nnir bug?

[Sebastian Tennant <sebyte@smolny.plus.com>]

In the thread 'Switching backends' quoth Kai Grossjohann <kai@emptydomain.de>:
> This seems somewhat obvious, though, so I'm not sure if it really
> helps.
>
> Kai

Hi Kai (et al),

Your advice was very helpful and I've switched gnus mail back ends.
(I always find doing something the first time a little bit hairy, but
now that I've done it, I can see why you thought it was 'somewhat
obvious').

Another issue has arisen, and being the author of nnir.el, there
couldn't be a better person to tell!

I've tried two different indexing back ends; swish-e, and most
recently, glimpse.  In the case of swish-e I added the following to my
~/.gnus:

 (require 'nnir)
 (setq nnir-search-engine      'swish-e
       nnir-swish-e-index-file "/home/sebyte/.gnus.d/nnml-index.swish-e")

Typing G-G in the group buffer, resulted in the message:

 gnus-group-read-ephemeral-group: Couldn't request group: Search produced empty results.

Even though swish-e searches worked fine on the command line (having
done the indexing, obviously) I decided to install and index my nnml
folder with glimpse instead, so I replaced the above lines in my
~/.gnus with the following:

 (require 'nnir)
 (setq nnir-search-engine                'glimpse
       nnir-glimpse-home                 "/home/sebyte/.gnus.d/glimpse"
       nnir-glimpse-remove-prefix        "/home/sebyte/.gnus.d/nnml/"
       nnir-glimpse-additional-switches  '("-i" "-w"))

Again, typing G-G in the Group buffer results in the same message,
despite the fact that glimpse searches work fine on the command line.

Am I simply missing something obvious? I hope not, because then I'm
going to feel very stupid indeed.  I fear that I am :-/

Sebastian