Fixed #18269 -- Applied unicode_literals for Python 3 compatibility.

Thanks Vinay Sajip for the support of his django3 branch and
Jannis Leidel for the review.

1 files changed, 4 insertions, 2 deletions

diff --git a/django/core/files/uploadhandler.py b/django/core/files/uploadhandler.py
index 88f78904bb..68d540e595 100644
--- a/django/core/files/uploadhandler.py
+++ b/django/core/files/uploadhandler.py
@@ -2,6 +2,8 @@
 Base file upload handler classes, and the built-in concrete subclasses
 """
 
+from __future__ import unicode_literals
+
 from io import BytesIO
 
 from django.conf import settings
@@ -33,9 +35,9 @@ class StopUpload(UploadFileException):
 
     def __unicode__(self):
         if self.connection_reset:
-            return u'StopUpload: Halt current upload.'
+            return 'StopUpload: Halt current upload.'
         else:
-            return u'StopUpload: Consume request data, then halt.'
+            return 'StopUpload: Consume request data, then halt.'
 
 class SkipFile(UploadFileException):
     """