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

[Greg Troxel <gdt@lexort.com>]

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.

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 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.

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.

Greg