[1.11.x] Fixed #28042 -- Fixed crash when using a two-tuple in EmailMessage's attachments arg.

Backport of dd00184892 from master

django/core/mail/message.py

@@ -286,7 +286,13 @@ class EmailMessage(object):
         self.from_email = from_email or settings.DEFAULT_FROM_EMAIL
         self.subject = subject
         self.body = body
-        self.attachments = attachments or []
+        self.attachments = []
+        if attachments:
+            for attachment in attachments:
+                if isinstance(attachment, MIMEBase):
+                    self.attach(attachment)
+                else:
+                    self.attach(*attachment)
         self.extra_headers = headers or {}
         self.connection = connection
 

docs/releases/1.11.1.txt

@@ -15,3 +15,6 @@ Bugfixes
 
 * Fixed a crash when using a ``__icontains`` lookup on a ``ArrayField``
   (:ticket:`28038`).
+
+* Fixed a crash when using a two-tuple in ``EmailMessage``’s ``attachments``
+  argument (:ticket:`28042`).

tests/mail/tests.py

@@ -387,6 +387,13 @@ class MailTests(HeadersCheckMixin, SimpleTestCase):
         self.assertEqual(payload[0].get_content_type(), 'multipart/alternative')
         self.assertEqual(payload[1].get_content_type(), 'application/pdf')
 
+    def test_attachments_two_tuple(self):
+        msg = EmailMessage(attachments=[('filename1', 'content1')])
+        filename, content, mimetype = self.get_decoded_attachments(msg)[0]
+        self.assertEqual(filename, 'filename1')
+        self.assertEqual(content, b'content1')
+        self.assertEqual(mimetype, 'application/octet-stream')
+
     def test_attachments_MIMEText(self):
         txt = MIMEText('content1')
         msg = EmailMessage(attachments=[txt])