Re: [Nmh-workers] Dealing with missing From: header during send.

[Robert Elz]

    Date:        Tue, 10 Jan 2012 18:36:59 -0500
    From:        Ken Hornstein <address@hidden>
    Message-ID:  <address@hidden>

  | >My question is: If the str buffer is zeroed, or set, via %(lit), should
  | >the cache be automatically cleared?
  | 
  | I am leaning towards no; does anyone else have an opinion?

You're right, it shouldn't, and none of the existing functions should
do that (I was behind in reading list e-mail, when I read the earlier
messages on this thread I could see you were running into the duplicate
address supression code, but then I see you had worked it out before I
got around to mentioning it).

Rather that adding code to fiddle with the cache, potentially breaking things,
and in any case, making it even harder to use mhl-format than it is now,
I'll suggest an alternative solution.

Split the implementation of formataddr() into two parts, one which does
what its name suggests now, and just formats an address, and the other that
does the duplicate supression (internally I suspect it is pretty much
like this already).

For compat, the (formataddr) function needs to do both halves, then we just
add a new user callable function, that simply formats an address and sticks
it in the buffer, without duplicate supression.

Then, when you're just formatting an address to use it in a match test,
you'd use the new function, and when you're formatting an address to put
in a header, you'd use (formataddr).

The problem with adding something like (clearaddr) is that it makes different
things happen to other lines in the format file, depending whether than happen
to come before, or after, the use of this new function, which would make the
construction of format files even more error prone than it now is.

kre

ps: incidentally, Tethys had a point - no matter what you do, you can't
figure out what address to use just from addresses in the headers of the
message you're replying to .. just consider messages on this list (like
this message) - where are any of your addresses in the headers of this
message?   If you were subscribed to the list with more than one address,
how could you tell which one resulted in the copy you're reading now?
This is not an nmh bug, and it requires MTA assistance to handle - I wouldn't
be surprised if google already has a solution to this (perhaps not 
X-Envelope-To, but perhaps something) and if not, asking them to provide one
would not be unreasonable - you should be told which delivery address resulted
in the message being placed in your mailbox (otherwise how do you ever
find out which of your addresses is the one the spammers have found?)

On the other hand, Tethys' X-Envelope-From is just Return-Path and should
be there already.