Fixed #18003 -- Preserved tracebacks when re-raising errors.

Thanks jrothenbuhler for draft patch, Konark Modi for updates.

1 files changed, 3 insertions, 1 deletions

diff --git a/django/http/multipartparser.py b/django/http/multipartparser.py
index 070874f234..0c07335f27 100644
--- a/django/http/multipartparser.py
+++ b/django/http/multipartparser.py
@@ -8,6 +8,7 @@ from __future__ import unicode_literals
 
 import base64
 import cgi
+import sys
 
 from django.conf import settings
 from django.core.exceptions import SuspiciousOperation
@@ -209,7 +210,8 @@ class MultiPartParser(object):
                                     chunk = base64.b64decode(chunk)
                                 except Exception as e:
                                     # Since this is only a chunk, any error is an unfixable error.
-                                    raise MultiPartParserError("Could not decode base64 data: %r" % e)
+                                    msg = "Could not decode base64 data: %r" % e
+                                    six.reraise(MultiPartParserError, MultiPartParserError(msg), sys.exc_info()[2])
 
                             for i, handler in enumerate(handlers):
                                 chunk_length = len(chunk)