bug#74467: 31.0.50; org-protocol emacsclient.desktop change is not fully functional

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 21 Nov 2024 18:53:21 +0000
> From:  Alexey Lebedeff via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> The change introduced by
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=65469 doesn't work anymore
> in 'generic' desktop environment (as detected by 'xdg-open').
> 
> I assume it works in some desktop environments, where `xdg-open`
> delegates opening to the desktop environment itself. But there is also a
> `generic` version, which tries to implent XDG specification itself.
> 
> On 2023-10-03 there was a change introduced in xdg-utils
> https://cgit.freedesktop.org/xdg/xdg-utils/commit/?id=b9d3ecf8180c57dbb5ca47253898ba0553e81c60
> to more strictly follow xdg specification, and only pass URL-like
> arguments to programs that explicitly requested this by using '%u' or
> '%U' parameters.
> 
> 'etc/emacsclient.desktop' uses '%F' parameter, which should be used for
> programs that do not understand the URL syntax
> (https://specifications.freedesktop.org/desktop-entry-spec/latest/exec-variables.html
> - section about '%f', but also applies to '%F').
> 
> "x-scheme-handler/org-protocol" is the only URL-like protocol that's
> mentioned in the 'etc/emacsclient.desktop', but 'xdg-open' refuses to
> use it.
> 
> Just changing '%F' to '%U' in 'etc/emacsclient.desktop' is not possible,
> as it allows 'xdg-open' to pass local files as "file:/" URL's if it
> wants to.
> 
> One solution would be introducing separate  .desktop file
> (i.e. 'etc/emacsclient-org-protocol.desktop'), analoguous to the already
> existing 'etc/emacsclient-mail.desktop' (which uses '%u').

Ihor, could you please look into this?

(Each time such issues pop up, I regret again that we agreed to
include these *.desktop files in our source tree, sigh.)