Merge branch 'no-ivar-in-modules' into tmp

* no-ivar-in-modules:
  Cache allowed_ids
  Fix a few layout error
  Make it clear that this is an acceptable use
  Reword Instance variables in views
  Move ModuleWithInstanceVariables to Gitlab namespace
  Explain how to disable it in the doc
  Just define allowed_ids and override it with empty value
  Updates based on feedback
  Remove codes from bad merge
  Allow initialize method and single ivar
  Use StrongMemoize and enable/disable cops properly
  WIP
  Fix grammar: judge -> judgement
  Allow simple ivar ||= form. Update accordingly
  Add cop to make sure we don't use ivar in a module

.rubocop.yml

@@ -1190,7 +1190,20 @@ RSpec/SubjectStub:
 RSpec/VerifiedDoubles:
   Enabled: false
 
-# GitlabSecurity ##############################################################
+# Gitlab ###################################################################
+
+Gitlab/ModuleWithInstanceVariables:
+  Enable: true
+  Exclude:
+    # We ignore Rails helpers right now because it's hard to workaround it
+    - app/helpers/*_helper.rb
+    # We ignore Rails mailers right now because it's hard to workaround it
+    - app/mailers/emails/*.rb
+    # We ignore spec helpers because it usually doesn't matter
+    - spec/support/**/*.rb
+    - features/steps/**/*.rb
+
+# GitlabSecurity ###########################################################
 
 GitlabSecurity/DeepMunge:
   Enabled: true

app/controllers/concerns/boards_responses.rb

@@ -24,11 +24,11 @@ def authorize_action_for!(resource, ability)
   end
 
   def respond_with_boards
-    respond_with(@boards)
+    respond_with(@boards) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def respond_with_board
-    respond_with(@board)
+    respond_with(@board) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def respond_with(resource)

app/controllers/concerns/creates_commit.rb

 module CreatesCommit
   extend ActiveSupport::Concern
+  include Gitlab::Utils::StrongMemoize
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def create_commit(service, success_path:, failure_path:, failure_view: nil, success_notice: nil)
     if can?(current_user, :push_code, @project)
       @project_to_commit_into = @project
@@ -45,6 +47,7 @@ def create_commit(service, success_path:, failure_path:, failure_view: nil, succ
       end
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def authorize_edit_tree!
     return if can_collaborate_with_project?
@@ -77,6 +80,7 @@ def final_success_path(success_path)
     end
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def new_merge_request_path
     project_new_merge_request_path(
       @project_to_commit_into,
@@ -88,20 +92,28 @@ def new_merge_request_path
       }
     )
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def existing_merge_request_path
-    project_merge_request_path(@project, @merge_request)
+    project_merge_request_path(@project, @merge_request) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
+  # rubocop:disable Gitlab/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 Gitlab/ModuleWithInstanceVariables
 
   def different_project?
-    @project_to_commit_into != @project
+    @project_to_commit_into != @project # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def create_merge_request?
@@ -109,6 +121,6 @@ def create_merge_request?
     # as the target branch in the same project,
     # we don't want to create a merge request.
     params[:create_merge_request].present? &&
-      (different_project? || @start_branch != @branch_name)
+      (different_project? || @start_branch != @branch_name) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 end

app/controllers/concerns/group_tree.rb

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

app/controllers/concerns/issuable_actions.rb

@@ -17,7 +17,7 @@ def show
   end
 
   def update
-    @issuable = update_service.execute(issuable)
+    @issuable = update_service.execute(issuable) # rubocop:disable Gitlab/ModuleWithInstanceVariables
 
     respond_to do |format|
       format.html do
@@ -83,7 +83,7 @@ def bulk_update
   def render_conflict_response
     respond_to do |format|
       format.html do
-        @conflict = true
+        @conflict = true # rubocop:disable Gitlab/ModuleWithInstanceVariables
         render :edit
       end
 
