bug#57325: closed (27.1; functions in ff-other-file-alist)

[GNU bug Tracking System]

Your message dated Tue, 30 Aug 2022 19:10:19 +0300
with message-id <83zgflu2z8.fsf@gnu.org>
and subject line Re: bug#57325: 27.1; functions in ff-other-file-alist
has caused the debbugs.gnu.org bug report #57325,
regarding 27.1; functions in ff-other-file-alist
to be marked as done.

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57325: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=57325
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--- Begin Message --- Subject: 27.1; functions in ff-other-file-alist Date: Sun, 21 Aug 2022 20:34:17 +0200 User-agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)

[There is a simple reproducer at end of the bug report.]

First, the documentation of ff-other-file-alist fails to mention that
the value of the variable does not have to be alist, it can be a symbol
as well.

More importantly, if the associated value is a function, then there's no
way for the function to signal that it cannot find a related file.

If the function returns "/nonexistent", then ff-find-the-other-file
(with the default settings) will try to create "/nonexistent".

If the function returns nil, then ff-find-the-other-file will call
ff-get-file-name and:

  (ff-get-file-name '("." "/usr/include" "/usr/local/include/*") nil nil)
  ==> "/home/nemethf/.emacs.d/News/drafts/drafts/679"

"emacs -Q -l bug.el" reproduces the problem by setting
uniquify-buffer-name-style.  However, my uniquify-buffer-name-style is
'forward and not nil.  Maybe Gnus changes uniquify-buffer-name-style
under the hood, because drafts/679 corresponds to a buffer named
"*sent wide reply to Somebody*<2>".

I tend to think this bug in line 577 of find-file.el:
http://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/find-file.el?id=958924a8126cf532d44c4b446d13ed744438cc9b#n577
But I don't understand the purpose of that string-match-p.

Thanks.

bug.el
Description: application/emacs-lisp

In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo 
version 1.16.0)
 of 2021-03-28, modified by Debian built on x86-conova-01
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Debian GNU/Linux 11 (bullseye)

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#57325: 27.1; functions in ff-other-file-alist
>
>
>
>
> Date: 
>
> Tue, 30 Aug 2022 19:10:19 +0300
>
>
>
>
> > From: Felician Nemeth <felician.nemeth@gmail.com>
> > Cc: 57325@debbugs.gnu.org
> > Date: Tue, 30 Aug 2022 15:48:44 +0200
> > 
> > Eli Zaretskii <eliz@gnu.org> writes:
> > 
> > > But then I think we should replace this code in ff-get-file-name:
> > >
> > >               (setq file (concat dir "/" filename))
> > > with
> > >               (setq file (expand-file-name filename dir))
> > >
> > > and then the code will work with absolute file names as well, even if
> > > the file is not already visited in a buffer.  Right?
> > 
> > Yes, I think that's right.
>
> Done.
>
> > The latest documentation still has this:
> > 
> >    Note: if an element of the alist names a FUNCTION as its cdr, that
> >    function must return a non-nil list of file-name extensions.  It
> >    cannot return nil, nor can it signal in any way a failure to find a
> >    suitable list of extensions.
> > 
> > The end of the first sentence should be "file-names."  Then I think this
> > bug report can be closed.
>
> Fixed, and closing.
>
> Thanks a lot for your help.
>
>
> --- End Message ---