fatal error when diffing changed symlinks

Hi,

with the commands below, you will get :

fatal: bad object 0000000000000000000000000000000000000000
show 0000000000000000000000000000000000000000: command returned error: 128

I am using version 2.5.5 fedora 23

cd /tmp
mkdir a
cd a
git init
touch b
ln -s b c
git add .
git commit -m 'first'
touch d
rm c
ln -s d c
git difftool --dir-diff

Thanks for your feedback,

Christophe