@@ -98,7 +98,7 @@ def render_conflict_response
   end
 
   def labels
-    @labels ||= LabelsFinder.new(current_user, project_id: @project.id).execute
+    @labels ||= LabelsFinder.new(current_user, project_id: @project.id).execute # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def authorize_destroy_issuable!
@@ -108,7 +108,7 @@ def authorize_destroy_issuable!
   end
 
   def authorize_admin_issuable!
-    unless can?(current_user, :"admin_#{resource_name}", @project)
+    unless can?(current_user, :"admin_#{resource_name}", @project) # rubocop:disable Gitlab/ModuleWithInstanceVariables
       return access_denied!
     end
   end
@@ -143,6 +143,7 @@ def resource_name
     @resource_name ||= controller_name.singularize
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def render_entity_json
     if @issuable.valid?
       render json: serializer.represent(@issuable)
@@ -150,6 +151,7 @@ def render_entity_json
       render json: { errors: @issuable.errors.full_messages }, status: :unprocessable_entity
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def serializer
     raise NotImplementedError
@@ -160,6 +162,6 @@ def update_service
   end
 
   def parent
-    @project || @group
+    @project || @group # rubocop:disable Gitlab/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
@@ -9,6 +10,7 @@ module IssuableCollections
 
   private
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def set_issuables_index
     @issuables          = issuables_collection
     @issuables          = @issuables.page(params[:page])
@@ -33,6 +35,7 @@ def set_issuables_index
       @users.push(author) if author
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def issuables_collection
     finder.execute.preload(preload_for_collection)
@@ -41,7 +44,7 @@ def issuables_collection
   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 Gitlab/ModuleWithInstanceVariables
 
     if out_of_range
       redirect_to(url_for(params.merge(page: total_pages, only_path: true)))
@@ -51,7 +54,7 @@ def redirect_out_of_range(total_pages)
   end
 
   def issuable_page_count
-    page_count_for_relation(@issuables, finder.row_count)
+    page_count_for_relation(@issuables, finder.row_count) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def page_count_for_relation(relation, row_count)
@@ -66,6 +69,7 @@ def issuable_finder_for(finder_class)
     finder_class.new(current_user, filter_params)
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def filter_params
     set_sort_order_from_cookie
     set_default_state
@@ -90,6 +94,7 @@ def filter_params
 
     @filter_params.permit(IssuableFinder::VALID_PARAMS)
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def set_default_state
     params[:state] = 'opened' if params[:state].blank?
@@ -131,9 +136,9 @@ def update_cookie_value(value)
   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 Gitlab/ModuleWithInstanceVariables
+    end
   end
 
   def collection_type

app/controllers/concerns/issues_action.rb

@@ -2,6 +2,7 @@ module IssuesAction
   extend ActiveSupport::Concern
   include IssuableCollections
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def issues
     @finder_type = IssuesFinder
     @label = finder.labels.first
@@ -17,4 +18,5 @@ def issues
       format.atom { render layout: 'xml.atom' }
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 end

app/controllers/concerns/merge_requests_action.rb

@@ -2,6 +2,7 @@ module MergeRequestsAction
   extend ActiveSupport::Concern
   include IssuableCollections
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def merge_requests
     @finder_type = MergeRequestsFinder
     @label = finder.labels.first
@@ -10,6 +11,7 @@ def merge_requests
 
     @issuable_meta_data = issuable_meta_data(@merge_requests, collection_type)
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   private
 

app/controllers/concerns/milestone_actions.rb

@@ -6,7 +6,7 @@ def merge_requests
       format.html { redirect_to milestone_redirect_path }
       format.json do
         render json: tabs_json("shared/milestones/_merge_requests_tab", {
-          merge_requests: @milestone.sorted_merge_requests,
+          merge_requests: @milestone.sorted_merge_requests, # rubocop:disable Gitlab/ModuleWithInstanceVariables
           show_project_name: true
         })
       end
@@ -18,7 +18,7 @@ def participants
       format.html { redirect_to milestone_redirect_path }
       format.json do
         render json: tabs_json("shared/milestones/_participants_tab", {
-          users: @milestone.participants
+          users: @milestone.participants # rubocop:disable Gitlab/ModuleWithInstanceVariables
         })
       end
     end
@@ -29,7 +29,7 @@ def labels
       format.html { redirect_to milestone_redirect_path }
       format.json do
         render json: tabs_json("shared/milestones/_labels_tab", {
-          labels: @milestone.labels
+          labels: @milestone.labels # rubocop:disable Gitlab/ModuleWithInstanceVariables
         })
       end
     end
@@ -43,6 +43,7 @@ def tabs_json(partial, data = {})
     }
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def milestone_redirect_path
     if @project
       project_milestone_path(@project, @milestone)
@@ -52,4 +53,5 @@ def milestone_redirect_path
       dashboard_milestone_path(@milestone.safe_title, title: @milestone.title)
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 end

