Pass exercise object instead of id to reject_illegal_file_attributes

app/controllers/concerns/file_parameters.rb

@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 module FileParameters
-  def reject_illegal_file_attributes(exercise_id, params)
-    if Exercise.exists?(id: exercise_id) && params
+  def reject_illegal_file_attributes(exercise, params)
+    if exercise && params
       params.reject do |_, file_attributes|
         file = CodeOcean::File.find_by(id: file_attributes[:file_id])
         # avoid that public files from other contexts can be created
-        file.nil? || file.hidden || file.read_only || file.context_id != exercise_id.to_i
+        file.nil? || file.hidden || file.read_only || file.context_id != exercise.id
       end
     else
       []

app/controllers/concerns/submission_parameters.rb

@@ -7,7 +7,8 @@ module SubmissionParameters
     submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes) : {}
     submission_params = merge_user(submission_params)
     files_attributes = submission_params[:files_attributes]
-    submission_params[:files_attributes] = reject_illegal_file_attributes(submission_params[:exercise_id].to_i, files_attributes)
+    exercise = Exercise.find_by(id: submission_params[:exercise_id])
+    submission_params[:files_attributes] = reject_illegal_file_attributes(exercise, files_attributes)
     submission_params
   end
   private :submission_params

app/controllers/remote_evaluation_controller.rb

@@ -76,7 +76,7 @@ class RemoteEvaluationController < ApplicationController
     submission_params[:user_id] = remote_evaluation_mapping.user_id
     submission_params[:cause] = cause
     submission_params[:user_type] = remote_evaluation_mapping.user_type
-    submission_params[:files_attributes] = reject_illegal_file_attributes(remote_evaluation_mapping.exercise_id, files_attributes)
+    submission_params[:files_attributes] = reject_illegal_file_attributes(remote_evaluation_mapping.exercise, files_attributes)
     submission_params
   end
   private :build_submission_params

spec/concerns/file_parameters_spec.rb

@@ -13,7 +13,7 @@ describe FileParameters do
   describe '#reject_illegal_file_attributes!' do
     def file_accepted?(file)
       files = [[0, FactoryBot.attributes_for(:file, context: hello_world, file_id: file.id)]]
-      filtered_files = controller.send(:reject_illegal_file_attributes, hello_world.id, files)
+      filtered_files = controller.send(:reject_illegal_file_attributes, hello_world, files)
       files.eql?(filtered_files)
     end