bug#72448: "xdg-mime query filetype" fails silently on many filetypes (with fixes I see)

[Liliana Marie Prikler <liliana.prikler@gmail.com>]

Am Samstag, dem 03.08.2024 um 20:33 +0200 schrieb Sébastien Lerique:
> Ahoy Guix!
> 
> "xdg-mime query filetype a-book.epub" or "whatever.pdf" returns
> nothing, which is both puzzling and limiting as it blocks "xdg-open"
> to work for many files.
> 
> My case was opening pdf or epub files from Emacs, which "xdg-open"
> always sends to the browser, whatever my config (instead of e.g.
> evince or Foliate).
> 
> So debugging shows that:
> in ".xdg-mime-real",
> (/gnu/store/06ll0ydqsf4bjxwpwsi68dmn2cg0biy6-xdg-utils-1.1.3/bin/xdg-
> mime
> points there),
> l.673-684 in "info_gnome()",
> even if the "if ... elif ... elif ... fi" fails
> (i.e. none of "gio", "gvfs-info", or "gnomevfs-info" are available),
> then l.696 "if [ $? -eq 0 ]" gives always true.
> 
> Why? I don't know. I guess having a "case ..." instead of "if ... fi"
> would solve this.
Could you prepare a patch to do so?  Or has one already been proposed
upstream?

> But the result is "exit_success" gets called whatever the situation,
> and xdg-mime often gives no output, which then bugs "xdg-open".
> 
> Running this in "guix shell gnome-vfs" solves it, but what should be
> done to fix? And how did this not appear earlier? (is xdg* new?)
> 
> The options I see are adding the "gnome-vfs" dependency ("gvfs"
> doesn't provide "gvfs-info", and "gio" is not a package), or
> proposing "case" instead of "if" upstream.
Note: In GNOME, prefer `gio open', it's part of glib:bin.  
On other desktops, I don't know what the preferred solution would be.

Cheers