When and why should I escape a path string?

[Matthias Kaeppler <matthias finitestate org>]

Hi,

I just encountered a bug in my program, where I would try to create a 
Gnome::Vfs::Uri from an escaped path (the directory in question was the 
'lost+found' directory which is found on ext3 partitions and which was 
converted by gnome-vfs to 'lost%2Bfound'). I was getting exceptions 
thrown at me when trying to create an URI from this string ("file does 
not exist").

After unescaping the string, creating an URI from it worked. So when and 
why am I supposed to use escaped paths? Obviously, gnome-vfs somewhere 
internally already escaped the path, so it should be able to deal with 
them. But then, why does creating an URI from an escaped path fail? ^^

Thanks,
Matthias