bug#39618: 28.0.50; gnus nnimap reports more group articles than actually exist

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Deus Max <deusmax@gmx.com> writes:

> Recently my gnus started displaying (in the *Group* buffer) some groups
> (which had previously no unread articles) with an unread "ghost" article
> but which groups could not be normally entered.
>
> Here is a description of what I observed:
>
> 1. When pressing <Return>, the cursor simply moves on to the next group
>    line. The number of unread articles remains unchanged and non-zero.
> 2. When pressing <c> for `gnus-group-catchup-current', the unread
>    article number becomes zero and upon <Return>, all read articles are
>    displayed in the group. Upon exit from the group, upon "g"
>    gnus-refresh the "ghost" unread article reappears.
>
> Luckily, this being nnimap the situation can be recovered by removing
> the .newsrc files and restarting gnus from scratch. This is not optimal,
> as all other relevant configurations will be lost, such as group levels,
> etc.
>
> This issue has happened before, it is not the first time.

This definitely happens to many of us from time to time. Unfortunately I
can't really reproduce the problem, as by the time it appears it's too
late to figure out where it came from, though I assume it has to do with
Gnus calculating unread messages from a high-low range, and not being
aware of "filled in" read messages within that range.

In the meantime, is "M-g" on the problematic group(s) enough to
permanently fix the problem? Not a great solution, though better than
doctoring your .newsrc.eld file...