bug#35219: 27.0.50; Problems with nnimap groups with non-ASCII characters

[Andy Moreton <andrewjmoreton@gmail.com>]

On Thu 18 Apr 2019, Eric Abrahamsen wrote:

> Andy Moreton <andrewjmoreton@gmail.com> writes:
>> I see a similar symptom, but with a different recipe:
>>  - start Gnus
>>  - open the server buffer, select a server, and subscribe to a new group
>>  - quit the server buffer
>>  - in the group buffer, kill the group line for the new group
>> At this point, emacs is busy but unresponsive. Breaking in with ^G
>> results in emacs becoming responsive agin, but all of the group lines
>> disappear from the group buffer.
>>
>> Something is still not quite right.
>
> I'm not able to reproduce that, using a nntp group from gmane -- can you
> give me more detail about how you trigger it?

I used an nntp group from gmane to check this. After hitting ^g in the
recipe above, emacs shows the last 3 lines of the original group buffer,
and typing 'g' toudpate the group buffer restores the display to all of
the missing groups.

After more testing, it seems that this wrong display depends on using
topics in the group buffer. If I toggle topics off ('t' in the group
buffer) then killing the newly added group appears to work normally.

With topics enabled, adding a new group and then saving .newsrc.eld ('s'
in the group buffer) still results in the bad behaviour when killing the
new group.

Killing/yanking a group that was already in .newsrc.eld before gnus was
started works normally.

I've only checked this with my usual config though, rather than
something stripped down to produce a minimal test case.

> Unfortunately, the last round of changes might have left some cruft in
> your .newsrc.eld file, if you had groups with non-ascii names. If you've
> got some of that cruft in your group list, I suppose it's possible that
> trying to kill a group might enter some sort of loop...

All of the groups in my .newsrc.eld have ASCII names.

    AndyM