app/controllers/concerns/notes_actions.rb

 module NotesActions
   include RendersNotes
+  include Gitlab::Utils::StrongMemoize
   extend ActiveSupport::Concern
 
   included do
@@ -30,6 +31,7 @@ def index
     render json: notes_json
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def create
     create_params = note_params.merge(
       merge_request_diff_head_sha: params[:merge_request_diff_head_sha],
@@ -47,7 +49,9 @@ def create
       format.html { redirect_back_or_default }
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def update
     @note = Notes::UpdateService.new(project, current_user, note_params).execute(note)
 
@@ -60,6 +64,7 @@ def update
       format.html { redirect_back_or_default }
     end
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def destroy
     if note.editable?
@@ -138,7 +143,7 @@ def diff_discussion_html(discussion)
         end
     else
       template = "discussions/_diff_discussion"
-      @fresh_discussion = true
+      @fresh_discussion = true # rubocop:disable Gitlab/ModuleWithInstanceVariables
 
       locals = { discussions: [discussion], on_image: on_image }
     end
@@ -191,7 +196,7 @@ def set_polling_interval_header
   end
 
   def noteable
-    @noteable ||= notes_finder.target || @note&.noteable
+    @noteable ||= notes_finder.target || @note&.noteable # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
 
   def require_noteable!
@@ -211,20 +216,21 @@ def note_serializer
   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/oauth_applications.rb

@@ -14,6 +14,6 @@ def prepare_scopes
   end
 
   def load_scopes
-    @scopes = Doorkeeper.configuration.scopes
+    @scopes ||= Doorkeeper.configuration.scopes
   end
 end

app/controllers/concerns/preview_markdown.rb

 module PreviewMarkdown
   extend ActiveSupport::Concern
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def preview_markdown
     result = PreviewMarkdownService.new(@project, current_user, params).execute
 
@@ -20,4 +21,5 @@ def preview_markdown
       }
     }
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 end

app/controllers/concerns/renders_commits.rb

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

app/controllers/concerns/renders_notes.rb

 module RendersNotes
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def prepare_notes_for_rendering(notes, noteable = nil)
     preload_noteable_for_regular_notes(notes)
     preload_max_access_for_authors(notes, @project)
@@ -7,6 +8,7 @@ def prepare_notes_for_rendering(notes, noteable = nil)
 
     notes
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   private
 

app/controllers/concerns/service_params.rb

@@ -67,7 +67,7 @@ module ServiceParams
   FILTER_BLANK_PARAMS = [:password].freeze
 
   def service_params
-    dynamic_params = @service.event_channel_names + @service.event_names
+    dynamic_params = @service.event_channel_names + @service.event_names # rubocop:disable Gitlab/ModuleWithInstanceVariables
     service_params = params.permit(:id, service: allowed_service_params + dynamic_params)
 
     if service_params[:service].is_a?(Hash)

app/controllers/concerns/snippets_actions.rb

@@ -4,6 +4,7 @@ module SnippetsActions
   def edit
   end
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def raw
     disposition = params[:inline] == 'false' ? 'attachment' : 'inline'
 
@@ -14,6 +15,7 @@ def raw
       filename: @snippet.sanitized_file_name
     )
   end
+  # rubocop:enable Gitlab/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
@@ -18,9 +19,9 @@ def mark_as_spam
   private
 
   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

@@ -12,7 +12,7 @@ def toggle_subscription
   private
 
   def subscribable_project
-    @project || raise(NotImplementedError)
+    @project ||= raise(NotImplementedError)
   end
 
   def subscribable_resource

app/models/concerns/mentionable.rb

@@ -44,13 +44,11 @@ def local_reference
   end
 
   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
@@ -69,6 +67,10 @@ def all_references(current_user = nil, extractor: nil)
     extractor
   end
 
+  def extractors
+    @extractors ||= {}
+  end
+
   def mentioned_users(current_user = nil)
     all_references(current_user).users
   end

app/models/concerns/milestoneish.rb

@@ -103,9 +103,11 @@ def count_issues_by_state(user)
   end
 
   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