Tags: patch

`org-store-link' has a number of related issues when storing links from
article buffers related to nnvirtual, nnselect, or nnir groups.  I
describe them here in prose without providing a full repro case, which
would be somewhat difficult to set up.  Just let me know if you think
you need more information, I have the data available.

The most obvious symptom is this:

- Create an nnselect group and open an article from that.  In the
   article buffer, do M-x org-store-link RET, then paste the link with
   C-c C-l in some Org mode buffer.  The resulting link looks like

     gnus:#E18xcfu-0004HT-00@fencepost.gnu.org

   That is, it lacks the group name before the hash sign.  Correct would
   have been:

     gnus:nnml+archive:test01#E18xcfu-0004HT-00@fencepost.gnu.org

   Starting with Emacs 30, you even more obviously get an error:

     Debugger entered--Lisp error: (wrong-type-argument 
number-or-marker-p nil)
       nnselect-article-group(nil)
       org-gnus-store-link()
       org-store-link(nil 1)
       funcall-interactively(org-store-link nil 1)
       call-interactively(org-store-link record nil)
       command-execute(org-store-link record)
       execute-extended-command(nil "org-store-link" nil)
       funcall-interactively(execute-extended-command nil 
"org-store-link" nil)
       call-interactively(execute-extended-command nil nil)
       command-execute(execute-extended-command)

Less obvious, occuring for nnvirtual groups:

- Create an nnvirtual group and open an article from that.  In the
   article buffer, do M-x org-store-link RET.  Observe the "current
   article arrow" in the fringe being set in the article header, even
   though that arrow should be used only in a summary buffer.

The root cause is that some of the Gnus functions used in
`org-gnus-store-link' must be called only in summary buffers, and not in
article buffers.  These are:

   gnus-summary-article-number
   nnselect-article-group

Not sure about these, but it is probably also better to call these in
summary buffers only:

   nnvirtual-map-article
   nnir-article-group

The remedy for these issues is simple: When calling above functions just
temporarily and unconditionally switch to the summary buffer with

   (with-current-buffer gnus-summary-buffer ...)

where buffer-local variable `gnus-summary-buffer' in an article buffer
points to the summary buffer where the articles comes from.  (And for
a summary buffer the variable points to the summary buffer itself.)

Finally, there is a related inefficiency when determining the article
header structure in function `org-gnus-store-link': Here the authors
indeed switch to the summary buffer when currently in the article
buffer, but using "user-land" interactive function
`gnus-article-show-summary' to do so where a simple

   (with-current-buffer gnus-summary-buffer ...)

would suffice.

Emacs  : GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 
3.24.24, cairo version 1.16.0)
  of 2023-07-20
Package: Org mode version 9.7-pre (release_9.6.7-570-gd6f3ae.dirty @ 
/home/jschmidt/work/org-mode/lisp/)