bug#70579: 30.0.50; gnus: Wrong unread count in the Group buffer

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Eli Zaretskii <eliz@gnu.org> writes:

> Ping!  Eric, can we make some progress here?
>
>> Cc: jimjoe@gmx.net
>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
>> Date: Thu, 25 Apr 2024 21:34:45 -0700
>> 
>> James Thomas via "Bug reports for GNU Emacs, the Swiss army knife of
>> text editors" <bug-gnu-emacs@gnu.org> writes:
>> 
>> > - (Preferably starting with an empty drafts folder) Compose a message
>> >   and save it.
>> > - Open the drafts group, press e on the message and then kill the new
>> >   buffer; then (incidentally, if you now do '/ N' then this bug does not
>> >   arise) delete the message (B DEL)
>> > - Press q
>> > - The message count is wrong (but can be corrected with M-g)
>> >
>> > cf. In gnus.general (gnus-summary-goto-article "87y192lr8f.fsf@gmx.net")

I've made some progress here -- the root of the problem seems to be
that, when we hit "e" in the draft summary buffer to resume editing a
draft, Gnus "jumps ahead" in message numbers. Basically what "editing"
actually means is that the old draft is deleted, and a new draft is
started, but the new draft has a article number that's the previous
draft's number + 2, and the "draft" group's active number is also
inflated (for instance (12 . 14) when it should be (12 . 13)). I was
also able to get it to jump three numbers in some cases.

From this point, *any* normal usage will end up correcting the error:
using "C-c C-k" to kill the editing buffer (instead of "C-x k") or as
you noted any of the commands that lead to refreshing the unread count.
But if you don't use any of those commands, you'll see the inflated
active/unread count when you get back to the *Group* buffer (the "B DEL"
isn't necessary for the recipe, and in fact at that stage the message
under point has already been deleted).

That's as far as I've gotten, and I'll keep working on why the article
number starts off inflated. But in the meantime, the solution is "don't
do that".

Eric