用户切换身份报错

app/models/homework_common.rb

@@ -104,7 +104,7 @@ class HomeworkCommon < ApplicationRecord
   end
 
   def user_work user_id
-    work = self.student_works.find_by_user_id(user_id) || StudentWork.create!(homework_common_id: id, user_id: user_id)
+    work = self.student_works.find_by_user_id(user_id)   # || StudentWork.create!(homework_common_id: id, user_id: user_id)
   end
 
   # 是否在补交阶段内