Hello,

I reported this as a bug. Here is the link:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22353

Alan

On 2016-01-10 22:21, Alan Schmitt <alan.schmitt@polytechnique.org> writes:

> Hello,
>
> I think I found a bug with `gnus-summary-refer-article'. If I fetch an
> article that comes from another group, it gets inserted in the summary
> with a number of -1. During the call to `gnus-summary-mark-article', the
> following is done
>
> (setq mark (gnus-request-update-mark gnus-newsgroup-name article mark))
>
> which results in mark being nil. This in turn makes the comparisons such
> as
>
> (= mark gnus-unread-mark)
>
> fail with a "Wrong type argument: number-or-marker-p, nil".
>
> Here is a trimmed-down backtrace:
>
> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>   =(nil 32)
>   ...
>   gnus-summary-mark-article(-1 82)
>   gnus-summary-mark-read-and-unread-as-read()
>   run-hooks(gnus-mark-article-hook)
>   apply(run-hooks gnus-mark-article-hook)
>   gnus-run-hooks(gnus-mark-article-hook)
>   gnus-article-prepare(-1 nil)
>   gnus-summary-display-article(-1 nil)
>   gnus-summary-select-article(nil nil nil -1)
>   (progn (gnus-summary-select-article nil nil nil number) (throw (quote found) t))
>   ...
>   gnus-summary-refer-article("52947012.308@cse.gu.se")
>   call-interactively(gnus-summary-refer-article nil nil)
>   command-execute(gnus-summary-refer-article)
>
> Is this a known bug?
>
> Thanks,
>
> Alan

-- 
OpenPGP Key ID : 040D0A3B4ED2E5C7
Athmospheric CO₂ (Updated January 10, 2016, Mauna Loa Obs.): 402.22 ppm