AdminEmailHandler can produce mails violating RFC2822

[Michal Čihař]

The RFC2822 specifies maximal length of line in a message to 998 characters (see also https://code.djangoproject.com/ticket/22561). However with AdminEmailHandler it's quite easy to reach it once settings contains some more complex dictionary, which is always printed on single line.

The problematic template is TECHNICAL_500_TEXT_TEMPLATE in django/views/debug.py:

​https://github.com/django/django/blob/master/django/views/debug.py#L1121

Specially this code:

Using settings module {{ settings.SETTINGS_MODULE }}{% for k, v in settings.items|dictsort:0 %}
{{ k }} = {{ v|stringformat:"r" }}{% endfor %}

I think best approach would be to use pformat for formatting those entries same as is used for request parameters.

[Carl Meyer]

Since there hasn't been progress in the 5 weeks since this ticket was assigned, I'm de-assigning it to free it up for a PyCon sprinter.

[Pyie Zone]

It looks like this is fixed by #22561. I modified the test like below and it passed for the use case.

   def test_send_long_lines(self):
        email = EmailMessage('Subject', "Commentçava},{'this': {'another': {'more': 'nested'}, 'inner': 'myinner'}, 'that': 'hi'}" * 100, 'from@example.com', ['to@example.com'])
        email.send()
        message = self.get_the_message()
        message_content = message.get_payload()
        has_long_lines = any(len(l) > 998 for l in message_content.splitlines())
        self.assertFalse(has_long_lines)

[Tim Graham]

More friendly formatting of dictionaries may still be useful if someone is so inclined to reopen the ticket and make that change.