitlab.user
     end
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def gitlab_user?
-      return @is_gitlab_user unless @is_gitlab_user.nil?
-
-      current_user = run_command(%w(whoami)).chomp
-      @is_gitlab_user = current_user == gitlab_user
+      strong_memoize(:is_gitlab_user) do
+        current_user = run_command(%w(whoami)).chomp
+        current_user == gitlab_user
+      end
     end
 
-    # rubocop:disable Cop/ModuleWithInstanceVariables
     def warn_user_is_not_gitlab
-      return if @warned_user_not_gitlab
+      return if gitlab_user?
 
-      unless gitlab_user?
+      strong_memoize(:warned_user_not_gitlab) do
         current_user = run_command(%w(whoami)).chomp
 
         puts " Warning ".color(:black).background(:yellow)
@@ -124,8 +125,6 @@ module Gitlab
         puts "  Things may work\/fail for the wrong reasons."
         puts "  For correct results you should run this as user #{gitlab_user.color(:magenta)}."
         puts ""
-
-        @warned_user_not_gitlab = true
       end
     end
 

qa/qa/runtime/scenario.rb

@@ -6,13 +6,15 @@ module QA
     module Scenario
       extend self
 
-      attr_reader :attributes
+      def attributes
+        @attributes ||= {}
+      end
 
       def define(attribute, value)
-        (@attributes ||= {}).store(attribute.to_sym, value)
+        attributes.store(attribute.to_sym, value)
 
         define_singleton_method(attribute) do
-          @attributes[attribute.to_sym].tap do |value|
+          attributes[attribute.to_sym].tap do |value|
             if value.to_s.empty?
               raise ArgumentError, "Empty `#{attribute}` attribute!"
             end