bug#44824: 27.1; Org export as pdf and open file does not open it

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Sat, 30 Jan 2021 07:09:50 +0100
> Cc: 44824@debbugs.gnu.org
> 
> This works:
> M-! xdg-open /tmp/test.pdf RET
> 
> This doesn't work:
> M-& xdg-open /tmp/test.pdf RET
> 
> This doesn't work:
> M-x shell RET xdg-open /tmp/test.pdf RET

How about asking the xdg-open developers to help us figure out the
reason?  Or, failing that, debug xdg-open in the problematic
situations to find out what fails there and why?  E.g., could it be
that it fails because stdin/stdout is a PTY? what happens if you bind
process-connection-type to nil when starting the async subprocess?