Consistently use created_at for submissions

Previously, we considered the `updated_at` attribute, i.e., for deadlines. However, since submissions are currently non-updatable by the user (and only receive a minor update once the testrun finished), it doesn't make much sense. We rather want to stick with the user-triggered creation date.

Author: MrSerth

app/controllers/exercises_controller.rb

@@ -494,7 +494,7 @@ def statistics
     contributor_statistics = {InternalUser => {}, ExternalUser => {}, ProgrammingGroup => {}}
 
     query = SubmissionPolicy::DeadlineScope.new(current_user, Submission).resolve
-      .select("contributor_id, contributor_type, MAX(score) AS maximum_score, COUNT(id) AS runs, MAX(updated_at) FILTER (WHERE cause IN ('submit', 'assess', 'remoteSubmit', 'remoteAssess')) AS updated_at, exercise_id")
+      .select("contributor_id, contributor_type, MAX(score) AS maximum_score, COUNT(id) AS runs, MAX(created_at) FILTER (WHERE cause IN ('submit', 'assess', 'remoteSubmit', 'remoteAssess')) AS created_at, exercise_id")
       .where(exercise_id: @exercise.id)
       .group('contributor_id, contributor_type, exercise_id')
       .includes(:contributor, :exercise)
@@ -513,13 +513,9 @@ def external_user_statistics
 
     submissions = SubmissionPolicy::DeadlineScope.new(current_user, Submission).resolve
       .where(contributor: @external_user, exercise: @exercise)
-      .order(submissions: {updated_at: :desc})
+      .order(submissions: {created_at: :desc})
       .includes(:exercise, testruns: [:testrun_messages, {file: [:file_type]}], files: [:file_type])
 
-    # From here on, we switch to sort by `created_at`. This is important for the working time estimation,
-    # since a submission is updated after the corresponding testrun finishes.
-    # Sorting by `updated_at` would lead to wrong working time estimations (but is more efficient for the database).
-
     if policy(@exercise).detailed_statistics?
       @show_autosaves = params[:show_autosaves] == 'true' || submissions.where.not(cause: 'autosave').none?
 

app/controllers/external_users_controller.rb

@@ -33,13 +33,13 @@ def working_time_query(tag = nil)
            max(score) as maximum_score,
            count(bar.id) as runs,
            sum(working_time_new) AS working_time,
-           max(max_updated_at) as updated_at
+           max(max_created_at) as created_at
     FROM
       (SELECT contributor_id,
               exercise_id,
               score,
               id,
-              max_updated_at,
+              max_created_at,
               CASE
                   WHEN #{StatisticsHelper.working_time_larger_delta} THEN '0'
                   ELSE working_time
@@ -48,18 +48,18 @@ def working_time_query(tag = nil)
          (SELECT contributor_id,
                  exercise_id,
                  max(score) AS score,
-                 max(filtered_submissions.updated_at) FILTER (WHERE cause IN ('submit', 'assess', 'remoteSubmit', 'remoteAssess')) AS max_updated_at,
+                 max(filtered_submissions.created_at) FILTER (WHERE cause IN ('submit', 'assess', 'remoteSubmit', 'remoteAssess')) AS max_created_at,
                  filtered_submissions.id,
-                 (filtered_submissions.updated_at - lag(filtered_submissions.updated_at) over (PARTITION BY contributor_id, exercise_id
-                                                     ORDER BY filtered_submissions.updated_at)) AS working_time
+                 (filtered_submissions.created_at - lag(filtered_submissions.created_at) over (PARTITION BY contributor_id, exercise_id
+                                                     ORDER BY filtered_submissions.created_at)) AS working_time
           FROM filtered_submissions
           JOIN exercises ON filtered_submissions.exercise_id = exercises.id
           WHERE #{ExternalUser.sanitize_sql(['contributor_id = ?', @user.id])}
             AND contributor_type = 'ExternalUser'
           GROUP BY exercise_id,
                    contributor_id,
                    filtered_submissions.id,
-                   filtered_submissions.updated_at
+                   filtered_submissions.created_at
           ) AS foo
       ) AS bar
     #{tag.nil? ? '' : " JOIN exercise_tags et ON et.exercise_id = bar.exercise_id AND #{ExternalUser.sanitize_sql(['et.tag_id = ?', tag])}"}
@@ -79,7 +79,7 @@ def statistics
     statistics = {}
 
