gksudo eats standard input when there's a sudo timestamp

Binary package hint: gksu

I was trying to use gksudo in a script, where the script could well run without a controlling terminal, so using sudo directly was not an option.

The exact use case was

echo "firefox-3.0 hold" | gksudo dpkg --set-selections

but I also have a simple contrived example that demonstrates the problem just as well without being as specific or complicated:

sudo -K # ensure there's no existing timestamp and that gksudo will prompt for a password
echo foo | gksudo cat # incidentally, where'd the output go?
echo foo | gksudo cat # this time it hangs
sudo -K # kill the timestamp again
echo foo | gksudo cat # this time it works again

I'm seeing this with Hardy, but I reproduced it with Intrepid as well