RuboCop: Rails/IndexBy

auto-corrected

Change-Id: I7f6ca0f5a10a2f04849c5d0378641e2d3e8fc704
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/278485
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jacob Burroughs <jburroughs@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>

.rubocop.common.yml

@@ -112,6 +112,8 @@ Rails/HasManyOrHasOneDependent:
   Enabled: false # legacy code + most things we soft delete anyway
 Rails/HelperInstanceVariable:
   Enabled: false # legacy code
+Rails/IndexBy:
+  Severity: error
 Rails/IndexWith:
   Severity: error
 Rails/SkipsModelValidations:

app/controllers/lti/message_controller.rb

@@ -245,7 +245,7 @@ module Lti
       end
       account_ids = @context.account_chain.map(&:id)
       bindings = ToolProxyBinding.where(context_type: 'Account', context_id: account_ids, tool_proxy_id: tool_proxy.id)
-      binding_lookup = bindings.each_with_object({}) { |binding, hash| hash[binding.context_id] = binding }
+      binding_lookup = bindings.index_by(&:context_id)
       sorted_bindings = account_ids.map { |account_id| binding_lookup[account_id] }
       sorted_bindings.first
     end

app/controllers/quizzes/quizzes_controller.rb

@@ -641,7 +641,7 @@ class Quizzes::QuizzesController < ApplicationController
 
       @submissions_from_users = @quiz.quiz_submissions.for_user_ids(students.map(&:id)).not_settings_only.to_a
 
-      @submissions_from_users = Hash[@submissions_from_users.map { |s| [s.user_id, s] }]
+      @submissions_from_users = @submissions_from_users.index_by(&:user_id)
 
       # include logged out submissions
       @submissions_from_logged_out = @quiz.quiz_submissions.logged_out.not_settings_only
@@ -849,10 +849,8 @@ class Quizzes::QuizzesController < ApplicationController
 
   def setup_attachments
     @attachments = if @submission
-                     Hash[@submission.attachments.map do |attachment|
-                       [attachment.id, attachment]
-                     end
-                     ]
+                     @submission.attachments.index_by(&:id)
+
                    else
                      {}
                    end

app/models/conversation_message.rb

@@ -81,8 +81,8 @@ class ConversationMessage < ActiveRecord::Base
               .select("conversation_messages.*, conversation_participant_id, conversation_message_participants.user_id, conversation_message_participants.tags")
               .order('conversation_id DESC, user_id DESC, created_at DESC')
               .distinct_on(:conversation_id, :user_id).to_a
-        map = Hash[ret.map { |m| [[m.conversation_id, m.user_id], m] }]
-        backmap = Hash[ret.map { |m| [m.conversation_participant_id, m] }]
+        map = ret.index_by { |m| [m.conversation_id, m.user_id] }
+        backmap = ret.index_by(&:conversation_participant_id)
         if author
           shard_participants.each { |cp| cp.last_authored_message = map[[cp.conversation_id, cp.user_id]] || backmap[cp.id] }
         else

app/models/quizzes/quiz_regrader/regrader.rb

@@ -67,9 +67,7 @@ module Quizzes::QuizRegrader
 
     # quiz question regrades keyed by question id
     def question_regrades
-      @questions ||= @quiz.current_quiz_question_regrades.each_with_object({}) do |qr, hash|
-        hash[qr.quiz_question_id] = qr
-      end
+      @questions ||= @quiz.current_quiz_question_regrades.index_by(&:quiz_question_id)
     end
   end
 end

app/models/quizzes/quiz_sortables.rb

@@ -52,8 +52,8 @@ class Quizzes::QuizSortables
   end
 
   def all_objects_hash
-    @quiz_objects_hash ||= all_objects.each_with_object({}) do |obj, hash|
-      hash["#{obj.class.name.demodulize.underscore}_#{obj.id}"] = obj
+    @quiz_objects_hash ||= all_objects.index_by do |obj|
+      "#{obj.class.name.demodulize.underscore}_#{obj.id}"
     end
   end
 

app/models/quizzes/quiz_statistics/student_analysis.rb

@@ -66,12 +66,12 @@ class Quizzes::QuizStatistics::StudentAnalysis < Quizzes::QuizStatistics::Report
     #  "answers"=> [{"id"=>6782},...],
     #  "assessment_question_id"=>1022,
     # }, ...}
-    questions = Hash[
+    questions =
       (quiz.quiz_data || []).map { |q| q[:questions] || q }
                             .flatten
                             .select { |q| q[:answers] }
-                            .map { |q| [q[:id], q] }
-    ]
+                            .index_by { |q| q[:id] }
+
     stats = {}
     found_ids = {}
     score_counter = Stats::Counter.new
@@ -128,10 +128,10 @@ class Quizzes::QuizStatistics::StudentAnalysis < Quizzes::QuizStatistics::Report
     end
 
