bug#13327: 24.2; rmail-cease-edit adds content-type line to non-MIME messages even when editting is aborted

[Mark Lillibridge <mdl@alum.mit.edu>]

Run Rmail on the following mbox file:

====================  cut here  ====================
From mdl  Wed Oct 26 10:18:58 2011
X-RMAIL-ATTRIBUTES: --EF----
X-RMAIL-KEYWORDS: *
X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED,
	RP_MATCHES_RCVD autolearn=unavailable version=3.3.1
From: Mark Lillibridge <mark.lillibridge@hp.com>
To: <bug-gnu-emacs@gnu.org>
Subject: 23.3; rmail-edit-current-message adds extra '>'s to Froms...
Date: Sat, 22 Oct 2011 12:05:57 -0700
Reply-To: <mark.lillibridge@hp.com>


Start with a Rmail message (this one will do) not containing MIME that
contains lines like the following:

>From level 1
>>From level 2
>>>From level 3

====================  cut here  ====================

    You should see one non-MIME message; edit it via 'e' then abort your
edit via C-c C-].  Note via 't' that an extra header has been added to
the end of the headers:

Content-type: text/plain; charset=us-ascii


    Something is very wrong here.  First, when you abort editing a
message it should never be modified under any circumstances.  Second,
Rmail should not be adding MIME headers to non-MIME messages.

- Mark