Remove cross-references user cannot see from issue discussions JSON

app/controllers/projects/issues_controller.rb

@@ -97,9 +97,11 @@ class Projects::IssuesController < Projects::ApplicationController
   end
 
   def discussions
-    @discussions = @issue.discussions
-    @discussions.reject! { |d| d.individual_note? && d.first_note.cross_reference_not_visible_for?(current_user) }
-    prepare_notes_for_rendering(@discussions.flat_map(&:notes))
+    notes = @issue.notes.inc_relations_for_view.includes(:noteable).fresh.to_a
+    notes.reject! { |n| n.cross_reference_not_visible_for?(current_user) }
+    prepare_notes_for_rendering(notes)
+
+    @discussions = Discussion.build_collection(notes, @issue)
 
     render json: DiscussionSerializer.new(project: @project, noteable: @issue, current_user: current_user).represent(@discussions)
   end

app/models/concerns/noteable.rb

@@ -38,7 +38,7 @@ module Noteable
 
   def grouped_diff_discussions(*args)
     # Doesn't use `discussion_notes`, because this may include commit diff notes
-    # besides MR diff notes, that we do no want to display on the MR Changes tab.
+    # besides MR diff notes, that we do not want to display on the MR Changes tab.
     notes.inc_relations_for_view.grouped_diff_discussions(*args)
   end