     assessment_questions = if questions_hash.any? { |_, q| q[:assessment_question_id] }
-                             Hash[
-                               AssessmentQuestion.where(:id => questions_hash.keys)
-                                                 .map { |aq| [aq.id, aq] }
-                             ]
+
+                             AssessmentQuestion.where(:id => questions_hash.keys)
+                                               .index_by(&:id)
+
                            else
                              {}
                            end
@@ -173,10 +173,7 @@ class Quizzes::QuizStatistics::StudentAnalysis < Quizzes::QuizStatistics::Report
     end.map do |hash|
       hash[:attachment_ids]
     end.flatten
-    @attachments = Hash[Attachment.where(:id => ids).map do |a|
-      [a.id, a]
-    end
-    ]
+    @attachments = Attachment.where(:id => ids).index_by(&:id)
   end
 
   def attachment_csv(answer)

app/models/tableless.rb

@@ -36,7 +36,7 @@ class Tableless < ActiveRecord::Base
     end
 
     def columns_hash
-      @columns_hash ||= Hash[columns.map { |c| [c.name, c] }]
+      @columns_hash ||= columns.index_by(&:name)
     end
 
     def column(name, sql_type = nil, default = nil, null = true)

lib/api/v1/assignment.rb

@@ -883,7 +883,7 @@ module Api::V1::Assignment
     else
       # assignment id -> specific submission. never return an array when
       # include[]=observed_users was _not_ supplied
-      hash = Hash[subs_list.map { |s| [s.assignment_id, s] }]
+      hash = subs_list.index_by(&:assignment_id)
     end
     hash
   end

lib/api/v1/discussion_topics.rb

@@ -50,7 +50,7 @@ module Api::V1::DiscussionTopics
 
     fields_with_id = fields.unshift(:id)
     root_topics_array = DiscussionTopic.select(fields_with_id).find(root_topic_ids)
-    root_topics_array.map { |root_topic| [root_topic.id, root_topic] }.to_h
+    root_topics_array.index_by(&:id)
   end
 
   # Public: Serialize an array of DiscussionTopic objects for returning as JSON.

lib/api/v1/moderation_grader.rb

@@ -28,7 +28,7 @@ module Api::V1::ModerationGrader
     provisional_graders = assignment.provisional_moderation_graders
     if assignment.can_view_other_grader_identities?(user)
       graders = provisional_graders.preload(:user)
-      graders_by_id = graders.each_with_object({}) { |grader, map| map[grader.id] = grader }
+      graders_by_id = graders.index_by(&:id)
 
       api_json(graders, user, session, only: %w(id user_id)).tap do |hash|
         hash.each do |grader_json|

lib/grade_calculator.rb

@@ -421,8 +421,8 @@ class GradeCalculator
 
   def group_score_rows
     enrollments_by_user.keys.map do |user_id|
-      current_group_scores = @current_groups[user_id].map { |group| [group[:global_id], group] }.to_h
-      final_group_scores = @final_groups[user_id].map { |group| [group[:global_id], group] }.to_h
+      current_group_scores = @current_groups[user_id].index_by { |group| group[:global_id] }
+      final_group_scores = @final_groups[user_id].index_by { |group| group[:global_id] }
       @groups.map do |group|
         agid = group.global_id
         current = current_group_scores[agid]
@@ -763,9 +763,8 @@ class GradeCalculator
     end
 
     assignments_by_group_id = visible_assignments.group_by(&:assignment_group_id)
-    submissions_by_assignment_id = Hash[
-      submissions.map { |s| [s.assignment_id, s] }
-    ]
+    submissions_by_assignment_id =
+      submissions.index_by(&:assignment_id)
 
     @groups.map do |group|
       assignments = assignments_by_group_id[group.id] || []

spec/models/conditional_release/stats_spec.rb

@@ -186,7 +186,7 @@ module ConditionalRelease
         expected_assignment_set([@student_id], @as2)
 
         details = Stats.student_details(@rule, @student_id).with_indifferent_access
-        details_by_id = details[:follow_on_assignments].each_with_object({}) { |f, acc| acc[f.dig(:assignment, :id)] = f }
+        details_by_id = details[:follow_on_assignments].index_by { |f| f.dig(:assignment, :id) }
         expect(details_by_id.map { |k, v| [k, v.dig(:submission, :score)] }).to match_array [
           [@b1.id, 3], [@b2.id, 88], [@b3.id, nil], [@b4.id, 93], [@b5.id, nil]
         ]