Re: Change in rmail-insert-mime-forwarded-message

[Mark Lillibridge]

"Stephen J. Turnbull" <address@hidden> writes:

>  Mark Lillibridge writes:
>   > 
>   > "Stephen J. Turnbull" <address@hidden> writes:
>   > 
>   > >  Mark Lillibridge writes:
>   > >  
>   > >   >     Messages stored in mbox format have lines starting with >*From\
>   > >   > escaped by adding an extra > at the front.  This escaping needs to 
> be
>   > >   > reversed to get the original message back.  See bug #13329 for more
>   > >   > details.
>   > >  
>   > >  It's not particularly relevant to the problem Richard is reporting,
>   > >  but that's incorrect.  mbox formats vary, but the most common ones
>   > >  stuff a ">" if and only if the string "From " occurs at the beginning
>   > >  of a line.  If ">From" occurs at the beginning of a line, you can't
>   > >  know whether it was stuffed by the MDA or by the message author or
>   > >  what.
>   > 
>   >     Yes, mbox formats vary; I was describing mboxrd above, which I
>   > believe is the current Rmail default and does not suffer from this
>   > problem.
>  
>  Of course it does, if the MDA being used From-stuffs.  Rmail is not a
>  substitute for the system MDA or MTA.  So by the time Rmail sees the
>  message, it's already ambiguous.

    Yes, Rmail cannot prevent/fix damage that has already been incurred
due to broken mail distribution agents.  Hopefully, in the future we can
get those broken mail distribution agents fixed so they use mboxrd and
do not cause damage.


>   > See bug #6574 for why mboxo, which you describe above, corrupts
>   > messages with ">From " lines.  Either way, unescaping is required
>   > for forwarding or resending messages (destination system may not
>   > use mbox at all).
>  
>  Of course it's not "required"; this is a cosmetic issue.  A stuffed
>  message is inherently ambiguous, and any attempt to unstuff is going
>  to be heuristic.  If you unstuff this:
>  
>  >From some of my correspondents, I occasionally receive mail
>  >containing quotes in this style.
>  
>  before forwarding, some recipients will undoubtedly be unhappy with
>  the results because their MDA doesn't stuff.  Others won't notice
>  because their MDA does stuff.  Is it worth trying to accurately
>  identify these odd cases?

    You would like Rmail to additionally damage the message again in the
hopes that the two damages cancel out?  You asked Rmail to send the
message:

!  From some of my correspondents, I occasionally receive mail
!  >containing quotes in this style.

("!  " added to prevent damage by broken mail distribution agents)

I would expect to see that on the destination modulo broken mail
distribution agents in the middle.  Note that the ">" before the From is
not part of the message per the mbox format rules; sending it would be
corrupting the message.  

    Maybe it's just me, but purposely corrupting the message in the
hopes that broken software on the other end will uncorrupt it seems
wrong.  (If you were sure the software the other end would predictably
react so as to fix things, that would be another matter.)

- Mark