Re: xdg-open and start-process-shell-command: Unable to open files in external apps

[Eli Zaretskii <eliz@gnu.org>]

> From: Chandan Babu R <chandanrlinux@gmail.com>
> Date: Sat, 28 Aug 2021 11:16:35 +0530
> 
> The above code was originally obtained from
> http://ergoemacs.org/emacs/emacs_dired_open_file_in_ext_apps.html.
> 
> After moving to (via a fresh install) Debian 11 (which ships Emacs 27.1) the
> code snippet has stopped working.
> 
> However, the command "xdg-open /home/chandan/2016-2017.pdf" when invoked from the
> shell command line opens the pdf application viewer (i.e. Okular)
> correctly.
> 
> The failure occurs only when start-process-shell-command procedure is invoked
> from within Emacs. The failure can also be recreated when
> start-process-shell-command is invoked from ielm buffer as shown below,
> 
> (start-process-shell-command
> 	"Opening file"
>         "sjihs async processes"
>         (concat "xdg-open "
>         	(shell-quote-argument "/home/chandan/2016-2017.pdf")))
> 
> I wrote the following trivial script ...
> 
> 	#!/usr/bin/zsh -f
> 
> 	echo "\$0 = $0; \$1 = $1" > /tmp/debug.log
> 
> and associated the script with application/pdf MIME type.
> 
> debug.log file contains the following string,
> 	$0 = /home/chandan/bin/open-pdf.sh; $1 = /home/chandan/2016-2017.pdf
> ... when xdg-open is invoked either from the command line or through Emacs'
> start-process-shell-command procedure. However, Okular does not get spawned
> only when trying to open the pdf file from within Emacs.
> 
> Any solutions or pointers to debugging this problem is very much appreciated.

I believe the reason for this was recently found and resolved in Git
on the master branch.