From b9b3a303a751bda315e0bdd228626d4cbdba3410 Mon Sep 17 00:00:00 2001
From: cxt <853663049@qq.com>
Date: Tue, 10 Dec 2019 11:06:51 +0800
Subject: [PATCH] =?UTF-8?q?=E8=B5=84=E6=BA=90=E9=80=89=E7=94=A8=E6=8A=A5?=
 =?UTF-8?q?=E9=94=99?=
MIME-Version: 1.0
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---
 app/models/attachment.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index a918f4e0a..292a409af 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -35,7 +35,7 @@ class Attachment < ApplicationRecord
 
   def title
     title = filename
-    if container.is_a?(StudentWork) && author_id != User.current.id
+    if container && container.is_a?(StudentWork) && author_id != User.current.id
       course = container&.homework_common&.course
       unless User.current.teacher_of_course?(course)
         title = "#{Time.now.strftime('%Y%m%d%H%M%S')}_#{DCODES.sample(8).join}" + File.extname(filename)