Re: Gnus sometimes reports new messages but not showing them on IMAP server

[Xiyue Deng <manphiz@gmail.com>]

Greg Troxel <gdt@lexort.com> writes:

> Xiyue Deng <manphiz@gmail.com> writes:
>
>> I'm having some issues that Gnus sometimes reports that there are new
>> messages on an IMAP server but it doesn't show them.  In my case it's
>> using Gmail IMAP, and if I check using other mail clients
>> (e.g. Thunderbird) or directly check on Gmail website I can seem them.
>> I'm not sure whether this issue is specific to IMAP either.  As I'm not
>> sure how to get more info, I didn't use report bug yet, but would like
>> to ask around and see whether this is a known issue, or otherwise I can
>> get some suggestions to get more debug info before I formally file a
>> bug.
>
> I have been having a problem for several years that may be the same
> thing.
>
> My mail is in IMAP via dovecot.  Other than the following I have zero
> problems with it.
>
> I read mail with gnus (emacs built w/o x11 running in tmux in an xterm,
> on NetBSD, currently 28.2 and thus the included gnus), with about 300
> folders, about half of which have server-side filing of list mail.  I
> also use K-9 Mail on Android (INBOX and maybe 3 more mailboxes, more or
> less, ignoring the folders for lists and storage).  Occasionally I use
> thunderbird for INBOX, to read something that should have been plain
> text and isn't :-) but this issue has happened with no tbird running at
> all.
>
> Often, I get a message on my phone that I just leave (marked read) to
> deal with later.  Sometimes, maybe 1 in 50, I can't find it in gnus, and
> on looking harder find that it is just not showing up there.  Yet K-9
> sees it as present and looking in ~/IMAP/cur shows it was well.
> Whenever this has happened and I look with Thunderbird, it sees it fine
> also.
>

Exactly this symptom.

> I have found that if I move the message to another folder (I have TMP
> for this very purpose) and then back to INBOX, it can then be found in
> gnus.  So something about the message as it sits in the folder was
> triggering gnus to miss it, while the very same message refiled does not
> trigger this.
>

I haven't tried this in this case, but there is actually another issue
that I haven't talked about: sometimes one of the empty folders may
report a number of new messages in it!  In one of the occurrences it
reports 52 new message on an empty folder.  The solution, however, is
similar to what you did but reverse: you move a number of messages from
another folder to it, and the new message count will reduce by the
number of messages you moved!  So in the previous case if you move 10
messages to the folder, the count becomes 42.  You move them out, and
move them back again, 32, etc.

Let me also try your solution in future.

> I have not been able to determine any pattern of which messages get this
> disappearing treatment.  It's not really the message, since moving and
> back fixes it.
>
> Early on, I sort of suspected dovecot, but other people don't have
> trouble with dovecot, and I have had zero flakiness other than this
> specific issue.
>
> I have not perceived "gnus says there are new messages but there
> aren't".  I am not at all sure I would have noticed, especially if gnus
> said 6 and there were 5.
>

I have only encountered such cases when the folder is empty.

> In your case, if you do "100<spc>" in group, do you see the missing
> message?  If not, you should be able to turn on some kind of debugging
> to figure out what's going on, but I am unclear on the details.
>

No, specifying a number didn't work for me, unfortunately.

And I guess to really understand this issue one may have to read the
code of Gnus or IMAP backend or hopefully someone that does may be able
to help.

> Greg
>
>

-- 
Xiyue Deng