From e9462409fd05fe796ba7485a9498ed382c5f775a Mon Sep 17 00:00:00 2001
From: Ralf Teusner <ralf.teusner@hpi.de>
Date: Wed, 16 May 2018 17:06:04 +0200
Subject: [PATCH] fixed the query, removed scopes, added paranthesis for
 clarity.

---
 app/controllers/exercises_controller.rb | 2 +-
 app/models/request_for_comment.rb       | 2 --
 app/models/submission.rb                | 6 +++++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/app/controllers/exercises_controller.rb b/app/controllers/exercises_controller.rb
index 467e71cc..ea72dfde 100644
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@@ -416,7 +416,7 @@ class ExercisesController < ApplicationController
           return
         end
 
-        if @is_experimental_course and @rfc_group == :hide_rfc
+        if @is_experimental_course and (@rfc_group == :hide_rfc)
           redirect_to_lti_return_path
           return
         end
diff --git a/app/models/request_for_comment.rb b/app/models/request_for_comment.rb
index fc77352c..d00d08eb 100644
--- a/app/models/request_for_comment.rb
+++ b/app/models/request_for_comment.rb
@@ -8,8 +8,6 @@ class RequestForComment < ActiveRecord::Base
   has_many :subscriptions
 
   scope :unsolved, -> { where(solved: [false, nil]) }
-  scope :stale, -> { where(exercise.exercise_collections.any{|ec| ec.id = 3}).where("user_id%10 < 3")}
-  scope :not, ->(scope) { where(scope.where_values.reduce(:and).not) }
 
     def self.last_per_user(n = 5)
       from("(#{row_number_user_sql}) as request_for_comments")
diff --git a/app/models/submission.rb b/app/models/submission.rb
index 74ffcd24..5f86d0b8 100644
--- a/app/models/submission.rb
+++ b/app/models/submission.rb
@@ -66,6 +66,10 @@ class Submission < ActiveRecord::Base
   end
 
   def unsolved_rfc
-    RequestForComment.unsolved.not(:stale).where(exercise_id: exercise).where.not(question: nil).order("RANDOM()").find { | rfc_element |(rfc_element.comments_count < MAX_COMMENTS_ON_RECOMMENDED_RFC) }
+    # old query
+    # RequestForComment.unsolved.not(:stale).where(exercise_id: exercise).where.not(question: nil).order("RANDOM()").find { | rfc_element |(rfc_element.comments_count < MAX_COMMENTS_ON_RECOMMENDED_RFC) }
+
+    # experimental query:
+    RequestForComment.unsolved.joins('JOIN exercise_collections_exercises ece ON ece.exercise_id = request_for_comments.exercise_id').where('ece.exercise_collection_id != 3 OR user_id%10 > 3').where.not(question: nil).order("RANDOM()").to_a
   end
 end