Re: [boost] [Filesystem] v3 path separator changes

Subject: Re: [boost] [Filesystem] v3 path separator changes
From: Michael Marcin (mike.marcin_at_[hidden])
Date: 2013-03-23 13:34:06

Yakov Galka wrote:
> On Sat, Mar 23, 2013 at 2:42 PM, Joseph Van Riper <
> fleeb.fantastique_at_[hidden]> wrote:
>
>> [...]
>> I have never seen a file system that wasn't, really, a tree with branches
>> and leaves.  It can have more than one base, but ultimately, it's a tree.
>>
> It is called a "forest". But filesystems aren't really forests. For
> starters, they are very often DAGs (you can hardlink the leaves). Much
> software assumes that path is a unique identifier of a resource and breaks
> on non-trees. If people would not make such assumption we could very well
> allow arbitrary graphs. The point is that there is no *a priori* reason
> that file systems are DAGs, it is the *result* of thinking of filesystems
> as trees of paths.
>

They can quite easily become non-DAGs with junction points / symlinks 
being able to create cycles.