Re: [Fetchmail-users] mail expunge mismatch

[Matthias A. <mat...@gm...>]

[re-send with fixed quotation markers]

Am 06.05.20 um 20:14 schrieb Hans Carlson:

> I'm using fetchmail-6.4.4.
>
> For about a year now I've been seeing the following in my log file for
> mail coming from yahoo (imap.mail.yahoo.com).  This happens regardless
> of the user.

Hans,

Yahoo's mail server is broken, and your trace proves it. Please report
this to Yahoo (but don't ask my how, I don't know their contacts).
Details below.


> I did a debug session and from what I can tell the problem appears to be
> the response from the imap EXPUNGE command.  It seems to be missing some
> information?  (at least based on the response from another server that
> does work - see below).


The Yahoo IMAP server is expunging prematurely, at a time when it is not
allowed to. This is a server behaviour (malfunction) that is EXPLICITLY
FORBIDDEN by the IMAP4r1 standard (RFC3501) page 73 section 7.4.1
EXPUNGE Response:

An EXPUNGE response MUST NOT be sent when no command is in
progress, nor while responding to a FETCH, STORE, or SEARCH
command. This rule is necessary to prevent a loss of
synchronization of message sequence numbers between client and
server.

>   # This is imap.mail.yahoo.com
>   $ fetchmail -vvv -d0 --nodetach --nosyslog SERVERNAME
>   ...
>   fetchmail: IMAP> A0009 STORE 1 +FLAGS (\Seen \Deleted)
>   fetchmail: IMAP< * 1 FETCH (FLAGS (\Deleted \Seen $NotJunk))
>   fetchmail: IMAP< * 1 EXPUNGE
>   fetchmail: IMAP< * 0 EXISTS
>   fetchmail: IMAP< A0009 OK STORE completed
>   fetchmail: IMAP> A0010 EXPUNGE
>   fetchmail: IMAP< A0010 OK EXPUNGE completed
>   fetchmail: mail expunge mismatch (0 actual != 1 expected)
>   fetchmail: IMAP> A0011 LOGOUT
>   fetchmail: IMAP< * BYE IMAP4rev1 Server logging out
>   fetchmail: IMAP< A0011 OK LOGOUT completed
>
> If I try an account on a different server that functions correctly
> (imap.gmx.com), the response from EXPUNGE shows what I assume
> fetchmail is expecting to see.  BUT comparing the yahoo response to
> the gmx response it appears yahoo may be sending that information as
> part of the STORE response?
>
>   # This is imap.gmx.com
>   $ fetchmail -vvv -d0 --nodetach --nosyslog SERVERNAME
>   ...
>   fetchmail: IMAP> A0008 STORE 1 +FLAGS (\Seen \Deleted)
>   fetchmail: IMAP< * 1 FETCH (FLAGS (\Recent \Deleted \Seen))
>   fetchmail: IMAP< A0008 OK STORE completed
>   fetchmail: IMAP> A0009 EXPUNGE
>   fetchmail: IMAP< * 1 EXPUNGE
>   fetchmail: IMAP< * 0 EXISTS
>   fetchmail: IMAP< * 0 RECENT
>   fetchmail: IMAP< A0009 OK EXPUNGE completed
>   fetchmail: selecting or re-polling default folder
>   fetchmail: 0 messages waiting after re-poll
>   fetchmail: IMAP> A0010 LOGOUT
>   fetchmail: IMAP< * BYE Server logging out
>   fetchmail: IMAP< A0010 OK LOGOUT completed
>
> So... is there any way around this issue?

I will not add new code that works around MUST-NOT violations of a server.

You may get away with avoiding to mark messages deleted (--keep), but
then you cannot use --all.

HTH

Regards,
Matthias