id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
23924	EmailMessage type checks should raise TypeError, not AssertionError	Martín Blech	nobody	"If I run the following code:

{{{#!python
email = EmailMessage(
    'Subject', 'Content',
    'from@example.com',
    'to@example.com')

print(email.message())
}}}

With the `-O` option, I get:

{{{
Traceback (most recent call last):
  File ""x.py"", line 6, in <module>
    'to@example.com')
  File ""/home/berker/hacking/django/django/core/mail/message.py"", line 227, in __init__
    assert not isinstance(to, six.string_types), '""to"" argument must be a list or tuple'
AssertionError: ""to"" argument must be a list or tuple
}}}

But without it, it fails silently and produces a broken `To` header:

{{{
From nobody Wed Nov 26 18:30:08 2014
MIME-Version: 1.0
Content-Type: text/plain; charset=""utf-8""
Content-Transfer-Encoding: 7bit
Subject: Subject
From: from@example.com
To: t, o, @, e, x, a, m, p, l, e, ., c, o, m
Date: Wed, 26 Nov 2014 18:30:08 -0000
Message-ID: <20141126183008.1632.71698@rama>

Content
}}}"	Bug	closed	Core (Mail)	dev	Normal	fixed		martinblech@…	Accepted	0	0	0	0	1	0