     # We fake the statistics hash to be "submissions"
-    # Available are: contributor_id, exercise_id, maximum_score, runs, working_time, updated_at
+    # Available are: contributor_id, exercise_id, maximum_score, runs, working_time, created_at
     working_time_statistics = Submission.find_by_sql(working_time_query(tag&.id))
     ActiveRecord::Associations::Preloader.new(records: working_time_statistics, associations: [:exercise]).call
     working_time_statistics.each do |tuple|

app/models/submission.rb

@@ -35,16 +35,16 @@ class Submission < ApplicationRecord
   scope :intermediate, -> { where.not(cause: %w[submit remoteSubmit]) }
 
   scope :before_deadline, lambda {
-                            joins(:exercise).where('submissions.updated_at <= exercises.submission_deadline OR exercises.submission_deadline IS NULL')
+                            joins(:exercise).where('submissions.created_at <= exercises.submission_deadline OR exercises.submission_deadline IS NULL')
                           }
   scope :within_grace_period, lambda {
-                                joins(:exercise).where('(submissions.updated_at > exercises.submission_deadline) AND (submissions.updated_at <= exercises.late_submission_deadline OR exercises.late_submission_deadline IS NULL)')
+                                joins(:exercise).where('(submissions.created_at > exercises.submission_deadline) AND (submissions.created_at <= exercises.late_submission_deadline OR exercises.late_submission_deadline IS NULL)')
                               }
   scope :after_late_deadline, lambda {
-                                joins(:exercise).where('submissions.updated_at > exercises.late_submission_deadline')
+                                joins(:exercise).where('submissions.created_at > exercises.late_submission_deadline')
                               }
 
-  scope :latest, -> { order(submissions: {updated_at: :desc}).first }
+  scope :latest, -> { order(submissions: {created_at: :desc}).first }
 
   validates :cause, inclusion: {in: CAUSES}
 
@@ -95,25 +95,25 @@ def to_s
 
   def before_deadline?
     if exercise.submission_deadline.present?
-      updated_at <= exercise.submission_deadline
+      created_at <= exercise.submission_deadline
     else
       false
     end
   end
 
   def within_grace_period?
     if exercise.submission_deadline.present? && exercise.late_submission_deadline.present?
-      updated_at > exercise.submission_deadline && updated_at <= exercise.late_submission_deadline
+      created_at > exercise.submission_deadline && created_at <= exercise.late_submission_deadline
     else
       false
     end
   end
 
   def after_late_deadline?
     if exercise.late_submission_deadline.present?
-      updated_at > exercise.late_submission_deadline
+      created_at > exercise.late_submission_deadline
     elsif exercise.submission_deadline.present?
-      updated_at > exercise.submission_deadline
+      created_at > exercise.submission_deadline
     else
       false
     end

app/policies/submission_policy.rb

@@ -95,7 +95,7 @@ def latest_submissions_assessed(highest_scored: false)
         submission_table[:contributor_type],
         submission_table[:contributor_id],
         highest_scored ? submission_table[:score].desc.nulls_last : nil,
-        submission_table[:updated_at].desc,
+        submission_table[:created_at].desc,
       ].compact
 
       Submission.from(

app/views/exercises/statistics.html.slim

@@ -82,7 +82,7 @@ h1 = @exercise
               td = link_to_if user_type == ExternalUser && policy(contributor).statistics?, contributor.displayname, statistics_external_user_exercise_path(contributor, @exercise)
               td = submission_stat['maximum_score'] || '0.0'
               td.align-middle
-                - if submission_stat.updated_at.present?
+                - if submission_stat.created_at.present?
                   - if submission_stat.before_deadline?
                     .deadline-result.positive-result
                   - elsif submission_stat.within_grace_period?

app/views/external_users/statistics.html.slim

@@ -16,7 +16,7 @@ h1 = t('.title', user: @user.displayname)
             td = link_to exercise, statistics_external_user_exercise_path(@user, exercise)
             td = submission_stat['maximum_score'] || 0.0
             td.align-middle
-              - if submission_stat.updated_at.present?
+              - if submission_stat.created_at.present?
                 - if submission_stat.before_deadline?
                   .deadline-result.positive-result
                 - elsif submission_stat.within_grace_period?

db/migrate/20241107004238_move_updated_at_index_to_created_at_on_submission.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class MoveUpdatedAtIndexToCreatedAtOnSubmission < ActiveRecord::Migration[7.2]
+  def change
+    remove_index :submissions, :updated_at, order: {updated_at: :desc}
+    add_index :submissions, :created_at, order: {updated_at: :desc}
+  end
+end