EmailMultiAlternatives and send_email do not handle ugettext_lazy translated strings correctly

[gary.hutspot@…]

When trying to send email with a subject that is lazily translated, the following TypeError is thrown:

argument of type 'proxy' is not iterable

Cut and paste compatible example:

from django.utils.translation import ugettext_lazy as _
from django.core.mail import send_mail
from django.conf import settings

# If you do not have smtp running on your local system, specify your smtp server here
settings.configure(EMAIL_HOST='your.smtp.server')

send_mail(_('Subject here'), 'Here is the message.', 'from@example.com', ['to@example.com'], fail_silently=False)

Produces:

$ python proof.py 
Traceback (most recent call last):
  File "proof.py", line 8, in <module>
    fail_silently=False)
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 333, in send_mail
    connection=connection).send()
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 259, in send
    return self.get_connection(fail_silently).send_messages([self])
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 168, in send_messages
    sent = self._send(message)
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 182, in _send
    email_message.message().as_string())
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 241, in message
    msg['Subject'] = self.subject
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 92, in __setitem__
    name, val = forbid_multi_line_headers(name, val)
  File "/usr/lib/python2.5/site-packages/django/core/mail.py", line 74, in forbid_multi_line_headers
    if '\n' in val or '\r' in val:
TypeError: argument of type '__proxy__' is not iterable

[Muriel Bowie]

I am having the same problem. Currently I use ugettext instead of ugettext_lazy as a workaround.

[Matthias Kestenholz]

Just changing the order of the force_unicode block and the \n/\r detection block is enough.

[Malcolm Tredinnick]

Since Header instances don't act as containers or sequences (they don't support in tests), this patch cannot work. Writing as test for the failing case might have helped detect that.

(Thanks for taking the time to write a patch, but please let somebody else triage it to "ready for checkin" so that we get another set of eyes on that patch for review.)

[Malcolm Tredinnick]

(In [8083]) Fixed #7574 -- Fixed the handling of lazy translation in email headers.