Add StudyGroup to submissions and show it for submissions and RfCs

Also take care of deleting a StudyGroup for existing submissions

app/controllers/concerns/lti.rb

@@ -168,6 +168,7 @@ module Lti
     end
     group.users |= [@current_user] # add current user if not already member of the group
     group.save
+    session[:study_group_id] = group.id
   end
 
   def set_embedding_options

app/controllers/concerns/submission_parameters.rb

@@ -16,7 +16,8 @@ module SubmissionParameters
       current_user_id = current_user.id
       current_user_class_name = current_user.class.name
     end
-    submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name) : {}
+    # The study_group_id might not be present in the session (e.g. for internal users), resulting in session[:study_group_id] = nil which is intended.
+    submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name, study_group_id: session[:study_group_id]) : {}
     reject_illegal_file_attributes!(submission_params)
     submission_params
   end

app/controllers/request_for_comments_controller.rb

@@ -83,17 +83,10 @@ class RequestForCommentsController < ApplicationController
     authorize!
   end
 
-  # GET /request_for_comments/new
-  def new
-    @request_for_comment = RequestForComment.new
-    authorize!
-  end
-
   # GET /request_for_comments/1/edit
   def edit
   end
 
-  # POST /request_for_comments
   # POST /request_for_comments.json
   def create
     # Consider all requests as JSON
@@ -149,8 +142,8 @@ class RequestForCommentsController < ApplicationController
 
     # Never trust parameters from the scary internet, only allow the white list through.
     def request_for_comment_params
-      # we are using the current_user.id here, since internal users are not able to create comments. The external_user.id is a primary key and does not require the consumer_id to be unique.
+      # The study_group_id might not be present in the session (e.g. for internal users), resulting in session[:study_group_id] = nil which is intended.
-      params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name)
+      params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name, study_group_id: session[:study_group_id])
     end
 
     def comment_params

app/models/study_group.rb

@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 class StudyGroup < ApplicationRecord
-  has_many :study_group_memberships
+  has_many :study_group_memberships, dependent: :destroy
   # Use `ExternalUser` as `source_type` for now.
   # Using `User` will lead ActiveRecord to access the inexistent table `users`.
   # Issue created: https://github.com/rails/rails/issues/34531
   has_many :users, through: :study_group_memberships, source_type: 'ExternalUser'
-  has_many :submissions
+  has_many :submissions, dependent: :nullify
   belongs_to :consumer
 
   def to_s

app/policies/application_policy.rb

@@ -25,6 +25,22 @@ class ApplicationPolicy
   end
   private :no_one
 
+  def everyone_in_study_group
+    study_group = @record.study_group
+    return false if study_group.blank?
+
+    users_in_same_study_group = study_group.users
+    return false if users_in_same_study_group.blank?
+
+    users_in_same_study_group.include? @user
+  end
+  private :everyone_in_study_group
+
+  def teacher_in_study_group
+    teacher? && everyone_in_study_group
+  end
+  private :teacher_in_study_group
+
   def initialize(user, record)
     @user = user
     @record = record

app/policies/submission_policy.rb

@@ -12,14 +12,8 @@ class SubmissionPolicy < ApplicationPolicy
     admin?
   end
 
-  def everyone_in_study_group
-    users_in_same_study_group = @record.study_groups.users
-    users_in_same_study_group.include? @user
-  end
-  private :everyone_in_study_group
 
-  def teacher_in_study_group
+  def show_study_group?
-    teacher? && everyone_in_study_group
+    admin? || teacher_in_study_group
   end
-  private :teacher_in_study_group
 end

app/views/request_for_comments/show.html.slim

@@ -9,6 +9,9 @@
     - testruns = Testrun.where(:submission_id => @request_for_comment.submission)
     = link_to_if(policy(user).show?, user.displayname, user)
     | | #{@request_for_comment.created_at.localtime}
+    - if @request_for_comment.submission.study_group.present? && policy(@request_for_comment.submission).show_study_group?
+      = ' | '
+      = link_to_if(policy(@request_for_comment.submission.study_group).show?, @request_for_comment.submission.study_group, @request_for_comment.submission.study_group)
   .rfc
     .description
       h5

app/views/submissions/show.html.slim

@@ -9,6 +9,7 @@ h1 = @submission
 
 = row(label: 'submission.exercise', value: link_to_if(policy(@submission.exercise).show?, @submission.exercise, @submission.exercise))
 = row(label: 'submission.user', value: link_to_if(policy(@submission.user).show?, @submission.user, @submission.user))
+= row(label: 'submission.study_group', value: link_to_if(policy(@submission.study_group).show?, @submission.study_group, @submission.study_group))
 = row(label: 'submission.cause', value: t("submissions.causes.#{@submission.cause}"))
 = row(label: 'submission.score', value: @submission.score)