DA - group discussion topic index works with DA on

fixes CNVS-19639

test plan:
  - in a course with DA on make a group discussion topic
    (without an attached assignment)
  - go to the group discussion topic index page
  - make sure it shows up
  - make sure that the courses assignment & discussion topic
    indeces are working like normal

Change-Id: Ibe5802a32e59e4ae0fab21707d66fb3bcba1a7fd
Reviewed-on: https://gerrit.instructure.com/51695
QA-Review: Adam Stone <astone@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>
Tested-by: Jenkins

app/controllers/discussion_topics_controller.rb

@@ -280,7 +280,7 @@ class DiscussionTopicsController < ApplicationController
     end
 
     if @context.feature_enabled?(:differentiated_assignments)
-      scope = DifferentiableAssignment.scope_filter(scope, @current_user, @context)
+      scope = scope_for_differentiated_assignments(scope)
     end
 
     @topics = Api.paginate(scope, self, topic_pagination_url)
@@ -332,6 +332,23 @@ class DiscussionTopicsController < ApplicationController
     end
   end
 
+  def scope_for_differentiated_assignments(scope)
+    return scope if @context.is_a?(Account)
+    return DifferentiableAssignment.scope_filter(scope, @current_user, @context) if @context.is_a?(Course)
+    return scope if @context.context.is_a?(Account)
+
+    # group context owned by a course
+    course = @context.context
+    course_scope = course.discussion_topics.active
+    course_level_topic_ids = DifferentiableAssignment.scope_filter(course_scope, @current_user, course).pluck(:id)
+    if course_level_topic_ids.any?
+      scope.where("root_topic_id IN (?) OR root_topic_id IS NULL OR id IN (?)", course_level_topic_ids, course_level_topic_ids)
+    else
+      scope.where(root_topic_id: nil)
+    end
+  end
+  private :scope_for_differentiated_assignments
+
   def is_child_topic?
     root_topic_id = params[:root_discussion_topic_id]
 

app/models/discussion_topic.rb

@@ -467,24 +467,24 @@ class DiscussionTopic < ActiveRecord::Base
   scope :by_position_legacy, -> { order("discussion_topics.position DESC, discussion_topics.created_at DESC, discussion_topics.id DESC") }
   scope :by_last_reply_at, -> { order("discussion_topics.last_reply_at DESC, discussion_topics.created_at DESC, discussion_topics.id DESC") }
 
-   scope :visible_to_students_in_course_with_da, lambda { |user_ids, course_ids|
-     without_assignment_in_course(course_ids).union(joins_assignment_student_visibilities(user_ids, course_ids))
-   }
+  scope :visible_to_students_in_course_with_da, lambda { |user_ids, course_ids|
+    without_assignment_in_course(course_ids).union(joins_assignment_student_visibilities(user_ids, course_ids))
+  }
 
-   scope :without_assignment_in_course, lambda { |course_ids|
-     where(context_id: course_ids, context_type: "Course").where("discussion_topics.assignment_id IS NULL")
-   }
+  scope :without_assignment_in_course, lambda { |course_ids|
+    where(context_id: course_ids, context_type: "Course").where("discussion_topics.assignment_id IS NULL")
+  }
 
-   scope :joins_assignment_student_visibilities, lambda { |user_ids, course_ids|
-     user_ids = Array.wrap(user_ids).join(',')
-     course_ids = Array.wrap(course_ids).join(',')
-     joins(sanitize_sql([<<-SQL, user_ids, course_ids]))
+  scope :joins_assignment_student_visibilities, lambda { |user_ids, course_ids|
+    user_ids = Array.wrap(user_ids).join(',')
+    course_ids = Array.wrap(course_ids).join(',')
+    joins(sanitize_sql([<<-SQL, user_ids, course_ids]))
       JOIN assignment_student_visibilities
         ON (assignment_student_visibilities.assignment_id = discussion_topics.assignment_id
-            AND assignment_student_visibilities.user_id IN (%s)
-            AND assignment_student_visibilities.course_id IN (%s)
+          AND assignment_student_visibilities.user_id IN (%s)
+          AND assignment_student_visibilities.course_id IN (%s)
         )
-      SQL
+    SQL
   }
 
   alias_attribute :available_from, :delayed_post_at

spec/controllers/discussion_topics_controller_spec.rb

@@ -72,6 +72,63 @@ describe DiscussionTopicsController do
       get 'index', :group_id => @group.id
       expect(response).to be_success
     end
+
+    context "graded group discussion" do
+      before do
+        @course.account.role_overrides.create!(
+          role: student_role,
+          permission: 'view_group_pages',
+          enabled: true
+        )
+        @course.enable_feature!(:differentiated_assignments)
+
+        group_discussion_assignment
+        @child_topic = @topic.child_topics.first
+        @group = @child_topic.context
+        @group.add_user(@student)
+        @assignment.only_visible_to_overrides = true
+        @assignment.save!
+      end
+      it "should return graded and visible group discussions properly" do
+        cs = @student.enrollments.first.course_section
+        create_section_override_for_assignment(@assignment, {course_section: cs})
+
+        user_session(@student)
+
+        get 'index', :group_id => @group.id
+        expect(response).to be_success
+        expect(assigns["topics"]).to include(@child_topic)
+      end
+
+      it "should not return graded group discussions if a student has no visibility" do
+        user_session(@student)
+
+        get 'index', :group_id => @group.id
+        expect(response).to be_success
+        expect(assigns["topics"]).not_to include(@child_topic)
+      end
+    end
+
+    it "should return non-graded group discussions properly" do
+      @course.account.role_overrides.create!(
+        role: student_role,
+        permission: 'view_group_pages',
+        enabled: true
+      )
+      @course.enable_feature!(:differentiated_assignments)
+
+      group_category(context: @course)
+      membership = group_with_user(group_category: @group_category, user: @student, context: @course)
+      @topic = @group.discussion_topics.create(:title => "group topic")
+      @topic.context = @group
+      @topic.save!
+
+      user_session(@student)
+
+      get 'index', :group_id => @group.id
+      expect(response).to be_success
+      expect(assigns["topics"]).to include(@topic)
+    end
   end
 
   describe "GET 'show'" do