bug#39026: 27.0.50; gnus-group-decoded-name needs running gnus

[Deus Max <deusmax@gmx.com>]

On Wed, Jan 08 2020, Eric Abrahamsen wrote:

> Deus Max <deusmax@gmx.com> writes:
>
>> Before starting gnus, running:
>>    (gnus-group-decoded-name  group-name) ; ex: "nnimap+myserver:GroupName"
>>
>> Gives the error:
>>    ** Eval error ***  Wrong type argument: hash-table-p, nil
>>
>> Tracking this down the path:
>>    - (gnus-group-decoded-name group-name)
>>      - (gnus-group-name-charset  nil group-name)
>>        - (gnus-find-method-for-group group-name)
>>          - (gnus-group-entry group-name)
>>
>> The tiny macro gnus-group-entry, simply does a:
>>     (gethash group-name gnus-newsrc-hashtb)
>>
>> The variable gnus-newsrc-hashtb is not a hashtable when gnus is not
>> running. Logical, it has not been assinged yet.
>>
>> To me, it seems unnecessary to require a running gnus for a simple group
>> name decoding. It is overkill, that loses a lot of offline functinality
>> and possibilities.
>
> In theory, the only way we can know how to decode a group name for sure
> is by asking its method for the appropriate charset to use, and we can
> only reasonably do that if Gnus is loaded.
>
> In practice, the same changes that put in the hash table also resulted
> in Gnus group names being always decoded, at least within a running Gnus
> system, so the call to `gnus-group-decoded-name' is usually unnecessary
> (the only time the server/method charset comes into play is when we're
> requesting the group names from the server).
>
> Of course if you're trying to do things with groups outside of a running
> Gnus system, you might be manually reading the group names from
> the.newsrc.eld file, in which case non-ASCII group names will be in an
> encoded format, using 'utf-8-emacs.
>
> What I'm saying is, depending on how you're using the group names and
> where you're getting them from, you should be safe simply running them
> through a 'utf-8-emacs decode.
>
> Eric

Yes, that's mostly how I'm using it, i.e. by reading group names from
.newsrc, but sometimes directly from a gnus group or article. So, it
would be nice to do some things independent of a running gnus and in a
consistent way.

I didn't see any charset info returned by querying the server
(with gnus-find-method-for-group, gnus-group-entry). Logically, the
method should be provided in the group name, except for the primary
method (gnus-select-method, perhaps another good reason to get rid of
this distinction among groups, but I digress, sorry).

It seems that all the real work (in gnus-group-name-charset), for finding
the charset, comes from the variables gnus-group-name-charset-group-alist
and gnus-group-name-charset-method-alist which are defined at startup
and don't need a running gnus.

DeusM