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

[Chandan Babu R <chandanrlinux@gmail.com>]

On 28 Aug 2021 at 12:56, Eli Zaretskii wrote:
>> 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.

Thanks for the response.

I built the code present in the master branch. The topmost commit was,

commit 55e77a811a6f137b02eb786fb00c43f0f14bb028
Author: Juri Linkov <juri@linkov.net>

    * lisp/progmodes/flymake.el: Bind mouse-3 to flymake-menu on mode-line.
    
    * lisp/progmodes/flymake.el (flymake--mode-line-title):
    Bind [mode-line down-mouse-3] to flymake-menu (bug#50067)

The problem described above is still recreatable.

-- 
chandan