Use a namedtuple for email attachments and alternatives.

This makes it more descriptive to pull out the named fields

django/core/mail/message.py

@@ -1,4 +1,5 @@
 import mimetypes
+from collections import namedtuple
 from email import charset as Charset
 from email import encoders as Encoders
 from email import generator, message_from_string
@@ -190,6 +191,10 @@ def __setitem__(self, name, val):
         MIMEMultipart.__setitem__(self, name, val)
 
 
+Alternative = namedtuple("Alternative", ["content", "mime_type"])
+EmailAttachment = namedtuple("Attachment", ["filename", "content", "mime_type"])
+
+
 class EmailMessage:
     """A container for email information."""
 
@@ -338,7 +343,7 @@ def attach(self, filename=None, content=None, mimetype=None):
                         # actually binary, read() raises a UnicodeDecodeError.
                         mimetype = DEFAULT_ATTACHMENT_MIME_TYPE
 
-            self.attachments.append((filename, content, mimetype))
+            self.attachments.append(EmailAttachment(filename, content, mimetype))
 
     def attach_file(self, path, mimetype=None):
         """
@@ -471,13 +476,15 @@ def __init__(
             cc,
             reply_to,
         )
-        self.alternatives = alternatives or []
+        self.alternatives = [
+            Alternative(*alternative) for alternative in (alternatives or [])
+        ]
 
     def attach_alternative(self, content, mimetype):
         """Attach an alternative content representation."""
         if content is None or mimetype is None:
             raise ValueError("Both content and mimetype must be provided.")
-        self.alternatives.append((content, mimetype))
+        self.alternatives.append(Alternative(content, mimetype))
 
     def _create_message(self, msg):
         return self._create_attachments(self._create_alternatives(msg))
@@ -492,5 +499,9 @@ def _create_alternatives(self, msg):
             if self.body:
                 msg.attach(body_msg)
             for alternative in self.alternatives:
-                msg.attach(self._create_mime_attachment(*alternative))
+                msg.attach(
+                    self._create_mime_attachment(
+                        alternative.content, alternative.mime_type
+                    )
+                )
         return msg

docs/releases/5.2.txt

@@ -128,7 +128,13 @@ Decorators
 Email
 ~~~~~
 
-* ...
+* Tuple items of ``attachments`` of :class:`~django.core.mail.EmailMessage`
+  and :class:`~django.core.mail.EmailMultiAlternatives` are now named tuples,
+  as opposed to regular tuples.
+
+* :attr:`EmailMultiAlternatives.alternatives
+  <django.core.mail.EmailMultiAlternatives.alternatives>` is now a list of
+  named tuples, as opposed to regular tuples.
 
 Error Reporting
 ~~~~~~~~~~~~~~~

docs/topics/email.txt

@@ -282,8 +282,13 @@ All parameters are optional and can be set at any time prior to calling the
   new connection is created when ``send()`` is called.
 
 * ``attachments``: A list of attachments to put on the message. These can
-  be either :class:`~email.mime.base.MIMEBase` instances, or ``(filename,
-  content, mimetype)`` triples.
+  be either :class:`~email.mime.base.MIMEBase` instances, or a named tuple
+  with attributes ``(filename, content, mimetype)``.
+
+  .. versionchanged:: 5.2
+
+    In older versions, tuple items of ``attachments`` were regular tuples,
+    as opposed to named tuples.
 
 * ``headers``: A dictionary of extra headers to put on the message. The
   keys are the header name, values are the header values. It's up to the
@@ -392,10 +397,10 @@ Django's email library, you can do this using the
 
 .. class:: EmailMultiAlternatives
 
-    A subclass of :class:`~django.core.mail.EmailMessage` that has an
-    additional ``attach_alternative()`` method for including extra versions of
-    the message body in the email. All the other methods (including the class
-    initialization) are inherited directly from
+    A subclass of :class:`~django.core.mail.EmailMessage` that allows
+    additional versions of the message body in the email via the
+    ``attach_alternative()`` method. This directly inherits all methods
+    (including the class initialization) from
     :class:`~django.core.mail.EmailMessage`.
 
     .. method:: attach_alternative(content, mimetype)
@@ -415,6 +420,21 @@ Django's email library, you can do this using the
             msg.attach_alternative(html_content, "text/html")
             msg.send()
 
+    .. attribute:: alternatives
+
+        A list of named tuples with attributes ``(content, mimetype)``. This is
+        particularly useful in tests::
+
+            self.assertEqual(len(msg.alternatives), 1)
+            self.assertEqual(msg.alternatives[0].content, html_content)
+
+        Alternatives should only be added using the ``attach_alternative()`` method.
+
+        .. versionchanged:: 5.2
+
+            In older versions, ``alternatives`` was a list of regular tuples, as opposed
+            to named tuples.
+
 Updating the default content type
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/logging_tests/tests.py

@@ -467,7 +467,7 @@ def test_emit_no_form_tag(self):
         msg = mail.outbox[0]
         self.assertEqual(msg.subject, "[Django] ERROR: message")
         self.assertEqual(len(msg.alternatives), 1)
-        body_html = str(msg.alternatives[0][0])
+        body_html = str(msg.alternatives[0].content)
         self.assertIn('<div id="traceback">', body_html)
         self.assertNotIn("<form", body_html)
 

tests/view_tests/tests/test_debug.py

@@ -1463,7 +1463,7 @@ def verify_unsafe_email(self, view, check_for_POST_params=True):
             self.assertNotIn("worcestershire", body_plain)
 
             # Frames vars are shown in html email reports.
-            body_html = str(email.alternatives[0][0])
+            body_html = str(email.alternatives[0].content)
             self.assertIn("cooked_eggs", body_html)
             self.assertIn("scrambled", body_html)
             self.assertIn("sauce", body_html)
@@ -1499,7 +1499,7 @@ def verify_safe_email(self, view, check_for_POST_params=True):
             self.assertNotIn("worcestershire", body_plain)
 
             # Frames vars are shown in html email reports.
-            body_html = str(email.alternatives[0][0])
+            body_html = str(email.alternatives[0].content)
             self.assertIn("cooked_eggs", body_html)
             self.assertIn("scrambled", body_html)
             self.assertIn("sauce", body_html)