Render json message with errors if note didn't pass validation

app/controllers/projects/notes_controller.rb

@@ -131,6 +131,7 @@ class Projects::NotesController < Projects::ApplicationController
   end
 
   def render_note_json(note)
+    if note.valid?
       render json: {
         id: note.id,
         discussion_id: note.discussion_id,
@@ -141,6 +142,9 @@ class Projects::NotesController < Projects::ApplicationController
         discussion_html: note_to_discussion_html(note),
         discussion_with_diff_html: note_to_discussion_with_diff_html(note)
       }
+    else
+      render json: { invalid: true, errors: note.errors }
+    end
   end
 
   def authorize_admin_note!