Re: Bug in 9.5.3 org--file-default-apps

[Max Nikulin]

Craig, discussing the issue with Ihor, I sent some messages to the mail 
list only without your address in Cc. You may check complete thread at 
https://list.orgmode.org

On 23/05/2022 19:40, Craig STCR wrote:
> OK, I did a first-try on this and was unsuccessful, but I'm sure it's 
> user error.  I need to refresh my knowledge on how to customize 
> user-local mime database, and that will write-out a new ~/.mailcap, etc, 
> I think?  I've done it before, but it was awhile ago, and I wasn't 
> paying attention to ~/.mailcap when I did it.  I know for Gnome I can 
> create a .desktop file.  But I know there's a way to customize 
> user-local mime database without Gnome desktop.  I'll take a closer look 
> when I have a little more time.

Debian package scripts (that work on Ubuntu as well) extract MIME info 
from *system* .desktop files to add them to mailcap database.

There were some mailcap related changes and bugs around Emacs-27 
release, e.g. https://debbugs.gnu.org/cgi/bugreport.cgi?bug=36771

> application/x-shellscript; emacs27 %s; test=test -n "$DISPLAY"

Notice that such entry will be ignored when DISPLAY is not set due to 
specified "test" property. You need to pass X socket and pass or set 
DISPLAY environment to you "headless" container.

update-mime likely assumes that you created ~/.mailcap.order to generate 
~/.mailcap from it. Emacs may just read ~/.mailcap, so if you created 
this file, nothing more is required.

Actually I do not think you wish to launch another emacs session in 
response to following a link in an .org file. I suppose, you experienced
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=40247
otherwise (mailcap-mime-info nil) (or "text/plain") would return 
view-mode and your scripts would be opened in another emacs window. It 
should work without mailcap entries.