Re: [EAI] UTF-8 in Message-IDs

"Charles Lindsey" <chl@clerew.man.ac.uk> Thu, 18 August 2011 15:33 UTC

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From: "Charles Lindsey" <chl@clerew.man.ac.uk>
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Subject: Re: [EAI] UTF-8 in Message-IDs
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On Wed, 17 Aug 2011 23:36:04 +0100, Chris Newman <chris.newman@oracle.com>  
wrote:

> Thank you for raising this use case.
>
> I believe a downgraded EAI message constitutes a "subsequent revision"  
> as described in RFC 5322 section 3.6.4. Specifically, it is likely that  
> attempts to reply to the author, sender and recipients of a downgraded  
> EAI message will fail so it is a fundamentally different message. And  
> thus it is important that it gets a new message id.
>
> So perhaps we should change the advice in RFC5335bis to say:
>
>   The Message-ID SHOULD include at least one UTF-8 character.

Absolutely NO-WAY!

If a message is evidently the SAME message, even though different  
recipients may encounter it in slightly different forms (possibly  
dowgreaded, possibly garbled, but still with the majority of it readable)  
then it MUST have the same Message-ID.

So if, by some complex rerouting, encapsulating, forwarding, someone  
manages to acquire copies of it in both forms, it will be clear it is the  
same (e.g. it will not need to be replied to twice, and in any threaded  
list both will appear together with the same parents and same children).

An essential property of <msg-id>s, which we managed to achieve during the  
discussions that lead to RFC 5322, is that two <msg-id>s can be compared  
for equality by a simnple byte-for-byte comparison. Threading algorithms  
need to rely on this, and within Netnews the same property is essential  
for the transport mechanism to sork (even if the transport proceeds by  
gatewaying into email and then nack into Netnews).

Therefore, IF we are going to permit utf-8 in <msg-id>s, then it is  
essential to include sufficient mandatory requirements on Normalization,  
and to scrutinize the set of allowed characters for troublesome cases. If  
this WG is prepared to put in the work to do then, then well and good, and  
I will support it.

But otherwise, please count me as OPPOSED.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
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