XDG environment variables with substitute user

[Peter Nowee]

Hi,

I was wondering what a substitute user application, like gksu, should
do with regard to XDG environment variables when launching an
application as another user? Should these variables by default be left
intact (seems to be the current behavior of gksu), cleared, or
replaced?

- http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html#variables
- https://savannah.nongnu.org/bugs/index.php?37872#comment2

And what can an XDG-compliant application, such as an editor or
terminal emulator, do when XDG environment variables, like
XDG_CONFIG_HOME, are set to locations not belonging to the user
running the application? Or should no program ever try to second guess
the XDG environment variables, not even as a workaround?

Bug examples:
- http://sourceforge.net/p/geany/bugs/471/  (gksu with geany)
- http://sourceforge.net/p/lxde/bugs/608/  (gksu with lxterminal)

See also:
- http://stackoverflow.com/questions/28809235/how-to-get-xdg-variables-with-sudo

Thanks,
Peter