[Nmh-workers] why does mhfixmsg dislike long text lines?

[Steven Winikoff]

I'm in the middle of integrating mhfixmsg (1.7) into my proxmail setup, and
just discovered this behaviour:

   # mhfixmsg -verbose -textcharset utf8 -fixcte -noreformat -fixboundary -file 
/tmp/msg -outfile /tmp/501.fm
   mhfixmsg: /tmp/msg, will not decode text/html;  charset="UTF-8" because it 
is binary (line length > 998)

The comments in the code where this happens are as follows (lines
2118-2123):

   /*
    * See if the decoded content is 7bit, 8bit, or binary.  It's binary
    * if it has any NUL characters, a CR not followed by a LF, or lines
    * greater than 998 characters in length.  If binary, reason is set
    *  to a string explaining why.
    */

I can certainly understand this in the general case, but:

   - The case which tripped this for me specifically involved a text part;
     the headers in the message were:

        Content-Transfer-Encoding: base64
        Content-Disposition: inline
        Content-Type: text/html;
                charset="UTF-8"
        MIME-Version: 1.0

     The message structure was as simple as it gets:

        # mhlist -file /tmp/msg
         msg part  type/subtype              size description
           0        text/html                  20K

     ...so it was clearly marked as text.  If a sender packages a binary
     file but describes it as text/html, it's already broken, and I really
     don't care if mhfixmsg "damages" it even further. :-/

   - More and more senders these days are using auto-generated HTML in
     which the entire body is a single line of text.  This message wasn't
     even one of those, but the point is that HTML with very long lines
     isn't unusual anymore.

     Instead of leaving it base64-encoded, arguably the right thing to do
     with something like that is to decode it and then run it through an
     HTML pretty-printer, although I acknowledge that that's beyond the
     scope of what mhfixmsg is designed to do. :-)

So I guess what I'm asking is:  I can easily modify my copy of nmh to raise
the 998-character limit, but it's not clear to me what I might break by
doing so.  Would someone please explain what I'm missing here?

     - Steven
-- 
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Steven Winikoff                |
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