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
-    note_project_id = params[:note_project_id]
-    @note_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)
-    @note_project
+    strong_memoize(:note_project) do
+      return nil unless project
+      note_project_id = params[:note_project_id]
+      the_project =
+        if note_project_id.present?
+          Project.find(note_project_id)
+        else
+          project
+        end
+      return access_denied! unless can?(current_user, :create_note, the_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:disable Cop/ModuleWithInstanceVariables
+  # rubocop:enable 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